DVSCM-02
DIRECT VENT/
SEALED
COMBUSTION
DIRECT VENT/
SEALED
PATTERSON-KELLEY
COMBUSTION
THERMIFIC®
DIRECT VENT/
DIRECT VENT/SEALED COMBUSTION
GAS-FIRED BOILER
SEALED
COMBUSTION
Supplement to the standard Installation and
Owner's Manual (TBIG - Latest Edition)
DIRECT VENT/
SEALED
C.S.A Design-Certified
Complies with ANSI Z21.13/CSA 4.9
Gas-Fired Low Pressure Steam and Hot Water Boilers
COMBUSTION
DIRECT VENT/
ASME Code, Section IV
Certified by Patterson-Kelley
SEALED
COMBUSTION
C.S.A Design-Certified
Complies with ANSI Z21.13/CSA 4.9
Gas-Fired Low Pressure Steam and Hot Water Boilers
DIRECT VENT/
SEALED
COMBUSTION
Installation Date: _______________________
DIRECT VENT/
SEALED
COMBUSTION
100 Burson Street, P.O. Box 458,
East Stroudsburg, PA 18301
DIRECT VENT/
Telephone: (877) 728-5351, Facsimile: (570) 476-7247
SEALED
COMBUSTION
DIRECT VENT/
Thermific® Gas-Fired Boiler
Introduction
1.0 INTRODUCTION
Direct vent (ANSI Z21.13) is a closed system method
of ducting the combustion air directly from the outside
of the building into the inlet compartment of the
burner, and a sealed exhaust vent from the combustion
chamber to the outdoors.
1.1.2 Fresh Air System
(ducted combustion air system)
In some instances compliance with ANSI Z21.13 may
not be required, in which case a "fresh air system" may
be used. Consultation with qualified professionals is
required to determine whether a "fresh air system" is
suitable for any particular application and in
The direct vent/sealed combustion option is available
on the Thermific® boilers on Series 700, 1000, 1200,
1500, 1700, and 2000.
compliance with all applicable codes and regulations.
All flue gas outlet (exhaust vent) material for a fresh
air system must be certified for use with a Category I
Appliance. (Standard B-vent is approved.) The
exhaust vent may be run horizontally or vertically.
Proper vent sizing by the vent manufacturer's
recommendation must be followed.
Advantages are:
•
•
•
Savings in energy costs due to the elimination of
using conditioned air (heated and/or cooled
building air) from going back up the stack.
Isolation of the burner from pressure changes in
the building which can cause erratic combustion
performance.
1.2 BASIC INLET/VENT CONFIGURATIONS
Combustion air is taken from the outside which is
generally more clean than indoor air. Halide
contaminants within a building, such as chlorides,
can cause excessive corrosion in the burner, heat
exchanger and venting system.
Four basic configurations are allowable for the
combustion air inlet and flue gas exhaust vent, as
follows; installation details are provided in Section 3.
•
Eliminates the need for two large combustion
air/ventilation air openings into the mechanical
space.
Exhaust
Vent
Roof
1.1 CODE COMPLIANCE
Sidewall
1.1.1 Direct Vent/Sealed Combustion System
(complying with ANSI Z21.13)
All flue gas outlet (exhaust vent) material must
comply with UL-1738. (Standard B-vent is not
approved.) Proper vent sizing by the vent
manufacturer's recommendation must be followed.
The exhaust vent may be run horizontally or vertically.
The maximum allowable length of the exhaust vent for
horizontal installations, including the boot tee/135º
(not a standard tee) and the termination is 100
equivalent feet. Refer to Section 3.4.5 for equivalent
lengths.
Air Inlet
1. Combustion air inlet duct through the sidewall and
the flue gas exhaust through the roof. This is the
preferred method.
Page 1
Thermific® Gas-Fired Boiler
Introduction/Safety
Sidewall
Air Inlet
Exhaust
Vent
Roof
Exhaust
Vent
Sidewall
Air Inlet
2. Both the combustion air inlet and flue gas exhaust
through the sidewall.
