Lochinvar KNIGHT 800 User Manual

KBX-I-O Rev G  
Installation & Operation Manual  
Models: 399 - 800  
This manual must only be used by a  
ƽ WARNING  
qualified heating installer / service  
technician. Read all instructions,  
including this manual and the  
Knight XL Service Manual, before  
installing. Perform steps in the order  
given. Failure to comply could result  
in severe personal injury, death, or  
substantial property damage.  
Save this manual for future reference.  
Installation & Operation Manual  
Please read before proceeding  
Installer  
Read all instructions,  
When servicing boiler –  
ƽ WARNING  
including this manual and the Knight XL  
Service Manual, before installing.  
Perform steps in the order given.  
To avoid electric shock, disconnect electrical supply  
before performing maintenance.  
To avoid severe burns, allow boiler to cool before  
performing maintenance.  
User – This manual is for use only by a  
qualified  
heating  
installer/service  
technician.  
Refer to the User’s  
Information Manual for your reference.  
Boiler operation –  
Have this boiler serviced/inspected by a  
qualified service technician, at least  
annually.  
• Do not block flow of combustion or ventilation air to  
the boiler.  
• Should overheating occur or gas supply fail to shut off,  
do not turn off or disconnect electrical supply to  
circulator. Instead, shut off the gas supply at a location  
external to the appliance.  
Failure to comply with the above could  
result in severe personal injury, death or  
substantial property damage.  
When calling or writing about the boiler –  
Please have the boiler model and serial  
number from the boiler rating plate.  
• Do not use this boiler if any part has been under water.  
The possible damage to a flooded appliance can be  
extensive and present numerous safety hazards. Any  
appliance that has been under water must be replaced.  
NOTICE  
Consider piping and installation when  
determining boiler location.  
Boiler water –  
Any claims for damage or shortage in  
shipment must be filed immediately  
against the transportation company by  
the consignee.  
• Thoroughly flush the system (without boiler  
connected) to remove sediment. The high-efficiency  
heat exchanger can be damaged by build-up or  
corrosion due to sediment.  
Factory warranty (shipped with unit)  
does not apply to units improperly  
installed or improperly operated.  
• Do not use petroleum-based cleaning or sealing  
compounds in the boiler system. Gaskets and seals in  
the system may be damaged. This can result in  
substantial property damage.  
Failure to adhere to the guidelines on this  
page can result in severe personal injury,  
death, or substantial property damage.  
ƽ WARNING  
• Do not use “homemade cures” or “boiler patent  
medicines. Serious damage to the boiler, personnel,  
and/or property may result.  
If the information in this manual is not  
followed exactly, a fire or explosion may  
result causing property damage, personal  
injury or loss of life.  
ƽ WARNING  
• Continual fresh make-up water will reduce boiler life.  
Mineral buildup in the heat exchanger reduces heat  
transfer, overheats the stainless steel heat exchanger,  
and causes failure. Addition of oxygen carried in by  
makeup water can cause internal corrosion in system  
components. Leaks in boiler or piping must be repaired  
at once to prevent makeup water.  
This appliance MUST NOT be installed  
in any location where gasoline or  
flammable vapors are likely to be present.  
WHAT TO DO IF YOU SMELL GAS  
• Do not try to light any appliance.  
• Do not touch any electric switch; do  
not use any phone in your building.  
• Immediately call your gas supplier  
from a near by phone. Follow the  
gas supplier’s instructions.  
Freeze protection fluids –  
• NEVER use automotive antifreeze. Use only inhibited  
propylene glycol solutions, which are specifically  
formulated for hydronic systems. Ethylene glycol is  
toxic and can attack gaskets and seals used in hydronic  
systems.  
• If you cannot reach your gas supplier,  
call the fire department.  
• Installation and service must be  
performed by a qualified installer,  
service agency, or the gas supplier.  
3
Installation & Operation Manual  
The Knight XL - How it works...  
1. Stainless steel heat exchanger  
16. SMART Control Module  
Allows system water to flow through specially designed  
coils for maximum heat transfer, while providing  
protection against flue gas corrosion. The coils are  
encased in a jacket that contains the combustion process.  
The SMART Control responds to internal and external signals  
and controls the blower, gas valve, and pumps to meet the  
heating demand.  
17. Automatic air vent  
Designed to remove trapped air from the heat exchanger  
coils.  
2. Heat exchanger access cover  
Allows access to the combustion side of the heat  
exchanger coils.  
18. Air intake adapter  
Allows for the connection of the PVC air intake pipe to  
the boiler.  
3. Blower  
The blower pulls in air and gas through the venturi (item  
5). Air and gas mix inside the blower and are pushed into the  
burner, where they burn inside the combustion chamber.  
19. High voltage junction box  
The junction box contains the connection points for the line  
voltage power and all pumps.  
4. Gas valve  
The gas valve senses the negative pressure created by the  
blower, allowing gas to flow only if the gas valve is  
powered and combustion air is flowing.  
20. Boiler drain port  
Location from which the heat exchanger can be drained.  
21. Low voltage connection board  
The connection board is used to connect external low voltage  
devices.  
5. Venturi  
The venturi controls air and gas flow into the burner.  
6. Flue gas sensor  
22. Low voltage wiring connections (knockouts)  
Conduit connection points for the low voltage  
connection board.  
This sensor monitors the flue gas exit temperature. The control  
module will modulate and shut down the boiler if the flue gas  
temperature gets too hot. This protects the flue pipe from  
overheating.  
23. Condensate drain connection  
Connects the condensate drain line to a 1/2" PVC union.  
7. Boiler outlet temperature sensor  
This sensor monitors boiler outlet water temperature (system  
supply). If selected as the controlling sensor, the control  
module adjusts boiler firing rate so the outlet temperature is  
correct.  
24. Access cover - front  
Provides access to the gas train and the heat exchanger.  
25. Ignition electrode  
Provides direct spark for igniting the burner.  
8. Boiler inlet temperature sensor  
26. Flame inspection window  
The quartz glass window provides a view of the burner  
surface and flame.  
This sensor monitors return water temperature (system  
return). If selected as the controlling sensor, the control  
module adjusts the boiler firing rate so the inlet temperature is  
correct.  
27. Gas shutoff valve  
Manual valve used to isolate the gas valve from the gas supply.  
9. Temperature and pressure gauge (field installed, not  
shown)  
28. High limit  
Monitors the outlet temperature of the boiler as well as the  
system water pressure.  
Device that monitors the outlet water temperature. If the  
temperature exceeds its setting, it will break the control circuit,  
shutting the boiler down.  
10. Electronic display  
The electronic display consists of 7 buttons and a dual line 32-  
character liquid crystal display.  
29. Relief valve  
Protects the heat exchanger from an over pressure condition.  
The relief valve will be set at 50 PSI.  
11. Flue pipe adapter  
Allows for the connection of the PVC vent pipe system to the  
boiler.  
30. Flame sensor  
Used by the control module to detect the presence of burner  
flame.  
12. Burner (not shown)  
Made with metal fiber and stainless steel construction,  
the burner uses pre-mixed air and gas and provides a  
wide range of firing rates.  
31. Line voltage wiring connections (knockouts)  
Conduit connection points for the high voltage junction box.  
32. Top panel  
13. Water outlet (system supply)  
Removable panel to gain access to the internal components.  
A 1-1/2" or 2" NPT (depending on the model) water  
connection that supplies hot water to the system.  
33. Power switch  
Turns 120 VAC ON/OFF to the boiler.  
14. Water inlet (system return)  
34. Leveling legs  
A 1-1/2" or 2" NPT (depending on the model) water  
connection that returns water from the system to the heat  
exchanger.  
Used to allow the heat exchanger to be leveled. This is needed  
for the proper draining of the condensate from the combustion  
chamber.  
15. Gas connection pipe  
35. Air shroud (Model 500 only)  
Threaded pipe connection, either 1" or 1-1/2", depending on  
the model. This pipe should be connected to the incoming gas  
supply for the purpose of delivering gas to the boiler.  
The air shroud controls air and gas flow into the burner.  
4
Installation & Operation Manual  
The Knight XL - How it works...  
(continued)  
37. Pump relay board  
36. Air pressure switch  
The pump relay board is used to connect the boiler, system and  
The air pressure switch detects blocked flue/inlet conditions.  
DHW pumps.  
Model 399  
32  
31  
10  
18  
22  
33  
15  
11  
24  
6
Front View - Model 399  
Rear View - Model 399  
19  
21  
27  
36  
7
37  
16  
4
5
8
1
3
25  
14  
2
29  
13  
26  
28  
20  
34  
30  
23  
17  
Left Side (inside unit) - Model 399  
Right Side (inside unit) - Model 399  
5
Installation & Operation Manual  
The Knight XL - How it works...  
Model 500  
35  
18  
15  
27  
4
Rear View - Model 500  
Left Side (inside unit) - Model 500  
Models 600 - 800  
5
18  
4
15  
27  
Rear View - Models 600 - 800  
Left Side (inside unit) - Models 600 - 800  
6
Installation & Operation Manual  
Ratings  
Knight XL Boiler  
I=B=R Rating  
Other Specifications  
Net  
Input  
I=B=R  
Gross  
Output  
MBH  
Boiler  
Water  
Model Number  
Vent  
Air  
MBH  
Ratings  
Water,  
MBH  
Water  
Gas  
Content Connections Connections  
Gallons  
Size  
Note: Change “N” to  
“L” for L.P. gas models.  
Size  
(Note 4)  
(Note 2)  
(Note 1)  
373  
(Note 3)  
4"  
Min  
80  
Max  
399  
KBN399  
KBN500  
KBN600  
KBN700  
KBN800  
324  
3.4  
4.2  
4.2  
5.0  
5.7  
1-1/2"  
1-1/2"  
2"  
1"  
1"  
1"  
1"  
1"  
4"  
4"  
4"  
4"  
4"  
100  
120  
140  
160  
500  
600  
700  
800  
467  
567  
660  
752  
406  
493  
574  
654  
4"  
4"  
6"  
6"  
2"  
2"  
Maximum allowed working pressure is located on the rating plate.  
NOTICE  
Notes:  
1. The ratings are based on standard test procedures  
prescribed by the United States Department of Energy.  
2. Net I=B=R ratings are based on net installed radiation of  
sufficient quantity for the requirements of the building and  
nothing need be added for normal piping and pickup.  
Ratings are based on a piping and pickup allowance of 1.15.  
UNIT EQUIPPED FOR  
HIGH ALTITUDE  
3. Knight XL boilers require special gas venting. Use only the  
vent materials and methods specified in the Knight XL  
Installation and Operation Manual.  
3,000 FT. TO 12,000 FT.  
4. Standard Knight XL boilers are equipped to operate from  
sea level to 4,500 feet only with no adjustments. The boiler  
will de-rate by 4% for each 1,000 feet above sea level up to  
4,500 feet.  
5. High altitude Knight XL boilers are equipped to operate  
from 3,000 to 12,000 feet only with no field adjustments.  
The boiler will de-rate by 2% for each 1,000 feet above  
3,000 feet. High altitude models are manufactured with a  
different control module for altitude operation, but the  
operation given in this manual remains the same as the  
standard boilers. A high altitude label (as shown in FIG. A)  
is also affixed to the unit.  
Figure A High Altitude Label Location  
6. Ratings have been confirmed by the Hydronics Institute,  
Section of AHRI.  
7
Installation & Operation Manual  
1 Determine boiler location  
This appliance is certified as an indoor  
appliance. Do not install the appliance  
outdoors or locate where the appliance will  
be exposed to freezing temperatures or to  
temperatures that exceed 100°F (37.8°C).  
Installation must comply with:  
ƽ WARNING  
Local, state, provincial, and national codes, laws,  
regulations, and ordinances.  
National Fuel Gas Code, ANSI Z223.1 – latest edition.  
Standard for Controls and Safety Devices for  
Automatically Fired Boilers, ANSI/ASME CSD-1, when  
required.  
Failure to install the appliance indoors could  
result in severe personal injury, death, or  
substantial property damage.  
National Electrical Code.  
For Canada only: B149.1 Installation Code, CSA C22.1  
Canadian Electrical Code Part 1 and any local codes.  
This appliance requires a special venting  
system. The vent connection to the  
appliance must be made with the starter  
CPVC/stainless steel pipe section provided  
with the appliance. The field provided PVC  
vent fittings must be cemented to the CPVC  
pipe section. Use only the vent materials,  
primer and cement specified in this manual  
to make the vent connections. Failure to  
follow this warning could result in fire,  
personal injury, or death.  
ƽ WARNING  
The Knight XL gas manifold and controls  
NOTICE  
met safe lighting and other performance  
criteria when the boiler underwent tests  
specified in ANSI Z21.13 – latest edition.  
Before locating the boiler, check:  
1. Check for nearby connection to:  
• System water piping  
Venting connections  
• Gas supply piping  
Closet and alcove installations  
• Electrical power  
A closet is any room the boiler is installed in which is less than  
171 cubic feet for KBN399 models, 193 cubic feet for KBN500  
models, 223 cubic feet for KBN600 models, 247 cubic feet for  
KBN700 models and 278 cubic feet for KBN800 models.  
2. Locate the appliance so that if water connections should  
leak, water damage will not occur. When such locations  
cannot be avoided, it is recommended that a suitable  
drain pan, adequately drained, be installed under the  
appliance. The pan must not restrict combustion air  
flow. Under no circumstances is the manufacturer to be  
held responsible for water damage in connection with  
this appliance, or any of its components.  
An alcove is any room which meets the criteria for a closet with  
the exception that it does not have a door.  
Example: Room dimensions = 5 feet long, 4 feet wide, and  
8 foot ceiling = 5 x 4 x 8 = 160 cubic feet. This would be  
considered a closet for a Knight XL Boiler.  
3. Check area around the boiler. Remove any combustible  
materials, gasoline and other flammable liquids.  
For closet and alcove installations as shown  
ƽ WARNING  
in FIG.’s 1-1 and 1-2, CPVC or stainless steel  
Failure to keep boiler area clear and free of  
combustible materials, gasoline, and other  
ƽ WARNING  
vent material must be used inside the  
structure. The ventilating air openings  
shown in FIG.’s 1-1 and 1-2 are required for  
this arrangement. Failure to follow this  
warning could result in fire, personal injury,  
or death.  
flammable liquids and vapors can result in  
severe personal injury, death, or  
substantial property damage.  
4. The Knight XL must be installed so that gas control  
system components are protected from dripping or  
spraying water or rain during operation or service.  
Provide clearances:  
Clearances from combustible materials  
1. Hot water pipes—at least 1" (25 mm) from combustible  
materials.  
2. Vent pipe – at least 1" (25 mm) from combustible materials.  
3. See FIG.’s 1-1 and 1-2 on page 9 for other clearance  
minimums.  
5. If a new boiler will replace an existing boiler, check for  
and correct system problems, such as:  
• System leaks causing oxygen corrosion or heat  
exchanger cracks from hard water deposits.  
• Incorrectly-sized expansion tank.  
• Lack of freeze protection in boiler water causing system  
and boiler to freeze and leak.  
Clearances for service access  
1. See FIG.’s 1-1 and 1-2 on page 9 for recommended  
service clearances. If you do not provide the minimum  
clearances shown, it may not be possible to service the  
boiler without removing it from the space.  
8
Installation & Operation Manual  
1 Determine boiler location  
(continued)  
Figure 1-1 Closet Installation - Minimum Required Clearances  
CLOSET INSTALLATION  
For closet installations, CPVC or  
ƽ WARNING  
1" (25 MM) MINIMUM CLEARANCE  
AROUND HOT WATER  
stainless steel material MUST BE  
used in a closet structure due to  
elevated temperatures. Failure to  
follow this warning could result in  
fire, personal injury, or death.  
PIPES AND VENT PIPE  
13" (330 MM)  
TOP  
VENTILATING*  
AIR OPENING  
CLOSED DOOR  
VENTILATING*  
AIR OPENING  
12" (305 MM)  
LEFT  
6" (152 MM)  
14" (356 MM)  
REAR  
RECOMMENDED SERVICE CLEARANCES:  
0"  
RIGHT  
Front  
Top  
-
-
30" (762 mm)  
24" (610 mm)  
6" (152 MM)  
F RONT  
Left Side - 24" (610 mm)  
*AREA OF EACH OPENING:  
1 SQ. INCH PER 1000 BTU PER HOUR INPUT  
WITH A MINIMUM OF 100 SQ. INCHES  
Rear -  
24" (610 mm)  
Figure 1-2 Alcove Installation - Minimum Required Clearances  
For alcove installations, CPVC or  
ALCOVE INSTALLATION  
1" (25 MM) MINIMUM CLEARANCE  
AROUND HOT WATER  
PIPES AND VENT PIPE  
ƽ WARNING  
stainless steel material MUST BE  
used in an alcove structure due to  
elevated temperatures. Failure to  
follow this warning could result in  
fire, personal injury, or death.  
13" (330 MM)  
TOP  
OPEN  
FRONT  
12"  
(305 MM)  
LEFT  
14" (356 MM)  
REAR  
RECOMMENDED SERVICE CLEARANCES:  
0"  
RIGHT  
Front  
Top  
-
-
30" (762 mm)  
24" (610 mm)  
18" (457 MM)  
FRONT  
Left Side - 24" (610 mm)  
Rear -  
24" (610 mm)  
9
Installation & Operation Manual  
1 Determine boiler location  
Provide air openings to room:  
Residential garage installation  
Precautions  
Knight XL alone in boiler room  
Take the following precautions when installing the appliance  
in a residential garage. If the appliance is located in a  
residential garage, it should be installed in compliance with  
the latest edition of the National Fuel Gas Code, ANSI Z223.1  
and/or CAN/CGA-B149 Installation Code.  
1. No air ventilation openings into the boiler room are  
needed when clearances around the Knight XL are at least  
equal to the SERVICE clearances shown in FIG.’s 1-1 and  
1-2. For spaces that do NOT supply this clearance,  
provide two openings as shown in FIG. 1-1. Each  
opening must provide one square inch free area per 1,000  
Btu/hr of boiler input.  
• Appliances located in residential garages and in  
adjacent spaces that open to the garage and are not part  
of the living space of a dwelling shall be installed so that  
all burners and burner ignition devices are located not  
less than 18 inches (46 cm) above the floor.  
Knight XL in same space with other gas or oil-fired  
appliances  
• The appliance shall be located or protected so that it is  
not subject to physical damage by a moving vehicle.  
1. Follow the National Fuel Gas Code (U.S.) or CSA B149.1  
(Canada) to size/verify size of the combustion/ventilation  
air openings into the space.  
Vent and air piping  
The Knight XL requires a special vent system, designed for  
pressurized venting.  
The space must be provided with  
ƽ WARNING  
combustion/ventilation air openings  
correctly sized for all other appliances  
located in the same space as the Knight XL.  
The boiler is to be used for either direct vent installation or  
for installation using indoor combustion air. When room air  
is considered, see the General Venting Section. Note  
prevention of combustion air contamination below when  
considering vent/air termination.  
Do not install the boiler in an attic.  
Failure to comply with the above warnings  
could result in severe personal injury,  
death, or substantial property damage.  
Vent and air must terminate near one another and may be  
vented vertically through the roof or out a side wall, unless  
otherwise specified. You may use any of the vent/air piping  
methods covered in this manual. Do not attempt to install the  
Knight XL using any other means.  
2. Size openings only on the basis of the other appliances in  
the space. No additional air opening free area is needed  
for the Knight XL because it takes its combustion air from  
outside (direct vent installation).  
Be sure to locate the boiler such that the vent and air piping  
can be routed through the building and properly terminated.  
The vent/air piping lengths, routing and termination method  
must all comply with the methods and limits given in this  
manual.  
Flooring and foundation  
Flooring  
The Knight XL is approved for installation on combustible  
flooring, but must never be installed on carpeting.  
Prevent combustion air contamination  
Install air inlet piping for the Knight XL as described in this  
manual. Do not terminate vent/air in locations that can allow  
contamination of combustion air. Refer to Table 1A, page 11  
for products and areas which may cause contaminated  
combustion air.  
Do not install the boiler on carpeting even  
ƽ WARNING  
if foundation is used. Fire can result,  
causing severe personal injury, death, or  
substantial property damage.  
If flooding is possible, elevate the boiler sufficiently to prevent  
water from reaching the boiler.  
You must pipe combustion air to the  
ƽ WARNING  
boiler air intake. Ensure that the  
combustion air will not contain any of the  
contaminants in Table 1A, page 11.  
Contaminated combustion air will  
damage the boiler, resulting in possible  
severe personal injury, death or substantial  
property damage. Do not pipe  
combustion air near a swimming pool, for  
example. Also, avoid areas subject to  
exhaust fumes from laundry facilities.  
These areas will always contain  
contaminants.  
10  
Installation & Operation Manual  
1 Determine boiler location  
(continued)  
Table 1A Corrosive Contaminants and Sources  
When using an existing vent system to  
install a new boiler:  
Products to avoid:  
Spray cans containing chloro/fluorocarbons  
Failure to follow all instructions can result  
ƽ WARNING  
in flue gas spillage and carbon monoxide  
emissions, causing severe personal injury  
or death.  
Permanent wave solutions  
Chlorinated waxes/cleaners  
Check the following venting components before installing:  
Chlorine-based swimming pool chemicals  
Calcium chloride used for thawing  
Sodium chloride used for water softening  
Refrigerant leaks  
• Material - For materials listed for use with this appliance,  
see Section 3 - General Venting, Table 3A. For stainless  
steel venting, an adapter of the same manufacturer  
(Table 3B) must be used at the flue collar connection.  
• Size - To ensure proper pipe size is in place, see Table 3D.  
Check to see that this size is used throughout the vent  
system.  
Paint or varnish removers  
Hydrochloric acid/muriatic acid  
Cements and glues  
• Manufacturer - For a stainless steel application, you  
must use only the listed manufacturers and their type  
product listed in Table 3A for CAT IV positive pressure  
venting with flue producing condensate.  
Antistatic fabric softeners used in clothes dryers  
Chlorine-type bleaches, detergents, and cleaning solvents  
found in household laundry rooms  
• Supports - Non-combustible supports must be in place  
allowing a minimum 1/4" rise per foot. The supports  
should adequately prevent sagging and vertical slippage,  
by distributing the vent system weight. For additional  
information, consult the vent manufacturer’s  
instructions for installation.  
Adhesives used to fasten building products and other similar  
products  
Areas likely to have contaminants  
Dry cleaning/laundry areas and establishments  
Terminations - Carefully review Sections 3 through 5 to  
ensure requirements for the location of the vent and air  
terminations are met and orientation of these fit the  
appropriate image from the Sidewall or Vertical  
options listed in the General Venting Section. For  
stainless steel vent, only use terminations listed in Table  
3B for the manufacturer of the installed vent.  
Swimming pools  
Metal fabrication plants  
Beauty shops  
Refrigeration repair shops  
Photo processing plants  
Auto body shops  
• Seal - With prior requirements met, the system should be  
tested to the procedure listed in parts (c) through (f) of  
the Removal of an Existing Boiler Section on page 12.  
Plastic manufacturing plants  
Furniture refinishing areas and establishments  
With stainless steel vent, seal and connect all pipe and  
components as specified by the vent manufacturer used; with  
PVC/CPVC vent, see the Installing Vent or Air Piping Section  
on page 17.  
New building construction  
Remodeling areas  
Garages with workshops  
If any of these conditions are not met, the  
ƽ WARNING  
existing system must be updated or  
replaced for that concern. Failure to  
follow all instructions can result in flue gas  
spillage and carbon monoxide emissions,  
causing severe personal injury or death.  
11  
Installation & Operation Manual  
1 Determine boiler location  
When removing a boiler from existing  
common vent system:  
Do not install the Knight XL into a  
g. Any improper operation of the common venting  
system should be corrected so the installation  
conforms with the National Fuel Gas Code, ANSI  
Z223.1/NFPA 54 and/or CAN/CSA B149.1, Natural  
Gas and Propane Installation Code. When resizing any  
portion of the common venting system, the common  
venting system should be resized to approach the  
minimum size as determined using the appropriate  
tables in Part 11 of the National Fuel Gas Code, ANSI  
Z223.1/NFPA and/or CAN/CSA B149.1, Natural Gas  
and Propane Installation Code.  
ƽ DANGER  
common vent with any other appliance.  
This will cause flue gas spillage or  
appliance malfunction, resulting in  
possible severe personal injury, death, or  
substantial property damage.  
