York Gf9s Dh User Manual

INSTALLATION MANUAL  
HIGH EFFICIENCY  
EFFICIENCY  
RATING  
CERTIFIED  
TUBULAR HEAT EXCHANGER SERIES  
MODELS: GY9S*DH / GM9S*DH / GF9S*DH  
(Single Stage Downflow/Horizontal)  
40 - 120 MBH INPUT  
ISO 9001  
Certified Quality  
Management System  
(11.72 - 35.17 KW) INPUT  
LIST OF SECTIONS  
SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1  
DUCTWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
FILTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7  
GAS PIPING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
ELECTRICAL POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10  
TWINNING AND STAGING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13  
COMBUSTION AIR AND VENT SYSTEM . . . . . . . . . . . . . . . . . . . . .14  
CONDENSATE PIPING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22  
SAFETY CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31  
START-UP AND ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . .31  
WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39  
LIST OF FIGURES  
Transition Kit Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6  
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7  
Return Filter Grill and Return Duct Installation . . . . . . . . . . . . . . . . . . . 8  
Typical Attic Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8  
Typical Suspended Furnace / Crawl Space Installation . . . . . . . . . . . . 9  
Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
Downflow Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
Horizontal Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
Electrical Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11  
Thermostat Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12  
Accessory Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13  
Typical Twinned Furnace Application . . . . . . . . . . . . . . . . . . . . . . . . 13  
Single Stage Twinning Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . 14  
Two-Stage Twinning Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . 14  
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16  
Home Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17  
Downflow/Horizontal Vent Assembly . . . . . . . . . . . . . . . . . . . . . . . . . 18  
Termination Configuration - 1 Pipe . . . . . . . . . . . . . . . . . . . . . . . . . . 18  
Termination Configuration - 2 Pipe . . . . . . . . . . . . . . . . . . . . . . . . . . 18  
Termination Configuration - 2 Pipe Horizontal . . . . . . . . . . . . . . . . . . 18  
Crawl Space Termination Configuration - 2Pipe . . . . . . . . . . . . . . . . 19  
Double Horizontal Sealed Combustion Air and Vent Termination . . . 19  
Double Vertical Sealed Combustion Air and Vent Termination . . . . . 19  
Sealed Combustion Air Intake Connection and Vent Connection . . .19  
Combustion Airflow Path Through The Furnace Casing to the Burner  
Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20  
Outside and Ambient Combustion Air . . . . . . . . . . . . . . . . . . . . . . . . .21  
Attic Combustion Air Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . .22  
Condensate Drain Internal Hose Routing . . . . . . . . . . . . . . . . . . . . . .22  
Downflow Condensate Drain Hose Configuration . . . . . . . . . . . . . . .23  
Horizontal Left Condensate Drain Hose Configuration . . . . . . . . . . . .24  
Horizontal Left Condensate Drain Hose Configuration . . . . . . . . . . . .25  
Horizontal Right Condensate Drain Hose Configuration  
(Option 1 - Front of Casing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27  
Horizontal Right Condensate Drain Hose Configuration  
(Option 1 - Front of Casing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28  
Horizontal Right Condensate Drain Hose Configuration  
(Option 2 - Back of Casing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29  
Horizontal Right Condensate Drain Hose Configuration  
(Option 2 - Back of Casing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30  
Pressure Switch Tubing Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . .31  
Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34  
Reading Gas Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35  
Furnace Control Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35  
Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39  
LIST OF TABLES  
Unit Clearances to Combustibles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
Minimum Duct Sizing For Proper Airflow . . . . . . . . . . . . . . . . . . . . . . . 5  
Round Duct Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5  
Cabinet and Duct Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7  
Recommended Filter Sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7  
Nominal Manifold Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10  
Electrical and Performance Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10  
Maximum Equivalent Pipe Length . . . . . . . . . . . . . . . . . . . . . . . . . . . 15  
Equivalent Length of Fittings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15  
Elbow Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16  
Combustion Air Intake and Vent Connection Size at Furnace  
(All Models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16  
Estimated Free Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20  
Free Area - Outdoor Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20  
Unconfined Space Minimum Area in Square Inches . . . . . . . . . . . . .20  
Condensate Drain Hose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22  
Inlet Gas Pressure Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34  
Nominal Manifold Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34  
Blower Performance CFM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37  
Filter Performance - Pressure Drop Inches W.C. and (kPa) . . . . . . . .37  
SECTION I: SAFETY  
This is a safety alert symbol. When you see this symbol on  
labels or in manuals, be alert to the potential for personal  
injury.  
Improper installation may create a condition where the operation of  
the product could cause personal injury or property damage.  
Improper installation, adjustment, alteration, service or mainte-  
nance can cause injury or property damage. Refer to this manual  
for assistance or for additional information, consult a qualified con-  
tractor, installer or service agency.  
Understand and pay particular attention to the signal words DANGER,  
WARNING, or CAUTION.  
DANGER indicates an imminently hazardous situation, which, if not  
avoided, will result in death or serious injury.  
WARNING indicates a potentially hazardous situation, which, if not  
avoided, could result in death or serious injury.  
CAUTION indicates a potentially hazardous situation, which, if not  
avoided may result in minor or moderate injury. It is also used to  
alert against unsafe practices and hazards involving only property dam-  
age.  
This product must be installed in strict compliance with the installa-  
tion instructions and any applicable local, state, and national codes  
including, but not limited to building, electrical, and mechanical  
codes.  
268890-UIM-B-0607  
268890-UIM-B-0607  
INSPECTION  
As soon as a unit is received, it should be inspected for possible dam-  
age during transit. If damage is evident, the extent of the damage  
should be noted on the carrier’s freight bill. A separate request for  
inspection by the carrier’s agent should be made in writing. Also, before  
installation the unit should be checked for screws or bolts, which may  
have loosened in transit. There are no shipping or spacer brackets  
which need to be removed.  
The furnace area must not be used as a broom closet or for any  
other storage purposes, as a fire hazard may be created. Never  
store items such as the following on, near or in contact with the fur-  
nace.  
1. Spray or aerosol cans, rags, brooms, dust mops, vacuum  
cleaners or other cleaning tools.  
2. Soap powders, bleaches, waxes or other cleaning com-  
pounds; plastic items or containers; gasoline, kerosene, ciga-  
rette lighter fluid, dry cleaning fluids or other volatile fluid.  
3. Paint thinners and other painting compounds.  
FURNACE LOCATION AND CLEARANCES  
The furnace shall be located using the following guidelines:  
1. Where a minimum amount of air intake/vent piping and elbows will  
be required.  
4. Paper bags, boxes or other paper products  
2. As centralized with the air distribution as possible.  
Never operate the furnace with the blower door removed. To  
do so could result in serious personal injury and/or equipment  
damage.  
3. Where adequate combustion air will be available (particularly  
when the appliance is not using outdoor combustion air).  
4. Where it will not interfere with proper air circulation in the confined  
space.  
FOR FURNACES INSTALLED IN THE COMMON-  
WEALTH OF MASSACHUSETTS ONLY  
5. Where the outdoor combustion air/vent terminal will not be blocked  
or restricted. Refer to “COMBUSTION AIR / VENT CLEAR-  
ANCES” located in SECTION VII of these instructions. These min-  
imum clearances must be maintained in the installation.  
For all side wall horizontally vented gas fueled equipment installed in  
every dwelling, building or structure used in whole or in part for resi-  
dential purposes, including those owned or operated by the Com-  
monwealth and where the side wall exhaust vent termination is less  
than seven (7) feet above finished grade in the area of the venting,  
including but not limited to decks and porches, the following require-  
ments shall be satisfied:  
6. Where the unit will be installed in a level position with no more  
than 1/4” (0.6 cm) slope side-to-side and front-to-back to provide  
proper condensate drainage.  