4. The combustion air inlet from the roof and the flue
gas exhaust through the sidewall.
1.3 PURPOSE AND SCOPE OF THIS MANUAL
Exhaust
Vent
Air Inlet
This manual is a supplement and companion to the
Thermific Installation and Owner's Manual. "TBIG."
Both documents must be used together.
This companion document describes those safety,
installation, adjustment, and maintenance procedures
which differ from the standard model. Information
that applies to both models is found in the "TBIG"
latest edition.
Roof
2.0 SAFETY
Refer to the manual for the standard Thermific® Gas-
Fired Boiler for safety information applicable to this
equipment. Safety information applicable only to the
direct vent option appears below.
3. The combustion air inlet from the roof and the flue
gas exhaust through the roof.
Danger!
Acceptable Venting Methods:
The only acceptable venting methods are the four
configurations shown in Section 1.2. Do not attempt
to use any other method of obtaining combustion air or
venting flue gases.
Page 2
Thermific® Gas-Fired Boiler
Installation
Do not manifold two (2) or more units into a common
sidewall vent system without provisions for additional
forced draft.
silicone sealant, or equivalent, must be used on each
circumferential and horizontal joint before joining
together. At least 24 hours must be allowed for cure
of this sealant and proper bond. Cure time can be
reduced through the application of heat (See
instructions provided with the sealant). After the cure
period, each joint must be wrapped with an aluminum
tape which is faced on the contact side with an
adhesive.
3.0 INSTALLATION
3.1 COMPONENTS PROVIDED
The direct vent/sealed combustion option is shipped
with the following items shipped loose for field
installation:
3.2.2.2 PVC Duct
Proper sealing of the tubing is necessary to prevent
flow of combustion air from conditioned space.
ƒ
Custom 6 inch diameter to 12 inch diameter
transition duct with extension, for attachment to
the combustion air inlet on the boiler.
The installation must follow the vent manufacturer's
instructions in all respects including proper joining and
sealing of the tubing and fittings. Clearances to
combustible materials and installation of firestops
must conform to applicable codes.
ƒ
ƒ
A 12" inlet damper assembly with actuator and
limit switch mounted to the damper shaft.
Auxiliary Control Panel to operate the inlet
damper assembly.
3.2.3 Air Inlet Termination
The inlet damper assembly and control panel will
prevent the flow of cold air through the boiler during
the off cycle and prevent freeze up and "off cycle"
losses. The use of these two items is optional.
Outside Plate
Centering
Support
Plate
Cover Plate
Fastener
Sealant
Recommended
Termination
(refer to text).
3.2 COMBUSTION AIR INLET SYSTEM
Note:
3.2.1 System Design - Pressure Drop
Sealant
The air inlet duct system shall be designed for a
maximum pressure drop of 0.05" W.C. taking into
account the equivalent length of all fittings. Refer to
Section 3.4.5 for equivalent length of fittings.
Field Provided
Inlet Screen
12" Min.
The boiler combustion air inlet duct must be fitted
with a termination device meeting the requirements of
ANSI Z21.13. There are four recommended sidewall
terminations:
3.2.2 Inlet Duct
Materials shall be single wall galvanized duct
(minimum thickness 26 gauge) or PVC duct tubing
(0.187 inch wall thickness) only. No substitutions.
•
•
•
•
Double wall B vent 90 degree elbow, or
Two double wall B vent 45 degree elbows, or
Schedule 40 PVC 90 degree elbow, or
Properly engineered intake louver screen.
3.2.2.1 Single Wall Galvanized Duct
Proper sealing of the tubing is necessary to prevent
flow of combustion air from conditioned space. If
single wall galvanized tubing is used, GE RTV 102
Page 3
Thermific® Gas-Fired Boiler
Installation
Whichever material is used, the termination must point
down and must be backed by a metal plate secured to
the wall.
Damper
Transition
Duct
Round
Important: The chosen inlet termination must be
included in the calculation of the maximum allowable
equivalent length. See Section 3.4.5 for equivalent
lengths.
Damper
Housing
Correct rain cap,
unrestricted.
Typical incorrect
rain cap.