At the time of removal of an existing boiler, the following  
steps shall be followed with each appliance remaining  
connected to the common venting system placed in  
operation, while the other appliances remaining connected to  
the common venting system are not in operation.  
a. Seal any unused openings in the common venting system.  
b. Visually inspect the venting system for proper size and  
horizontal pitch and determine there is no blockage or  
restriction, leakage, corrosion, or other deficiencies,  
which could cause an unsafe condition.  
c. Test vent system – Insofar as is practical, close all building  
doors and windows and all doors between the space in  
which the appliances remaining connected to the  
common venting system are located and other spaces of  
the building. Turn on clothes dryers and any appliance  
not connected to the common venting system. Turn on  
any exhaust fans, such as range hoods and bathroom  
exhausts, so they will operate at maximum speed. Do not  
operate a summer exhaust fan. Close fireplace dampers.  
d. Place in operation the appliance being inspected. Follow  
the lighting instructions. Adjust thermostat so appliance  
will operate continuously.  
e. Test for spillage at the draft hood relief opening after  
5 minutes of main burner operation. Use the flame of a  
match or candle, or smoke from a cigarette, cigar, or pipe.  
f. After it has been determined that each appliance  
remaining connected to the common venting system  
properly vents when tested as outlined herein, return  
doors, windows, exhaust fans, fireplace dampers, and any  
other gas-burning appliance to their previous conditions  
of use.  
12  
Installation & Operation Manual  
2 Prepare boiler  
Remove boiler from wood pallet  
Model 399  
1. After removing the outer shipping carton from the boiler,  
1. Remove the top and front access covers from the unit (no  
tools required for removal).  
remove the parts box.  
2. Remove the three screws securing the venturi to the blower.  
Note: When separating the venturi from the blower, take  
care not to damage the O-ring inside the blower (FIG. 2-2).  
2. Remove the front door to access the lag bolts in front of  
the unit (FIG. 2-1).  
3. To remove the boiler from the pallet (after removing the  
front door):  
3. Remove the four star-drive screws securing the gas valve to  
the venturi (FIG. 2-2).  
a. Remove the two lag bolts from the wood pallet  
inside the boiler (FIG. 2-1).  
b. Detach the boiler from the lag bolts in the rear of the  
unit, see FIG. 2-1.  
4. Locate the propane orifice disk from the conversion kit bag.  
Verify that the stamping on the orifice disk matches the  
boiler size (Model 399 - 8.0 LP orifice stamping).  
5. Remove the existing orifice from the O-ring in the side of the  
gas valve and replace it with the orifice from the kit. Position  
and secure the orifice in the valve as shown in FIG. 2-2.  
Do not drop the boiler or bump the jacket  
NOTICE  
on the floor or pallet. Damage to the  
boiler can result.  
6. Reposition the gas valve against the venturi and replace the  
star-drive screws (FIG. 2-2) securing the valve to the venturi.  
Figure 2-1 Boiler Mounted on Shipping Pallet  
7. Inspect the O-ring inside the blower. Handle the O-ring  
with care, do not damage. Reposition the venturi against the  
blower and replace the screws securing the venturi to the  
blower (FIG. 2-2).  
8. After installation is complete, attach the propane conversion  
label (in the conversion kit bag) next to the boiler rating  
plate. Attach the LP caution label (in the conversion kit bag)  
to the left side of the unit in the lower left corner.  
9. Replace the top and front access covers.  
After converting to LP, check combustion per  
ƽ WARNING  
the Start-up procedure in Section 10 of this  
manual.  
Failure to check and verify  
Gas conversions  
combustion could result in severe personal  
injury, death, or substantial property  
damage.  
For a boiler already installed, you must  
ƽ WARNING  
turn off gas supply, turn off power and  
allow boiler to cool before proceeding. You  
must also completely test the boiler after  
conversion to verify performance as  
described under Start-up, Section 10 of  
this manual. Failure to comply could result  
in severe personal injury, death, or  
substantial property damage.  
Model 399: Inspect the O-ring when the  
blower is disassembled. The O-ring must be  
in good condition and must be installed.  
Failure to comply will cause a gas leak,  
resulting in severe personal injury or death.  
ƽ DANGER  
Figure 2-2 Installing Propane Orifice - Model 399  
For the 399 Model you must install a  
propane orifice to operate the Knight XL  
on propane gas. Verify when installing that  
the orifice size marking matches boiler size  
(Model 399 - 8.0 LP orifice stamping).  
BLOWER  
O-RING  
VENTURI  
SCREWS  
Models 500 - 800 do not require an orifice  
installation for propane operation, but  
they will require a valve adjustment.  
QTY. 3  
SCREWS  
QTY. 4  
O-RING  
BRASS ORIFICE  
GAS VALVE  
13  
Installation & Operation Manual  
2 Prepare boiler  
After converting to LP, check combustion  
per the Start-up procedure in Section 10  
of this manual. Failure to check and verify  
combustion could result in severe  
personal injury, death, or substantial  
property damage.  
Model 500  
ƽ WARNING  
1. Remove the top access cover from the unit (no tools  
required for removal).  
2. Turn the adjustment screw on the gas valve clockwise until  
it stops. Then turn the adjustment screw counterclockwise  
four and three quarter (4 3/4) turns (see FIG. 2-3).  
3. Use a combustion analyzer to verify CO2 is within the range  
Figure 2-4 Gas Valve Adjustment - Models 600 - 800  
of 9.6 – 10.5%. If not, adjust the screw counterclockwise  
incrementally to raise CO2 and clockwise to lower CO2  
COVER  
(FIG. 2-3).  
4. After adjustment is complete, attach the propane conversion  
label (in the conversion kit bag) next to the boiler rating  
plate. Attach the LP caution label (in the conversion kit bag)  
to the left side of the unit in the lower left corner.  
ALLEN WRENCH  
ADJUSTMENT SCREW  
5. Replace the top access cover.  
After converting to LP, check combustion  
ƽ WARNING  
per the Start-up procedure in Section 10 of  
this manual. Failure to check and verify  
combustion could result in severe personal  
injury, death, or substantial property  
damage.  
Figure 2-3 Gas Valve Adjustment - Model 500  
ALLEN WRENCH  
Leveling the boiler  
1. Set the boiler in place and check level.  
a) Adjust legs if necessary to level boiler, see FIG. 2-5  
below.  
Figure 2-5 Leveling Legs on the Boiler  
ADJUSTMENT SCREW  
SCREWDRIVER  
SLOT  
Models 600 - 800  
1. Remove the top access cover from the unit (no tools  
required for removal).  
2. Remove the cover on top of the gas valve (FIG. 2-4).  
3. Turn the adjustment screw on top of the gas valve clockwise  
one and three quarter (1 3/4) turns on the 600 Model, one  
and a half (1 1/2) turns on the 700 Model, and one turn on  
the 800 Model (see FIG. 2-4).  
4. Use a combustion analyzer to verify CO2 is within the range  
LOWER  
RAISE  
of 9.6 – 10.5%. If not, adjust the screw counterclockwise  
incrementally to raise CO2 and clockwise to lower CO2  
(FIG. 2-4).  
5. After adjustment is complete, attach the propane conversion  
label (in the conversion kit bag) next to the boiler rating  
plate. Attach the LP caution label (in the conversion kit bag)  
to the left side of the unit in the lower left corner.  
6. Replace the gas valve cover along with the top access cover.  
14  
Installation & Operation Manual  
3 General venting  
Direct venting options - Sidewall Vent  
PVC/CPVC Two Pipe  
See Figure 4-1A  
Models 399 - 600 Only  
Stainless Steel  
Two Pipe  
See Figure 4-1C  
Models 399 - 600 Only  
PVC/CPVC Alternate  
Two Pipe  
See Figure 4-2A  
PVC/CPVC Concentric  
See Figure 4-7  
Models 399 - 600 Only  
Stainless Steel  
Alternate Two Pipe  
See Figure 4-2B  
15  
Installation & Operation Manual  
3 General venting  
Direct venting options - Vertical Vent  
PVC/CPVC  
Two Pipe  
See Figure 5-1A  
Stainless Steel  
Two Pipe  
See Figure 5-1B  
PVC/CPVC  
Concentric  
See Figure 5-5  
Direct venting options - Vertical Vent, Sidewall Air  
PVC/CPVC  
Vertical Vent, Sidewall Air  
Stainless Steel  
Vertical Vent, Sidewall Air  
Stainless steel vent/air design and terminations will vary slightly by manufacturer.  
NOTICE  
16  
Installation & Operation Manual  
3 General venting  
(continued)  
Install vent and combustion air piping  
The Knight XL must be vented and  
Requirements for installation in  
Canada  
ƽ DANGER  
supplied with combustion and ventilation  
air as described in this section. Ensure the  
vent and air piping and the combustion air  
supply comply with these instructions  
regarding vent system, air system, and  
combustion air quality. See also Section 1  
of this manual.  
1. Installations must be made with a vent pipe system  
certified to ULC-S636.  
IPEX is an approved vent manufacturer in Canada  
supplying vent material listed to ULC-S636.  
Inspect finished vent and air piping  
thoroughly to ensure all are airtight and  
comply with the instructions provided and  
with all requirements of applicable codes.  
2. The first three (3) feet of plastic vent pipe from the  
appliance flue outlet must be readily accessible for visual  
inspection.  
3. The components of the certified vent system must not be  
interchanged with other vent systems or unlisted  
pipe/fittings. For concentric vent installations, the inner  
vent tube must be replaced with field supplied certifiedvent  
material to comply with this requirement.  
Failure to provide a properly installed vent  
and air system will cause severe personal  
injury or death.  
PVC/CPVC vent piping materials  
Use only the materials listed in Table 3A  
ƽ WARNING  
Improper installation of PVC or CPVC  
ƽ CAUTION  
(pg. 18) for vent pipe, and fittings. Failure  
systems may result in injury or death.  
to comply could result in severe personal  
injury, death, or substantial property  
damage.  
Installing vent or air piping  
Use only cleaners, primers, and solvents that  
NOTICE  
Installation must comply with local  
NOTICE  
are approved for the materials which are  
requirements and with the National Fuel  
joined together.  
Gas Code, ANSI Z223.1 for U.S.  
installations or CSA B149.1 for Canadian  
installations.  
1. Work from the boiler to vent or air termination. Do not  
exceed the lengths given in this manual for the air or vent  
piping.  
For closet and alcove installations, CPVC  
ƽ WARNING  
material MUST BE used in a closet/alcove  
structure. Failure to follow this warning  
could result in fire, personal injury, or  
death.  
2. Cut pipe to the required lengths and deburr the inside and  
outside of the pipe ends.  
3. Chamfer outside of each pipe end to ensure even cement  
distribution when joining.  
All PVC vent pipes must be glued, properly  
NOTICE  
supported, and the exhaust must be pitched  
a minimum of a 1/4 inch per foot back to  
the boiler (to allow drainage of  
condensate).  
4. Clean all pipe ends and fittings using a clean dry rag.  
(Moisture will retard curing and dirt or grease will prevent  
adhesion.)  
This appliance requires a special venting  
ƽ WARNING  
5. Dry fit vent or air piping to ensure proper fit up before  
assembling any joint. The pipe should go a third to  
two-thirds into the fitting to ensure proper sealing after  
cement is applied.  
system. The vent connection to the  
appliance must be made with the starter  
CPVC pipe section provided with the  
appliance if PVC/CPVC vent is to be used.  
For stainless steel venting use an adapter  
from Table 3B (pg. 20) that corresponds  
with the intended vent manufacturer to be  
used and discard the CPVC starter piece.  
The field provided vent fittings must be  
cemented to the CPVC pipe section using  
an All Purpose Cement” suitable for PVC  
and CPVC pipe. Use only the vent  
materials, primer, and cement specified in  
this manual to make the vent connections.  
Failure to follow this warning could result  
in fire, personal injury, or death.  
17  
Installation & Operation Manual  
3 General venting  
6. Priming and Cementing:  
f. While primer is still wet, apply an even coat of  
approved cement to the fitting socket.  
a. Handle fittings and pipes carefully to prevent  
contamination of surfaces.  
g. Apply a second coat of cement to the pipe.  
h. While the cement is still wet, insert the pipe into the  
fitting, if possible twist the pipe a 1/4 turn as you insert  
it. NOTE: If voids are present, sufficient cement was  
not applied and joint could be defective.  
b. Apply a liberal even coat of primer to the fitting  
socket.  
c. Apply a liberal even coat of primer to the pipe end to  
approximately 1/2" beyond the socket depth.  
d. Apply a second primer coat to the fitting socket.  
e. While primer is still wet, apply an even coat of  
approved cement to the pipe equal to the depth of  
the fitting socket.  
j. Wipe excess cement from the joint removing ring or  
beads as it will needlessly soften the pipe.  
Table 3A Vent Pipe, and Fittings  
All vent pipe materials and fittings must comply with the following:  
Standards for installation in:  
Item  
Material  
United States  
ANSI/ASTM D1785  
ANSI/ASTM D2665  
Canada  
CPVC and PVC venting must be ULC-  
S636 Certified. IPEX is an approved  
manufacturer in Canada supplying vent  
material listed to ULC-S636.  
PVC schedule 40  
PVC-DWV  
Vent pipe and fittings  
Pipe cement/primer  
CPVC schedule 40  
AL29-4C  
PVC  
ANSI/ASTM F441  
UL1738  
ULC-S636  
ANSI/ASTM D2564  
ANSI/ASTM F493  
IPEX System 636  
Cements & Primers  
CPVC  
NOTICE: DO NOT USE CELLULAR (FOAM) CORE PIPE  
Approved Stainless Steel Vent Manufacturers  
Make  
Model  
FasNSeal Vent  
Z-Vent  
ProTech Systems (Simpson Dura-Vent Co.)  
Z-Flex (Nova Flex Group)  
Heat Fab (Selkirk Corporation)  
Saf-T Vent  
PVC/CPVC air intake/vent connections  
1. Combustion Air Intake Connector (FIG.’s 3-9 and 3-10) - Used to provide combustion air directly to the unit from  
outdoors. A fitting is provided on the unit for final connection. Combustion air piping must be supported per guidelines  
listed in the National Mechanical Code, Section 305, Table 305.4 or as local codes dictate.  
2. Vent Connector (FIG.’s 3-9 and 3-10) - Used to provide a passageway for conveying combustion gases to the outside.  
Transition fittings are provided with the unit for final connection. Vent piping must be supported per the National Building  
Code, Section 305, Table 305.4 or as local codes dictate.  
Figure 3-10 Near Boiler PVC/CPVC Venting  
-
Figure 3-9 Near Boiler PVC/CPVC Venting - Models 399 - 600  
Models 700 - 800  
AIR  
VENT  
AIR  
VENT  
6” COUPLING  
(FIELD SUPPLIED)  
*
6” CPVC  
STARTER  
* 4” CPVC STREET ELBOW  
MAY BE SUBSTITUTED  
4" CPVC PIPE SUPPLIED WITH  
BOILER MUST BE USED FOR VENT CONNECTION  
PIECE  
(FACTORY SUPPLIED)  
NOTE: CPVC VENT PIPE AND VENT FITTINGS MUST BE USED IN  
CLOSET AND ALCOVE INSTALLATIONS.  
THE 6” STAINLESS STEEL ADAPTER SUPPLIED  
WITH THE BOILER MUST BE USED FOR VENT  
CONNECTION TO PVC/CPVC. THE 6” CPVC  
STARTER PIECE MUST BE USED FOR PVC ONLY.  
18  
Installation & Operation Manual  
3 General venting  
(continued)  
When a sidewall or vertical rooftop combustion air supply  
system is disconnected for any reason, the air inlet pipe must  
be resealed to ensure that combustion air will be free of  
contaminants and supplied in proper volume.  
Air inlet pipe materials:  
The air inlet pipe(s) must be sealed. Choose acceptable  
combustion air inlet pipe materials from the following list:  
PVC, CPVC or ABS  
Dryer Vent or Sealed Flexible Duct (not recommended for  
rooftop air inlet)  
Galvanized steel vent pipe with joints and seams sealed as  
specified in this section.  
Type “B” double-wall vent with joints and seams sealed as  
specified in this section.  
Failure to properly seal all joints and  
ƽ DANGER  
seams as required in the air inlet piping  
may result in flue gas recirculation,  
spillage of flue products and carbon  
monoxide emissions causing severe  
personal injury or death.  
AL29-4C, stainless steel material to be sealed to  
specification of its manufacturer.  
Stainless steel vent  
This product has been approved for use with stainless steel  
using the manufacturers listed in Table 3A.  
*Plastic pipe may require an adapter (not provided) to  
transition between the air inlet connection on the appliance  
and the plastic air inlet pipe.  
Use only the materials, vent systems, and  
ƽ WARNING  
terminations listed in Table 3B. DO NOT  
mix vent systems of different types or  
manufacturers, unless listed in this  
manual. Failure to comply could result in  
severe personal injury, death, or  
substantial property damage.  
Using vent or air intake materials other  
ƽ WARNING  
than those specified, failure to properly seal  
all seams and joints or failure to follow vent  
pipe manufacturer’s instructions can result  
in personal injury, death or property  
damage. Mixing of venting materials will  
void the warranty and certification of the  
appliance.  
Installations must comply with applicable  
NOTICE  
national, state, and local codes. Stainless  
steel vent systems must be listed as a  
UL-1738 approved system for the United  
States and a ULC-S636 approved system  
for Canada.  
The use of double-wall vent or insulated  
NOTICE  
material for the combustion air inlet pipe is  
recommended in cold climates to prevent  
the condensation of airborne moisture in  
the incoming combustion air.  
Installation of a stainless steel vent system  
NOTICE  
should adhere to the stainless steel vent  
manufacturer’s installation instructions  
supplied with the vent system.  
Sealing of Type “B” double-wall vent material or galvanized  
vent pipe material used for air inlet piping on a sidewall or  
vertical rooftop Combustion Air Supply System:  
The installer must use a specific vent  
a. Seal all joints and seams of the air inlet pipe using either  
Aluminum Foil Duct Tape meeting UL Standard 723 or  
181A-P or a high quality UL Listed silicone sealant such as  
those manufactured by Dow Corning or General Electric.  
NOTICE  
starter adapter at the flue collar  
connection, supplied by the vent  
manufacturer to adapt to its vent system.  
See Table 3B for approved vent adapters.  
Discard CPVC starter piece.  
b. Do not install seams of vent pipe on the bottom of  
horizontal runs.  
c. Secure all joints with a minimum of three sheet metal  
screws or pop rivets. Apply Aluminum Foil Duct Tape or  
silicone sealant to all screws or rivets installed in the vent  
pipe.  
d. Ensure that the air inlet pipes are properly supported.  
The PVC, CPVC, or ABS air inlet pipe should be cleaned and  
sealed with the pipe manufacturer’s recommended solvents  
and standard commercial pipe cement for the material used.  
The PVC, CPVC, ABS, Dryer Vent or Flex Duct air inlet pipe  
should use a silicone sealant to ensure a proper seal at the  
appliance connection and the air inlet cap connection. Dryer  
vent or flex duct should use a screw type clamp to seal the vent  
to the appliance air inlet and the air inlet cap. Proper sealing  
of the air inlet pipe ensures that combustion air will be free of  
contaminants and supplied in proper volume.  
19  
Installation & Operation Manual  
3 General venting  
Table 3B Approved Stainless Steel Terminations and Adapters  
ProTech  
FasNSeal  
Heat Fab  
Saf-T Vent  
Z Flex  
Z-Vent  
Model  
Intake  
Air  
Termination  
Intake  
Boiler  
Flue  
Boiler Intermediate  
Adapter Adapter  
Flue  
Termination  
Boiler  
Flue  
Intake Air  
Air  
Adapter Termination  
Adapter Termination Termination  
Termination  
FSBS4  
F303759  
FSAIH04  
9492  
5400CI  
2SVSTP04  
2SVSRCX04  
KB285600 9454BUREZ-1*  
9414TERM 2SVSLA04  
2SVSTEX0490  
399-600  
700-800  
FSRC4(R.C)  
303888  
F303759  
FSAIH04  
303888  
(Intake  
Only)  
FSBS6  
* = This adapter must be used in addition to the boiler adapter for Saf-T vent pipe as shown in FIG. 3-11, unless approved vent  
other than standard diameter is used. Consult a Heat Fab representative for questions.  
Figure 3-11 Near Boiler Stainless Steel Venting Models  
399 - 600  
Table 3C Stainless Steel Vent Termination Kit(s)  
Model  
Kit Number  
700 - 800  
KIT3137  
VENT  
Stainless  
connections  
steel  
air  
intake/vent  
1. Combustion Air Intake Connector (FIG.’s 3-11 and  
3-12) - Used to provide combustion air directly to the  
unit from outdoors. A fitting is provided on the unit  
for final connection. Combustion air piping must be  
supported per guidelines listed in the National  
Mechanical Code, Section 305, Table 305.4 or as local  
codes dictate.  
2. Vent Connector (FIG.’s 3-11 and 3-12) - Used to  
provide  
a
passageway for conveying combustion  
4" S.S. ADAPTER  
gases to the outside. A transition fitting is provided  
on the unit for final connection. Vent piping must  
be supported per the National Building Code,  
Section 305, Table 305.4 or as local codes dictate.  
4" S.S. INTERMEDIATE  
(FOR SAF-T VENT ONLY)  
Figure 3-12 Near Boiler Stainless Steel Venting Models  
700 - 800  
20  
Installation & Operation Manual  
3 General venting  
(continued)  
The Knight XL uses model specific combustion air intake and  
vent piping sizes as detailed in Table 3D below.  
Vent and air piping  
Vent and air system:  
Table 3D Air Intake/Vent Piping Sizes  
Installation must comply with local  
NOTICE  
requirements and with the National Fuel Gas  
Code, ANSI Z223.1 for U.S. installations or  
CSA B149.1 for Canadian installations.  
Model  
399 - 600  
700 - 800  
Air Intake  
Vent  
4 inches (102 mm)  
4 inches (102 mm)  
4 inches (102 mm)  
6 inches (152 mm)  
You must also install air piping from outside to the boiler air  
intake adapter. The resultant installation is direct vent (sealed  
combustion).  
Increasing or decreasing combustion air  
or vent piping is not authorized.  
NOTICE  
You may use any of the vent/air piping methods covered in this  
manual. Do not attempt to install the Knight XL using any  
other means.  
Minimum  
/
Maximum  
allowable  
combustion air and vent piping lengths  
are as follows:  
DO NOT mix components from different  
ƽ WARNING  
systems. The vent system could fail, causing  
Combustion Air = 12 equivalent feet (3.7 m) minimum / 100  
leakage of flue products into the living  
space. Use only approved stainless steel,  
PVC or CPVC pipe and fittings. For  
PVC/CPVC use with primer and cement  
specifically designed for the material used.  
equivalent feet (30.5 m) maximum  
Vent = 12 equivalent feet (3.7 m) minimum / 100 equivalent  
feet (30.5 m) maximum  
When determining equivalent combustion air and vent  
length, add 5 feet (1.5m) for each 90° elbow and 3 feet (.9 m)  
for each 45° elbow.  
Vent, air piping and termination:  
The Knight XL vent and air piping can be installed through the  
roof or through a sidewall. Follow the procedures in this  
manual for the method chosen. Refer to the information in this  
manual to determine acceptable vent and air piping length.  
EXAMPLE: 20 feet (6 m) of PVC pipe + (3) 90° elbows + (3)  
45° elbows + (1) concentric vent kit (CVK3007) = 49  
equivalent feet (15 m) of piping.  
The appliance output rating will reduce by  
up to 1.5% for each 25 feet (68 m) of vent  
length.  
Optional room air  
NOTICE  
Optional room air is intended for  
NOTICE  
commercial applications. Combustion air  
piping to the outside is recommended for  
residential applications.  
Table 3E Concentric Vent Kit Equivalent Vent Lengths  
Equivalent  
Commercial applications utilizing the Knight XL boiler may be  
installed with a single pipe carrying the flue products to the  
outside while using combustion air from the equipment room.  
In order to use the room air venting option the following  
conditions and considerations must be followed.  
Model  
Kit Number  
Vent Length  
5 Feet (1.5 m)  
30 Feet (9 m)  
30 Feet (9 m)  
399  
500  
600  
CVK3007  
CVK3007  
CVK3007  
The unit MUST be installed with the appropriate  
room air kit (Table 3F).  
Removing from existing vent  
The equipment room MUST be provided with  
properly sized openings to assure adequate  
combustion air. Please refer to instructions provided  
with the room air kit.  
Follow the instructions in Section 1, page 12 of this manual  
when removing a boiler from an existing vent system.  
There will be a noticeable increase in the noise level  
during normal operation from the inlet air opening.  
Using the room air kit makes the unit vulnerable to  
combustion air contamination from within the  
building.  
Please review Section 1, Prevent  
Combustion Air Contamination, to ensure proper  
installation.  
Vent system and terminations must comply with the  
standard venting instructions set forth in this manual.  