Installation in freezing temperatures:  
1. Furnace shall be installed in an area where ventilation facilities  
provide for safe limits of ambient temperature under normal oper-  
ating conditions. Ambient temperatures must not fall below 32°F  
(0°C) unless the condensate system is protected from freezing.  
1. INSTALLATION OF CARBON MONOXIDE DETECTORS. At  
the time of installation of the side wall horizontal vented gas  
fueled equipment, the installing plumber or gasfitter shall  
observe that a hard wired carbon monoxide detector with an  
alarm and battery back-up is installed on the floor level where  
the gas equipment is to be installed. In addition, the installing  
plumber or gasfitter shall observe that a battery operated or  
hard wired carbon monoxide detector with an alarm is installed  
on each additional level of the dwelling, building or structure  
served by the side wall horizontal vented gas fueled equipment.  
It shall be the responsibility of the property owner to secure the  
services of qualified licensed professionals for the installation of  
hard wired carbon monoxide detectors  
2. Do not allow return air temperature to be below 55º F (13° C) for  
extended periods. To do so may cause condensation to occur in  
the main heat exchanger, leading to premature heat exchanger  
failure.  
Improper installation in an ambient below 32ºF (0.0° C) could create  
a hazard, resulting in damage, injury or death.  
a. In the event that the side wall horizontally vented gas  
fueled equipment is installed in a crawl space or an attic,  
the hard wired carbon monoxide detector with alarm and  
battery back-up may be installed on the next adjacent floor  
level.  
3. If this furnace is installed in any area where the ambient tempera-  
ture may drop below 32° F (0° C), a UL listed self-regulated heat  
tape must be installed on any condensate drain lines. It is required  
that self regulating heat tape rated at 3 watts per foot be used.  
This must be installed around the condensate drain lines in the  
unconditioned space. Always install the heat tape per the manu-  
facturer's instructions. Cover the self-regulating heat tape with  
fiberglass, Armaflex or other heat resistant insulating material.  
b. In the event that the requirements of this subdivision can  
not be met at the time of completion of installation, the  
owner shall have a period of thirty (30) days to comply with  
the above requirements; provided, however, that during  
said thirty (30) day period, a battery operated carbon mon-  
oxide detector with an alarm shall be installed.  
4. If this unit is installed in an unconditioned space and an extended  
power failure occurs, there will be potential damage to the conden-  
sate trap, drain lines and internal unit components. Following a  
power failure situation, do not operate the unit until inspection and  
repairs are performed.  
2. APPROVED CARBON MONOXIDE DETECTORS. Each car-  
bon monoxide detector as required in accordance with the  
above provisions shall comply with NFPA 720 and be ANSI/UL  
2034 listed and IAS certified.  
Clearances for access:  
Ample clearances should be provided to permit easy access to the unit.  
The following minimum clearances are recommended:  
3. SIGNAGE. A metal or plastic identification plate shall be perma-  
nently mounted to the exterior of the building at a minimum  
height of eight (8) feet above grade directly in line with the  
exhaust vent terminal for the horizontally vented gas fueled  
heating appliance or equipment. The sign shall read, in print  
size no less than one-half (1/2) inch in size, "GAS VENT  
DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUC-  
TIONS".  
1. Twenty-four (24) inches (61 cm) between the front of the furnace  
and an adjacent wall or another appliance, when access is  
required for servicing and cleaning.  
2. Eighteen (18) inches (46 cm) at the side where access is required  
for passage to the front when servicing or for inspection or  
replacement of flue/vent connections.  
4. INSPECTION. The state or local gas inspector of the side wall  
horizontally vented gas fueled equipment shall not approve the  
installation unless, upon inspection, the inspector observes car-  
bon monoxide detectors and signage installed in accordance  
with the provisions of 248 CMR 5.08(2)(a)1 through 4.  
In all cases, accessibility clearances shall take precedence over clear-  
ances for combustible materials where accessibility clearances are  
greater.  
Unitary Products Group  
3
268890-UIM-B-0607  
When the furnace is used in conjunction with a cooling coil, the coil  
must be installed parallel with, or in the supply air side of the furnace to  
avoid condensation in the primary heat exchanger. When a parallel flow  
arrangement is used, dampers or other means used to control airflow  
must be adequate to prevent chilled air from entering the furnace. If  
manually operated, the damper must be equipped with means to pre-  
vent the furnace or the air conditioner from operating unless the damper  
is in full heat or cool position.  
Downflow/Horizontal furnaces for installation on combustible floor-  
ing only when installed on the accessory combustible floor base on  
wood flooring only and shall not be installed directly on carpeting,  
tile or other combustible material.  
Check the rating plate and power supply to be sure that the electri-  
cal characteristics match. All models use nominal 115 VAC, 1  
Phase 60Hz power supply.  
Furnace shall be installed so the electrical components are pro-  
tected from water.  
The duct system must be properly sized to obtain the correct airflow  
for the furnace size that is being installed.  
Refer to Table 7 and the furnace rating plate for the correct rise  
range and static pressures  
If the ducts are undersized, the result will be high duct static pres-  
sures and/or high temperature rises which can result in a heat  
exchanger OVERHEATING CONDITION. This condition can result  
in premature heat exchanger failure, which can result in personal  
injury, property damage, or death.  
Installation in a residential garage:  
1. A gas-fired furnace for installation in a residential garage must be  
installed so the burner(s) and the ignition source are located not  
less than 18 inches (46 cm) above the floor, and the furnace must  
be located or protected to avoid physical damage by vehicles.  
TABLE 1: Unit Clearances to Combustibles  
Application  
Top  
Downflow  
1 (2.5)  
3 (7.6)  
0 (0)  
Horizontal  
0 (0)  
FLOOR BASE AND DUCTWORK INSTALLATION  
Downflow Combustible Floor Base  
In. (cm)  
In. (cm)  
In. (cm)  
In. (cm)  
In. (cm)  
In. (cm)  
In. (cm)  
Front  
3 (7.6)  
0 (0)  
Rear  
Installations on combustible materials require the use a com-  
bustible floor base shown in Figure 1.  
Left Side  
Right Side  
Flue  
0 (0)  
1 (2.5)  
1 (2.5)  
0 (0)  
0 (0)  
The floor base must be secured to the floor. A supply air duct  
plenum with 1" (2.54 cm) flange is installed through the  
opening provided. The supply air duct is then secured to the  
duct system with screws and sealed to prevent leaks. Do not  
shoot screws through the flanges of the supply air duct into the top of  
the combustible floor base. Install the furnace on the combustible floor  
base so that the corners of the furnace are parallel with the corner  
brackets of the floor base. Follow the instructions supplied with the  
combustible floor base accessory.  
0 (0)  
1 (2.5)1  
Floor / Bottom  
Closet  
0 (0)  
Yes  
Yes  
Alcove  
Yes  
Yes  
Attic  
Yes  
Yes  
Yes2  
Line Contact  
NA  
1. Combustible floor base or air conditioning coil required for use on combusti-  
ble floor.  
2. Line contact only permitted between lines formed by the intersection of the  
rear panel (top in horizontal position) of the furnace jacket and building  
joists, studs or framing.  
This combustible floor base can be replaced with a matching cooling  
coil, properly sealed to prevent leaks. Follow the instructions supplied  
with the cooling coil cabinet for installing the cabinet to the duct connec-  
tor. Refer to the installation instructions for additional information.  
SECTION II: DUCTWORK  
DUCTWORK GENERAL INFORMATION  
When replacing an existing furnace, if the existing plenum is not the  
same size as the new furnace then the existing plenum must be  
removed and a new plenum installed that is the proper size for the new  
furnace.  
The duct system’s design and installation must:  
1. Handle an air volume appropriate for the served space and within  
the operating parameters of the furnace specifications.  
Ductwork Installation  
2. Be installed in accordance with standards of NFPA (National Fire  
Protection Association) as outlined in NFPA pamphlets 90A and  
90B (latest editions) or applicable national, provincial, or state, and  
local fire and safety codes.  