(Sidewall installation shown.)
The boiler is equipped with a special collar attached to
the air inlet opening on the back of the unit (at the
blower housing on Series 700, 1000, and 1200; at the
back of the cabinet on Series 1500, 1700 and 2000.).
A separate box of accessories is sent with the boiler.
If the combustion air inlet duct is routed through the
roof, the termination must be either the same type as
described for a sidewall installation or a rain cap. The
rain cap must be unrestrictive type similar to the
illustration below.
1. Attach the 6 inch diameter end of the custom
transition duct and the extension to the collar using
a minimum of 4 sheet metal screws spaced
approximately at 90 degree intervals. This joint
must then be wrapped with an aluminum tape
backed on the contact side with an adhesive. Do
not use "duct tape."
3.2.4 Inlet Duct Assembly at the Boiler
Important: do not insulate the transition duct or
extension.
Roof
Refer to Section 3.2 for instructions for installing and
wiring the auxiliary control panel; it is required if the
optional inlet damper is used.
Round
Transition
Duct
Damper
3.2.4.1 Sealing PVC Duct Tubing to the Inlet Duct
90o Elbow
Apply a 3/4" wide x 1/8" thick gasket to the outside
surface edge of the entire circumference of the
transition duct (or extension). A closed cell foam
rubber gasket with pressure sensitive adhesive works
very well. Insert 3/4" of the transition duct into the
PVC duct tubing so that the gasket lines up with the
edge of the PVC tubing. Lay an approximate 3/8"
wide bead of GE RTV-102 silicone sealant, or
equivalent, along the gap between the gasket and
inside wall of the tubing. Allow the silicone sealant to
cure for 24 hours. The cure time can be shortened
Damper
Housing
(Roof installation shown.)
Page 4
Thermific® Gas-Fired Boiler
Installation
with the application of heat. Refer to the
manufacturer's instructions. Wrap the joint with
aluminum tape which is backed with an adhesive on
the contact side.
1. Terminals for the damper actuator:
DO = Damper Open (CW)
DC = Damper Closed (CCW)
DN = Neutral/Common
2. Terminals for the limit (end) switch
3.2.5 Inlet Damper and Auxiliary Control
Panel (optional)
SI = N.O. (Normally Open)
S2 = Common
Note:
The inlet damper assembly and control panel will
prevent the flow of cold air through the boiler during
the off cycle and prevent freeze up. These two items
are optional in all installations.
3.3 EXHAUST VENTING SYSTEM
3.3.1 System Design - Materials, Length, Size,
and Construction
Refer to Section 4.1 for a description of the control
sequence applicable to the inlet damper.
The flue gas outlet (exhaust vent) must be designed to
comply with UL 1738 and ULC-636. (Refer to
Section 1.1.2 for situations where alternate compliance
may be permitted.) The exhaust vent can be run
horizontally or vertically.
The damper must be field installed into a section of
horizontal or vertical inlet ductwork. Orient the
damper such that the arrow points towards the boiler.
The vent must be sized according to the vent
manufacture's recommendations. Consult the vent
supplier for correct sizing and structural support
requirements. Vent diameter is dictated by the length
and height of horizontal and vertical portions of the
vent installation and materials of construction. Design
calculations should be based on a negative 0.03 W.C.
with a stack temperature of 325º F (gross) and a CO2
level of 7.6%; (these values are to be used for vent
sizing calculations.) The maximum allowable length
of the vent duct, including the boot tee/135º tee (not a
standard tee) and the termination is 100 equivalent
feet. See Section 3.4.5 for the equivalent length of the
fittings.
3.2.5.1 Field Wiring to Auxiliary Control Panel
The auxiliary control panel controls the inlet damper
(if used). The auxiliary control panel does not have to
be mounted on or near the boiler; it can be remotely
mounted.
Use 16GA MTW Wire for all field wiring. See
Section 6 for the logic and wiring diagrams of this
auxiliary control panel and the sealed combustion
boilers.
There are five (5) field run wires between the boiler
and its auxiliary control panel; three (3) for main
power supply and two (2) wires for boiler
interconnect.