21  
Installation & Operation Manual  
3 General venting  
If the boiler combustion air inlet is  
located in a laundry room or pool  
facility, for example, these areas will  
When utilizing the single pipe method,  
ƽ WARNING  
ƽ WARNING  
provisions for combustion and ventilation  
air must be in accordance with Air for  
Combustion and Ventilation, of the latest  
edition of the National Fuel Gas Code,  
ANSI Z223.1, in Canada, the latest edition  
of CGA Standard B149 Installation Code  
for Gas Burning Appliances and  
Equipment, or applicable provisions of the  
local building codes.  
always  
contain  
hazardous  
contaminants.  
To prevent the potential of severe  
personal injury or death, check for  
areas and products listed in Table 1A,  
page 11 before installing the boiler or  
air inlet piping.  
ƽ WARNING  
Table 3F Optional Room Air Kit  
If contaminants are found, you  
MUST:  
Model  
Description  
Kit Number  
KIT30022  
KIT30053  
• Remove products permanently.  
—OR—  
• Relocate air inlet and vent  
terminations to other areas.  
Filter Box Assembly  
90° Elbow with Screen  
399 - 800  
Air contamination  
Pool and laundry products and common household and hobby  
products often contain fluorine or chlorine compounds. When  
these chemicals pass through the boiler, they can form strong  
acids. The acid can eat through the boiler wall, causing serious  
damage and presenting a possible threat of flue gas spillage or  
boiler water leakage into the building.  
Please read the information given in Table 1A, page 11, listing  
contaminants and areas likely to contain them.  
If  
contaminating chemicals will be present near the location of  
the boiler combustion air inlet, have your installer pipe the  
boiler combustion air and vent to another location, per this  
manual.  
22  
Installation & Operation Manual  
4 Sidewall direct venting  
Vent/air termination – sidewall  
Figure 4-1A PVC/CPVC Sidewall Termination of Air and  
Vent  
Follow instructions below when  
ƽ WARNING  
determining vent location to avoid  
possibility of severe personal injury, death,  
or substantial property damage.  
TO BOILER  
INTAKE AIR  
CONNECTION  
FROM BOILER  
VENT PIPE  
CONNECTION  
12"  
A gas vent extending through an exterior  
ƽ WARNING  
wall shall not terminate adjacent to a wall  
MIN  
or below building extensions such as  
eaves, parapets, balconies, or decks.  
Failure to comply could result in severe  
personal injury, death, or substantial  
property damage.  
POSSIBLE ORIENTATIONS  
TO  
OVER-  
HANG  
VENT / AIR  
TERMINATION  
Do not connect any other appliance to the  
ƽ WARNING  
12"  
MIN  
vent pipe or multiple boilers to a common  
vent pipe. Failure to comply could result  
in severe personal injury, death, or  
substantial property damage.  
GRADE OR  
SNOW LINE  
Installation must comply with local  
NOTICE  
Table 4A Sidewall Vent Kits  
requirements and with the National Fuel  
Gas Code, ANSI Z223.1 for U.S.  
installations or CSA B149.1 for Canadian  
installations.  
Model Kit Number  
Vent Size  
4 inch vent  
399 - 600  
KIT30046  
700 - 800  
KIT30048  
6 inch vent  
Determine location  
If using the alternate sidewall termination:  
3. The air piping must terminate in a down-turned elbow as  
shown in FIG. 4-1B. This arrangement avoids recirculation  
of flue products into the combustion air stream.  
Locate the vent/air terminations using the following  
guidelines:  
1. The total length of piping for vent or air must not exceed  
the limits given in the General Venting Section on page 21  
of this manual.  
4. The vent piping must terminate in an elbow pointed  
outward or away from the air inlet, as shown in FIG. 4-1B.  
2. You must consider the surroundings when terminating  
the vent and air:  
Do not exceed the maximum lengths of the  
ƽ WARNING  
a. Position the vent termination where vapors will  
not damage nearby shrubs, plants or air  
conditioning equipment or be objectionable.  
b. The flue products will form a noticeable plume as  
they condense in cold air. Avoid areas where the  
plume could obstruct window views.  
c. Prevailing winds could cause freezing of  
condensate and water/ice buildup where flue  
products impinge on building surfaces or plants.  
d. Avoid possibility of accidental contact of flue  
products with people or pets.  
outside vent piping shown in FIG. 4-1B.  
Excessive length exposed to the outside could  
cause freezing of condensate in the vent pipe,  
resulting in potential boiler shutdown.  
Figure 4-1B Alternate PVC/CPVC Sidewall Termination  
of Air and Vent w/Field Supplied Fittings  
e. Do not locate the terminations where wind eddies  
could affect performance or cause recirculation,  
such as inside building corners, near adjacent  
buildings or surfaces, window wells, stairwells,  
alcoves, courtyards, or other recessed areas.  
Sidewall vent and air inlet terminations  
must terminate in the same pressure  
zone.  
ƽ WARNING  
f. Do not terminate above any door or window.  
Condensate can freeze, causing ice formations.  
g. Locate or guard vent to prevent condensate damage  
to exterior finishes.  
23  
Installation & Operation Manual  
4 Sidewall direct venting  
Vent/air termination – sidewall  
Figure 4-2B Alternate Stainless Steel Sidewall  
Termination Models 700 - 800 w/Field Supplied Fittings  
Figure 4-1C Alternate Stainless Steel Vent Termination  
- Typical Stainless Steel Sidewall Termination of Air and  
Vent Models 399 - 600 w/Field Supplied Fittings,  
Utilizing FasNSeal’s Hood Intake. Available Through  
FasNSeal Only  
TO BOILER INTAKE  
AIR CONNECTION  
BIRD SCREEN  
TO BOILER  
INTAKE AIR  
CONNECTION  
12" (305 MM) MIN  
15" (381 MM) MAX  
12" (305 MM) MIN  
15" (381 MM) MAX  
FROM BOILER VENT  
PIPE CONNECTION  
12" (305 MM) MIN  
FROM BOILER  
VENT PIPE  
CONNECTION  
NOTICE  
PVC/CPVC or ABS is acceptable air inlet pipe material.  
5. Maintain clearances as shown in FIG.’s 4-1A thru 4-4B,  
pages 23 thru 25. Also maintain the following:  
a. Vent must terminate:  
12" (305 MM) MIN  
• At least 6 feet (1.8 m) from adjacent walls.  
• No closer than 12 inches (305 mm) below roof  
overhang.  
• At least 7 feet (2.1 m) above any public walkway.  
• At least 3 feet (.9 m) above any forced air intake  
within 10 feet (3 m).  
• No closer than 12 inches (305 mm) below or  
horizontally from any door or window or any other  
gravity air inlet.  
Figure 4-1D Alternate PVC/CPVC/SS Vent Termination  
- Typical Stainless Steel Sidewall Termination of Air and  
Vent Models 399 - 600 w/Field Supplied Fittings,  
Utilizing 90° Elbow Intake  
b. Air inlet must terminate at least 12 inches (305 mm)  
above grade or snow line; at least 12 inches (305 mm)  
below the vent termination (FIG. 4-1B); and the vent  
pipe must not extend more than 24 inches (610 mm)  
vertically outside the building.  
c. Do not terminate closer than 4 feet (1.2 m)  
horizontally from any electric meter, gas meter,  
regulator, relief valve, or other equipment. Never  
terminate above or below any of these within 4 feet  
(1.2 m) horizontally.  
TO BOILER  
INTAKE AIR  
CONNECTION  
FROM BOILER  
VENT PIPE  
CONNECTION  
12" MIN  
15" MAX  
12" MIN  
6. Locate terminations so they are not likely to be damaged by  
foreign objects, such as stones or balls, or subject to buildup  
of leaves or sediment.  
BIRD SCREEN  
Figure 4-2A Alternate PVC/CPVC Sidewall Termination  
Models 399 - 800 w/Field Supplied Fittings  
Figure 4-3A Clearance to Gravity Air Inlets  
BIRD SCREEN  
TO BOILER  
INTAKE AIR  
CONNECTION  
12" (305 MM) MIN  
15" (381 MM) MAX  
FROM BOILER  
VENT PIPE  
CONNECTION  
12"  
MIN.  
BIRD SCREEN  
VENT / AIR  
TERMINATION  
12"  
MIN.  
12" (305 MM) MIN  
12"  
MIN.  
24  
Installation & Operation Manual  
4 Sidewall direct venting  
(continued)  
Vent/air termination – sidewall  
Prepare wall penetrations  
1. Use the factory supplied wall plate as a template to locate  
the vent and air intake holes and mounting holes.  
Figure 4-3B Alternate Clearance to Gravity Air  
Inlets w/Field Supplied Fittings  
Air pipe penetration:  
a. Cut a hole for the air pipe. Size the air pipe hole as  
close as desired to the air pipe outside diameter.  
Vent pipe penetration:  
a. Cut a hole for the vent pipe. For either combustible or  
noncombustible construction, size the vent pipe hole  
with at least a 1/2 inch clearance around the vent pipe  
outer diameter:  
12” (305 MM)  
MIN  
• 5½ inch hole (140 mm) hole for 4 inch (102 mm)  
vent pipe  
BIRD  
SCREEN  
(TYPICAL)  
• 7½ inch hole (191 mm) hole for 6 inch (152 mm)  
vent pipe  
Drill 3/16" diameter holes for inserting the plastic anchors  
into the wall.  
12” (305 MM)  
MIN  
2. Install the vent and air intake piping through the wall into  
the vent plate openings. Seal all gaps between the pipes and  
wall. Use RTV silicone sealant to seal the air pipe. Use the  
cement/primer listed in Table 3A on page 18 to seal the vent  
pipe.  
12” (305 MM)  
MIN  
Figure 4-4A Clearance to Forced Air Inlets  
IF LESS  
THAN 10’  
3. Mount and secure the vent plate to the wall using stainless  
steel screws. Seal around the plate to the wall assuring no  
air gaps.  
VENT / AIR  
TERMINATION  
36"  
MIN.  
4. Assemble the vent cap to the vent plate (see FIG. 4-4A).  
Insert the stainless steel screws into the vent cap screw hole  
openings and securely attach the vent cap to the vent plate.  
FORCED AIR  
INLET  
5. Seal all wall cavities.  
Figure 4-5A Sidewall Termination Assembly  
7' MIN. ABOVE ANY  
PUBLIC WALKWAY  
AIR PIPING  
VENT PIPING  
Figure 4-4B Alternate Clearance to Forced Air Inlets  
w/Field Supplied Fittings  
VENT PLATE  
WALL PLATE  
VENT CAP  
IF LESS  
THAN 10’ (3 M)  
GALVANIZED  
THIMBLE  
36” (914 MM)  
MIN  
FORCED AIR  
INLET  
BIRD  
SCREEN  
(TYPICAL)  
7’ (2.1 M) MIN ABOVE ANY  
PUBLIC WALKWAY  
25  
Installation & Operation Manual  
4 Sidewall direct venting  
Prepare wall penetrations (Alternate - Field Multiple vent/air terminations  
Supplied Option)  
1. When terminating multiple Knight XL’s terminate each  
1. Air pipe penetration:  
vent/air connection as described in this manual  
(FIG. 4-6A).  
a. Cut a hole for the air pipe. Size the air pipe hole as  
close as desired to the air pipe outside diameter.  
All vent pipes and air inlets must  
2. Vent pipe penetration:  
ƽ WARNING  
terminate at the same height to avoid  
possibility of severe personal injury,  
death, or substantial property damage.  
a. Cut a hole for the vent pipe. For either combustible  
or noncombustible construction, size the vent pipe  
hole with at least a 1/2 inch clearance around the vent  
pipe outer diameter:  
2. Place wall penetrations to obtain minimum clearance of  
12 inches (305 mm) between vent pipe and adjacent air  
inlet elbow, as shown in FIG. 4-6A for U.S. installations.  
For Canadian installations, provide clearances required by  
CSA B149.1 Installation Code.  
5½ inch hole (140 mm) hole for 4 inch (102 mm)  
vent pipe  
7½ inch hole (191 mm) hole for 6 inch (152 mm)  
vent pipe  
b. Insert a galvanized metal thimble in the vent pipe  
hole as shown in FIG. 4-5B.  
3. The air inlet of a Knight XL is part of a direct vent  
connection. It is not classified as a forced air intake with  
regard to spacing from adjacent boiler vents.  
3. Use a sidewall termination plate as a template for correct  
location of hole centers.  
4. Follow all local codes for isolation of vent pipe when passing  
through floors or walls.  
Figure 4-6A Multiple Vent Terminations (must also  
comply with Figure 4-1A)  
5. Seal exterior openings thoroughly with exterior caulk.  
12" MIN. BETWEEN EDGE OF AIR  
INLET AND ADJACENT VENT OUTLET  
Figure 4-5B A Typical Sidewall Termination Assembly  
- Models 399 - 800 PVC/CPVC or Stainless Steel  
GALVANIZED  
VENT  
SIDEWALL  
TERMINATION PLATE  
THIMBLE  
(WHEN REQUIRED BY LOCAL CODES)  
AIR  
ELBOW  
VENT  
PIPING  
AIR PIPING  
BIRD SCREEN  
VENT / AIR  
TERMINATION  
ELBOW  
BIRD SCREEN  
Figure 4-6B Alternate Multiple Vent Terminations  
w/Field Supplied Fittings (must also comply with  
Figure 4-1B)  
Termination and fittings  
1. Prepare the vent termination elbow and the air termination  
elbow (FIG. 4-5B) by inserting bird screens. Bird screens  
can be obtained locally.  
VENT  
2. When completed, the air termination coupling must be  
oriented at least 12 inches (305 mm) below the vent  
termination and at least 12 inches (305 mm) above grade or  
snow line as shown in FIG. 4-1A, page 23.  
12” (305 MM) MIN  
15” (381 MM) MAX  
3. Maintain the required dimensions of the finished  
termination piping as shown in FIG. 4-1A, page 23.  
4. Do not extend exposed vent pipe outside of building more  
than shown in this document. Condensate could freeze and  
block vent pipe.  
12” (305 MM) MIN. BETWEEN EDGE  
OF AIR PIPE AND ADJACENT VENT  
PIPE  
5. PVC/CPVC terminations are designed to accommodate any  
wall thickness of standard constructions per the directions  
found in this manual.  
AIR  
6. Stainless steel terminations are designed to penetrate walls  
with a thickness up to 9.25 inches of standard construction.  
26  
Installation & Operation Manual  
4 Sidewall direct venting  
(continued)  
Sidewall termination – optional concentric vent: Models 399 - 600 Only  
Description and usage  
Lochinvar offers an optional concentric combustion air and 3. You must consider the surroundings when terminating the  
vent pipe termination kit (#CVK3007 for 4" (102 mm)  
diameter - Models 399 - 600). Both combustion air and vent  
pipes must attach to the termination kit. The termination kit  
must terminate outside the structure and must be installed as  
shown below in FIG. 4-7.  
vent and air:  
a. Position the vent termination where vapors will not  
damage nearby shrubs, plants or air conditioning  
equipment or be objectionable.  
b. The flue products will form a noticeable plume as  
they condense in cold air. Avoid areas where the  
plume could obstruct window views.  
c. Prevailing winds could cause freezing of condensate  
and water/ice buildup where flue products impinge  
on building surfaces or plants.  
d. Avoid possibility of accidental contact of flue  
products with people or pets.  
Field supplied pipe and fittings are required to complete the  
installation.  
The required combustion vent pipe materials are listed in  
Table 3A, on page 18 of this manual.  
Figure 4-7 Concentric Sidewall Termination - Models  
399 - 600  
f. Do not terminate above any door or window.  
Condensate can freeze, causing ice formations.  
g. Locate or guard vent to prevent condensate damage  
to exterior finishes.  
OVERHANG  
OR ROOF  
Figure 4-8 Kit Contents_CVK3007 - Models 399 - 600  
RAIN CAP  
12" (305 MM)  
MIN  
6" (152 MM) TO 4" (102 MM) REDUCER  
6" (152 MM) DIA.  
6" (152 MM) DIA.  
12" (305 MM)  
MIN  
4" (102 MM) DIA.  
"Y" CONCENTRIC  
FITTING  
GRADE / SNOW LINE  
6" (152 MM) DIA.  
Sidewall termination installation  
1. Determine the best location for the termination kit (see  
FIG. 4-7).  
"FLEXIBLE" PIPE  
COUPLING  
2. The total length of piping for vent or air must not exceed  
the limits given in the General Venting section on page 21  
of this manual.  
4. Cut one (1) hole (7 inch (178 mm) diameter for #CVK3007  
installations into the structure to install the termination kit.  
5. Partially assemble the concentric vent termination kit.  
Clean and cement using the procedures found in these  
instructions.  
a. Cement the Y concentric fitting to the larger kit pipe  
(FIG. 4-8).  
b. Cement the rain cap to the smaller diameter kit pipe  
(FIG. 4-8).  
27  
Installation & Operation Manual  
4 Sidewall direct venting  
Sidewall termination – optional concentric vent: Models 399 - 600 Only  
Figure 4-9 Concentric Vent Dimensional Drawing - Models 399 - 600  
"A"  
"B" DIA.  
"C" DIA.  
"D"  
3"  
(76 MM)  
"E"  
"G"  
"H" DIA.  
"B" DIA. PVC  
VENT / EXHAUST  
"F"  
A
B
C
D
E
F
G
H
60"  
4"  
6"  
(152 MM)  
21 1/8"  
10"  
7 5/8"  
3"  
(76 MM)  
6 5/8"  
(168 MM)  
(537 MM) (254 MM) (194 MM)  
(1524 MM) (102 MM)  
Instead of cementing the smaller pipe to the  
rain cap, a field-supplied stainless steel  
screw may be used to secure the two (2)  
6. Install the Y concentric fitting and pipe assembly through  
the structure’s hole from an inside wall.  
NOTICE  
Do not allow insulation or other materials  
to accumulate inside the pipe assembly  
when installing through the hole.  
components  
disassembly is desired for cleaning (see  
FIG. 4-10).  
together  
when  
field  
NOTICE  
When using the alternate screw assembly  
method, drill a clearance hole in the rain cap  
and a pilot hole in the vent pipe for the  
screw size being used. Failure to drill  
adequate holes may cause cracking of PVC  
components, allowing combustion products  
to be recirculated. Failure to follow this  
warning could result in personal injury or  
death.  
7. Install the rain cap and small diameter pipe assembly into  
the Y concentric fitting and large pipe assembly from an  
outside wall. Ensure small diameter pipe is fastened  
tightly into the rubber adapter for #CVK3007  
installations.  
ƽ WARNING  
8. Secure the assembly to the structure as shown in  
FIG. 4-11 using field-supplied metal strapping or  
equivalent support material.  
Ensure termination location clearance  
NOTICE  
Do not operate the appliance with the rain  
cap removed or recirculation of combustion  
products may occur. Water may also collect  
inside the larger combustion air pipe and  
flow to the burner enclosure. Failure to  
follow this warning could result in product  
damage or improper operation, personal  
injury, or death.  
ƽ WARNING  
dimensions are as shown in FIG. 4-7.  
If assembly needs to be extended to allow  
NOTICE  
sidewall thickness requirement, the two  
(2) pipes supplied in the kit may be  
replaced by using the same diameter, field-  
supplied standard schedule 40 PVC for  
CVK3007. Do not extend dimension D*  
more than 60 inches (1524 mm) (see  
FIG. 4-9).  
Figure 4-10 Rain Cap to Vent Pipe Alternate Assembly  
STAINLESS STEEL SCREW  
(FIELD SUPPLIED)  
If assembly depth needs to be reduced,  
dimension D can be as short as possible.  
NOTICE  
DRILL CLEARANCE HOLE IN  
RAIN CAP & PILOT HOLE  
IN VENT PIPE  
28  
Installation & Operation Manual  
4 Sidewall direct venting  
(continued)  
Sidewall termination – optional concentric vent: Models 399 - 600 Only  
Figure 4-11 Concentric Vent Sidewall Attachment  
STRAP  
(FIELD SUPPLIED)  
ELBOW  
(FIELD SUPPLIED)  
COMBUSTION AIR  
COMBUSTION AIR  
VENT  
VENT  
Multiventing sidewall terminations  
DO NOT use field-supplied couplings to  
extend pipes. Airflow restriction will  
occur and may cause intermittent  
operation.  
CAUTION  
When two (2) or more direct vent appliances are vented near  
each other, each appliance must be individually vented (see  
FIG. 4-12). NEVER common vent or breach vent this appliance.  
When two (2) or more direct vent appliances are vented near  
each other, two (2) vent terminations may be installed as shown  
in FIG. 4-12. The next two (2) terminations must be at least 36  
inches (914 mm) away from the first two (2) terminations. It is  
important that vent terminations be made as shown to avoid  
recirculation of flue gases. Dimension A in FIG. 4-12 represents  
the distance between pipes or rain shields, as touching or a  
2 inch (51 mm) maximum separation.  
9. Cement appliance combustion air and vent pipes to the  
concentric vent termination assembly. See FIG. 4-11  
for proper pipe attachment.  
10. Operate the appliance one (1) heat cycle to ensure  
combustion air and vent pipes are properly connected  
to the concentric vent termination connections.  
"A"  
36"  
(914 MM)  
VENT  
COMBUSTION  
AIR  
Figure 4-12 Concentric Vent and Combustion Air Termination Dimension A as  
Touching or 2 inches (51 mm) Maximum Separation  
29  
Installation & Operation Manual  
5 Vertical direct venting  
Vent/air termination – vertical  
Rooftop vent and air inlet terminations  
must terminate in the same pressure zone,  
unless vertical vent sidewall air is set up as  
shown in the General Venting - Vertical  
Vent, Sidewall Air Section.  
ƽ WARNING  
Follow instructions below when  
ƽ WARNING  
determining vent location to avoid  
possibility of severe personal injury, death  
or substantial property damage.  
Do not connect any other appliance to the  
ƽ WARNING  
vent pipe or multiple boilers to a common  
Figure 5-1A PVC/CPVC Vertical Termination of Air and  
vent pipe. Failure to comply could result in  
severe personal injury, death, or substantial  
property damage.  
Vent  
ALTERNATE INTAKE LOCATIONS:  
INTAKE PIPES MAY BE LOCATED  
ANYWHERE WITHIN 24" (610 MM)  
OF VENT PIPE  
Installation must comply with local  
NOTICE  
requirements and with the National Fuel  
Gas Code, ANSI Z223.1 for U.S.  
installations or CSA B149.1 for Canadian  
installations.  
BIRD SCREEN  
(TYPICAL)  
VENT  
Determine location  
Locate the vent/air terminations using the following  
guidelines:  
COUPLING  
(FIELD SUPPLIED)  
6" (152 MM) MINIMUM  
ABOVE ROOF /  
SNOW LINE  
1. The total length of piping for vent or air must not exceed  
the limits given in the General Venting Section on page 21  
of this manual.  
VENT OUTLET  
COMBUSTION  
12" MINIMUM  
AIR  
ABOVE AIR INLET  
2. The vent must terminate at least 3 feet above the highest  
place in which the vent penetrates the roof and at least  
2 feet above any part of a building within 10 horizontal  
feet.  
Figure 5-1B Stainless Steel Vertical Termination of Air  
and Vent  
ALTERNATE INTAKE LOCATIONS:  
INTAKE PIPES MAY BE LOCATED  
ANYWHERE WITHIN 24” (610 MM)  
OF VENT PIPE  
3. The air piping must terminate in a down-turned 180°  
return pipe no further than 2 feet (.6 m) from the center  
of the vent pipe. This placement avoids recirculation of  
flue products into the combustion air stream.  
BIRD SCREEN  
(TYPICAL)  
VENT  
4. The vent piping must terminate in an up-turned coupling  
as shown in FIG. 5-1A. The top of the coupling must be  
at least 1 foot above the air intake. When the vent  
termination uses a rain cap as illustrated in FIG. 5-1B  
maintain at least 36" (914 mm) above the air inlet. The  
air inlet pipe and vent pipe can be located in any desired  
position on the roof, but must always be no further than  
2 feet (.6 m) apart and with the vent termination at least  
1 foot above the air intake.  
6" (152 MM) MINIMUM  
ABOVE ROOF /  
SNOW LINE  
COM,BUSTION  
AIR  
VENT OUTLET  
36” (914 MM) MINIMUM  
ABOVE AIR INLET  
5. Locate terminations so they are not likely to be damaged by  
foreign objects, such as stones or balls, or subject to buildup  
of leaves or sediment.  
30  
Installation & Operation Manual  
5 Vertical direct venting  
(continued)  
Vent/air termination – vertical  
Prepare roof penetrations  
Multiple vent/air terminations  
1. Air pipe penetration:  
1. When terminating multiple Knight XL boilers, terminate  
each vent/air connection as described in this manual  
(FIG. 5-2).  
a. Cut a hole for the air pipe. Size the air pipe hole as  
close as desired to the air pipe outside diameter.  