NOTE: When attaching duct flange, do not shoot the screw down into  
the casing. Use the formed flange intended for duct flange attachment.  
A proper Heat Loss/Gain Calculation should be done on all installations  
for proper application of equipment. From this the ductwork sizing can  
be calculated, ACCA Manual J and D and industry standards are help-  
ful.  
3. Create a closed duct system. For residential and Non-HUD Modu-  
lar Home installations, when a furnace is installed so that the sup-  
ply ducts carry air circulated by the furnace to areas outside the  
space containing the furnace, the return air shall also be handled  
by a duct(s) sealed to the furnace casing and terminating outside  
the space containing the furnace.  
The duct system is a very important part of the installation. If the duct  
system is improperly sized the furnace will not operate properly.  
The ducts attached to the furnace plenum, should be of sufficient size  
so that the furnace plenum should be if sufficient size so that the fur-  
nace operates at the specified external static pressure and within the air  
temperature rise specified on the nameplate.  
4. Complete a path for heated or cooled air to circulate through the  
air conditioning and heating equipment and to and from the condi-  
tioned space.  
Table 2 is a guide for determining whether the rectangular duct system  
that the furnace is being connected to be of sufficient size for proper fur-  
nace operation.  
The cooling coil must be installed in the supply air duct, down-  
stream of the furnace. Cooled air may not be passed over the heat  
exchanger.  
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Unitary Products Group  
268890-UIM-B-0607  
Use the Example below to help you in calculating the duct area to deter-  
mine whether the ducts have sufficient area so that the furnace oper-  
ates at the specified external static pressure and within the air  
temperature rise specified on the nameplate.  
2. The square inch area for 7 inch round ducts, 38.4 square inch x 2  
= 76.8 square inches,  
3. Then take the 192 square inch from the rectangular duct and add it  
to the 76.8 square inch of round duct. The total square inch of duct  
attached to the furnace supply plenum is 268.8 square inches.  
This exceeds the recommended 216 square inch of duct.  
The following are general duct sizing guidelines that may not serve to  
requirements of every application.  
In this example, the duct system attached to the plenum has a sufficient  
area so that the furnace operates at the specified external static pres-  
sure and within the air temperature rise specified on the nameplate.  
Providing the return duct is properly sized as well.  
Example: The furnace input is 80,000 BTUH, 1,200 CFM blower  
requirement. The recommended duct area is 216 sq.in, there are two 8  
x 12 rectangular ducts attached to the plenum and there are two 7 inch  
round ducts attached to the furnace.  
1. Take 8 x 12, which equals 96 square inch x 2 = 192 square inches  
then go to round duct size located in Table 3.  
TABLE 2: Minimum Duct Sizing For Proper Airflow  
Return1  
In² (cm²)  
Rectangular2  
Round2  
in. (cm)dia.  
18 (45.7)  
18 (45.7)  
18 (45.7)  
22 (55.8)  
22 (55.8)  
24 (60.9)  
24 (60.9)  
Supply3  
In²(cm²)  
Rectangular2  
Round2  
in. (cm)dia.  
16 (40.6)  
16 (40.6)  
16 (40.6)  
18 (45.7)  
18 (45.7)  
22 (55.8)  
22 (55.8)  
Input  
Nominal Airflow  
BTU/H(kW)  
40,000 (11.7)  
60,000 (17.6)  
80,000 (23.4)  
80,000 (23.4)  
100,000 (29.3)  
100,000 (29.3)  
120,000 (35.2)  
CFM(m³/min)  
1,200 (34.0)  
1,200 (34.0)  
1,200 (34.0)  
1,600 (45.3)  
1,600 (45.3)  
2,000 (56.6)  
2,000 (56.6)  
in. x in.(cm x cm)  
in. x in.(cm x cm)  
280 (1806)  
280 (1806)  
280 (1806)  
360 (2322)  
360 (2322)  
440 (2839)  
440 (2839)  
14 x 20 (35.6 x 90.8)  
14 x 20 (35.6 x 50.8)  
14 x 20 (35.6 x 50.8)  
18 x 20 (45.7 x 50.8)  
18 x 20 (45.7 x 50.8)  
20 x 22 (50.8 x 55.8)  
20 x 22 (50.8 x 55.8)  
216 (1394)  
216 (1394)  
216 (1394)  
280 (1806)  
280 (1806)  
390 (2516)  
390 (2516)  
12 x 18 (30.5 x 45.7)  
12 x 18 (30.5 x 45.7)  
12 x 18 (30.5 x 45.7)  
14 x 20 (35.6 x 50.8)  
14 x 20 (35.6 x 50.8)  
16 x 22 (40.6 x 55.8)  
16 x 22 (40.6 x 55.8)  
NOTE: This chart does not replace proper duct sizing calculations or take into account static pressure drop for run length and fittings. Maintain proper temperature rise  
and static pressures.  
1. Maximum return air velocity in rigid duct @ 700 feet per minute (213 m/min).  
2. Example return main trunk duct minimum dimensions.  
3. Maximum supply air velocity in rigid duct @ 900 feet per minute (274m/min).  
The transition duct must be the same dimensional size as the rectangu-  
lar opening in the base of the furnace.  
TABLE 3: Round Duct Size  
Round Duct Size  
Inches (cm)  
Calculated Area For Each Round Duct Size  
Sq.in (cm2)  
19.6 (126)  
28.2 (182)  
38.4 (248)  
50.2 (324)  
63.6 (410)  
78.5 (506)  
95 (613)  
DOWNFLOW  
FURNACE  
5 (13)  
6 (15)  
7 (18)  
WARM AIR PLENUM  
WITH 1” FLANGES  
8 (20)  
9 (23)  
FIBERGLASS  
INSULATION  
10 (25)  
11 (28)  
12 (30)  
13 (33)  
14 (36)  
113.1 (730)  
132.7 (856)  
153.9 (993)  
FIBERGLASS TAPE  
UNDER FLANGE  
1. The Air Temperature Rise is determined by subtracting the Return  
COMBUSTIBLE FLOOR  
BASE ACCESSORY  
Air Temperature Reading from the Supply Air Temperature Read-  
ing.  
2. The External Static Pressure is determined by adding the Supply  
Duct Static Pressure reading to the Return Duct Static Pressure  
reading.  
FIGURE 1 : Combustible Floor Base Accessory  
TABLES 2 AND 3 are to be used as a guide only to help the installer  
determine if the duct sizes are large enough to obtain the proper air flow  
(CFM) through the furnace. TABLES 2 and 3 ARE NOT to be used to  
design ductwork for the building where the furnace is being installed.  
There are several variables associated with proper duct sizing that are  
not included in the tables. To properly design the ductwork for the build-  
ing, Refer to the ASHRAE Fundamentals Handbook, Chapter on  
“DUCT DESIGN” or a company that specializes in Residential and Mod-  
ular Home duct designs.  
The supply air temperature MUST NEVER exceed the Maximum  
Supply Air Temperature, specified on the nameplate.  
Operating the furnace above the maximum supply air temperature  
will cause the heat exchanger to overheat, causing premature heat  
exchanger failure. Improper duct sizing, dirty air filters, incorrect  
manifold pressure, incorrect gas orifice and/or a faulty limit switch  
can cause the furnace to operate above the maximum supply air  
temperature. Refer to sections II, III, IX & X for additional informa-  
tion on correcting the problem.  
IMPORTANT: If the supply air duct is being connected to the furnace  
without the use of an accessory duct connector, then a transition duct  
must be installed with flanges or tabs that are securely attach and  
sealed to the supply air duct and to the base of the furnace. The transi-  
tion duct must have insulation between the transition duct and any com-  
bustible material.  