3.3.2 Flue Gas Outlet Duct
1. The main power supply (G/H/N) must come from
the same boiler that the damper is connected to.
The installation must follow the vent manufacturer's
instructions in all respects including proper joining and
sealing of the tubing and fittings, clearances to
combustible materials and installation of firestops.
2. Remove the blue jumper wire in the terminal block
on the boiler when wiring.
There are also five (5) field run wires between the
auxiliary control panel and the inlet damper assembly;
three (3) to the damper actuator and two (2) to the
limit switch.
Page 5
Thermific® Gas-Fired Boiler
Installation
3.3.3 Exhaust Vent Connection at the Boiler
from the outlet of the boot tee/ 135º tee to the inlet of
the elbow. In addition, for sidewall venting, it is very
important to provide a downward pitch of at least 1/4
inch per foot of run from the termination at the wall
toward the boiler for proper drainage of the condensate
and for buoyancy assist of the flue gas. Furthermore,
do not locate sidewall terminations over area of
pedestrian or vehicular traffic due to potential
Pitch toward boiler
1/4" per foot min.
condensate drippage and ice build-up. See Section 3.4
Clearances for more information.
6' Min.
When joining the double wall tubing and fittings, it is
important to orient the male end of the section toward
the boiler. The female end is positioned away from
the boiler towards the vent terminal. Follow the vent
manufacturer's instructions for proper installation.
Boot Tee/
135o Tee
Trap Loop
3.3.4 Flue Gas Termination
3" Min.
Condensate Drain
To sewer trap
Outside Plate
Centering
Support
Plate
Cover Plate
Fastener
or condensate pump.
Recommended
termination
(refer to text).
Sealant
At the outlet of the boiler, an adjustable or fixed length
(minimum 2 feet for clearance from inlet duct;
maximum 3 feet for proper lift) section may be
utilized. This section must be secured to the outlet
collar by a minimum of 4 sheet metal screws spaced at
approximately 90 degree intervals.
Sealant
Even though the unit is classified as a Category I
boiler (Non-pressurized-non condensing), there are
certain abnormal conditions which may cause
condensation in the flue vent. Therefore, it is
recommended that a tee cover with a drain be provided
at the bottom of the boot tee/135º tee. For proper
disposal of the condensate, corrosion resistant tubing
or plastic tubing should be connected to the drain
nipple. Before connecting the tubing to the tee cover
nipple, the trap loop must be primed by pouring a
small quantity of water into the drain line. The
condensate drain line can be routed to a sewer drain
trap or pump. Consult the vent manufacturer's
instructions for proper installation of drain line.
12" Min.
The exhaust vent termination must be a P-K
recommended device. There are four approved
sidewall terminations:
ƒ
ƒ
ƒ
ƒ
90º elbow pointing down, or
Two 45º elbows pointing down, or
45º elbow pointing down, or
Standard tee pointing up/down.
Important: The equivalent length of the chosen
termination must be included in the calculation of the
maximum allowable equivalent length. See Section
3.4.5 for equivalent lengths.
In transitioning from horizontal to vertical, a double
wall boot tee/135º tee must be installed (not a standard
tee). If the flue gas exhaust is to be routed through the
sidewall, a minimum vertical rise of 6 feet is required
Page 6
Thermific® Gas-Fired Boiler
Installation
Whichever termination is chosen, it must be double
wall vent certified under UL 1738, or ULC-636.
When installing a sidewall exhaust system the
termination must be backed by a metal plate secured to
the wall as shown in the figure.
unrestrictive type similar to the figure above. Elbows
are also acceptable.
3.4.5 Equivalent Length of Fittings
Fitting Description
90º Elbow
45º Elbow
Equivalent Length
10 feet
5 feet
Correct rain cap,
unrestricted.
Typical incorrect
rain cap.