2. Vent pipe penetration:  
Terminate all vent pipes at the same height  
ƽ WARNING  
a. Cut a hole for the vent pipe. For either combustible  
or noncombustible construction, size the vent pipe  
hole with at least a 1/2 inch clearance around the  
vent pipe outer diameter:  
and all air pipes at the same height to  
avoid recirculation of flue products and  
the possibility of severe personal injury,  
death, or substantial property damage.  
5½ inch hole (140 mm) hole for 4 inch (102 mm)  
2. Place roof penetrations to obtain minimum clearance of  
12 inches (305 mm) between edge of air intake elbow and  
adjacent vent pipe of another boiler for U.S. installations  
(see FIG. 5-2). For Canadian installations, provide  
clearances required by CSA B149.1 Installation Code.  
vent pipe  
7½ inch hole (191 mm) hole for 6 inch (152 mm)  
vent pipe  
b. Insert a galvanized metal thimble in the vent pipe  
hole (when required by local codes).  
3. The air inlet of a Knight XL boiler is part of a direct vent  
connection. It is not classified as a forced air intake with  
regard to spacing from adjacent boiler vents.  
3. Space the air and vent holes to provide the minimum  
spacing shown in FIG.’s 5-1A and 5-1B, page 30.  
4. Follow all local codes for isolation of vent pipe when  
passing through floors, ceilings, and roofs.  
Figure 5-2 Vertical Terminations with Multiple Boilers  
5. Provide flashing and sealing boots sized for the vent pipe  
and air pipe.  
12" (305 MM) MINIMUM  
VERTICALLY FROM VENT  
OUTLET TO ANY AIR INLET  
Termination and fittings  
VENT  
AIR  
12" (305 MM) MINIMUM FROM EDGE  
OF AIR INTAKE PIPE TO ADJACENT  
VENT PIPE FROM ANOTHER BOILER  
1. Prepare the vent termination coupling and the air  
termination elbow (FIG.’s 5-1A and 5-1B) by inserting  
bird screens. Bird screens should be obtained locally.  
VENT  
AIR  
2. The air piping must terminate in a down-turned 180°  
return bend as shown in FIG.’s 5-1A and 5-1B. Locate the  
air inlet pipe no further than 2 feet (.6 m) from the center  
of the vent pipe. This placement avoids recirculation of  
flue products into the combustion air stream.  
Figure 5-3 Alternate Vertical Terminations with Multiple  
3. The vent piping must terminate in an up-turned  
coupling as shown in FIG. 5-1A. The top of the coupling  
must be at least 1 foot (.3 m) above the air intake. When  
the vent termination uses a rain cap as illustrated in  
FIG. 5-1B maintain at least 36" (914 mm) above the air  
inlet. The air inlet pipe and vent pipe can be located in  
any desired position on the roof, but must always be no  
further than 2 feet (.6 m) apart and with the vent  
termination at least 1 foot (.3 m) above the air intake.  
Boilers  
VENT  
VENT  
12" (305 MM) MINIMUM  
VERTICALLY FROM VENT  
OUTLET TO ANY AIR INLET  
4. Maintain the required dimensions of the finished  
termination piping as shown in FIG.’s 5-1A and 5-1B.  
AIR  
AIR  
5. Do not extend exposed vent pipe outside of building  
more than shown in this document. Condensate could  
freeze and block vent pipe.  
31  
Installation & Operation Manual  
5 Vertical direct venting  
Vertical termination – optional concentric vent: Models 399 - 600 Only  
Description and usage  
2. Cut one (1) hole (7 inch (178 mm) diameter for #CVK3007  
Lochinvar offers an optional concentric combustion air and  
vent pipe termination kit. Both combustion air and vent  
pipes must attach to the termination kit. The termination kit  
must terminate outside the structure and must be installed as  
shown in FIG. 5-4.  
installations) into the structure to install the termination  
kit.  
3. Partially assemble the concentric vent termination kit.  
Clean and cement following the cleaning procedures in  
these instructions.  
Field supplied pipe and fittings are required to complete the  
installation.  
a. Cement the Y concentric fitting to the larger  
diameter kit pipe (see FIG. 4-8, page 27).  
b. Cement rain cap to the smaller diameter kit pipe (see  
FIG. 4-8, page 27).  
The required combustion vent pipe fittings are listed in  
Table 3A, on page 18 of this manual.  
Vertical termination installation  
Instead of cementing the smaller pipe to the  
rain cap, a field supplied stainless steel screw  
may be used to secure the two (2)  
NOTICE  
1. See Section 5, Vertical Direct Venting - Determine  
Location (where applicable).  
components  
together  
when  
field  
disassembly is desired for cleaning (see  
FIG. 4-10, page 28).  
Figure 5-4 Concentric Vertical Termination  
When using the alternate screw assembly  
method, drill a clearance hole in the rain cap  
and a pilot hole in the vent pipe for the  
screw size being used. Failure to drill  
adequate holes may cause cracking of PVC  
components, allowing combustion products  
to be recirculated. Failure to follow this  
warning could result in personal injury or  
death.  
ƽ WARNING  
VENT  
COMBUSTION  
AIR  
12" (305 MM) (18" (457 MM)  
FOR CANADA) MINIMUM  
CLEARANCE ABOVE HIGHEST  
ANTICIPATED SNOW  
LEVEL. MAXIMUM OF  
24" (610 MM) ABOVE ROOF.  
Figure 5-5 Do Not Install U-Bent to Rain Cap  
32  
Installation & Operation Manual  
5 Vertical direct venting  
(continued)  
Vertical termination – optional concentric vent: Models 399 - 600 Only  
Do not operate the appliance with the rain  
DO NOT use field-supplied couplings to  
extend pipes. Airflow restriction will  
occur.  
ƽ WARNING  
CAUTION  
cap removed or recirculation of  
combustion products may occur. Water  
may also collect inside the larger  
combustion air pipe and flow to the  
burner enclosure. Failure to follow this  
warning could result in product damage  
or improper operation, personal injury, or  
death.  
6. Install the rain cap and the small diameter pipe assembly  
into the roof penetration assembly. Ensure the small  
diameter pipe is fastened tightly into the rubber adapter  
for #CVK3007 installations.  
7. Cement the appliance combustion air and vent pipes to  
the concentric vent termination assembly. See FIG. 5-6  
for proper pipe attachment.  
4. Install the Y concentric fitting pipe assembly up through  
the structure’s hole and field supplied roof boot/flashing.  
8. Operate the appliance through one (1) heat cycle to  
ensure combustion air and vent pipes are properly  
connected to the concentric vent termination  
connections.  
Do not allow insulation or other materials  
to accumulate inside the pipe assembly  
when installing through the hole.  
NOTICE  
5. Secure the assembly to the roof structure as shown below  
in FIG. 5-6 using field supplied metal strapping or  
equivalent support material.  
Multiventing vertical terminations  
When two (2) or more direct vent appliances are vented near  
each other, each appliance must be individually vented (see  
FIG. 5-7). NEVER common vent or breach vent this  
appliance. When two (2) or more direct vent appliances are  
vented near each other, two (2) vent terminations may be  
installed as shown in FIG. 5-7. The next two (2) terminations  
must be at least 36 inches (914 mm) away from the first two  
(2) terminations. It is important that vent terminations be  
made as shown to avoid recirculation of flue gases.  
Dimension A in FIG. 5-7 represents the distance between  
pipes or rain shields, as touching or a 2 inch (51 mm)  
maximum separation.  
Figure 5-6 Concentric Vent Roof Installation  
VENT  
12" (305 MM) (18" (457 MM) FOR CANADA)  
MINIMUM CLEARANCE ABOVE HIGHEST  
ANTICIPATED SNOW LEVEL. MAXIMUM OF  
24” (610 MM) ABOVE ROOF.  
COMBUSTION  
AIR  
ROOF BOOT /  
FLASHING  
(FIELD SUPPLIED)  
SUPPORT  
(FIELD SUPPLIED)  
Figure 5-7 Concentric Vent and Combustion Air Vertical  
Termination (Dimension A as Touching or 2 inches  
(51 mm) Maximum Separation)  
ELBOW  
(FIELD SUPPLIED)  
"A"  
COMBUSTION  
AIR  
VENT  
36" (914 MM)  
MIN.  
COMBUSTION  
AIR (TYPICAL)  
Ensure termination height is above the  
roof surface or anticipated snow level  
(12 inches (305 mm) in U.S.A. or 18  
inches (457 mm) in Canada) as shown in  
FIG. 5-4, page 32.  
NOTICE  
NOTICE  
VENT  
(TYP)  
If assembly is too short to meet height  
requirement, the two (2) pipes supplied in  
the kit may be replaced by using the same  
diameter, field supplied standard schedule  
40 PVC for CVK3007. Do not extend  
dimension D* more than 60 inches  
(1524 mm) (see FIG. 4-9, page 28).  
12" (305 MM) (18" (457 MM)  
FOR CANADA) MINIMUM  
CLEARANCE ABOVE  
HIGHEST ANTICIPATED  
SNOW LEVEL. MAXIMUM OF  
24" (610 MM) ABOVE ROOF.  
DIMENSTION "A" IS TOUCHING  
OR 2" (51 MM) MAXIMUM  
SEPARATION  
33  
Installation & Operation Manual  
6 Hydronic piping  
System water piping methods  
General piping information  
The Knight XL is designed to function in a closed loop Basic steps are listed below along with illustrations on the  
pressurized system not less than 12 psi (83 kPa). following pages (FIG.’s 6-7 and 6-8), which will guide you  
A
temperature and pressure gauge is included to monitor through the installation of the Knight XL (reference FIG.’s 6-4A  
system pressure and outlet temperature and should be located and 6-4B).  
on the boiler outlet.  
1. Connect the system return marked “Inlet, make sure to  
install with pipe sealant compound.  
It is important to note that the boiler has a minimal amount  
2. Connect the system supply marked “Outlet, make sure to  
install with pipe sealant compound.  
of pressure drop which must be figured in when sizing the  
circulators. Each boiler installation must have an air  
elimination device, which will remove air from the system.  
Install the boiler so the gas ignition system components are  
protected from water (dripping, spraying, etc.) during  
appliance operation or basic service of circulator  
replacement, valves, and others.  
3. Install purge and balance valve or shutoff valve and drain  
on system return to purge air out of each zone.  
4. Install a backflow preventer on the cold feed make-up water  
line.  
5. Install a pressure reducing valve on the cold feed make-up  
water line, (15 psi (103 kPa) nominal). Check temperature  
and pressure gauge (shipped separately), which should read  
a minimum pressure of 12 psi (83 kPa).  
Observe a minimum of 1 inch (25 mm) clearance around all  
un-insulated hot water pipes when openings around the pipes  
are not protected by non-combustible materials.  
6. Install a circulator as shown on the piping diagrams in this  
section. Make sure the circulator is properly sized for the  
system and friction loss.  
Low water cutoff device  
On a boiler installed above radiation level, some states and  
local codes require a low water cutoff device at the time of  
installation.  
7. Install an expansion tank on the system supply. Consult the  
tank manufacturer’s instruction for specific information  
relating to tank installation. Size the expansion tank for the  
required system volume and capacity.  
Chilled water system  
8. Install an air elimination device on the system supply.  
If the boiler supplies hot water to heating coils in air handler  
units, flow control valves or other devices must be installed to  
prevent gravity circulation of heater water in the coils during  
the cooling cycle. A chilled water medium must be piped in  
parallel with the heater.  
9. Install a drain valve at the lowest point of the system.  
Note: The boiler cannot be drained completely of water  
without purging the unit with an air pressure of 15 psi  
(103 kPa).  
10. This appliance is supplied with a relief valve sized in  
accordance with ASME Boiler and Pressure Vessel Code,  
Section IV (“Heating Boilers”). Pipe the discharge of the  
safety relief valve to prevent injury in the event of pressure  
relief. Pipe the discharge to a drain. Provide piping that is  
the same size as the safety relief valve outlet. Never block  
the outlet of the safety relief valve.  
Freeze protection  
Freeze protection for new or existing systems must use glycol  
that is specially formulated for this purpose. This includes  
inhibitors, which prevent the glycol from attacking the  
metallic system components. Make certain to check that the  
system fluid is correct for the glycol concentration and  
inhibitor level. The system should be tested at least once a  
year and as recommended by the producer of the glycol  
solution. Allowance should be made for the expansion of the  
glycol solution in the system piping.  
The relief valve, tee and any other necessary  
ƽ WARNING  
fittings are shipped in the install kit with the  
boiler and are to be field installed  
(FIG.’s 6-1 and 6-2).  
11. On any pre-existing system, it is good practice to install a  
field supplied strainer to prevent damage to the heat  
exchanger.  
Use only inhibited propylene glycol  
ƽ WARNING  
solutions,  
which  
are  
specifically  
formulated for hydronic systems. Ethylene  
glycol is toxic and can attack gaskets and  
seals used in hydronic systems.  
See the piping illustrations included in this section, FIG.’s 6-7  
and 6-8 for suggested guidelines in piping the Knight XL.  
Please note that these illustrations are meant  
NOTICE  
to show system piping concept only, the  
installer is responsible for all equipment and  
detailing required by local codes.  
34  
Installation & Operation Manual  
6 Hydronic piping  
(continued)  
Flow  
switch,  
relief  
valve  
and  
Figure 6-1 Flow Switch, Relief Valve and Temperature and  
Pressure Gauge Installation_Models 399 - 500  
temperature and pressure gauge  
installation  
Basic steps are listed below to guide you through the  
installation of the flow switch, relief valve, and temperature  
and pressure gauge provided with the unit.  
1. For Models 399 - 500 install the close nipple on the  
outlet connection of the heat exchanger. Install the tee  
with the 3/4 inch fitting positioned vertically and on  
the top as shown in FIG. 6-1. For Models 600 - 800  
install the tee directly to the outlet connection of the  
heat exchanger with the 3/4 inch fitting positioned  
vertically and on the top (see FIG. 6-2).  
RELIEF VALVE  
FLOW SWITCH  
PADDLE  
TEMPERATURE AND  
PRESSURE  
GAUGE  
2. For Models 700 - 800 install the 3/4 inch close nipple  
in the tee. Install the relief valve on the 3/4 inch close  
nipple (FIG. 6-2). For Models 399 - 600 install the  
relief valve directly into the 3/4 inch fitting on the tee  
(FIG. 6-1).  
TEE WITH FITTING ON TOP  
(FIELD PROVIDED)  
CLOSE NIPPLE (FIELD PROVIDED)  
TEE WITH 1” FITTING ON TOP  
CLOSE NIPPLE  
3. Install the close nipple on the downstream side of  
the relief valve tee (FIG. 6-1).  
TEE WITH 3/4” FITTING ON TOP  
CLOSE NIPPLE  
4. Install the tee with the 1 inch fitting positioned  
vertically and on the top (FIG. 6-1).  
5. Attach paddle #3 to the flow switch per the  
manufacturer’s instructions.  
Figure 6-2 Flow Switch, Relief Valve and Temperature and  
Pressure Gauge Installation_Models 600 - 800  
6. Install the assembled flow switch into the 1 inch fitting  
of the tee installed in Step 4 (see FIG. 6-1).  
7. Install a field provided close nipple on the downstream  
side of the flow switch (see FIG.’s 6-1 and 6-2).  
8. Install a field provided tee with the gauge fitting  
positioned vertically and on the top (FIG.’s 6-1 and  
6-2)  
RELIEF VALVE  
CLOSE NIPPLE  
9. Install the temperature and pressure gauge provided  
with the unit into the top fitting of the tee (a bushing  
may be necessary) installed in Step 8 (FIG.’s 6-1 and  
6-2).  
FLOW SWITCH  
PADDLE  
TEMPERATURE AND  
PRESSURE  
GAUGE  
Be sure to install the flow switch so that  
NOTICE  
the arrow on the flow switch is pointing  
in the direction of the flow (see FIG.  
6-3).  
TEE WITH FITTING ON TOP  
(FIELD PROVIDED)  
CLOSE NIPPLE (FIELD PROVIDED)  
TEE WITH 1” FITTING ON TOP  
CLOSE NIPPLE  
TEE WITH 3/4” FITTING ON TOP  
CLOSE NIPPLE  
35  
Installation & Operation Manual  
6 Hydronic piping  
Flow switch adjustment  
Near boiler piping connections  
Refer to Table 6A for the proper setting of the sensitivity  
screw. For reference, the position of the screw prior to setting Figure 6-4A Near Boiler Piping w/Y-Strainer  
should be turned clockwise with a Phillips driver until it stops  
(FIG. 6-3). Proceed to turn the screw counterclockwise the  
amount of turns listed in Table 6A based on the model.  
Consult the manufacturer’s instructions for wiring the flow  
switch to your system.  
DOMESTIC HOT  
WATER PUMP  
Table 6A Paddle Size / Sensitivity Screw Adjustment  
INDIRECT  
DOMESTIC  
HOT WATER  
TANK  
SYSTEM PUMP  
SENSITIVITY SCREW  
MODEL  
PADDLE SIZE  
ADJUSTMENT  
Note: Paddles are included with the flow switch.  
399  
500  
600  
700  
800  
#3  
#3  
#3  
#3  
#3  
7½ turns  
5½ turns  
7¼ turns  
5¼ turns  
3¼ turns  
BOILER PUMP  
Y-STRAINER  
(RECOMMENDED)  
Turn the sensitivity screw clockwise to  
increase the flow rate required to activate  
the switch. Turn the sensitivity screw  
counterclockwise to decrease the flow rate  
required to activate the switch.  
NOTICE  
TO FLOOR  
DRAIN  
Figure 6-3 Flow Switch Adjustment  
NORMALLY  
OPEN  
SENSITIVITY  
ADJUSTMENT  
Figure 6-4B Near Boiler Piping w/Low Loss Header  
SYSTEM PUMP  
SYSTEM SENSOR  
AIR SEPARATOR  
DRAIN  
(TYPICAL)  
AIR VENT VALVE  
LOW LOSS HEADER  
(TYPICAL)  
GROUND  
EXPANSION TANK  
NORMALLY  
CLOSED  
COMMON  
FAST FILL VALVE  
INDIRECT  
DOMESTIC  
HOT WATER  
TANK  
DRAIN VALVE  
Circulator sizing  
The Knight XL heat exchanger does have a pressure drop,  
which must be considered in your system design. Refer to the  
graphs in FIG’s 6-5 and 6-6 for pressure drop through the  
Knight XL heat exchanger.  
Y-STRAINER  
(RECOMMENDED)  
TO FLOOR  
DRAIN  
36  
Installation & Operation Manual  
6 Hydronic piping  
(continued)  
Figure 6-5 Pressure Drop vs. Flow - Models 399 and 500  
Pressure Drop vs Flow  
(Includes Boiler Secondary Piping)  
20  
18  
16  
14  
12  
10  
8
KBN500  
KBN399  
6
4
2
0
0
5
10  
15  
20  
25  
30  
35  
40  
45  
Flow Rate (GPM)  
Figure 6-6 Pressure Drop vs. Flow - Models 600 thru 800  
Pressure Drop vs Flow  
(Includes Boiler Secondary Piping)  
60  
50  
40  
30  
20  
10  
0
KBN800  
KBN700  
KBN600  
0
10  
20  
30  
40  
50  
60  
70  
80  
90  
Flow Rate (GPM)  
Table 6B Sizing Information for Temperature Rise Applications_20°F, 2F, 30°F and 35°F  
TEMPERATURE RISE APPLICATIONS  
20°F  
25°F  
30°F  
35°F  
MINIMUM  
PIPE  
Model  
GPM  
FT/HD  
GPM  
FT/HD  
GPM  
FT/HD  
GPM  
FT/HD  
SIZE  
399  
500  
600  
700  
800  
1 1/2"  
1 1/2"  
2"  
37  
46  
55  
65  
74  
21  
23  
31  
30  
33  
30  
37  
44  
52  
60  
14  
16  
22  
20  
23  
26  
32  
38  
45  
51  
11  
13  
18  
16  
18  
21  
26  
32  
37  
42  
8
10  
13  
11  
12  
2"  
2"  
37  
Installation & Operation Manual  
6 Hydronic piping  
Pump sizing and flow requirements are 5. Check valves:  
NOTICE  
based on 20 feet (6 m) of piping, 4 - 90°  
elbows, and 2 - fully ported ball valves.  
Field supplied. Check valves are recommended for  
installation as shown in FIG.’s 6-7 and 6-8. Failure to  
install check valves could result in a reverse flow condition  
during pump(s) off cycle.  
It is required that near boiler piping  
NOTICE  
systems  
utilize  
Primary/Secondary  
6. Domestic indirect hot water isolation valves:  
configurations as shown in FIG.’s 6-7 and  
6-8 only. The use of other near boiler  
piping configurations could result in  
improper building and system flow rates  
leading to inadvertent boiler high limit  
shutdowns and poor system performance.  
Field supplied.  
Full port ball valves are  
required. Failure to use full port ball valves could  
result in a restricted flow rate through the boiler.  
7. Anti-scald mixing valve:  
Field supplied.  
An anti-scald mixing valve is  
recommended when storing domestic hot water above  
115°F (46°C).  
Near boiler piping components  
1. Boiler system piping:  
8. Unions:  
Boiler system piping MUST be sized per the pipe  
requirements listed in Table 6B. Reducing the pipe size  
can restrict the flow rate through the boiler, causing  
inadvertent high limit shutdowns and poor system  
performance. Flow rates are based on 20 feet (6 m) of  
piping, 4 - 90° elbows, and 2 - fully ported ball valves.  
Field supplied. Recommended for unit serviceability.  
9. Temperature and pressure gauge:  
Factory supplied. The temperature and pressure gauge is  
shipped loose. It is the responsibility of the contractor to  
install the temperature and pressure gauge on the boiler  
water outlet.  
2. Boiler system circulating pump:  
Field supplied. The boiler circulating pump should be  
based on 20 feet (6 m) of piping, 4 - 90° elbows, and  
2 - fully ported ball valves.  
10. Pressure relief valve:  
Factory supplied. The pressure relief valve is sized to  
ASME specifications.  
11. Boiler purge valve:  
3. Domestic hot water circulating pump:  
Field supplied. The pump MUST be sized to meet  
the specified minimum flow requirements listed in  
FIG.’s 6-5 and 6-6. Consult the indirect water heater  
operating guide to determine flow characteristics for the  
selected product used.  
Field supplied. The boiler purge valve is used to  
remove entrapped air from the heat exchanger during  
start-up.  
12. System temperature sensor:  
Lochinvar supplies  
a
system temperature sensor.  
The sensor is to be installed in the heating loop  
downstream from the boiler hot water piping and  
4. Boiler isolation valves:  
Field supplied. Full port ball valves are required. Failure  
to use full port ball valves could result in a restricted flow  
rate through the boiler.  
heating loop junction.  
The sensor should be  
located far enough downstream to sense system diluted  
water temperature.  
13. Y-Strainer:  
Field supplied. A Y-strainer or equivalent multipurpose  
strainer is recommended at the inlet of the heat exchanger  
to remove system particles from older hydronic systems and  
protect newer systems.  
38  
Installation & Operation Manual  
6 Hydronic piping  
(continued)  
Figure 6-7 Single Boiler - Primary/Secondary Piping  
AIR SEPARATOR  
MAY SUBSTITUTE  
LOW LOSS HEADER  
DRAIN POINT  
(TYPICAL)  
BALL VALVE  
(TYPICAL)  
SYSTEM SUPPLY SENSOR  
(WHEN USED)  
NOT TO EXCEED 4 PIPE DIA OR MAX. OF 12" APART  
SYSTEM CIRCULATOR  
PRESSURE GAUGE  
EXPANSION TANK  
BOILER CIRCULATOR  
Y-STRAINER  
MAKE UP WATER  
(RECOMMENDED)  
BACK FLOW  
PREVENTER  
PRESSURE REDUCING  
VALVE  
INDIRECT DHW  
TANK  
ANTI-SCALD  
MIXING VALVE  
HOT WATER OUT  
DOMESTIC  
HOT WATER  
CIRCULATOR  
UNION (TYPICAL)  
BOILER  
COLD WATER IN  
TEMPERATURE / PRESSURE  
GAUGE  
PRESSURE RELIEF  
VALVE  
DRAIN  
FLOW CHECK  
VALVE (TYPICAL)  
Please note that these illustrations are meant to show system piping concept only, the installer is responsible  
for all equipment and detailing required by local codes.  
NOTICE  
NOTICE  
System flow should always remain higher than the required flow for the boiler(s) when the boiler(s) is in  
operation to prevent short cycling and high limit issues.  