Unitary Products Group  
5
268890-UIM-B-0607  
Downflow Air Conditioning Coil Cabinet  
Horizontal Models  
The Cooling Coil Cabinet can be used in place of the combustible floor  
base for downflow installations on combustible materials. The furnace  
should be installed with the cooling coil cabinet specifically intended for  
downflow applications. The cooling coil cabinet must be secured to the  
floor. A supply air duct plenum is installed through the opening pro-  
vided. The supply air duct is then secured to the duct system with  
screws and sealed to prevent leaks. If a matching cooling coil is used, it  
may be placed directly on the furnace outlet using the accessory transi-  
tion kit and sealed to prevent leakage. The transition kit must be used to  
secure the cooling coil cabinet to the furnace casing when installed in a  
downflow configuration.  
IMPORTANT: This furnace may be installed in a horizontal position on  
either side as shown above. It must not be installed on its back.  
Horizontal Installations With a Cooling Coil Cabinet  
The furnace should be installed with the cooling coil cabinet specifically  
intended for horizontal applications. If a matching cooling coil is used, it  
may be placed directly on the supply air side of the furnace and sealed  
to prevent leakage. A warm air duct plenum with 1" (2.54 cm) is  
installed through the opening provided. The supply air duct system is  
connected to the warm air plenum and sealed to prevent leaks.  
These kits are required in downflow application when using G*F* series  
coils. These kits are not required with MC/FC series coils, but please  
ensurethat the coil and furnace are sucured and that there are noair  
leaks.  
This transition kit may be installed in one of two ways. The transition kit  
may be installed and secured to either the furnace or the cooling coil  
cabinet by the use of screws and then it must be sealed to prevent  
leaks.  
IMPORTANT: The furnace, the cooling coil cabinet, and all duct work  
MUST BE SEALED as needed to prevent leaks, AND SECURED. Refer  
to the assembly drawing in Figure 2.  
Attach the supply plenum to the air conditioning coil cabinet outlet duct  
flanges through the use of S cleat material when a metal plenum is  
used. The use of an approved flexible duct connector is recommended  
on all installations. The connection to the furnace, air conditioning coil  
cabinet and the supply plenum should be sealed to prevent air leakage.  
If the transition kit has been installed on the cooling coil cabinet it  
must be secured to the cooling coil cabinet with screws. The sup-  
ply air side of the furnace is then placed on the cooling coil cabi-  
net and then sealed for leaks.  
If the transition kit has been installed on the supply air side of the  
furnace it must be secured to the furnace with screws. The fur-  
nace and the transition kit are then placed on the cooling coil cab-  
inet and then sealed for leaks.  
The sheet metal plenum should be crosshatched to eliminate any pop-  
ping of the sheet metal when the indoor fan is energized. The minimum  
plenum height is 12" (30.5 cm). If the plenum is shorter than 12" (30.5  
cm) the turbulent air flow may cause the limit controls not to operate as  
designed, or the limit controls may not operate at all. Also the plastic  
drain pan in the under the air conditioning coil can overheat and melt  
Refer to the installation instructions supplied with the air conditioning  
coil for additional information.  
NOTE: Refer to instructions packed out with coil cabinet, for securing  
and sealing to the furnace.  
IMPORTANT: The furnace, transition kit, and the cooling coil cabinet  
MUST BE SEALED as needed to prevent leaks, AND SECURED. Refer  
to the assembly drawing in Figure 2.  
Horizontal Installations Without a Cooling Coil Cabinet  
IMPORTANT: On all installations without a coil, a removable access  
panel is recommended in the outlet duct such that smoke or reflected  
light would be observable inside the casing to indicate the presence of  
leaks in the heat exchanger. This access cover shall be attached in  
such a manner as to prevent leaks.  
When installing this appliance, the furnace must be installed so as to  
create a closed duct system, the supply duct system must be con-  
nected to the furnace outlet and the supply duct system must terminate  
outside the space containing the furnace. When replacing an existing  
furnace, if the existing plenum is not the same size as the new furnace  
then the existing plenum must be removed and a new plenum installed  
that is the proper size for the new furnace.  
AIRFLOW  
Attach the supply plenum to the furnace outlet duct flanges through the  
use of S cleat material when a metal plenum is used. The use of an  
approved flexible duct connector is recommended on all installations.  
This connection should be sealed to prevent air leakage. The sheet  
metal should be crosshatched to eliminate any popping of the sheet  
metal when the indoor fan is energized. On all installations without a  
coil, a removable access panel is recommended in the outlet duct such  
that smoke or reflected light would be observable inside the casing to  
indicate the presence of leaks in the heat exchanger. This access cover  
shall be attached in such a manner as to prevent leaks.  
TRANSITION  
KIT  
DOWNFLOW  
FURNACE  
REFRIGERANT  
LINES  
AIRFLOW  
COOLING  
COIL  
CABINET  
DRAIN  
CONNECTIONS  
AIRFLOW  
TRANSITION  
KIT  
AIRFLOW  
FIGURE 2: Transition Kit Assembly  
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268890-UIM-B-0607  
A
T-STAT WIRING 7/8” K.O.  
T-STAT WIRING 7/8” K.O.  
HORIZONTAL CONDENSATE  
DRAIN OPENING 1-3/4”  
HORIZONTAL CONDENSATE  
DRAIN OPENING 1-3/4”  
HORIZONTAL CONDENSATE  
DRAIN OPENING 2”  
HORIZONTAL  
CONDENSATE  
DRAIN OPENING 1-3/4”  
40  
JUNCTION BOX  
HOLE 7/8”  
JUNCTION BOX  
HOLE 7/8”  
GAS PIPE ENTRY 1-1/2”  
GAS PIPE  
ENTRY 1-1/2”  
CONDENSATE DRAIN  
HOLE 7/8”  
SIDE PIPING HOLE 3-3/8”  
CONDENSATE DRAIN  
HOLE 7/8”  
28-1/2  
FRONT  
LEFT SIDE  
RIGHT SIDE  
23-5/8  
1-1/4  
5/8  
19-1/4  
1-1/4  
5/8  
D
B
C
20  
2-1/4  
23-1/4  
TOP IMAGE  
RETURN END  
BOTTOM IMAGE  
SUPPLY END  
FIGURE 3: Dimensions  
TABLE 4: Cabinet and Duct Dimensions  
Cabinet Dimension  
BTUH (kW)  
CFM  
Cabinet  
Size  
Input/Output  
A (in.)  
A (cm)  
B (in.)  
B (cm)  
33.7  
41.3  
41.3  
50.2  
50.2  
50.2  
59.1  
C (in.)  
12  
C (cm)  
30.5  
38.1  
38.1  
47.0  
47.0  
47.0  
55.9  
D (in.)  
1-3/4  
1-3/4  
1-3/4  
2-1/8  
2-1/8  
2-1/8  
2-1/2  
D (cm)  
4.44  
4.44  
4.44  
5.40  
5.40  
5.40  
6.35  
40/37 (11.7/10.8)  
60/56 (17.6/16.4)  
80/75 (23.4/22.0)  
80/75 (23.4/22.0)  
100/95 (29.3/27.8)  
100/95 (29.3/27.8)  
120/112 (35.1/32.8)  
1200 (34.0)  
A
B
B
C
C
C
D
14-1/2  
17-1/2  
17-1/2  
21  
36.8  
44.4  
44.4  
53.3  
53.3  
53.3  
62.2  
13-1/4  
16-1/4  
16-1/4  
19-3/4  
19-3/4  
19-3/4  
23-1/4  
1200 (34.0)  
1200 (34.0)  
1600 (45.3)  
1600 (45.3)  
2000 (56.6)  
2000 (56.6)  
15  
15  
18-1/2  
18-1/2  
18-1/2  
22  
21  
21  
24-1/2  
RESIDENTIAL AND NON HUD MODULAR HOME  
DOWNFLOW AND HORIZONTAL RETURN PLENUM  
CONNECTION  
The return duct system must be connected to the furnace inlet and the  
return duct system must terminate outside the space containing the fur-  
nace. When replacing an existing furnace, if the existing plenum is not  
the same size as the new furnace then the existing plenum must be  
removed and a new plenum installed that is the proper size for the new  
furnace.  