Rain Cap
10 feet
Boot Tee/135º Tee
10 feet
Standard Tee Used as a 10 feet
Vent Termination
3.4 CLEARANCES
If the exhaust vent is routed through the roof, the
termination must be either the same type as described
for a sidewall installation or a rain cap. The preferred
method to terminate the exhaust vent is with a rain cap
to minimize the drippage of condensate onto the roof
and ice build-up. The rain cap should be an
In addition to any clearance requirements in Sections
3.1 and 3.3 the following clearances must be
maintained for inlet and vent components.
3.4.1 Sidewall Installations
Flue Gas
Outlet
Flue Gas
Outlet
Combustion
Air Intake
2' to snow
line
Page 7
Thermific® Gas-Fired Boiler
Installation
If the air inlet and/or exhaust vent terminal are through
the sidewall, clearances from other exhaust/inlet,
windows, doors, building openings, snow line, etc
must be as shown in the figure above.
Clearances which must be maintained when both inlet
and exhaust are through the roof are shown in the
figures above.
There must be either 5' vertical separation or 10'
horizontal separation between the flue gas outlet and
the combustion air inlet.
3.4.3 Minimum Clearance for Boiler
Connections
The bottom of the flue gas outlet must be located at
least 12 inches above finish grade or snow line, but
must be at least 7 feet above finish grade when located
adjacent to a public walkway. It must also have a
minimum clearance of 4 feet horizontally from, and in
no case above or below, (unless a 4 foot horizontal
distance is maintained,) electric meters, gas meters,
regulators and relief equipment.
There are special considerations needed when
installing the air inlet and exhaust duct systems
because of the orientation of these connections on the
boilers.
3.4.3.1 Series 700, 1000, 1200
Air Inlet
Round
3.4.2 Rooftop Installations
10' min.
Damper
Flue Gas
Outlet
Combustion
Air Inlet
90o Elbow
4' min.
4' min.
26" Min.
*
above
snow line
* Dimension shown above is based on 12" round
ductwork.
10' min.
A minimum clearance of 26 inches is required on the
left side of the boiler to permit the connection of the
air inlet duct to the boiler.
Vent
Flue Gas
Outlet
Combustion
Air Inlet
4' min.
4' min.
above
snow line
Page 8
Thermific® Gas-Fired Boiler
Installation/Operation
3.4.3.2 Series 1500, 1700, 2000
normally closed contacts on the time delay relay
and energizes the coil on the relay in the Auxiliary
Control Panel. The relay will in turn energize the
damper actuator to open the damper. When the
damper is in the full open position, the limit switch
will close and supply power to the contactor for
the blower motor.
Exhaust
Vent
Air Inlet
Round
Damper
90o Elbow
During this time (about 20 seconds), the air switch
will indicate low air flow with the "LowAir"
indicator. This indicator will remain on until
sufficient air flow is sensed. If the air flow switch
is not closed in 120 seconds, the time delay relay
will open its normally closed contacts. This will
turn off the blower motor and close the inlet
damper. The "Low Air" indicator will remain
illuminated and the boiler will not operate.
Transition
Duct
27" Min.*
31"
*
Boot Tee/
135o Tee
4.2 COMBUSTION OPERATING CONDITIONS
The combustion air characteristic of the burner in this
boiler is factory set at a condition of utilizing
approximately 50% excess air at room temperature
(70ºF). Therefore, when taking combustion air from
the outdoors in a direct vent system, adjustment of the
combustion air damper linkage should not be made
until the carbon dioxide or oxygen reading is referred
to this condition.
To Drain
24"
44" Min.
*
* Dimension shown above is based on 12" round
ductwork.
A minimum of 44 inches is required behind the boiler
to fit the inlet and exhaust connections.
The density of cold outdoor air will be greater than
warm air taken from inside the building. Thus, the
combustion air blower with outdoor air will deliver a
higher air density flow to the burner.
The figure above suggests a duct arrangement using
standard duct pieces that will maintain this minimum
clearance of 44 inches.
A boiler can be subjected to varying combustion air
temperatures. You must put some thought into the
air/fuel adjustments to prevent hard start and/or light
off rumbling problems. Due to a wide range of
operating conditions, Patterson-Kelley developed a
guide for different conditions.
P-K recommends that the service technician observe
the combustion air temperature range. Identify the
temperature operating conditions of your boiler.