39  
Installation & Operation Manual  
6 Hydronic piping  
Figure 6-8 Multiple Boilers - Primary/Secondary Piping  
Number of Units  
Model  
2
3
4
5
6
7
8
Manifold Pipe Sizes in Inches (mm)  
2 1/2 (64) 3 (76) 3 1/2 (89) 4 (102) 4 (102) 5 (127) 6 (152)  
3 (76) 3 1/2 (89) 4 (102) 5 (127) 5 (127) 6 (152) 6 (152)  
3 1/2 (89) 4 (102) 5 (127) 5 (127) 6 (152) 6 (152) 8 (203)  
399  
500  
600  
3 1/2 (89) 5 (127) 5 (127) 6 (152) 6 (152) 8 (203) 8 (203)  
4 (102) 5 (127) 5 (127) 6 (152) 8 (203) 8 (203) 8 (203)  
700  
800  
BALL VALVE  
(TYPICAL)  
MAY SUBSTITUTE  
LOW LOSS HEADER  
AIR SEPARATOR  
DRAIN POINT  
(TYPICAL)  
SYSTEM SUPPLY SENSOR  
(WHEN USED)  
SYSTEM CIRCULATOR  
MAKE UP WATER  
BOILER CIRCULATOR  
(TYPICAL)  
EXPANSION  
TANK  
BACK FLOW  
PREVENTER  
PRESSURE REDUCING  
VALVE  
BOILER 4  
PRESSURE GAUGE  
(MEMBER 3)  
INDIRECT DHW  
TANK  
BOILER 3  
(MEMBER 2)  
ANTI-SCALD  
MIXING VALVE  
BOILER 2  
(MEMBER 1)  
HOT WATER OUT  
BOILER 1  
(LEADER)  
DOMESTIC  
HOT WATER  
CIRCULATOR  
UNION (TYPICAL)  
COLD WATER IN  
PRESSURE RELIEF  
VALVE  
DRAIN  
FLOW CHECK  
Y-STRAINER  
(TYPICAL)  
VALVE (TYPICAL)  
(RECOMMENDED)  
TEMPERATURE /  
PRESSURE GAUGE  
Please note that these illustrations are meant to show system piping concept only, the installer is responsible  
for all equipment and detailing required by local codes.  
NOTICE  
NOTICE  
System flow should always remain higher than the required flow for the boiler(s) when the boiler(s) is in  
operation to prevent short cycling and high limit issues.  
40  
Installation & Operation Manual  
7 Gas connections  
Connecting gas supply piping  
Figure 7-3 Gas Supply Piping - Models 600 - 800  
1. Remove the top access panel and refer to FIG.’s 7-1 thru  
7-3 to pipe gas to the boiler.  
a. Install ground joint union for servicing, when  
required.  
MANUAL  
SHUTOFF VALVE  
(FACTORY SUPPLIED)  
b. Install a manual shutoff valve in the gas supply  
piping outside boiler jacket when required by local  
codes or utility requirements.  
GAS SUPPLY  
c. In Canada – When using manual main shutoff  
valves, it must be identified by the installer.  
2. Install sediment trap / drip leg.  
Figure 7-1 Gas Supply Piping - Model 399  
DRIP LEG  
UNION  
UNION  
3. Support piping with hangers, not by the boiler or its  
accessories.  
GAS SUPPLY  
The gas valve and blower will not support  
ƽ WARNING  
the weight of the piping. Do not attempt  
to support the weight of the piping with  
the boiler or its accessories. Failure to  
comply could result in severe personal  
injury, death, or substantial property  
damage.  
SEDIMENT TRAP / DRIP LEG  
MANUAL  
SHUTOFF VALVE  
(FIELD SUPPLIED)  
4. Purge all air from the gas supply piping.  
5. Before placing the boiler in operation, check the boiler  
and its gas connection for leaks.  
a. The appliance must be disconnected from the gas  
supply piping system during any pressure testing of  
that system at a test pressure in excess of 1/2 PSIG  
(3.5 kPa).  
Figure 7-2 Gas Supply Piping - Model 500  
b. The appliance must be isolated from the gas supply  
piping system by closing a manual shutoff valve  
during any pressure testing of the gas supply piping  
system at test pressures equal to or less than 1/2 PSIG  
(3.5 kPa).  
UNION  
FIELD SUPPLIED  
GAS SUPPLY  
c. The appliance and its gas connection must be leak  
tested before placing it in operation.  
Do not check for gas leaks with an open  
ƽ WARNING  
flame – use the bubble test. Failure to use  
the bubble test or check for gas leaks can  
cause severe personal injury, death, or  
substantial property damage.  
SEDIMENT TRAP / DRIP LEG  
MANUAL  
SHUTOFF VALVE  
(FACTORY SUPPLIED)  
6. Use pipe sealing compound compatible with propane  
gases. Apply sparingly only to male threads of the pipe  
joints so that pipe dope does not block gas flow.  
41  
Installation & Operation Manual  
7 Gas connections  
Failure to apply pipe sealing compound  
Natural gas:  
Pipe sizing for natural gas  
ƽ WARNING  
as detailed in this manual can result in  
severe personal injury, death, or  
substantial property damage.  
1. Refer to Table 7A for pipe length and diameter. Based on  
rated boiler input (divide by 1,000 to obtain cubic feet per  
hour).  
Use two wrenches when tightening gas  
piping at boiler (FIG. 7-4), using one  
wrench to prevent the boiler gas line  
connection from turning. Failure to  
support the boiler gas connection pipe  
to prevent it from turning could damage  
gas line components.  
ƽ WARNING  
a. Table 7A is only for natural gas with specific gravity  
0.60 inches, with a pressure drop through the gas  
piping of 0.5 inches w.c.  
b. For additional gas pipe sizing information, refer to  
ANSI Z223.1 (or B149.1 for Canadian installations).  
Natural gas supply pressure requirements  
Figure 7-4 Inlet Pipe with Backup Wrench  
1. Pressure required at the gas valve inlet pressure port:  
• Maximum 14 inches w.c. (3.5 kPa) with no flow  
(lockup) or with boiler on.  
• Minimum 4 inches w.c. (.99 kPa) with gas flowing (verify  
during boiler startup).  
2. Install 100% lockup gas pressure regulator in supply line if  
inlet pressure can exceed 14 inches w.c. (3.5 kPa) at any  
time. Adjust lockup regulator for 14 inches w.c. (3.5 kPa)  
maximum.  
Propane Gas:  
Knight XL boilers are typically shipped  
ƽ WARNING  
ready to fire on natural gas. Check boiler  
rating plate to determine which fuel the  
boiler is set for. If set to natural gas, it may  
be converted to LP by installing an orifice or  
by making a gas valve adjustment (see pages  
13 and 14). In order to operate on LP gas, an  
orifice MUST BE installed or a gas valve  
adjustment MUST BE made. Failure to  
comply could result in severe personal  
injury, death, or substantial property  
damage.  
USE BACK UP WRENCH TO  
PREVENT PIPE FROM ROTATING  
Maximum inlet gas pressure must not  
NOTICE  
Pipe sizing for propane gas  
exceed the value specified. Minimum  
value listed is for the purposes of input  
adjustment.  
1. Contact gas supplier to size pipes, tanks, and 100% lockup  
gas pressure regulator.  
Propane Supply Pressure Requirements  
1. Adjust propane supply regulator provided by the gas  
supplier for 14 inches w.c. (3.2 kPa) maximum pressure.  
2. Pressure required at gas valve inlet pressure port:  
• Maximum 14 inches w.c. (3.2 kPa) with no flow (lockup)  
or with boiler on.  
• Minimum 8 inches w.c. (1.9 kPa) with gas flowing (verify  
during boiler startup).  
Ensure that the high gas pressure regulator  
is at least 10 feet (3 m) upstream of the  
appliance.  
ƽ WARNING  
42  
Installation & Operation Manual  
7 Gas connections  
Table 7A Natural Gas Pipe Size Chart  
(continued)  
Maximum  
Nominal  
Iron Pipe  
Size  
Natural Gas Pipe Capacity Chart  
Length of Pipe in Straight Feet  
Capacity of Pipe  
in Thousands of  
Btu/hr per hour  
for gas pressures  
of 14 Inches  
Water Column  
(0.5 PSIG) or less  
and a pressure  
drop of 0.5 Inch  
Water Column  
(Based on NAT  
GAS, 1025 Btu/hr  
per Cubic Foot of  
Gas and 0.60  
(inches)  
10  
20  
30  
97  
205  
384  
789  
40  
82  
174  
328  
677  
50  
60  
70  
80  
90 100 125 150 175 200  
175  
369  
697  
120  
256  
477  
N/A  
155  
292  
595  
N/A N/A N/A N/A N/A N/A N/A N/A N/A  
141 128 121 113 106  
267 246 236 210 200 179 164 149 138  
543 502 472 441 410 369 333 308 287  
830 769 707 666 636 564 513 472 441  
1/2  
3/4  
1
1-1/4  
1-1/2  
2
2-1/2  
3
4
95  
86  
79  
74  
1400 974  
2150 1500 1210 1020 923  
4100 2820 2260 1950 1720 1560 1440 1330 1250 1180 1100 974 871 820  
6460 4460 3610 3100 2720 2460 2310 2100 2000 1900 1700 1540 1400 1300  
11200 7900 6400 5400 4870 4410 4000 3800 3540 3330 3000 2720 2500 2340  
23500 16100 13100 11100 10000 9000 8300 7690 7380 6870 6150 5640 5130 4720  
Specific Gravity)  
Check inlet gas supply  
CSA or UL listed flexible gas connections  
4. Slowly turn on the gas supply at the field installed  
manual gas valve.  
NOTICE  
are acceptable, but you must exercise  
caution to ensure that the line has adequate  
capacity to allow your boiler to fire at full  
rate. Consult with local codes for proper  
installation or service procedures.  
5. Turn the power switch to the “ON” position.  
6. Adjust the temperature set point on the control panel of  
the SMART SYSTEM control module to call for heat.  
7. Observe the gas supply pressure as the burner fires at  
100% of rated input. Percent of burner input will be  
displayed on the control panel.  
DO NOT adjust or attempt to measure gas  
valve outlet pressure. Attempting to alter  
or measure the gas valve outlet pressure  
could result in damage to the valve, causing  
potential severe personal injury, death, or  
substantial property damage.  
ƽ WARNING  
8. Ensure inlet pressure is within specified range.  
Minimum and maximum gas supply pressures are  
specified in this section of the manual.  
9. If gas supply pressure is within normal range and no  
adjustments are needed, proceed on to Step 11.  
The gas piping must be sized for the proper flow and length of  
pipe, to avoid excessive pressure drop. Both the gas meter and  
the gas regulator must be properly sized for the total gas load.  
10. If the gas pressure is out of range, contact the gas utility,  
gas supplier, qualified installer or service agency to  
determine the necessary steps to provide proper gas  
pressure to the control.  
If you experience a pressure drop greater than 1 inch w.c.  
(249 Pa), the meter, regulator, or gas line is undersized or in  
need of service. Perform the steps below when checking inlet  
gas supply:  
11. Turn the power switch to the “OFF” position.  
12. Shut off the gas supply at the manual gas valve in the gas  
piping to the appliance.  
1. Turn the main power switch to the “OFF” position.  
13. Remove the manometer from the pressure tap on top of  
the gas valve. On Models 399 - 500 re-tighten the set  
screw inside the pressure tap. On Models 600 - 800  
remove the 1/8" (3 mm) field supplied fitting and  
reinstall the pipe plug removed in Step 3.  
2. Shut off gas supply at the manual gas valve in the gas  
piping to the appliance.  
3. On Models 399 - 500 loosen the set screw one (1) full turn  
from inside the pressure tap on top of the gas valve. On  
Models 600 - 800 remove the 1/8" (3 mm) pipe plug on the  
inlet flange to the valve and install a suitable 1/8" (3 mm)  
fitting (field supplied) for the manometer tubing. Place  
the tubing of the manometer over the tap once the set  
screw is loosened or the 1/8" (3 mm) fitting is installed  
(depending on model) as shown in FIG.’s 7-5 thru 7-7 on  
page 44.  
43  
Installation & Operation Manual  
7 Gas connections  
When re-tightening the set screw, be sure  
Figure 7-7 Inlet Gas Supply Check - Models 600 - 800  
ƽ WARNING  
to tighten securely to prevent gas leaks.  
REMOVE THE 1/8” (3 MM) PIPE PLUG ON  
THE INLET FLANGE TO THE VALVE AND  
INSTALL A SUITABLE 1/8” (3 MM) FITTING  
(FIELD SUPPLIED) FOR THE MANOMETER  
TUBING.  
Do not check for gas leaks with an open  
flame -- use the bubble test. Failure to use  
the bubble test or check for gas leaks can  
cause severe personal injury, death, or  
substantial property damage.  
14. Turn on the gas supply at the manual gas valve.  
15. Turn the power switch to the “ON” position.  
16. Adjust the temperature set point on the control panel of  
the SMART SYSTEM control module to the desired  
water temperature so the appliance will call for heat.  
17. Check burner performance by cycling the system while  
you observe burner response. The burner should ignite  
promptly. Flame pattern should be stable. Turn system  
off and allow burner to cool, then cycle burner again to  
ensure proper ignition and flame characteristics.  
DETAIL  
Gas Pressure  
Figure 7-5 Inlet Gas Supply Check - Model 399  
The gas pressure must remain between 4 inches w.c.  
(.99 kPa) minimum and 14 inches w.c. (3.5 kPa) maximum  
for Natural gas and between 8 inches w.c. (1.9 kPa)  
minimum and 14 inches w.c. (3.2 kPa) maximum for LP gas  
during standby (static) mode and while in operating  
(dynamic) mode. If an in-line regulator is used, it must be a  
minimum of 10 feet (3 m) from the Knight XL boiler. It is  
very important that the gas line is properly purged by the gas  
supplier or utility company. Failure to properly purge the  
lines or improper line sizing, will result in ignition failure.  
LOOSEN THE SET SCREW ONE (1) FULL TURN  
AND PLACE THE MANOMETER TUBING OVER  
THE PRESSURE TAP.  
The problem is especially noticeable in NEW LP installations  
and also in empty tank situations. This can also occur when  
a utility company shuts off service to an area to provide  
maintenance to their lines.  
Figure 7-6 Inlet Gas Supply Check - Model 500  
Gas valve replacement  
LOOSEN THE SET SCREW ONE (1) FULL TURN  
AND PLACE THE MANOMETER TUBING OVER  
THE PRESSURE TAP.  
The gas valve MUST NOT be replaced with a conventional  
gas valve under any circumstances. As an additional safety  
feature, this gas valve has a flanged connection to the venturi  
and blower.  
Failure to follow all precautions could  
result in fire, explosion, or death!  
ƽ WARNING  
DO NOT adjust or attempt to measure  
ƽ WARNING  
gas valve outlet pressure. Attempting to  
alter or measure the gas valve outlet  
pressure could result in damage to the  
valve, causing potential severe personal  
injury, death, or substantial property  
damage.  
DETAIL  
44  
Installation & Operation Manual  
8 Field wiring  
ELECTRICAL SHOCK HAZARD – For  
Installation must comply with:  
1. National Electrical Code and any other national, state,  
provincial, or local codes, or regulations.  
ƽ WARNING  
your safety, turn off electrical power  
supply before making any electrical  
connections to avoid possible electric  
shock hazard. Failure to do so can cause  
severe personal injury or death.  
2. In Canada, CSA C22.1 Canadian Electrical Code Part 1, and  
any local codes.  
Wiring must be N.E.C. Class 1.  
NOTICE  
Line voltage connections  
1. Connect 120 VAC power wiring to the line voltage terminal  
strip in the junction box, as shown in FIG. 8-1.  
If original wiring as supplied with boiler  
must be replaced, use only type 105°C  
wire or equivalent.  
2. Provide and install a fused disconnect or service switch  
(15 amp recommended) as required by the code (see  
FIG. 8-1).  
Boiler must be electrically grounded as  
required by National Electrical Code  
ANSI/NFPA 70 – latest edition.  
3. When connecting a domestic hot water (DHW) pump,  
connect the wiring to the line voltage terminal strip as  
shown in FIG. 8-1.  
Label all wires prior to disconnection  
when servicing controls. Wiring errors  
can cause improper and dangerous  
operation.  
ƽ CAUTION  
4. To activate a system pump, wire as shown in FIG. 8-1. Dry  
contacts are sized for 1.5 hp/120V, 3 hp/240V or 30 amps.  
Figure 8-1 Line Voltage Field Wiring Connections  
120V SUPPLY  
NEUTRAL  
W
GROUND  
G
LINE  
BK  
SERVICE  
SWITCH  
BK  
G
SYSTEM  
PUMP  
W
BK  
BOILER  
PUMP  
G
W
BK  
DOMESTIC  
HOT WATER  
PUMP  
G
W
L2/N  
G
L1  
45  
Installation & Operation Manual  
8 Field wiring  
Low voltage connections  
DHW tank sensor  
By installing a tank sensor, the SMART SYSTEM control can  
perform the tank thermostat function. The SMART SYSTEM  
control automatically detects the presence of this sensor, and  
generates a DHW call for heat when the tank temperature  
drops 6°F (3°C) below the tank set point, and finishes the call  
for heat when the tank temperature reaches the tank set point.  
1. Route all low voltage wires through the knockouts in the  
rear of the boiler, as shown in FIG. 8-2.  
2. Connect low voltage wiring to the low voltage connection  
board as shown in FIG. 8-3 on page 48 of this manual and  
the boiler wiring diagram.  
Figure 8-2 Routing Field Wiring  
The tank sensor included with the Lochinvar Squire® indirect  
DHW tanks (TST2032) is the only sensor suitable for use with  
the SMART SYSTEM control. Connect the sensor leads to the  
DHW Tank Sensor (AUX) terminals on the low voltage  
connection board (FIG. 8-3). Consult the tank manufacturer  
for application and performance when used with any other  
indirect tank.  
LOW VOLTAGE  
CONNECTION BOARD  
LINE VOLTAGE  
JUNCTION BOX  
Failure to use the correct sensor may result  
ƽ WARNING  
in the tank temperature being either above  
LOW VOLTAGE  
WIRING KNOCKOUTS  
or below the set point. Failure to consult the  
manufacturer of the indirect tank, when the  
Squire is not used, may result in decreased  
performance or the risk of scald injury.  
LINE VOLTAGE  
WIRING KNOCKOUTS  
If TST2032 is not compatible with the indirect tank, a tank  
thermostat can be used to control the boiler. The tank  
thermostat should be installed per the manufacturer’s  
instructions and wired to the DHW Thermostat terminals on  
the low voltage connection board (FIG. 8-3).  
Thermostat  
1. Connect the room thermostat or end switch (isolated  
contact only) to terminals R and W, as shown in FIG. 8-3.  
2. Install the thermostat on the inside wall away from  
influences of drafts, hot or cold water pipes, lighting  
fixtures, television, sunlight, or fireplaces.  
Auxiliary device proving switch  
1. When the operation of an auxiliary device needs to be  
verified before the boiler fires, remove the jumper wire  
from these terminals and connect them to the normally  
open contacts on its proving switch (FIG. 8-3).  
3. Thermostat anticipator (if applicable):  
a. If connected directly to boiler, set for 0.1 amps.  
b. If connected to relays or other devices, set to match  
total electrical power requirements of connected High gas pressure switch  
devices. See device manufacturers’ specifications  
and thermostat instructions for details.  
1. If a switch is provided to detect excessive gas pressure,  
remove the jumper wire from the terminals on the  
connection board, and then connect them to its normally  
closed contacts (FIG. 8-3).  
Outdoor temperature sensor  
1. Connect the outdoor temperature sensor (FIG. 8-3) to the  
Outdoor Sensor terminals on the connection board to  
enable outdoor reset operation of the Knight XL. Do not  
install the outdoor sensor.  
Low gas pressure switch  
1. If a switch is provided to detect low gas pressure, remove  
the jumper wire from the terminals on the connection  
board and connect them to its normally open contacts  
(FIG. 8-3).  
2. Mount the sensor on an exterior wall, shielded from direct  
sunlight or flow of heat or cooling from other sources.  
2. If both a high and low gas pressure switch is used, connect  
their respective contacts in series, and connect them to the  
terminals on the connection board (FIG. 8-3).  
3. Route sensor wires through a knockout at the rear of the  
boiler (see FIG. 8-2).  
Flow switch  
1. A flow switch is used to guarantee flow through the boiler  
before allowing it to fire. The flow switch must be installed  
in line with the boiler.  
DHW  
(Domestic  
Hot  
Water)  
thermostat  
1. Connect the DHW tank thermostat to the Tank  
Thermostat terminals on the connection board (FIG. 8-3).  
2. Remove the jumper wire from the terminals on the  
connection board and connect these terminals to the  
normally open contacts on the flow switch (FIG. 8-3).  
46  
Installation & Operation Manual  
8 Field wiring  
(continued)  
System supply sensor  
Wiring of the cascade  
1. By installing the system supply sensor into the supply of the When wiring the boilers for Cascade operation, select one  
primary loop, the temperature of the system supply can be boiler as the Leader boiler. The remaining boilers will be  
controlled. The SMART SYSTEM control automatically designated as Members. See page 55 “Configuration of the  
detects the presence of this sensor, and controls the boiler Cascade” for a detailed explanation of this procedure.  
firing rate to maintain the system supply temperature to the  
Connect the system supply sensor and outdoor air sensor (if  
set point (if the outlet sensor control is currently selected).  
used) to the Leader boiler. For the Cascade system to work  
See the Knight XL Service Manual for instructions on how  
properly the system supply sensor must be installed. The  
to use the inlet sensor as the controlling sensor. When the  
location of the system supply sensor should be downstream of  
inlet sensor is programmed as the controlling sensor, it is  
the boiler connections in the main system loop (FIG.’s 6-7 and  
vital that the SYSTEM SUPPLY sensor be installed. DO  
6-8). The system supply sensor should be wired to the Low  
NOT INSTALL THE SYSTEM SUPPLY SENSOR INTO  
Voltage Connection Board at the terminals marked for the  
THE SYSTEM RETURN.  
system supply sensor (see FIG. 8-3). The Leader control will  
2. Connect these terminals to the system supply sensor  
(FIG. 8-3).  
use the water temperature at the system supply sensor to  
control the operation of the Cascade.  
If outdoor air reset is desired, the outdoor air sensor should be  
wired to the Low Voltage Connection Board at the terminals  
marked for the outdoor air sensor (FIG. 8-3). If the outdoor  
air sensor is connected, the Leader control will calculate the  
water temperature set point based on the programmed reset  
curve parameters. If the outdoor air sensor is not connected,  
the Leader control will maintain the fixed water temperature  
set point that is programmed into the control.  
Boiler management system  
1. An external control may be connected to control either the  
firing rate or the set point of the boiler. Connect the Room  
Thermostat / Zone Control terminals to the enable output  
of the external control and connect the 0 - 10 VDC  
terminals to the 0 - 10 VDC output of the external control.  
2. Make sure the ground terminal is connected to the ground  
output terminal of the external control, and the 0 - 10 VDC  
terminal is connected to the 0 - 10 VDC terminal of the  
external control.  
If a Thermostat or Zone Control enable output is available, it  
should be wired to the Low Voltage Connection Board on the  
Leader boiler at the terminals marked for the Room  
Thermostat/Zone Control (FIG. 8-3). If the boilers are to run  
continuously, connect a jumper wire between the R and W  
terminals for the Thermostat/Zone Control input. This will  
initiate a call for heat on the Cascade.  
Runtime contacts  
The SMART SYSTEM control closes a set of dry contacts  
whenever the burner is running. This is typically used by  
Building Management Systems to verify that the boiler is  
responding to a call for heat.  
Communication between the Leader boiler and the Member  
boilers is accomplished by using shielded, 2-wire twisted pair  
communication cable. Connect one of the twisted pair wires  
to terminal A on each of the Low Voltage Connection boards,  
and the other wire of the twisted pair to terminal B on each of  
the Low Voltage Connection Boards. Connect the shield wires  
to one of the shield ground terminals on the Low Voltage  
Connection Boards (FIG. 8-3). If more than two boilers are  
on the Cascade, daisy chain the wiring from the Sequencing  
terminals on the second boiler to the Sequencing terminals on  
the third boiler, then from the third to the forth, and so on.  
The connections between boilers can be made in any order,  
regardless of the addresses of the boilers. Try to keep each  
cable as short as possible.  
Alarm contacts  
The SMART SYSTEM control closes another set of contacts  
whenever the boiler is locked out or the power is turned off.  
This can be used to turn on an alarm, or signal a Building  
Management System that the boiler is down. Note that these  
contacts will close momentarily at the end of each call for heat  
or at least every 24 hours.  