IMPORTANT: If an external mounted filter rack is being used see the  
instructions provided with that accessory for proper hole cut size.  
SECTION III: FILTERS  
FILTER INSTALLATION  
All applications require the use of a filter. Replacement filter size is  
shown in Table 5.  
TABLE 5: Recommended Filter Sizes  
Attach the return plenum to the furnace inlet duct flanges. This is typi-  
cally through the use of S cleat material when a metal plenum is used.  
The use of an approved flexible duct connector is recommended on all  
installations. The connection of the plenum to the furnace and all the  
ducts connecting to the plenum must be sealed to prevent air leakage.  
The sheet metal should be crosshatched to eliminate any popping of  
the sheet metal when the indoor fan is energized.  
CFM  
Input / Output  
BTU/H (kW)  
Cabinet  
Size  
Top Return  
Filter in(cm)  
(m3/min)  
1200 (34)  
1200 (34)  
1200 (34)  
1600 (45)  
1600 (45)  
2000 (57)  
2000 (57)  
40 (11.7)  
60 (17.8)  
80 (23.4)  
80 (23.4)  
100 (29.3)  
100 (29.3)  
120 (35.1)  
A
B
B
C
C
C
D
(2) 14 x 20 (36 x 51)  
(2) 14 x 20 (36 x 51)  
(2) 14 x 20 (36 x 51)  
(2) 14 x 20 (36 x 51)  
(2) 14 x 20 (36 x 51)  
(2) 14 x 20 (36 x 51)  
(2) 14 x 20 (36 x 51)  
The duct system is a very important part of the installation. If the duct  
system is improperly sized the furnace will not operate properly. The  
ducts attached to the furnace must be of sufficient size so that the fur-  
nace operates at the specified external static pressure and within the air  
temperature rise specified on the nameplate.  
NOTES:  
1. Air velocity through throwaway type filters may not exceed 300 feet  
per minute. All velocities over this require the use of high velocity fil-  
ters.  
Attic installations must meet all minimum clearances to combustibles  
and have floor support with required service accessibility.  
Unitary Products Group  
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Downflow Filters  
HORIZONTAL APPLICATION  
Downflow furnaces typically are installed with the filters located above  
the furnace, extending into the return air plenum or duct. Any branch  
duct (rectangular or round duct) attached to the plenum must attach to  
the vertical plenum above the filter height.  
Horizontal Filters  
All filters and mounting provision must be field supplied. Filters(s) may  
be located in the duct system external to the furnace or in a return filter  
grille(s). Filters(s) may be located in the duct system using an external  
duct filter box attached to the furnace plenum. Any branch duct (rectan-  
gular or round duct) attached to the plenum must attach to the vertical  
plenum above the filter height. The use of straps and / or supports is  
required to support the weight of the external filter box.  
Filters(s) may be located in the duct system external to the furnace  
using an external duct filter box attached to the furnace plenum or at the  
end of the duct in a return filter grille(s). The use of straps and / or sup-  
ports is required to support the weight of the external filter box.  
If the accessory electronic air cleaner is installed, be sure the air  
cleaner is designed to accommodate the furnace CFM (cm/m) and the  
air cleaner is installed so it does not obstruct the return airflow. Consid-  
eration should be given when locating the air cleaner for maintenance  
and temperatures should the indoor fan motor fail to operate. The use  
of straps and / or supports is required to support the weight of the elec-  
tronic air cleaner. It is recommended that the air cleaner not be located  
within 12 inches (30.5 cm) from the top of the return air opening on the  
furnace. Refer to the instructions supplied with the electronic air  
cleaner.  
An accessory filter rack is available.  
ATTIC INSTALLATION  
LINE CONTACT ONLY PERMISSIBLE  
BETWEEN LINES FORMED BY THE  
INTERSECTION OF FURNACE TOP  
AND TWO SIDES AND BUILDING  
JOISTS, STUDS OR FRAMING  
COMBUSTION  
AIR  
FILTER RACK  
GAS  
PIPING  
RETURN  
AIR  
SUPPLY  
AIR  
All loose accessories shipped with the furnace must be removed  
from the blower compartment, prior to installation.  
VENT PIPE  
If pleated media air filters or any filter that has a large pressure drop is  
installed in the return air duct system be sure that the pressure drop  
caused by the air filter will not prevent the furnace from operating within  
the rise range specified on the rating plate. If the furnace does not oper-  
ate within the specified rise range then a larger air filter or an air filter  
that has a lower pressure drop must be installed.  
(maintain required  
clearances to  
combustible)  
30” MIN.  
WORK AREA  
12” CLEARANCE  
FOR SERVICE  
FIGURE 5: Typical Attic Installation  
This appliance is design certified for line contact when the furnace is  
installed in the horizontal left or right position. The line contact is only  
permissible between lines are formed by the intersection of the top and  
two sides of the furnace and the building joists, studs or framing. This  
line may be in contact with combustible material.  
IMPORTANT: For easier filter access in a downflow configuration, a  
removable access panel is recommended in the vertical run of the  
return air plenum immediately above the furnace.  
CLOSET  
IMPORTANT: In either a horizontal left or right installation, a minimum  
of 8" (20.3 cm) clearance is required beneath the furnace to allow for  
the installation of the condensate trap and drain pipe. Refer to "CON-  
DENSATE PIPING" section of this manual for more information.  
COMBUSTION  
AIR  
RETURN  
AIR  
VENT  
PIPE  
AIR  
FILTERS  
When a furnace is installed in an attic or other insulated space,  
keep all insulating materials at least 12 inches (30.5 cm) away from  
furnace and burner combustion air openings.  
ELECTRICAL  
SUPPLY  
GAS SUPPLY  
(EITHER SIDE)  
If this furnace is installed over a finished space, a condensate  
safety pan must be installed.  
FIGURE 4: Return Filter Grill and Return Duct Installation  
SUSPENDED FURNACE / CRAWL SPACE  
INSTALLATION  
IMPORTANT: Air velocity through throwaway type filters must not  
exceed 300 feet per minute (91 m/min). All velocities over this require  
the use of high velocity filters. Refer to Table 19.  
The furnace can be hung from floor hoists or installed on suitable blocks  
or pad. Blocks or pad installations shall provide adequate height to  
ensure the unit will not be subject to water damage. Units may also be  
suspended from rafters or floor joists using rods, pipe angle supports or  
straps. Angle supports should be placed at the supply air end and near  
the blower deck. Do not support at return air end of unit. All four sus-  
pension points must be level to ensure quite furnace operation. When  
suspending the furnace use a secure a platform constructed of plywood  
or other building material secured to the floor joists. Refer to Figure 6  
for typical crawl space installation.  
All installations must have a filter installed.  
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Unitary Products Group  
268890-UIM-B-0607  
EXTERNAL MANUAL  
SHUTOFF VALVE  
TO GAS  
SUPPLY  
TO GAS  
SUPPLY  
SUPPORT  
BRACKET  
ANGLE IRON  
BRACKET  
1” MAX. BETWEEN  
ROD & FURNACE  
6” MIN. BETWEEN  
ROD & FURNACE  
GROUNDED JOINT UNION  
MAY BE INSTALLED  
INSIDE OR OUTSIDE UNIT.  
1” MAX. BETWEEN  
ROD & FURNACE  
DRIP  
LEG  
FIGURE 6: Typical Suspended Furnace / Crawl Space Installation  
FIGURE 8: Downflow Gas Piping  
MANUAL  
SHUT-OFF  
VALVE  
In any application where temperatures below freezing are possible,  
see “BELOW FREEZING LOCATIONS”.  