The operational range setting for O2 is 6.0% to 8.0%.
Insert your 100º F operating temperature range in the
chart below. Start with the Minimum Temperature at
the top of the chart; insert temperatures using 5º F
increments.
4.0 OPERATION
4.1 SEQUENCE OF OPERATION
This sequence applies if the optional inlet damper
assembly and auxiliary control panel are used. If not
the standard Thermific® control sequence applies.
(Replaces step #6 of the Sequence of Operation in the
Installation and Owner's Manual. "TBIG.")
6. The programmer first energizes Terminal 4 which
supplies power to the airflow switch and initiates
the adjustable 120 sec. timer on the time delay
relay. Terminal 4 also supplies power through the
Page 9
Thermific® Gas-Fired Boiler
Operation/Maintenance
When the chart is completed, set up your boiler's
combustion to the corresponding information at the
temperature relative during the time of the start up.
4.2.1 Combustion Air Requirement, SCFM
Series Series
Series
1200
291
Series
1500
364
Series
1700
413
Series
2000
501
Enter your 100º F
operational range.
% Oxygen
% Carbon
Dioxide
700
170
1000
251
8
7.2
7.3
7.4
7.4
7.5
7.5
7.6
7.6
7.7
7.7
7.8
7.8
7.9
8
7.9
7.8
7.7
7.6
7.5
7.4
7.3
7.2
7.1
7.0
6.9
6.8
6.7
6.6
6.5
6.4
6.3
6.2
6.1
6
5.0 MAINTENANCE
Maintenance procedures for the Direct Vent option are
the same as for the standard Thermific® model. Refer
to the Thermific Installation and Owner's Manual.
"TBIG," latest edition.
8
8.1
8.1
8.2
8.2
8.3
8.3
Important: measure combustion air temperature at the
unit; do not assume the combustion air temperature is
the same as the outside air temperature.
Page 10
Thermific® Gas-Fired Boiler
Wiring Diagrams
6.0 WIRING DIAGRAMS
6.1 ON-OFF SERIES 700, 1000, 1200
Wiring Diagram
Page 11
Thermific® Gas-Fired Boiler
Wiring Diagrams
6.1 ON-OFF SERIES 700, 1000, 1200
Logic Diagram
Page 12
Thermific® Gas-Fired Boiler
Wiring Diagrams
6.1A ON-OFF IRI SERIES 700, 1000, 1200
Wiring Diagram
Page 13
Thermific® Gas-Fired Boiler
Wiring Diagrams
6.1A ON-OFF IRI SERIES 700, 1000, 1200
Logic Diagram
Page 14
Thermific® Gas-Fired Boiler
Wiring Diagrams
6.1B LO-HI LO
Wiring Diagram
Page 15
Thermific® Gas-Fired Boiler
Wiring Diagrams
6.1B LO-HI LO
Logic Diagram
Page 16
Thermific® Gas-Fired Boiler
Wiring Diagrams
6.1C LO-HI-LO IRI
Wiring Diagram
Page 17
Thermific® Gas-Fired Boiler
Wiring Diagrams
6.1C LO-HI-LO IRI
Logic Diagram
Page 18
Thermific® Gas-Fired Boiler
Wiring Diagrams
6.1D ON-OFF SERIES 1500, 1700, 2000
Wiring Diagram
Page 19
Thermific® Gas-Fired Boiler
Wiring Diagrams
6.1D ON-OFF SERIES 1500, 1700, 2000
Logic Diagram
Page 20
Thermific® Gas-Fired Boiler
Wiring Diagrams
6.1E ON-OFF IRI SERIES 1500, 1700, 2000
Wiring Diagram
Page 21
Thermific® Gas-Fired Boiler
Wiring Diagrams
6.1E ON-OFF IRI SERIES 1500, 1700, 2000
Logic Diagram
Page 22
Thermific® Gas-Fired Boiler
Wiring Diagrams
6.2 AUXILIARY CONTROL PANEL
6.2.1 On-Off Auxiliary Control Panel
Page 23
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