47  
Installation & Operation Manual  
8 Field wiring  
Figure 8-3 Low Voltage Field Wiring Connections  
F F O C U T  
R
T A E W W L O  
48  
Installation & Operation Manual  
9 Condensate disposal  
Use materials approved by the authority  
having jurisdiction. In the absence of other  
authority, PVC and CPVC pipe must comply  
with ASTM D1785 or D2845. Cement and  
primer must comply with ASME D2564 or  
F493. For Canada use CSA or ULC certified  
PVC or CPVC pipe, fittings, and cement.  
Condensate drain  
NOTICE  
NOTICE  
1. This boiler is a high efficiency appliance that produces  
condensate.  
2. The side of the boiler has a 1/2 inch (12.7 mm) PVC  
union for connection of a 1/2 inch (12.7 mm) PVC pipe  
(FIG. 9-1).  
To allow for proper drainage on large  
horizontal runs, a second line vent may be  
required and tubing size may need to increase  
to 1 inch (25 mm).  
3. Slope condensate tubing down and away from the boiler  
into a drain or condensate neutralizing filter. Condensate  
from the Knight XL will be slightly acidic (typically with  
a pH from 3 to 5). Install a neutralizing filter if required  
by local codes.  
The condensate line must remain  
unobstructed, allowing free flow of  
condensate. If condensate is allowed to  
freeze in the line or if the line is obstructed in  
any other manner, condensate can exit from  
the boiler tee, resulting in potential water  
damage to property.  
A Neutralizer Kit (FIG. 9-1) is available from the factory  
(KIT3087 for Models 399 - 500 and KIT3046 for Models  
600 - 800).  
4. Install the 1/2 inch (12.7 mm) PVC tee assembly (shipped  
with the unit) as shown in FIG. 9-1.  
8. A condensate removal pump is required if boiler is below  
drain. When installing a condensate pump, select one  
approved for use with condensing boilers and furnaces. The  
pump should have an overflow switch to prevent property  
damage from condensate spillage. The switch should be  
wired to the auxiliary device proving switch terminals on  
the low voltage connection board.  
5. Leave the top of the 1/2 inch (12.7 mm) tee OPEN. This  
is needed as a vacuum break.  
6. Do not expose condensate line to freezing temperatures.  
7. Use only plastic tubing or piping as a condensate drain  
line (FIG. 9-1).  
Figure 9-1 Condensate Disposal  
1/2" (12.7 mm) PVC TEE ASSEMBLY  
(FACTORY SUPPLIED)  
1/2" (12.7 mm) PVC UNION  
(FACTORY SUPPLIED)  
NEUTRALIZER KIT  
FLOOR DRAIN OR  
DRAIN PAN  
KIT3087 shown for illustration purposes.  
49  
Installation & Operation Manual  
10 Start-up  
4. At initial fill and during boiler startup and testing, check  
system thoroughly for any leaks. Repair all leaks before  
proceeding further.  
Check/control water chemistry  
Do not use petroleum-based cleaning or  
ƽ CAUTION  
sealing compounds in the boiler system.  
Damage to elastomer seals and gaskets in  
the system could occur, resulting in  
substantial property damage.  
Eliminate all system leaks. Continual fresh  
ƽ WARNING  
makeup water will reduce boiler life.  
Minerals can build up in the heat  
exchanger, reducing heat transfer,  
overheating the heat exchanger, and  
causing heat exchanger failure.  
Hardness less than 7 grains  
1. Consult local water treatment companies for hard water  
areas (above 7 grains hardness).  
Purge air from water system  
Chlorine concentration less than 200 ppm  
1. Purge air from system:  
1. Do not fill boiler or operate with water containing  
chlorine in excess of 200 ppm.  
a. Connect a hose to the purge valve (see purge/drain  
valves, in piping diagrams on page 41). Route the  
hose to an area where water can drain and be seen.  
b. Close the boiler or system isolation valve between  
the purge valve and fill connection to the system.  
c. Close zone isolation valves.  
2. Filling with chlorinated fresh water should be acceptable  
since drinking water chlorine levels are much lower.  
3. Do not use the boiler to directly heat swimming pool or  
spa water.  
d. Open quick-fill valve on cold water makeup line.  
e. Open purge valve.  
Test/replace freeze protection fluid  
f. One zone at a time, open the isolation valves. Allow  
water to run through the zone, pushing out the air.  
Run until no noticeable air flow is present. Close the  
zone isolation valves and proceed with the next zone.  
Follow this procedure until all zones are purged.  
g. Close the quick-fill water valve and purge valve and  
remove the hose. Open all isolation valves. Watch  
that system pressure rises to correct cold-fill  
pressure.  
h. After the system has operated for a while, eliminate  
any residual air by using the manual air vents located  
throughout the system.  
i. If purge valves are not installed in the system, open  
the manual air vents in the system one at a time,  
beginning with the lowest floor. Close the vent when  
water squirts out. Repeat with remaining vents.  
1. For systems using freeze protection fluids, follow fluid  
manufacturer’s instructions.  
2. Freeze protection fluid must be replaced periodically due  
to degradation of inhibitors over time. Follow all fluid  
manufacturer’s instructions.  
Freeze protection (when used)  
1. Determine freeze protection fluid quantity using system  
water content, following fluid manufacturer’s  
instructions. Boiler water content is listed on page 7.  
Remember to include expansion tank water content.  
2. Local codes may require a backflow preventer or actual  
disconnect from city water supply.  
3. When using freeze protection fluid with automatic fill,  
install a water meter to monitor water makeup. Freeze  
protection fluid may leak before the water begins to leak,  
causing concentration to drop, reducing the freeze  
protection level.  
2. Open automatic air vent (diaphragm-type or bladder-  
type expansion tank systems only) one turn.  
3. Open other vents:  
a. Starting on the lowest floor, open air vents one at a  
time until water squirts out.  
b. Repeat with remaining vents.  
Fill and test water system  
1. Fill system only after ensuring the water meets the  
requirements of this manual.  
4. Refill to correct pressure.  
2. Close manual and automatic air vents and boiler drain  
valve.  
3. Fill to correct system pressure. Correct pressure will vary  
with each application.  
a. The minimum cold water fill pressure for a  
commercial system is 12 psi (82.7 kPa).  
b. Pressure will rise when boiler is turned on and  
system water temperature increases.  
50  
Installation & Operation Manual  
10 Start-up  
(continued)  
Propane boilers only – Your propane  
supplier mixes an odorant with the  
propane to make its presence detectable.  
In some instances, the odorant can fade,  
and the gas may no longer have an odor.  
Before startup (and periodically  
thereafter), have the propane supplier  
verify the correct odorant level in the gas.  
Check for gas leaks  
ƽ WARNING  
Before starting the boiler, and during  
initial operation, smell near the floor and  
around the boiler for gas odorant or any  
unusual odor. Remove the top access  
panel and smell the interior of the boiler  
enclosure. Do not proceed with startup if  
there is any indication of a gas leak. Use an  
approved leak detection solution. Repair  
any leaks at once.  
ƽ WARNING  
Check thermostat circuit(s)  
1. Disconnect the two external wires connected to the room  
thermostat terminals on the connection board.  
DO NOT adjust or attempt to measure gas  
valve outlet pressure. The gas valve is  
factory set for the correct outlet pressure.  
This setting is suitable for natural gas and  
propane, requiring no field adjustment.  
Attempting to alter or measure the gas  
valve outlet pressure could result in  
damage to the valve, causing potential  
severe personal injury, death, or  
substantial property damage.  
ƽ WARNING  
2. Connect a voltmeter across these two incoming wires.  
Close each thermostat, zone valve, and relay in the  
external circuit one at a time and check the voltmeter  
reading across the incoming wires.  
3. There should NEVER be a voltage reading.  
4. If a voltage does occur under any condition, check and  
correct the external wiring. (This is a common problem  
when using 3-wire zone valves.)  
5. Once the external thermostat circuit wiring is checked  
and corrected if necessary, reconnect the external  
thermostat circuit wires to the connection board. Allow  
the boiler to cycle.  
Figure 10-1 Condensate Trap  
RETAINING  
SCREW  
2” PVC CAP WITH  
BLOCKED DRAIN SWITCH  
Inspect/fill condensate system  
Inspect/check condensate lines and fittings  
PVC TEE ASSEMBLY  
(FACTORY SUPPLIED)  
1. Inspect the condensate drain line, condensate PVC  
fittings and condensate trap.  
Fill condensate trap with water  
1. Remove the PVC cap retaining screw from the PVC cap  
(FIG. 10-1).  
2. Remove the 2 inch PVC cap with the switch located at the  
top of the trap (FIG. 10-1).  
CONDENSATE FROM  
HEAT EXCHANGER  
TO FLOOR  
DRAIN  
3. Fill with fresh water until the water begins to pour out of  
the drain.  
4. Replace the cap. Press the cap onto the trap until the cap  
makes contact with the drain.  
5. Replace the retaining screw.  
The condensate trap (FIG. 10-1) must be  
ƽ WARNING  
filled with water during all times of boiler  
operation to avoid flue gas emission from  
the condensate drain line. Failure to fill  
the trap could result in severe personal  
injury or death.  
51  
Installation & Operation Manual  
10 Start-up  
Final checks before starting the boiler  
Check vent piping and air piping  
1. Check for gastight seal at every connection, seam of air  
piping, and vent piping.  
Read the Knight XL Service Manual to familiarize  
yourself with SMART SYSTEM control module  
operation. Read this manual, page 53 for proper steps to  
start boiler.  
Venting system must be sealed gastight to  
ƽ WARNING  
prevent flue gas spillage and carbon  
monoxide emissions, which will result in  
severe personal injury or death.  
Verify the boiler and system are full of water and all  
system components are correctly set for operation.  
Check gas piping  
Verify the preparation procedures of Section 10, pages 50  
1. Check around the boiler for gas odor following the  
procedure on page 41 of this manual (connecting gas  
supply piping).  
and 51 have been completed.  
Fill the vent condensate trap with water (removing the  
retaining screw in order to remove the 2 inch PVC cap  
with the switch located at the top of the trap). Replace  
the cap. Press the cap onto the trap until the cap makes  
contact with the drain. Replace the retaining screw.  
If you discover evidence of any gas leak,  
ƽ WARNING  
shut down the boiler at once. Find the  
leak source with a bubble test and repair  
immediately. Do not start the boiler again  
until corrected. Failure to comply could  
result in severe personal injury, death, or  
substantial property damage.  
Verify electrical connections are correct and securely  
attached.  
Propane boilers – verify conversion  
Inspect vent piping and air piping for signs of  
deterioration from corrosion, physical damage or  
sagging. Verify air piping and vent piping are intact and  
correctly installed per this manual.  
1. Verify propane conversion has been completed per the  
Propane Conversion instructions.  
DO NOT adjust or attempt to measure  
ƽ WARNING  
gas valve outlet pressure. The gas valve is  
Start the boiler  
factory-set for the correct outlet pressure.  
This setting is suitable for natural gas and  
propane, requiring no field adjustment.  
Attempting to alter or measure the gas  
valve outlet pressure could result in  
damage to the valve, causing potential  
severe personal injury, death, or  
substantial property damage.  
1. Read and follow the Operating instructions in FIG. 10-2,  
page 53.  
If boiler does not start correctly  
1. Check for loose connections, blown fuse or service switch  
off?  
2. Is external limit control (if used) open? Is boiler water  
temperature above 200°F (93°C)?  
Knight XL boilers are typically shipped  
ƽ WARNING  
ready to fire on natural gas. Check boiler  
rating plate to determine which fuel the  
boiler is set for. If set to natural gas, it may  
be converted to LP by installing an orifice  
or by making a gas valve adjustment (see  
pages 13 and 14). In order to operate on  
LP gas, an orifice MUST BE installed or a  
gas valve adjustment MUST BE made.  
Failure to comply could result in severe  
personal injury, death, or substantial  
property damage.  
3. Is thermostat set below room temperature?  
4. Is gas turned on at meter or boiler?  
5. Is incoming gas pressure less than 4 inches w.c. (.99 kPa)?  
If none of the above corrects the problem, refer to the  
Troubleshooting Section of the Knight XL Service Manual.  
Check system and boiler  
Check water piping  
Check flame and combustion  
1. Check system piping for leaks. If found, shut down the  
boiler and repair immediately. (See WARNINGS on  
pages 50 and 51 (startup) regarding failure to repair  
leaks.)  
1. Turn the main power off to the boiler by placing the  
“On/Offswitch in the OFF position.  
2. Remove the flue temperature sensor from the flue pipe  
connection. NOTE: Combustion measurements will be  
made at this point.  
2. Vent any remaining air from the system using manual  
vents. Air in the system will interfere with circulation and  
cause heat distribution problems and noise.  
3. Turn the main power on to the boiler by placing the  
“On/Offswitch in the ON position.  
52  
Installation & Operation Manual  
10 Start-up  
(continued)  
Figure 10-2 Operating Instructions  
FOR YOUR SAFETY READ BEFORE OPERATING  
WARNING: If you do not follow these instructions exactly, a fire or explosion  
may result causing property damage, personal injury, or loss of life.  
• Immediately call your gas supplier from a  
A. This appliance does not have a pilot. It is  
neighbor’s phone. Follow the gas supplier’s  
equipped with an ignition device which  
instructions.  
• If you cannot reach your gas supplier, call  
the fire department.  
automatically lights the burner. Do not try  
to light the burner by hand.  
B. BEFORE OPERATING smell all around  
the appliance area for gas. Be sure to  
smell next to the floor because some gas  
is heavier than air and will settle on the  
floor.  
C. Use only your hand to turn the gas control knob.  
Never use tools. If the handle will not turn by  
hand, don’t try to repair it, call a qualified service  
technician. Force or attempted repair may result  
in a fire or explosion.  
WHAT TO DO IF YOU SMELL GAS  
D. Do not use this appliance if any part has been  
under water. Immediately call a qualified  
• Do not try to light any appliance.  
service technician to inspect the appliance and  
to replace any part of the control system and  
any gas control which has been under water.  
• Do not touch any electric switch; do  
not use any phone in your building.  
OPERATING INSTRUCTIONS  
1. STOP! Read the safety information  
above on this label.  
2. Set the thermostat to lowest setting.  
8. Turn gas shutoff valve clockwise to “ON”.  
Handle will be parallel to pipe.  
9. Install top cover.  
10. Turn on all electric power to appliance.  
11. Set thermostat to desired setting.  
3. Turn off all electric power to the  
appliance.  
4. This appliance is equipped with an  
ignition device which automatically lights  
the burner. Do not try to light the burner  
by hand.  
12. If the appliance will not operate, follow the  
instructions “To Turn Off Gas To Appliance” and  
call your service technician or gas supplier.  
5. Remove top cover.  
6. Turn gas shutoff valve counterclockwise  
to “OFF”. Handle will be perpendicular to  
pipe. Do not force.  
7. Wait five (5) minutes to clear out any gas.  
If you then smell gas, STOP! Follow “B”  
in the safety information above on this label.  
If you don’t smell gas, go to next step.  
TO TURN OFF GAS TO APPLIANCE  
1. Set the thermostat to lowest setting.  
2. Turn off all electric power to the appliance  
if service is to be performed.  
4. Turn gas shut off valve counterclockwise to  
“OFF”. Handle will be perpendicular to pipe.  
Do not force.  
5. Install top cover.  
3. Remove top cover.  
LBL2284 REV -  
53  
Installation & Operation Manual  
10 Start-up  
Check flame and combustion (continued)  
Set space heating operation  
4. Place the boiler into the active position by pressing the  
SHUTDOWN button on the display board (FIG. 11-1,  
Determine controlling sensor  
For space heating systems, the temperature control can be  
based on one of three sensors; the inlet, outlet, or system  
supply sensor. The SMART SYSTEM control is programmed  
at the factory to control the temperature of the outlet sensor.  
The control will automatically switch to the system supply  
sensor once it is connected. If it is desired to base the  
temperature control on the inlet sensor, the appropriate  
parameter must be changed in the control. See the Knight XL  
Service Manual for a detailed explanation of this procedure.  
page 61) until  
window.  
B
L
R
:
S
t
a
n
d
b
y
a
p
p
e
a
r
s
i
n
t
h
e
d
i
s
p
l
a
y
5. Locate the pinhole button above the “T” in the Knight  
XL logo on the display board (FIG. 11-1). Insert a thin  
wire (such as a paper clip) into the hole and press the  
button once and hold for 5 seconds to place the boiler  
into Service Mode. In Service Mode the boiler will fire  
at ignition speed and will then modulate up to full fire.  
6. Insert the probe from a combustion analyzer into the  
hole left by the removal of the flue temperature sensor.  
Verify space heat circulator mode  
The Space Heating Mode controls both the system (primary)  
pump (if connected), and the boiler (secondary) pump.  
When the SMART SYSTEM control receives a space heating  
call for heat, it turns on the system pump. If the boiler is not  
heating an indirect DHW (Domestic Hot Water) tank, it also  
turns on the boiler pump. After the space heating call for heat  
ends, the system pump continues to run for a short period of  
time. If the boiler pump was running, it continues to run for  
a short period of time as well. These pump delays are factory  
set to 30 seconds. If different delays are desired, the  
appropriate parameters in the control must be changed. See  
the Knight XL Service Manual for a detailed explanation of  
this procedure.  
7. Once the boiler has modulated up to full fire, measure  
the combustion. The values should be in the range  
listed in Table 10A below. The CO levels should be less  
than 150 ppm for a properly installed unit.  
If the combustion is not within the specified range,  
reference the Troubleshooting Section of the Knight XL  
Service Manual for possible causes and corrective  
actions.  
Table 10A Flue Products Chart  
Set space heating set point temperature  
Natural Gas  
CO2 O2  
Propane  
The UP and DOWN keys may be used during normal  
operation to adjust the space heating set point temperature.  
Once the desired temperature is displayed, press the  
ENTER/RESET key to save the new setting. If the  
ENTER/RESET key is not pressed, the new setting will be  
used for the current heating cycle only. The old setting will  
become active after the current heating cycle ends.  
CO2  
O2  
8.0% - 10% 3.0% - 6.5% 9.0% - 11% 4.1% - 6.9%  
8. Once the combustion analysis is complete, test the  
safety shutoff device by turning the manual shutoff  
valve to the OFF position and ensuring that the boiler  
shuts down and registers an alarm. Open the manual  
shutoff valve, reset the control, and return to Service  
Mode.  
9. Turn the main power off to the boiler and replace the  
flue temperature sensor into the flue pipe connection.  
10. Place the boiler back into normal operation.  
You must replace the flue gas  
ƽ WARNING  
temperature sensor to prevent flue gas  
spillage into the room. Failure to  
comply could result in severe personal  
injury, death, or substantial property  
damage.  
54  
Installation & Operation Manual  
10 Start-up  
(continued)  
9. The date and time are displayed as “YY:MM:DD W  
hh:mm, where:  
Set domestic hot water (DHW) operation  
Verify DHW circulator mode  
mm:  
hh:  
minutes  
hour (24 hour time; e.g., 2:00 PM = 14:00)  
The DHW Mode is programmed to heat an indirect domestic  
hot water tank. When the tank thermostat calls for heat, the  
SMART SYSTEM control will turn on the DHW pump and  
turn off the boiler pump (if running). If the system pump is  
running, it will remain on. When the DHW call for heat ends,  
and there is no space heating call for heat, the DHW pump  
will continue to run for a period of time. This pump delay is  
set at the factory to 30 seconds. If a shorter or longer delay is  
desired, the appropriate parameter in the control must be  
changed. See the Knight XL Service Manual for a detailed  
explanation of this procedure. If there is an active space  
heating call for heat, then the boiler pump will be turned on  
and the DHW pump will be turned off.  
W:  
day of the week (1 = Monday, 2 = Tuesday,  
3 = Wednesday, etc.,)  
date  
month  
year  
DD:  
MM:  
YY:  
The internal clock does not adjust for  
Daylight Savings Time and therefore, will  
require a manual adjustment.  
NOTICE  
Use the UP and DOWN keys to increment or decrement the  
flashing number, and the NEXT and PREVIOUS keys to select  
which number flashes.  
Set DHW target temperature  
10. Press the ENTER key to save the setting.  
When in the DHW Mode, the control will modulate to  
maintain the outlet temperature to a set point. This set point  
is set at the factory to 180°F. If a different set point is desired,  
the appropriate parameter in the control must be changed.  
See the Knight XL Service Manual for a detailed explanation  
of this procedure.  
11. Press the MENU key twice to exit the Programming  
Mode.  
Configuration of the cascade  
When installed in a Cascade system, the individual controls  
must be programmed for cascade operation. This is  
accomplished by accessing the control parameters.  
Set clock  
The SMART SYSTEM control has a built-in clock that it uses  
for its night setback feature and for logging events. This clock  
must be set when the boiler is installed, and anytime the boiler  
has been powered off for more than one month. Use the  
following procedure to set the clock:  
Input the Installer code as described in the Knight XL Service  
Manual. Once the control parameters have been accessed, use  
the DOWN arrow key to select the H Control Mode parameters.  
Press the ENTER key to access these parameters. Use the UP  
arrow key to access parameter H2 SH Source. Press the ENTER  
key to access this parameter. Use the DOWN arrow key to select  
Cascade. Press the ENTER key to program this into the control.  
1. Press and hold the MENU key for at least 5 seconds.  
2. The display changes to ready “ENTER MENU CODE,  
with four (4) zeros below it.  
Press the UP arrow key to select the parameter H3 BLR Address.  
Press the ENTER key to access this parameter. Each unit in the  
Cascade system must be programmed with its own address. The  
boiler designated as the Leader will have an address of 0. The  
remaining boilers in the Cascade will be Members and have  
addresses from 1 - 7. Use the UP and DOWN arrow keys to  
select the appropriate address. Press the ENTER key to program  
this into the control.  
3. Change the zeros to match the user code (factory set at  
“0704”). Use the UP and DOWN keys to  
increment or decrement the flashing digit, and the NEXT  
and PREVIOUS keys to select which digit flashes.  
4. Press the ENTER key.  
Press the MENU key twice to exit the control parameters. Repeat  
this procedure for all boilers in the Cascade, designating the  
Leader control and the Member controls.  
5. The display changes to read USER CODE for a few  
seconds, then displays a menu.  
6. Press the ENTER key.  
7. Press the UP key twice to display A3 DATE AND  
TIME.  
8. Press the ENTER key once.  
55  
Installation & Operation Manual  
11 Operating information  
General  
DHW / space heating (SH) cycling  
If a DHW call for heat is received while a space heating call is in  
progress, the control will start the DHW pump and shut the  
boiler pump off. The system pump will remain on. If the space  
heating call is still active while the DHW call is in operation, the  
control will wait for 30 minutes (time adjustable by installer)  
then it will switch back to the space heating demand. The  
control will switch back and forth until one of the heat demands  
end. This function does not apply to cascade systems.  
How the boiler operates  
The Knight XL uses an advanced stainless steel heat exchanger  
and electronic control module that allows fully condensing  
operation. The blower pulls in air and pushes flue products  
out of the boiler through the heat exchanger and flue piping.  
The control module regulates blower speed to control the  
boiler firing rate. The gas valve senses the amount of air  
flowing into the boiler and allows only the right amount of  
gas to flow.  
Programmable controlling sensor  
The control module is programmed to use the outlet sensor as  
the control sensor by default. If a system supply sensor is  
connected, the control automatically uses it as the control  
sensor. The control sensor can be changed by the installer to the  
inlet sensor. If the inlet sensor is chosen as the controlling  
sensor, it is recommended that the system supply sensor be  
installed.  
How the control module operates  
The SMART SYSTEM control module receives input from  
boiler sensors and external inputs. The control module  
activates and controls the blower and gas valve to regulate  
heat input and switches the boiler, Domestic Hot Water  
(DHW), and system pumps on and off as needed. The user  
programs the module to meet system needs by adjusting  
control parameters. These parameters set operating  
temperatures and boiler operating modes. Boiler operation  
can be based on boiler outlet water temperature, boiler inlet  
water temperature, or system temperature, depending on the  
parameter setting.  
Anti-cycling  
After a space heating demand has been satisfied, the control will  
delay the next space heating call for a set time period (time is  
adjustable by the installer). The time delay will be bypassed if  
the inlet water temperature drops too far during the delay.  
Control inputs and outputs  
Boiler, system, and DHW pump control  
When a space heating call for heat starts and no DHW call is on,  
the system and boiler pumps are turned on. As long as the space  
heating call for heat is on, the system pump will remain on. If a  
DHW call for heat is on, the boiler pump will wait to turn on  
until just before the DHW pump turns off. After the space  
heating call for heat ends, both pumps will run for an additional  
period of time.  
Room thermostat / zone control  
This input tells the boiler to provide water for space heating.  
Domestic Hot Water (DHW) tank thermostat  
This input tells the boiler to provide water for heating an  
indirect DHW tank.  