DRIP  
LEG  
GAS  
PIPE  
GAS BURNERS  
GAS VALVE  
SECTION IV: GAS PIPING  
GAS SAFETY  
GAS  
PIPE  
MANUAL  
SHUT-OFF VALVE  
DRIP  
LEG  
An overpressure protection device, such as a pressure regulator,  
must be installed in the gas piping system upstream of the furnace  
and must act to limit the downstream pressure to the gas valve so it  
does not exceed 0.5 PSI {14" w.c. (3.48 kPa)}. Pressures exceed-  
ing 0.5 PSI {14” w.c. (3.48 kPa)} at the gas valve will cause damage  
to the gas valve, resulting in a fire or explosion or cause damage to  
the furnace or some of its components that will result in property  
damage and loss of life.  
FIGURE 9: Horizontal Gas Piping  
IMPORTANT: An accessible manual shutoff valve must be installed  
upstream of the furnace gas controls and within 6 feet (1.8 m) of the fur-  
nace.  
The furnace must be isolated from the gas supply piping system by  
closing its individual external manual shutoff valve during any pressure  
testing of the gas supply piping system at pressures equal to or less  
than 1/2 psig (3.5 kPa).  
OUTLET  
PRESSURE  
PORT  
VENT PORT  
INLET  
OUTLET  
Never apply a pipe wrench to the body of the gas valve when  
installing piping. A wrench must be placed on the octagonal hub  
located on the gas inlet side of the valve. Placing a wrench to the  
body of the gas valve will damage the valve causing improper oper-  
ation and/or the valve to leak.  
WRENCH  
BOSS  
INLET  
PRESSURE  
PORT  
MAIN REGULATOR  
ADJUSTMENT  
ON/OFF SWITCH  
(Shown in ON position)  
Gas piping may be connected from either side of the furnace using any  
of the gas pipe entry knockouts on both sides of the furnace. Refer to  
Figure 3 dimensions.  
FIGURE 7: Gas Valve  
IMPORTANT: Plan your gas supply before determining the correct gas  
pipe entry. Use 90-degree service elbow(s), or short nipples and con-  
ventional 90-degree elbow(s) to enter through the cabinet access holes.  
GAS ORIFICE CONVERSION FOR PROPANE (LP)  
This furnace is constructed at the factory for natural gas-fired operation,  
but may be converted to operate on propane (LP) gas by using a fac-  
tory-supplied LP conversion kit. Follow the instructions supplied with  
the LP kit. Refer to Table 6 or the instructions in the propane (LP) con-  
version kit for the proper gas orifice size.  
GAS PIPING INSTALLATION  
Properly sized wrought iron, approved flexible or steel pipe must be  
used when making gas connections to the unit. If local codes allow the  
use of a flexible gas appliance connection, always use a new listed con-  
nector. Do not use a connector that has previously serviced another gas  
appliance.  
HIGH ALTITUDE GAS ORIFICE CONVERSION  
This furnace is constructed at the factory for natural gas-fired operation  
at 0 – 8,000 feet (0-m – 2,438 m) above sea level.  
Some utility companies or local codes require pipe sizes larger than the  
minimum sizes listed in these instructions and in the codes. The furnace  
rating plate and the instructions in this section specify the type of gas  
approved for this furnace - only use those approved gases. The instal-  
lation of a drip leg and ground union is required. Refer to Figure 8.  
The manifold pressure must be changed in order to manitain proper  
and safe operation when the furnace is installed in a location where the  
altitude is greater than 8,000 feet (2,438 m) above sea level. Refer to to  
Table 6 for proper manifold pressure settings.  
HIGH ALTITUDE PRESSURE SWITCH CONVERSION  
For installation where the altitude is less than 8,000 feet (2,438 m), it is  
not required that the pressure switch be changed. For altitudes above  
8,000 feet (2,438 m), see Field Installed Accessories - High Altitude  
pressure Switch.  
Unitary Products Group  
9
268890-UIM-B-0607  
TABLE 6: Nominal Manifold Pressure  
Manifold Pressures (in wc)  
Altitude (feet)  
Manifold Pressures (kpa)  
Altitude (m)  
0-7999  
3.5  
8000-8999  
3.5  
9000-9999  
3.5  
0-2437  
0.87  
0.87  
0.87  
0.87  
0.87  
0.87  
0.80  
2.44  
2438-2742  
0.87  
2743-3048  
0.87  
800  
850  
29.8  
31.7  
3.5  
3.5  
3.5  
0.87  
0.87  
900  
3.5  
3.5  
3.5  
33.5  
0.87  
0.87  
950  
3.5  
3.5  
3.3  
35.4  
0.87  
0.81  
1000  
1050  
1100  
3.5  
3.2  
2.9  
37.3  
0.80  
0.73  
3.5  
2.9  
2.7  
39.1  
0.73  
0.67  
3.2  
2.7  
2.4  
41.0  
0.66  
0.61  
2500 (LP)  
9.8  
8.2  
7.5  
93.2 (LP)  
2.03  
1.86  
PROPANE AND HIGH ALTITUDE CONVERSION KITS  
It is very important to choose the correct kit and/or gas orifices for the altitude and the type of gas for which the furnace is being installed.  
Only use natural gas in furnaces designed for natural gas. Only use propane (LP) gas for furnaces that have been properly converted to use pro-  
pane (LP) gas. Do not use this furnace with butane gas.  
Incorrect gas orifices or a furnace that has been improperly converted will create an extremely dangerous condition resulting in premature heat  
exchanger failure, excessive sooting, high levels of carbon monoxide, personal injury, property damage, a fire hazard and/or death.  
High altitude and propane (LP) conversions are required in order for the appliance to satisfactory meet the application.  
An authorized distributor or dealer must make all gas conversions.  
In Canada, a certified conversion station or other qualified agency, using factory specified and/or approved parts, must perform the conversion.  
The installer must take every precaution to insure that the furnace has been converted to the proper gas orifice size when the furnace is installed.  
Do not attempt to drill out any orifices to obtain the proper orifice size. Drilling out a gas orifice will cause misalignment of the burner flames,  
causing premature heat exchanger burnout, high levels of carbon monoxide, excessive sooting, a fire hazard, personal injury, property damage  
and/or death.  
SECTION V: ELECTRICAL POWER  
ELECTRICAL POWER CONNECTIONS  
Field wiring to the unit must be grounded. Electric wires that are field  
installed shall conform to the temperature limitation for 63°F (35°C) rise  
Use copper conductors only.  
wire when installed in accordance with instructions. Refer to Table 7 in  
these instructions for specific furnace electrical data.  
TABLE 7: Electrical and Performance Data  
Input/Cabinet  
Output  
MBH  
Nominal Airflow  
Cabinet Width  
Total Unit  
AFUE  
Air Temp. Rise  
m3/min  
CFM  
MBH  
40/A  
kW  
12  
18  
23  
23  
29  
29  
35  
kW  
In.  
14-1/2  
17-1/2  
17-1/2  
21  
mm  
368  
444  
444  
533  
533  
533  
622  
Amps  
9
%
94  
92  
92  
92  
92  
92  
92  
°F  
°C  
37  
55  
74  
74  
93  
93  
112  
10.8  
16.1  
21.7  
21.7  
27.3  
27.3  
32.8  
1200  
1200  
1200  
1600  
1600  
2000  
2000  
34  
35 - 65  
35 - 65  
35 - 65  
35 - 65  
35 - 65  
35 - 65  
35 - 65  
19 - 36  
19 - 36  
19 - 36  
19 - 36  
19 - 36  
19 - 36  
19 - 36  
60/B  
34.0  
34.0  
45.3  
45.3  
56.6  
56.6  
9
80/B  
9
80/C  
12  
12  
14  
14  
100/C  
100/C  
120/D  
21  
21  
24-1/2  
Max. Outlet  
Air Temp.  