When a DHW call for heat starts, the DHW pump is turned on.  
If a space heating call for heat was on, the boiler pump will turn  
off a few seconds after the DHW pump turns on.  
0 - 10V input (set point or power)  
The Knight XL can be controlled by a Building Management  
System (BMS) using a 0 - 10 VDC signal. The control can be  
configured by the installer to use this signal to either control  
set point or firing rate.  
Temperature control  
Modulation  
DHW priority  
The Knight XL is capable of modulating its firing rate from a  
minimum of 20% to a maximum of 100%. The firing rate is  
dictated by the call for heat (i.e., space heating or domestic hot  
water), the heating load, ramp delay (if enabled), and various  
other temperature limitations.  
The SMART SYSTEM control module allows connection of a  
DHW thermostat to the low voltage connection board. When  
the DHW thermostat calls for heat, the module activates the  
DHW pump, shuts down the boiler pump, and immediately  
sets the target outlet water temperature to 180°F (82.2°C).  
This provides automatic priority heat allocation to the  
indirect water heater for maximum response and recovery.  
The DHW pump continues for 30 seconds after the heating  
cycle to deliver the most possible heat.  
56  
Installation & Operation Manual  
11 Operating information  
(continued)  
Ramp delay  
Protection features  
For systems with lower flow, the SMART SYSTEM can limit  
the firing rate (when enabled) when a space heating call for  
heat starts, or when switching from a DHW call for heat to  
a space heating call for heat. There are six (6) limits that  
can be programmed, as well as six (6) time intervals  
corresponding to each limit. The sixth limit will also limit  
the firing rate for the rest of the call for heat.  
Outlet temperature, flue temperature, and  
temperature rise limiting  
The outlet temperature is monitored by the boiler outlet  
temperature sensor. When the outlet temperature exceeds  
185°F, the unit will reduce the fan speed. If the outlet water  
temperature exceeds 195°F (90°C) the control will shut the unit  
down until it cools off.  
Gradient limiting  
The control module monitors the flue temperature by a sensor  
located in the flue exhaust. If the flue temperature exceeds  
215°F (102°C) the control will reduce the maximum fan speed.  
If the flue temperature exceeds 240°F (115°C) the control will  
shut the unit down. The unit will restart automatically once the  
flue temperature drops 25°F (-4°C) and the minimum off time  
has expired.  
If during operation of the boiler the outlet water  
temperature is rising too quickly, the control will reduce the  
firing rate to its lowest setting.  
Outdoor air reset  
If an outdoor air sensor is connected, the control module  
will calculate the set point based on the programmed reset  
curve. The installer can change the slope of the reset curve  
by several adjustable parameters. The user can limit the  
maximum set point for the system using the space heating  
set point.  
The control monitors the temperature difference between the  
inlet and the outlet sensor. If this difference exceeds 55°F  
(13°C) the control will reduce the fan speed. If the  
temperature difference exceeds 60°F (15°C) the control will  
shut the unit down. The unit will restart automatically once the  
temperature difference has dropped below 55°F (13°C) and the  
minimum off time has expired.  
Boost function  
If outdoor air reset is active, and a space heating demand  
has been active continuously for a set period of time (time  
adjustable by installer) and there has been no DHW  
demands, the control will increase the set point by a fixed  
number of degrees (adjustable by installer). This process  
will continue until the space heating demand ends, the set  
point reaches the programmed set point or a maximum of  
20 increases has occurred. Once the system heat demand is  
satisfied, the set point will revert to the value determined by  
the reset curve.  
Freeze protection  
DO NOT install the boiler in a room likely to freeze.  
The following integral feature of the SMART SYSTEM control  
module provides some protection for the boiler only -- not for  
the system.  
The SMART SYSTEM control module provides  
freeze-up protection as follows when the boiler  
water temperature drops below 45°F (7°C):  
Below 45°F (7°C), the boiler and system pumps  
operate constantly.  
Night setback  
The controller may be programmed to reduce the space  
heating set point during a certain time each day. A start  
and stop time can be programmed for each day of the week.  
Below 37°F (3°C), the boiler turns on.  
Boiler and pumps turn off if boiler water  
temperature rises above 45°F (7°C).  
Flame current support  
This feature of the SMART SYSTEM  
ƽ CAUTION  
control module does not eliminate the  
possibility of freezing. The installation  
must still use recognized design,  
installation and maintenance practice to  
prevent freeze potential for the boiler and  
system.  
To prevent nuisance shutdowns when the boiler is firing at  
minimum rates, the control will increase the firing rate  
when the flame signal drops too low.  
57  
Installation & Operation Manual  
11 Operating information  
Monitor external limits  
High limit operations  
Connections are provided on the connection board for  
external limits such as flow switch, low water cutoff, gas  
pressure switches, and an auxiliary device proving switch.  
The SMART SYSTEM will shut off the burner and inhibit  
relighting whenever any of these external limits open.  
When outlet temperature exceeds 200°F (93.3°C), high limit  
action occurs. The boiler shuts down until the outlet water  
cools down.  
Low water cutoff protection  
1. The SMART SYSTEM control module uses temperature  
sensing of both supply and return areas of the heat  
exchanger. If the flow rate is too low or the outlet  
temperature too high, the control module modulates and  
shuts the boiler down. This ensures boiler shutdown in the  
event of low water or low flow conditions.  
Run-time and alarm outputs  
The boiler provides dry contacts for indicating when the  
boiler is running, and when it is unable to operate.  
Run-time and cycle counting  
The control uses two timers to monitor the total hours of  
burner operation. One timer monitors the time the boiler  
is firing under 50% of rate. The other timer monitors the  
time the boiler is firing over 50% rate.  
2. Some codes and jurisdiction may accept these integral  
features of the control in lieu of requiring an additional  
limit control or low water cutoff. Consult local jurisdiction  
to determine. A low water cutoff is available from the  
factory (WTR20009).  
The control uses four (4) ignition counters to monitor the  
amount of boiler cycles. The first counter counts all  
ignitions of the control. The second counter counts only  
ignition attempts that have failed. The third and fourth  
counters are the same as the first and second respectively,  
but can be reset by the installer.  
Outdoor reset operation, if used  
Target temperature with outdoor reset  
This feature improves the system’s efficiency as the outdoor  
temperature warms up.  
Service reminder  
See the Knight XL Service Manual to change the settings.  
The control can be programmed for service reminder  
notification. This notification will become active when  
either a set time frame has expired, or a set amount of  
running hours or cycles has expired (all adjustable by the  
installer). The display will alternate the standard text on  
the display screen with Service Due every 5 seconds. The  
service reminder notification can be reset by the installer.  
Reset curve  
The reset curve looks at outdoor air temperature and adjusts the  
set point.  
Cascade  
When multiple boilers are installed, they can be wired together  
in a cascade sequence. A maximum of eight boilers can be  
controlled from a single control. In this application one boiler  
would be designated as the Leader control and all others would  
be designated as Member controls.  
Error logging  
The control will hold in memory the last 10 error codes as  
well as the last 10 turn-off functions. The date and time of  
the occurrence will be recorded as well. Only the 10 most  
current occurrences will be held in memory.  
Once the Leader boiler receives a call for heat from a room  
thermostat, the control will determine what the set point will be.  
If outdoor air reset is desired, connect the outdoor air sensor to  
the terminals on the Low Voltage Connection Board on the  
Leader boiler. The set point will be calculated based on the  
programmed reset curve parameters. See the Knight XL Service  
Manual to program the reset curve. If outdoor air reset is not  
desired, do not connect the outdoor air sensor. A fixed  
temperature set point can be programmed into the control. See  
page 54 of this manual to program the set point.  
Boiler temperature regulation  
Operating temperature (target)  
The SMART SYSTEM control module senses water  
temperature and regulates boiler firing and firing rate to  
achieve a target temperature. The target temperature can  
be set between 70°F (21°C) and 190°F (88°C).  
Target temperature is fixed when the outdoor  
sensor is not installed.  
Target temperature is calculated as described  
on this page under “Outdoor Reset Operation”  
and “Target Temperature Boost” when the  
outdoor sensor is connected.  
58  
Installation & Operation Manual  
11 Operating information  
(continued)  
DHW, Night Setback, and Ramp Delay operation with  
cascade  
Cascade (continued)  
If the water temperature at the system supply sensor is less  
than the set point + the turn-off offset - the off-on  
differential, then the control will initiate a call for heat on  
the Cascade (see the Knight XL Service Manual for an  
explanation of the offset and differential). The Leader will  
energize the lead boiler on the Cascade. For a new startup  
this will be the Leader boiler.  
For DHW operation any boiler(s) in the Cascade can be selected  
to provide heat for a DHW call. Select a boiler to be designated  
as the DHW boiler. Connect the DHW thermostat to the  
terminals on the Low Voltage Connection Board marked for the  
DHW Thermostat. When the boiler receives a DHW call, the  
Leader control will take that boiler out of the Cascade sequence.  
If another boiler is available, the Leader will start it up to take its  
place.  
The boiler will fire at its ignition speed and will then  
modulate its firing rate to maintain the set point. If the first  
boiler reaches 100% of its firing rate, the Leader will  
calculate at what point the second boiler could fire at 20%  
of its firing rate. At this point, the Leader will fire the second  
boiler on the Cascade. For a new startup, this would be the  
first Member boiler. The boiler will fire at its ignition speed  
and will then modulate its firing rate to maintain the set  
point.  
The DHW boiler will adjust its set point to the programmed  
DHW set point and will adjust its firing rate to maintain this.  
Once the DHW call has been satisfied, the Leader control will  
place that boiler back into the Cascade sequence.  
Switching of the boiler between DHW operation and SH  
operation when there is a call for both does not occur. The boiler  
will provide heat for the DHW demand until it is satisfied.  
If the set point still cannot be met, the Leader will continue  
firing more Members until either the heat demand is met or  
all boilers on the Cascade are firing. As the heat demand  
decreases, the last boiler on will modulate down to 20% of  
its firing rate. Once the demand for that boiler is zero, it will  
shut down. As the heat demand decreases further, the  
second to last boiler will modulate down and shut off. This  
will continue until the demand is satisfied and all boilers are  
shut off.  
Night Setback operation of the boilers within the Cascade is  
available. Programming of the Night Setback will be done  
through the Leader boiler. Refer to the Knight XL Service  
manual for information regarding Night Setback.  
Ramp Delay operation of the boilers as described in the Knight  
XL Service Manual is not active when the boilers are part of a  
Cascade system.  
Sequence of the cascade  
To equalize the run time of all boilers on the Cascade, the  
firing sequence will automatically be changed at set  
intervals.  
For the first 24 hours after initializing the Cascade, the  
sequence will be changed every hour. After that the  
sequence will be changed once every 24 hours. The  
switching on/off sequence will be as follows:  
DAY  
Day 1  
SWITCHING ON SEQUENCE  
L-M1-M2-M3-M4-M5-M6-M7  
M1-M2-M3-M4-M5-M6-M7-L  
Day 1 + 1 hour  
Day 1 + 2 hours  
M2-M3-M4-M5-M6-M7-L-M1  
59  
Installation & Operation Manual  
11 Operating information  
Sequence of operation  
OPERATION  
DISPLAY  
1. Upon a call for heat, the control turns on the appropriate pumps  
(system and boiler pumps for space heating call; DHW pump  
for DHW call).  
B
L
R
:
:
S
t
a
n
d
b
y
O
U
T
1
2
3
.
8
F
(
1
2
9
)
)
2. The control connects 120 VAC to the blower. The blower  
does not run at this time.  
• The manual reset high limit must be closed and reset.  
• Once the pumps are turned on, the flow switch must close.  
• If the unit is equipped with gas pressure switches, they must  
close.  
• If an auxiliary limit is connected to the unit, it must close.  
• The air pressure switch must be closed.  
B
L
R
:
:
S
t
a
n
d
b
y
(
O
U
T
1
2
3
.
8
F
1
2
9
B
L
R
:
:
P
R
E
P
U
R
G
E
3. The control then starts a 15 second prepurge cycle.  
O
U
T
1
2
3
.
9
F
(
1
2
9
)
4. Once the prepurge cycle is complete, and the blocked drain  
switch is closed, the control starts the 4 second trial for ignition  
by sending spark voltage to the spark electrode and opening  
the gas valve.  
B
L
R
:
:
I
G
N
I
T
I
O
N
1
O
U
T
1
2
3
.
9
F
(
2
9
)
5. If the control does not detect flame before the trial for ignition  
ends, the control will perform a 10 second postpurge. The 399  
model will start another prepurge and trial for ignition. If the  
burner does not light after 4 trials on the 399 model, the control  
will lock out for one hour and then try again.  
B
L
R
:
:
P
O
S
T
P
U
R
G
E
,
9
P
R
E
P
U
R
G
E
O
U
T
1
2
3
.
9
F
(
1
2
)
If the burner does not light after 1 retry on Models 500 - 800 the  
control will lock out.  
6. If the control detects a flame before the trial for ignition ends, it  
begins to modulate the burner in order to maintain the set point.  
If the boiler lights due to a space heating call for heat, and the  
ramp delay function is active (default is off), the modulation  
will be held to a series of increasing limits afterthe burner has lit.  
B
L
R
:
:
S
H
2
2
0
%
R
A
T
E
O
U
T
1
4
.
8
F
(
1
2
9
)
7. If the space heating call for heat is active, and the DHW  
thermostat or sensor starts a DHW call for heat, the control will  
turn on the DHW pump, wait 2 seconds, and then turn off the  
boiler pump. This will divert the hot water away from the  
heating zone(s) and send it to the DHW tank instead. The  
control will then modulate to maintain the outlet temperature to  
the DHW boiler set point.  
B
L
R
:
:
D
H
W
7
8
5
%
R
A
T
E
O
U
T
1
7
.
8
(
1
8
0
)
8. If the boiler is not part of a cascade, and the DHW call for heat  
remains active for more than 30 minutes, and the space heating  
call for heat is also active, then the control will turn on the boiler  
pump, turn off the DHW pump after 2 seconds, and resume  
modulating based on the space heating set point. As long as  
both the space heating and DHW calls for heat remain active,  
the control will switch back and forth between the two modes  
until one of them is satisfied.  
B
L
R
:
:
S
H
2
4
1
%
R
A
T
E
O
U
T
1
3
.
0
F
(
1
2
9
)
9. Once both calls for heat are satisfied, the control will turn off the  
burner. The blower will remain on for the 10 second postpurge  
cycle. Any pumps that are running will continue to run for their  
respective pump delay times, then turn off.  
B
L
R
:
:
P
O
S
T
P
U
R
G
E
2
O
U
T
1
2
7
.
4
F
(
1
9
)
B
L
R
:
S
t
a
n
d
b
y
(
10. Boiler pump off, system pump continues its delay if longer.  
O
U
T
:
1
2
4
.
7
F
1
2
9
)
)
B
L
R
:
:
S
t
a
n
d
b
y
(
11. System pump off.  
O
U
T
1
2
2
.
9
F
1
2
9
60  
Installation & Operation Manual  
11 Operating information  
(continued)  
Knight XL control module  
Use the control panel (FIG. 11-1) to set temperatures, operating conditions, and monitor boiler operation.  
Figure 11-1 Control Panel  
• Press to turn boiler off or  
back on  
• Press to select a menu item  
• Press after parameter programming  
to store parameter data  
• Press to exit Service Mode  
• Hold 5 seconds to enter code  
Input Mode (Menu Mode)  
• Press to move up one level  
in Menu Mode or to exit  
Menu Mode  
SHUTDOWN  
ENTER / RESET  
MENU / EXIT  
DISPLAY SCREEN  
SERVICE  
BUTTON  
PC  
CONNECTION  
PORT  
UP  
DOWN  
PREVIOUS  
NEXT  
• Press to toggle display during normal  
operation to show outlet and return  
temperatures, fan speed, and flame  
signal  
• Press to toggle between digits when  
entering access code or between hour,  
minutes, etc., when entering date and  
time  
• Press to change boiler water  
temperature set point during  
normal operation  
• Press to change displayed data  
values in Menu Mode  
• Press to navigate through menu  
listing in Menu Mode  
61  
Installation & Operation Manual  
11 Operating information  
Access modes  
User  
The user can adjust space heating target temperature by using the UP and  
DOWN buttons (FIG. 11-1) at any time during normal operation. By  
entering the USER code (0704), the user can also change temperature  
units, time and date, and night setback settings. In User Mode, the  
following parameters can be viewed but not changed:  
• Boiler outlet water target temperature in DHW Mode  
• Boiler model number  
• Software version  
Total operating hours  
Total cycles  
Installer  
Most parameters are available only to the installer, accessible only by  
entering the installer access code, see the Knight XL Service Manual.  
Saving parameters (reference the Parameter Table in the Knight  
XL Service Manual)  
To save parameters and exit programming:  
Press the ENTER/RESET button.  
To keep parameter settings only for a current operating cycle:  
Press the MENU/EXIT button 3 times after making all desired parameter  
changes.  
To enter a parameter and continue programming:  
Press the MENU/EXIT button 1 time to return to the parameter listings;  
press again to return to the menu listings. Remember to press the  
ENTER/RESET button when finished programming in order to save the  
changes made.  
See the Knight XL Service Manual for a detailed description of parameters  
and access modes.  
62  
Installation & Operation Manual  
11 Operating information  
(continued)  
Status Display Screens  
By using the Previous/Next (, ) arrow keys on the SMART SYSTEM display panel, you can navigate through the eight (8)  
display screens. Each screen will contain two (2) viewable items. The following is a description of the individual items and what  
they can display:  
Screen  
Display shows:  
Description  
The unit has been turned OFF by the Enter/Reset button on the  
SMART SYSTEM display panel.  
BLR: OFF  
The unit has not received a call for heat from a remote thermostat nor  
has it received a call for heat from a DHW thermostat.  
Standby  
The unit has met the water temperature set point, but is still receiving  
a call for heat from either a remote thermostat or a DHW thermostat.  
Set Point Met  
The unit has initiated a 10 second purge period on a call for heat.  
Note: On the 800 model the unit will initiate a 20 second purge  
period on a call for heat.  
Prepurge  
Ignition  
The unit has begun a 5 second spark period to ignite the main burner.  
The unit has fired and is running at the displayed percentage.  
SH***% Rate  
#1  
The call for heat has been satisfied and the unit runs the fan for an  
additional 10 seconds to clear the combustion chamber and vent  
system of residual flue products.  
Postpurge  
Service  
The unit has been placed in a temporary mode that will allow the unit  
to fire at 100% of rate for the purpose of combustion analysis.  
When the outlet sensor has been selected as the control sensor  
(default), the control will display the outlet temperature as well as the  
set point in parenthesis.  
OUT: ***.*F(***)  
***.*F  
If the outlet sensor has not been selected as the control sensor, only  
the outlet temperature will be displayed.  
Open  
The control does not detect the outlet sensor.  
Shorted  
The outlet sensor wires or the sensor itself has become shorted.  
Press the Next arrow key on the SMART SYSTEM display to access Screen #2.  
If the inlet sensor has not been selected as the control sensor, only the  
inlet temperature will be displayed.  
IN: ***.*F  
When the inlet sensor has been selected as the control sensor, the  
control will display the inlet temperature as well as the set point in  
parenthesis.  
***.*F (***)  
#2  
Open  
The control does not detect the inlet sensor.  
Shorted  
The inlet sensor wires or the sensor itself has become shorted.  
The difference between the inlet temperature and the outlet  
temperature.  
RISE: ***.*F  
Press the Next arrow key on the SMART SYSTEM display to access Screen #3.  
63  
Installation & Operation Manual  
11 Operating information  
Status Display Screens (cont’d)  
By using the Previous/Next (, ) arrow keys on the SMART SYSTEM display panel, you can navigate through the eight (8)  
display screens. Each screen will contain two (2) viewable items. The following is a description of the individual items and what  
they can display:  
Screen  
Display shows:  
Description  
If the system supply sensor has not been selected as the control sensor,  
only the system temperature will be displayed.  
SYS: ***.*F  
When the system supply sensor has been selected as the control  
sensor, the control will display the system temperature as well as the  
set point in parenthesis.  
***.*F (***)  
Open  
The control does not detect the system supply sensor.  
The system supply sensor wires or the sensor itself has become  
shorted.  
#3  
Shorted  
The control will display the outdoor air temperature as sensed by the  
outdoor air sensor.  
OUTDOOR: ***.*F  
Open  
The control does not detect the outdoor air sensor.  
Shorted  
The outdoor air sensor wires or the sensor itself has become shorted.  
Press the Next arrow key on the SMART SYSTEM display to access Screen #4.  
FLUE: ***.*F  
Open  
The control will display the flue temperature.  
The control does not detect the flue sensor.  
Shorted  
The flue sensor wires or the sensor itself has become shorted.  
The control will display the temperature.  
#4  
AUX: ***.*F  
Open  
The control does not detect the auxiliary sensor.  
Shorted  
The auxiliary sensor wires or the sensor itself has become shorted.  
Press the Next arrow key on the SMART SYSTEM display to access Screen #5.  
FAN SPD: ****RPM  
FLAME SIG: **.*uA  
The control will display the actual fan motor RPM.  
#5  
#6  
The control will display the flame signal in dc microamps.  
Press the Next arrow key on the SMART SYSTEM display to access Screen #6.  
SH CFH: OFF  
ON  
The control has not received a call for heat from a remote thermostat.  
The control has received a call for heat from a remote thermostat.  
The control has not received a call for heat from a SH remote  
thermostat.  
DHW CFH: OFF  
ON  
The control has received a call for heat from a DHW thermostat.  
Press the Next arrow key on the SMART SYSTEM display to access Screen #7.  
64  
Installation & Operation Manual  
11 Operating information  
(continued)  
Status Display Screens (cont’d)  
By using the Previous/Next (, ) arrow keys on the SMART SYSTEM display panel, you can navigate through the eight (8)  
display screens. Each screen will contain two (2) viewable items. The following is a description of the individual items and what  
they can display:  
Screen  
Display shows:  
Description  
The control has not received a DHW call for heat and has not  
powered the DHW pump.  
DHW PUMP: OFF  
The control has received a DHW call for heat and has powered the  
DHW pump.  
ON  
#7  
The DHW call for heat has been satisfied and the DHW pump is  
running for a fixed time to remove any residual heat.  
Delay  
The control will display a 0-10Vdc signal received from a Building  
Management System (BMS) connected to the unit.  
0-10V IN: **.Vdc  
Press the Next arrow key on the SMART SYSTEM display to access Screen #8.  
The control has not received a call for heat from a remote thermostat  
and has not powered the system pump.  
SYS PUMP: OFF  
ON  
The control has received a call for heat from a remote thermostat and  
has powered the system pump.  
The system call for heat has been satisfied and the system pump is  
running for a fixed time to remove any residual heat.  
Delay  
The control has either not received a call for heat from a remote  
thermostat, a remote thermostat is not connected to the unit and the  
water temperature has not dropped below the temperature set point  
of the control to initiate a call for heat, or the control has received a  
DHW call for heat from a DHW thermostat.  
BLR PUMP: OFF  
#8  
The control has received a call for heat from a remote thermostat or a  
remote thermostat is not connected and the water temperature has  
dropped below the temperature set point of the control to initiate a  
call for heat.  
ON  
The call for heat has been satisfied and the boiler pump is running for  
a fixed time to remove any residual heat.  
Delay  
Press the Next arrow key on the SMART SYSTEM display to access Screen #9.  
65  
Installation & Operation Manual  
11 Operating information  
Status Display Screens (cont’d)  
Operation of the cascade  
The boiler designated as the Leader will have two additional display screens that can be viewed. These screens will provide  
information regarding the operation of the Cascade. Each screen will contain two viewable items. The following is a description  
of the individual items and what they can display:  
Screen  
Display shows:  
Description  
The Leader control has been turned off by the Enter/Reset button on  
the Smart System display.  
Cas: Off  
The Leader boiler has not received a call for heat from a remote  
thermostat.  
Cas: Standby  
The Cascade is now active. The system supply temperature will be  
displayed. The Cascade set point will be displayed in parenthesis.  
Cas: 127.4F (130)  
The Cascade has met the water temperature set point, but is still  
receiving a call for heat from a remote thermostat.  
Cas: Setpoint Met  
Cas: No Members  
Cas: S6 Not Present  
PMP: Off  
The Leader control could not detect any Member controls to  
participate in the Cascade.  
#9  
The system supply sensor is not connected to the Leader boiler.  
The Leader control has not received a call for heat from a remote  
thermostat and has not powered the system pump.  
The Leader control has received a call for heat from a remote  
thermostat and has powered the system pump.  
PMP: On  
The system call for heat has been satisfied and the system pump is  
running for a fixed time to remove any residual heat.  
PMP: Delay  
Press the Next arrow key on the SMART SYSTEM display to access Screen #10.  