Operation  
Weight  
Max.  
Min. Wire Size  
Input/Cabinet  
Blower  
Blower Size  
Over-current (awg) @ 75 ft.  
Protect  
One Way  
MBH  
40/A  
kW  
12  
18  
23  
23  
29  
29  
35  
°F  
°C  
HP  
1/2  
1/2  
1/2  
3/4  
3/4  
1
Amps  
7.0  
In.  
cm  
Lbs.  
120  
130  
145  
155  
170  
175  
180  
Kg.  
165  
165  
165  
165  
165  
165  
165  
73.9  
73.9  
73.9  
73.9  
73.9  
73.9  
73.9  
11 x 8  
11 x 8  
11 x 8  
27.9 x 20.3  
27.9 x 20.3  
27.9 x 20.3  
20  
20  
20  
20  
20  
20  
20  
14  
14  
14  
14  
14  
12  
12  
54.5  
59.0  
65.9  
70.5  
77.3  
79.5  
81.8  
60/B  
7.0  
80/B  
7.0  
80/C  
10.2  
10.2  
12.7  
12.7  
11 x 10 27.9 x 25.4  
11 x 10 25.4 x 25.4  
11 x 11 27.9 x 27.9  
11 x 11 27.9 x 27.9  
100/C  
100/C  
120/D  
1
Annual Fuel Utilization Efficiency (AFUE) numbers are determined in accordance with DOE Test procedures.  
Wire size and over current protection must comply with the National Electrical Code (NFPA-70-latest edition) and all local codes.  
The furnace shall be installed so that the electrical components are protected from water.  
NOTES:  
1. For altitudes above 2000 ft. (609 m) reduce capacity 4% for each 1000 ft. above sea level.  
2. Wire size based on copper conductors, 140° F (60°C), 3% voltage drop.  
3. Continuous return air temperature must not be below 55°F (12.8° C).  
10  
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SUPPLY VOLTAGE CONNECTIONS  
IMPORTANT: The power connection leads and wiring box may be relo-  
cated to the left side of the furnace. Remove the screws and cut wire tie  
holding excess wiring. Reposition on the left side of the furnace and fas-  
ten using holes provided.  
BLOWER  
COMPARTMENT  
COMBUSTION  
AIR  
VENT PIPE  
1. Provide a power supply separate from all other circuits. Install  
overcurrent protection and disconnect switch per local/national  
electrical codes. The switch should be close to the unit for conve-  
nience in servicing. With the disconnect or fused switch in the OFF  
position, check all wiring against the unit wiring label. Refer to the  
wiring diagram shown in Figure 41.  
CLASS 2 SYSTEM  
CONTROL WIRING  
TO THERMOSTAT  
IGNITION  
MODULE  
TRANSFORMER  
(BLK) LI (HOT)  
(WHT) N  
(GRN)GND  
2. Remove the screws retaining the junction box cover. Route the  
power wiring through the opening in the unit into the junction box  
with a conduit connector or other proper connection. In the junc-  
tion box there will be three wires, a Black Wire, a White Wire and a  
Green Wire. Connect the power supply as shown on the unit-wir-  
ing label on the inside of the blower compartment door or Figure  
10. The black furnace lead must be connected to the L1 (hot) wire  
from the power supply. The white furnace lead must be connected  
to neutral. Connect the green furnace lead (equipment ground) to  
the power supply ground. An alternate wiring method is to use a  
field provided 2” (5.08 cm) x 4” (10.2 cm) box and cover on the  
outside of the furnace. Route the furnace leads into the box using  
a protective bushing where the wires pass through the furnace  
panel. After making the wiring connections replace the wiring box  
cover and screws.  
JUNCTION  
BOX  
FIGURE 10: Electrical Wiring  
LOW VOLTAGE CONTROL WIRING CONNECTIONS  
Install the field-supplied thermostat by following the instructions that  
come with the thermostat. With the thermostat set in the OFF position  
and the main electrical source disconnected, connect the thermostat  
wiring from the wiring connections on the thermostat to the terminal  
board on the ignition module, as shown in Figure 11. Electronic thermo-  
stats may require the common wire to be connected as shown with the  
dashed line in Figure 11. Apply strain relief to thermostat wires passing  
through cabinet. If air conditioning equipment is installed, use thermo-  
stat wiring to connect the Y and C terminals on the furnace control  
board to the yellow and brown wires on the condensing unit (unit out-  
side). Refer to Figure 11.  
3. The furnace's control system requires correct polarity of the power  
supply and a proper ground connection. If the power supply polar-  
ity is reversed, the control board will flash 9 times. The furnace will  
not operate until the polarity is corrected. Refer to “Furnace Diag-  
nostics” section of the “User’s Information, Maintenance, & Ser-  
vice Manual” provided with this furnace.  
IMPORTANT: Set the heat anticipator in the room thermostat to 0.45  
amps. Setting it lower will cause short cycles. Setting it higher will cause  
the room temperature to exceed the set points.Some electronic thermo-  
stats do not have adjustable heat anticipators. They may have other  
type cycle rate adjustments. Follow the thermostat manufacturer's  
instructions.  
The 24-volt, 40 VA transformer is sized for the furnace components  
only, and should not be connected to power auxiliary devices such as  
humidifiers, air cleaners, etc. The transformer may provide power for an  
air conditioning unit contactor.  
For additional connection diagrams for all UPG equipment refer to “Low  
in the Product Catalog Section.  
Unitary Products Group  
11  
268890-UIM-B-0607  
FIGURE 11: Thermostat Chart  
12  
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ACCESSORY CONNECTIONS  
TWINNING DUCT SYSTEM  
The furnace control will allow power-switching control of various acces-  
sories. Refer to Figure 12, for connection details.  
Twinned furnaces must only be applied on a common duct system. A  
single air supply plenum must be used for both furnaces and coil(s).  
Separate plenums and supply ducts systems cannot be utilized. A sin-  
gle return air plenum, common to both furnaces must be used.  
HUM. HOT  
BLK  
115 VOLT  
HUMIDIFER  
Both furnaces must be identical models in both heating capacity and  
CFM capacity. Both furnaces must be operated on the same motor  
speed tap. See typical application, Figure 13.  
WHT  
EAC  
SWITCHED  
HUM CIRCUITS  
If furnace staging is desired with two single stage furnaces on a com-  
mon duct, where the gas burner on the first furnace operates on W1  
and the gas burner on the second furnace operates on W2, then the  
use of an air-mixing device in the plenum to mix the air from both fur-  
naces is strongly recommended. The mixing device must be installed  
before any ducts that supply air to occupied spaces. Twinning causes  
both indoor fans to operate simultaneously. If a mixing device is not  
used, any ducts that are connected down stream from the furnace that  
operates on W2, will be supplying cold air in the Heating mode to the  
occupied spaces unless W2 is energized.  
EAC HOT  
115 VOLT  
ELECTRONIC  
AIR CLEANER  
BLK  
WHT  
NEUTRALS  
FIGURE 12: Accessory Connections  
VENT PIPE  
ELECTRONIC AIR CLEANER CONNECTION  
Two 1/4” (0.64 cm) spade terminals (EAC and NEUTRAL) for electronic  
air cleaner connections are located on the control board. The terminals  
provide 115 VAC (1.0 amp maximum) during circulating blower opera-  
tion.  