The first percentage shows the firing rate that is being sent to the last  
Cas Pow: ***% ***%  
boiler called on. The second percentage shows the total power  
available to the Cascade.  
Shows the number of boilers connected to the Cascade. The Leader is  
designated as 0. Members will be designated 1 - 7. If a “-“ is used in  
place of a number, that boiler is either not connected, or in a lockout  
mode and not available for the Cascade. If a “d” is used in place of a  
number, that boiler is handling a DHW demand and is not available  
for the Cascade. If the number is flashing, then that boiler is providing  
heat to the Cascade. As the lead boiler is changed from day to day, that  
boiler’s address will be shown first in the string of numbers. In the  
example, boilers 0 - 3 are present, boiler 2 is the lead boiler, and boiler  
0 is heating an indirect DHW tank.  
Present: 01234567  
#10  
Example:  
Present: 23----d1  
Press the Next arrow key on the SMART SYSTEM display to roll back to Screen #1. At any point if you wish to access an  
earlier screen, press the Previous arrow key on the SMART SYSTEM display.  
66  
Installation & Operation Manual  
12 Maintenance  
Maintenance and annual startup  
Table 12A Service and Maintenance Schedules  
Owner maintenance  
Service technician  
(see the Knight XL User’s Information Manual for  
instructions)  
(see the following pages for instructions)  
General:  
• Address reported problems  
• Check boiler area  
• Inspect interior; clean and vacuum if  
necessary;  
Daily  
• Check pressure/temperature  
gauge  
• Clean condensate trap and fill with fresh  
water  
Check for leaks (water, gas, flue,  
condensate)  
• Verify flue and air lines in good condition  
and sealed tight  
• Check vent piping  
• Check air piping  
Check system water pressure/system  
piping/expansion tank  
• Check control settings  
• Check air and vent termination  
Monthly  
screens  
• Check ignition and flame sense  
electrodes (sand off any deposits; clean  
and reposition)  
• Check relief valve  
• Check wiring and connections  
• Check condensate drain system  
• Check automatic air vents  
• Perform start-up checkout and  
performance verification per Section 10.  
• Flame inspection (stable, uniform)  
• Flame signal (at least 10 microamps at  
high fire)  
Test low water cutoff (if used)  
Periodically  
• Reset button (low water cutoff)  
• Clean the heat exchanger if flue  
temperature is more than 54°F (30°C)  
above return water temperature.  
If combustion or performance  
indicate need:  
• Check boiler piping (gas and  
Every  
6 months  
water) for leaks  
• Clean heat exchanger  
• Operate relief valve  
• Remove and clean burner using  
compressed air only  
• Clean the blower wheel  
End  
Shut boiler down (unless boiler  
of season  
used for domestic hot water)  
months  
67  
Installation & Operation Manual  
12 Maintenance  
Follow the Service and maintenance procedures given throughout this manual and in component literature  
shipped with the boiler. Failure to perform the service and maintenance could result in damage to the boiler  
or system. Failure to follow the directions in this manual and component literature could result in severe  
personal injury, death, or substantial property damage.  
ƽ WARNING  
The boiler should be inspected annually only by a qualified service technician. In addition, the maintenance  
and care of the boiler designated in Table 12A and explained on the following pages must be performed to  
assure maximum boiler efficiency and reliability. Failure to service and maintain the boiler and system could  
result in equipment failure.  
ƽ WARNING  
Electrical shock hazard – Turn off power to the boiler before any service operation on the boiler except as  
noted otherwise in this instruction manual. Failure to turn off electrical power could result in electrical shock,  
causing severe personal injury or death.  
ƽ WARNING  
Address reported problems  
Figure 12-1 Condensate Trap  
1. Inspect any problems reported by the owner and correct  
before proceeding.  
RETAINING  
SCREW  
2” PVC CAP WITH  
BLOCKED DRAIN SWITCH  
Inspect boiler area  
1. Verify that boiler area is free of any combustible  
materials, gasoline and other flammable vapors and  
liquids.  
PVC TEE ASSEMBLY  
(FACTORY SUPPLIED)  
2. Verify that air intake area is free of any of the  
contaminants listed in Section 1 of this manual. If any of  
these are present in the boiler intake air vicinity, they  
must be removed. If they cannot be removed, reinstall  
the air and vent lines per this manual and the Knight XL  
Service Manual.  
CONDENSATE FROM  
HEAT EXCHANGER  
Inspect boiler interior  
TO FLOOR  
DRAIN  
1. Remove the front access cover and inspect the interior of  
the boiler.  
The condensate trap must be filled with  
water during all times of boiler operation to  
avoid flue gas emission from the condensate  
drain line. Failure to fill the trap could result  
in severe personal injury or death.  
ƽ WARNING  
2. Vacuum any sediment from inside the boiler and  
components. Remove any obstructions.  
Clean condensate trap  
Check all piping for leaks  
Eliminate all system or boiler leaks.  
1. Inspect the condensate drain line, condensate PVC  
fittings, and condensate trap.  
ƽ WARNING  
Continual fresh makeup water will reduce  
boiler life. Minerals can build up in sections,  
reducing heat transfer, overheating heat  
exchanger, and causing heat exchanger  
failure. Leaking water may also cause severe  
property damage.  
2. Remove the PVC cap retaining screw from the PVC cap  
(FIG. 12-1).  
3. Remove the 2 inch PVC cap with the switch located at the  
top of the trap (FIG. 12-1).  
4. Remove any sediment in the trap.  
1. Inspect all water and gas piping and verify to be leak free.  
5. Fill with fresh water until the water begins to pour out of  
the drain.  
2. Look for signs of leaking lines and correct any problems  
found.  
6. Replace the cap. Press the cap onto the trap until the cap  
makes contact with the drain.  
3. Check gas line using the procedure found in Section 7 -  
Gas Connections.  
7. Replace the retaining screw.  
68  
Installation & Operation Manual  
12 Maintenance  
(continued)  
Safety relief valves should be re-inspected AT  
LEAST ONCE EVERY THREE YEARS, by a  
licensed plumbing contractor or authorized  
inspection agency, to ensure that the product  
has not been affected by corrosive water  
conditions and to ensure that the valve and  
discharge line have not been altered or  
tampered with illegally. Certain naturally  
occurring conditions may corrode the valve  
or its components over time, rendering the  
valve inoperative. Such conditions are not  
detectable unless the valve and its  
components are physically removed and  
inspected. This inspection must only be  
conducted by a plumbing contractor or  
authorized inspection agency – not by the  
owner. Failure to re-inspect the boiler relief  
valve as directed could result in unsafe  
pressure buildup, which can result in severe  
personal injury, death, or substantial  
property damage.  
Flue vent system and air piping  
ƽ WARNING  
1. Visually inspect the entire flue gas venting system and air  
piping for blockage, deterioration or leakage. Repair any  
joints that show signs of leakage. Verify that air inlet pipe  
is connected and properly sealed.  
2. Verify that boiler vent discharge and air intake are clean  
and free of obstructions.  
Failure to inspect for the above conditions  
and have them repaired can result in  
severe personal injury or death.  
ƽ WARNING  
Check water system  
1. Verify all system components are correctly installed and  
operational.  
2. Check the cold fill pressure for the system. Verify it is  
correct (must be a minimum of 12 psi (82.7 kPa)).  
3. Watch the system pressure as the boiler heats up (during  
testing) to ensure pressure does not rise too high.  
Excessive pressure rise indicates expansion tank sizing or  
performance problem.  
Following installation, the valve lever must  
be operated AT LEAST ONCE A YEAR to  
ensure that waterways are clear. Certain  
naturally occurring mineral deposits may  
adhere to the valve, rendering it inoperative.  
When manually operating the lever, water  
will discharge and precautions must be  
taken to avoid contact with hot water and to  
avoid water damage. Before operating lever,  
check to see that a discharge line is  
connected to this valve directing the flow of  
hot water from the valve to a proper place of  
disposal. Otherwise severe personal injury  
may result. If no water flows, valve is  
inoperative. Shut down the boiler until a  
new relief valve has been installed.  
ƽ WARNING  
4. Inspect automatic air vents and air separators. Remove  
air vent caps and briefly press push valve to flush vent.  
Replace caps. Make sure vents do not leak. Replace any  
leaking vents.  
Check expansion tank  
1. Expansion tanks provide space for water to move in and  
out as the heating system water expands due to  
temperature increase or contracts as the water cools.  
Tanks may be open, closed or diaphragm or bladder type.  
See Section 6 - Hydronic Piping for suggested best  
location of expansion tanks and air eliminators.  
Check boiler relief valve  
2. After following the above warning directions, if the relief  
valve weeps or will not seat properly, replace the relief  
valve. Ensure that the reason for relief valve weeping is  
the valve and not over-pressurization of the system due to  
expansion tank waterlogging or undersizing.  
1. Inspect the relief valve and lift the lever to verify flow.  
Before operating any relief valve, ensure that it is piped  
with its discharge in a safe area to avoid severe scald  
potential. Read Section 6 - Hydronic Piping before  
proceeding further.  
69  
Installation & Operation Manual  
12 Maintenance  
Inspect ignition and flame sense Check burner flame  
electrodes  
1. Inspect flame through observation window.  
1. Remove the ignition and flame sense electrodes from the  
boiler heat exchanger access cover.  
2. If the flame is unsatisfactory at either high fire or low fire,  
turn off boiler and allow boiler to cool down. Remove the  
burner and clean it thoroughly using a vacuum cleaner or  
compressed air. Do not use compressed air to clean burner  
if performed inside a building.  
2. Remove any deposits accumulated on the ignition/flame  
sense electrode using sandpaper. If the electrodes cannot  
be cleaned satisfactorily, replace with new ones.  
3. Remove the burner, reference FIG.’s 12-2 thru 12-4.  
3. Replace ignition/flame sense electrode, making sure  
gasket is in good condition and correctly positioned.  
4. When replacing the burner, ensure gasket is in good  
condition and positioned correctly (FIG.’s 12-2 thru 12-4).  
Check ignition ground wiring  
1. Inspect boiler ground wire from the heat exchanger access  
cover to ground terminal strip.  
Figure 12-2 Burner Assembly - Model 399  
2. Verify all wiring is in good condition and securely  
attached.  
3. Check ground continuity of wiring using continuity  
meter.  
AIR / GAS ARM  
4. Replace ground wires if ground continuity is not  
satisfactory.  
Check all boiler wiring  
1. Inspect all boiler wiring, making sure wires are in good  
condition and securely attached.  
BURNER  
GASKET  
Check control settings  
SCREWS  
(QTY. 5)  
1. Set the SMART SYSTEM control module display to  
Parameter Mode and check all settings. See Section 1 of  
the Knight XL Service Manual. Adjust settings if  
necessary. See Section 1 of the Knight XL Service Manual  
for adjustment procedures.  
Figure 12-3 Burner Assembly - Model 500  
2. Check settings of external limit controls (if any) and  
adjust if necessary.  
Perform start-up and checks  
1. Start boiler and perform checks and tests specified in  
Section 10 - Start-up.  
AIR / GAS ARM  
2. Verify cold fill pressure is correct and that operating  
pressure does not go too high.  
BURNER  
GASKET  
SCREWS  
(QTY. 5)  
70  
Installation & Operation Manual  
12 Maintenance  
(continued)  
Cleaning boiler heat exchanger  
Figure 12-4 Burner Assembly - Models 600 - 800  
1. Shut down boiler:  
• Follow the “To Turn Off Gas to Appliance” instructions  
for the boiler in Section 10 - Startup.  
• Do not drain the boiler unless it will be exposed to  
freezing temperatures. If using freeze prevention fluid  
in system, do not drain.  
AIR ARM  
2. Allow time for the boiler to cool to room temperature if  
it has been firing.  
3. Remove the blower assembly (gas air/arm) from the heat  
exchanger access cover. Set bolts aside.  
BURNER  
GASKET  
4. Remove the nuts securing the heat exchanger access cover  
to the heat exchanger and set aside.  
SCREWS  
(QTY. 5)  
5. Remove the heat exchanger access cover, cover gasket(s)  
and chamber insulation assembly.  
The boiler contains ceramic fiber  
Check flame signal  
ƽ WARNING  
materials. Use care when handling these  
materials per instructions in the Handling  
Ceramic Fibers Section of the Knight XL  
Service Manual. Failure to comply could  
result in severe personal injury.  
1. At high fire the flame signal shown on the display should  
be at least 10 microamps.  
2. A lower flame signal may indicate a fouled or damaged  
flame sense electrode. If cleaning the flame sense  
electrode does not improve, ground wiring is in good  
condition, and ground continuity is satisfactory, replace  
the flame sense electrode.  
6. Use a vacuum cleaner to remove any accumulation on the  
boiler heating surfaces. Do not use any solvent.  
7. Finish cleaning using a clean cloth dampened with warm  
water.  
3. See Section 3 - Troubleshooting in the Knight XL Service  
Manual for other procedures to deal with low flame  
signal.  
8. Install access cover gasket, chamber insulation assembly  
and cover.  
Review with owner  
9. Secure nuts on the studs. DO NOT overtighten.  
10. Re-install the blower assembly (gas air/arm) using the  
bolts set aside in Step 3.  
1. Review the Knight XL User’s Information Manual with  
the owner.  
11. Close isolation valves on piping to isolate boiler from  
system. Attach a hose to the boiler drain and flush boiler  
thoroughly with clean water by using purging valves to  
allow water to flow through the water make-up line to the  
boiler.  
2. Emphasize the need to perform the maintenance  
schedule specified in the Knight XL User’s Information  
Manual (and in this manual as well).  
3. Remind the owner of the need to call a licensed  
contractor should the boiler or system exhibit any  
unusual behavior.  
12. When the boiler has been flushed, restore boiler to  
operation.  
4. Remind the owner to follow the proper shutdown  
procedure and to schedule an annual start-up at the  
beginning of the next heating season.  
13. Perform start-up and check-out procedures in Section 10  
- Startup.  
71  
Installation & Operation Manual  
13 Diagrams  
Figure 13-1 Wiring Diagram  
LOW VOLTAGE  
120 VAC  
HIGH VOLTAGE  
BOX DEPICTS  
OPTIONAL ITEMS  
INTEGRATED CONTROL  
X3  
JUNCTION  
BOX  
RELAY  
PC  
X8  
BOARD  
INTERFACE  
OR  
OR  
CONNECTION BOARD  
X1-3  
CN2-4  
K1  
K2  
K3  
CN1-5  
DHW  
PUMP  
AUX.  
DEVICE  
PILOT  
CN2  
CN2-1  
OR  
CN1-6  
BR  
CN1-3  
R
CN2-16  
CN2-15  
CN2-14  
CN2-13  
CN2-12  
CN2-11  
SUPPLY  
BR  
PR  
X1-4  
X1-2  
Y
CN4-8  
X6-8  
BOILER  
PUMP  
AUX.  
DEVICE  
PROVING  
BR  
CN1-4  
PR  
CN1-1  
OR  
P
CN4-2  
CN4-9  
CN4-3  
X6-10  
X6-4  
X6-5  
SYSTEM  
PUMP  
GAS  
PRESSURE  
SWITCH  
PR  
CN1-2  
BK  
SOLENOID  
VALVE  
RELAY  
ON/OFF  
SWITCH  
FLOW  
CN2-10  
CN2-9  
CN2-8  
CN2-7  
CN2-6  
CN2-5  
CN2-4  
CN2-3  
CN2-2  
CN2-1  
SWITCH  
L
BK  
W
BK  
W
X1-6  
X1-5  
120V  
GND  
GND  
N
BELL JUMPER  
SUPPLY  
PR  
PR  
R
CN4-10  
CN4-4  
X3-4  
X3-2  
X3-1  
X3-3  
ALARM  
CONTACTS  
G
R
X1-8  
X1-1  
CN4-11  
CN4-12  
RUN-TIME  
CONTACTS  
R
DHW  
THERMOSTAT  
R W G  
BLOWER  
W
BL  
GY  
CN4-5  
CN4-7  
CN4-13  
X6-1  
X6-2  
X6-6  
1
2
3
ROOM  
THERMOSTAT  
ZONE  
1 2 3 4  
5
CONTROL  
R
T
X5-5  
X5-13  
X5-6  
W
CN5-1  
CN4-14  
24 VAC  
LOW  
BK  
BL  
PR  
OR  
P
CN5-3  
CN5-4  
X5-12  
X5-7  
WATER  
CUT-OFF  
BR  
Y
BL  
PR  
CN4-6  
CN4-1  
X6-9  
X6-3  
MANUAL RESET  
HI-LIMIT  
CN5-2  
CN5  
COM  
X5-14  
X5-11  
X5-3  
AIR PRESS. SWITCH  
OR  
P
BLOCKED  
DRAIN  
CN4  
OR  
GY  
BK  
S6  
X5-4  
SYSTEM  
CN1-12  
CN1-11  
CN1-10  
CN1-9  
CN1-8  
CN1-7  
CN1-6  
CN1-5  
CN1-4  
CN1-3  
CN1-2  
CN1-1  
BL  
SENSOR  
X5-10  
X5-8  
(AUX) DWH  
TANK  
SENSOR  
S4  
S5  
S2  
INLET  
SENSOR  
R
S1  
X5-1  
OUTLET  
SENSOR  
FLUE  
SENSOR  
OUTDOOR  
SENSOR  
W
Y
X4  
CN3  
CN3  
S3  
X5-2  
X5-9  
SHIELD  
A
B
RS485  
BK  
Y
X2-2  
X2-1  
GAS  
VALVE  
SHIELD  
FLAME  
ROD  
+
-
EXTERNAL  
CONTROL  
W/R  
0-10V  
TR1  
G
SPARK  
ROD  
CN1  
CAUTION HIGH VOLTAGE SPARK LEAD  
Notes:  
1. All wiring must be installed in accordance with: local, state, provincial and national code requirements per either N.E.C. in USA or C.S.A. in Canada.  
2. If any original equipment wire as supplied with the appliance must be replaced, it must be replaced with wire having same wire gauge (AWG) and rated for a  
minimum of 105°C. Exceptions: Replacement high voltage spark lead and ribbon cables must be purchased from the factory. Use of a non-approved spark lead  
or ribbon cables can lead to operational problems which could result in non-repairable damage to the integrated controller or other components.  
3. Actual connector block locations may vary from those shown on diagrams. Refer to actual components for proper connector block locations when using  
diagrams to troubleshoot unit.  
WIRING DIAGRAM  
LBL2364 REV D  
72  
Installation & Operation Manual  
13 Diagrams  
(continued)  
Figure 13-2 Ladder Diagram  
BOX DEPICTS  
OPTIONAL ITEMS  
JUNCTION BOX  
120VAC  
NEUTRAL  
GROUND  
LOW VOLTAGE  
120 VAC  
HIGH VOLTAGE  
TERMINAL STRIP  
120V SUPPLY "L"  
TERMINAL STRIP  
120V SUPPLY "N"  
INTEGRATED CONTROL  
F5  
ON / OFF  
SWITCH  
L
IN  
L
OUT  
SYSTEM PUMP  
RELAY  
X1-2  
SYSTEM  
PUMP  
5A  
SYSTEM PUMP  
RELAY  
X1-6  
X1-8  
CONTACTS  
BOILER PUMP  
RELAY  
SYSTEM  
X1-4  
X1-3  
X1-1  
PUMP  
BOILER  
PUMP  
CONTACTS  
BOILER PUMP  
RELAY  
DHW PUMP  
RELAY  
JUNCTION  
BOX  
BOILER  
PUMP  
DHW  
PUMP  
CONTACTS  
DHW PUMP  
RELAY  
BLOWER  
F4  
1
2
DHW  
PUMP  
3.5A  
BLOWER  
RELAY  
RELAY BOARD  
3
F3  
1.25A  
X1-5  
X6-8  
120 VAC  
JUNCTION BOX  
F2  
X5-7  
CONNECTION BOARD  
24 VAC  
X6-7  
X6-2  
3.5A  
RESISTOR  
X6-3  
CN4-1  
CONNECTION  
BOARD  
CN5-1  
CN5-2  
CN5-4  
CN4-7  
INTEGRATED  
CONTROL  
LWCO  
CONNECTION  
BOARD  
FLOW  
SWITCH  
CN5-3  
CN4-6  
X6-9  
CN4-14  
CN2-10  
CN2-9  
CN2-2  
ROOM THERMOSTAT  
ZONE CONTROL  
CN4-13 X6-6  
CN2-1  
CN2-3  
DHW  
THERMOSTAT  
CN4-5  
CN4-3  
X6-1  
X6-5  
CN2-4  
LOW GAS  
PRESSURE  
SWITCH  
HIGH GAS  
PRESSURE  
SWITCH  
CONNECTION  
BOARD  
MANUAL RESET  
HIGH LIMIT  
X6-4  
CN4-9  
X5-14  
CN2-12  
CN2-11  
CN2-16  
INTEGRATED  
CONTROL  
INTEGRATED  
CONTROL  
AUX. DEVICE  
PILOT SUPPLY  
DISPLAY  
CN2-15  
CN2-14  
24VAC  
AUX. DEVICE  
PROVING  
CN4-2  
X6-10  
CN2-13  
X3  
AIR PRESSURE  
SWITCH  
X5-11  
X5-4  
RIBBON CABLE  
PC  
X8  
INTERFACE  
BLOCKED  
DRAIN SWITCH  
X5-3  
X5-8  
X5-1  
S2  
INLET  
SENSOR  
CN2-15  
X5-10  
S1  
S3  
GAS VALVE  
BLOWER  
OUTLET  
SENSOR  
X2-2  
X2-1  
X5-2  
X5-9  
GAS VALVE  
RELAY  
CN2-10  
CN2-9  
CN2-8  
CN2-7  
FLUE  
SENSOR  
1
2
4
5
X5-5  
X5-13  
X5-6  
CONNECTION BOARD  
CN4-11  
CN4-12  
X3-1  
X3-3  
RUN-TIME  
CONTACTS  
CN2-6  
CN2-5  
X5-12  
CN4-10  
CN4-4  
X3-4  
X3-2  
ALARM  
CN2-8  
CN2-7  
TR1  
X1-7  
CONTACTS  
CN3-8  
CN3-7  
CN3-9  
CN3-6  
X4-8  
X4-7  
X4-9  
X4-6  
S6  
SYSTEM  
SENSOR  
FLAME ROD  
CN1-12  
CN1-11  
CN1-10  
CN1-9  
CN1-8  
CN1-7  
CN1-6  
CN1-5  
CN1-4  
CN1-3  
CN1-2  
CN1-1  
SPARK  
ROD  
(AUX) DHW  
TANK  
SENSOR  
S4  
S5  
CAUTION HIGH VOLTAGE SPARK LEAD  
OUTDOOR  
SENSOR  
CN3-5  
X4-5  
NOTES:  
1. Where possible, switches are shown without utilities (gas, water or  
electricity) connected to the unit. As such, actual switch states may  
vary from those shown on diagrams depending upon whether utilities  
are connected or a fault condition is present.  
SHIELD  
CN3-2  
CN3-1  
CN3-3  
X4-2  
X4-1  
X4-3  
A
RS485  
B
2. See wiring diagram for additional notes.  
SHIELD  
CN3-10 X4-10  
CN3-4  
X4-4  
+
-
EXTERNAL  
CONTROL  
0-10V  
LADDER DIAGRAM  
LBL2356 REV C  
73  
Notes  
Notes  
Revision Notes: Revision B (ECO #C02407) reflects gas valve  
adjustment, room air, new sidewall vent termination, piping diagrams,  
flow switch, relief valve, T & P gauge, Maintenance Section, FIG. 8-1  
(Line Voltage), and high altitude changes.  
Revision C (ECO #C02545) reflects the addition of references to the  
safety shutoff testing and instructions, sediment trap, periodic cleaning  
of screens in vent terminations, removal of B149.2 references, changed  
the arrow direction on FIG. 6-8, wall thickness for direct vent  
terminations and sidewall vent termination kit number correction.  
Revision D (ECO #C02738) reflects updates made to the line voltage  
image (FIG. 8-1 on page 43), and edits made to the gas conversion  
section for the new orifice on the 399 model (page 12).  
Revision E (ECO #C03223) reflects edits made to the high altitude  
section on page 7 and updates made to the condensate trap image on  
pages 49 and 66.  
Revision F (ECO #C03735) reflects, room air, LWCO, pump, hydro and  
dirt separator changes.  
Revision G (ECO #C04433) reflects the addition of the illustrations  
disclaimer on all the piping drawings (ECR #R02431), changing out “dirt  
separator” for “Y-Strainer” (ECR #R02455), address Step #5 of the  
Sequence of Operation, add a description column in Table 3F, and  
change the direction of the arrows on FIG. 6-8.  
KBX-I-O Rev G  
9/09  

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