GAS SUPPLY  
ELECTRICAL  
(BOTH SIDES)  
SUPPLY  
HUMIDIFIER CONNECTION  
Two 1/4” (0.64 cm) spade terminals (HUM and NEUTRAL) for humidi-  
fier connections are located on the control board. The terminals provide  
115 VAC (1.0 amp maximum) during heating system operation.  
1 COIL FOR  
EACH FURNACE  
SUPPLY  
AIR  
SECTION VI: TWINNING AND STAGING  
NOTE: You can twin two furnaces that have the same integrated control  
module. Check the part number on the integrated control module. You  
cannot twin two furnaces that have different integrated control module  
part numbers. If the part numbers of the two integrated control modules  
are different they may not communicate with each other so they will not  
work in a twinning application.  
FIGURE 13: Typical Twinned Furnace Application  
IMPORTANT: When two furnaces are twinned, typical system total air-  
flow will be approximately 85% of additive individual furnaces, i.e., two  
2000 CFM (56.6 m3/m) units will yield a total 3400 CFM (96.3 m3/m).  
In applications where more heating capacity or more airflow capacity is  
needed than what one furnace can deliver, twinning can be used to  
make two furnaces operate in tandem. When two furnaces are installed  
using the same duct system, it is very important that the two furnace cir-  
culating air blowers operate in unison. If one blower starts before the  
second blower, the duct system will become pressurized and the blower  
on the second furnace will turn backwards causing the second furnace  
to overheat, resulting in damage to the furnace. Twinning is used to  
make two furnaces operate in tandem, using one duct system, one  
room thermostat and causing both furnaces to turn on and off simulta-  
neously.  
GAS PIPING  
Furnace gas supplies must be provided as specified with these instruc-  
tions. Since the furnaces are side by side, with no space between, gas  
supplies must enter on the right and left respectively. All gas piping  
must be in accordance with the national fuel gas code, ANSI Z223.1,  
latest edition, and/or all local code or utility requirements.  
TWINNING  
In applications where more heating capacity or more airflow capacity is  
needed than what one furnace can deliver, twinning can be used to  
make two furnaces operate in tandem, using one duct system and one  
room thermostat. When one duct system is used for two furnaces, it is  
necessary that the two blowers operate in unison. The twinning function  
of the board in this furnace ensures that both blowers turn on and off  
simultaneously, and operate on the same blower speed.  
Before installing the relay and wiring, disconnect electrical power to  
both furnaces. Failure to cut power could result in electrical shock  
or equipment damage.  
Single-Wire Twinning  
The control in the furnace has the single-wire twinning feature. With this  
feature, a single wire is connected between the TWIN terminal on one  
furnace board to the TWIN terminal on the second furnace board. The  
board then communicates the blower status from one furnace to the  
other along this wire. This communication makes the second furnace  
blower come on at the same time, and on the same speed, as the first  
furnace blower.  
The relay must not be installed in any location where it could be  
exposed to water. If the relay has been exposed to water in any  
way, it must not be used.  
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Single-Wire Twinning Instructions  
Single-Wire Staging Instructions  
Connect the control wiring as shown in the Figure 15.  
Connect the control wiring as shown in the Figure 14.  
1. Connect the low voltage wiring from the wall thermostat to the ter-  
minal strip on the control board of Furnace #1. For staging applica-  
tions, the wire from thermostat W1 is connected to the W  
connection on the board on Furnace #1. The wire from thermostat  
W2 is connected to Furnace #2 through a separate relay, as  
described below.  
1. Connect the low voltage wiring from the wall thermostat to the ter-  
minal strip on the control board of Furnace #1.  
2. Connect a wire from the TWIN terminal of Furnace #1 to the TWIN  
terminal of Furnace #2.  
3. Install a separate 24V relay as shown in the diagram below. Use of  
this relay is required, as it ensures that the transformers of the two  
furnaces are isolated, thus preventing the possibility of any safety  
devices being bypassed.  
2. Connect a wire from the TWIN terminal of Furnace #1 to the TWIN  
terminal of Furnace #2.  
3. Install a separate 24V relay as shown in the diagram below. Use of  
this relay is required, as it ensures that the transformers of the two  
furnaces are isolated, thus preventing the possibility of any safety  
devices being bypassed.  
Single-Wire Twinning Operation  
Heating - On a call for heat (W signal) from the wall thermostat, both  
furnaces will start the ignition sequence and the burners on both fur-  
naces will light. About thirty seconds after the burners light, the blowers  
on both furnaces will come on in heating speed. When the thermostat is  
satisfied, the burners will all shut off and, after the selected blower off  
delay time, both blowers will shut off at the same time. The twinning  
control ensures that both blowers come on and shut off at the same  
time.  
Single-Wire Staging Operation  
Heating - On a call for first-stage heat (W1 signal) from the wall thermo-  
stat, Furnace #1 will start the ignition sequence and the burners will  
light. About thirty seconds after the burners light, the blowers on both  
furnaces will come on in heating speed. When the thermostat is satis-  
fied, the burners will shut off and, after the selected blower off delay  
time, both blowers will shut off at the same time. On a call for second  
stage of heat, the burners of Furnace #2 will also light and both blowers  
will run. The twinning control ensures that both blowers come on and  
shut off at the same time.  
Cooling - On a call for cooling (Y signal) from the wall thermostat, both  
furnace blowers will come on at the same time in cooling speed. When  
the thermostat is satisfied, both blowers will stay on for 60 seconds,  
then will shut off at the same time.  
Continuous Fan - On a thermostat call for continuous fan (G signal),  
both furnace blowers will come on at the same time in cooling speed  
and will stay on until the G signal is removed.  
Cooling - On a call for cooling (Y signal) from the wall thermostat, both  
furnace blowers will come on at the same time. When the thermostat is  
satisfied, both blowers will stay on for 60 seconds, then will shut off at  
the same time.  
FURNACE 2 CONTROL BOARD  
FURNACE 1 CONTROL BOARD  
Continuous Fan - On a thermostat call for continuous fan (G signal),  
both furnace blowers will come on at the same time in cooling speed  
and will stay on until the G signal is removed.  
W
G
C
W
G
C
FURNACE 2 CONTROL BOARD  
FURNACE 1 CONTROL BOARD  
R
Y
TWIN  
R
Y
TWIN  
W
G
C
W
G
C
ISOLATION  
RELAY  
R
Y
TWIN  
R
Y
TWIN  
ISOLATION  
RELAY  
TO A/C  
W
G
R
Y
WALL THERMOSTAT  
FIGURE 14: Single Stage Twinning Wiring Diagram  
TO A/C  
W1  
G
R
Y
W2  
STAGING  
WALL THERMOSTAT  
In applications where more heating capacity or more airflow capacity is  
needed than what one furnace can deliver, twinning can be used to  
make two furnaces operate in tandem, using one duct system and one  
room thermostat. This control can also be used along with a two-stage  
wall thermostat to stage two twinned furnaces, making them operate  
like a single two-stage furnace. This allows only one furnace to supply  
heat during times when the heat output from one furnace is sufficient to  
satisfy the demand. When one duct system is used for two furnaces, it  
is necessary that the two blowers operate in unison. The twinning func-  
tion of this board ensures that both blowers turn on and off simulta-  
neously, and operate on the same blower speed. Even when only one  
furnace is supplying heat, both furnace blowers must run.  
FIGURE 15: Two-Stage Twinning Wiring Diagram  
SECTION VII: COMBUSTION AIR AND  
VENT SYSTEM  
COMBUSTION AIR AND VENT SAFETY  
This Category IV, dual certified direct vent furnace is designed for resi-  
dential application. It may be installed without modification to the con-  
densate system in a basement, garage, equipment room, alcove, attic  
or any other indoor location provided the space temperature is 32 °F  
(0°C) or higher and where all required clearance to combustibles and  
other restrictions are met. The combustion air and the venting system  
must be installed in accordance with Section 5.3, Air for Combustion  
and Ventilation, of the National Fuel Gas Code Z223.1/NFPA 54 (latest  
edition), or Sections 7.2, 7.3 or 7.4 of CSA B149.1, National Gas and  
Propane Codes (latest edition) or applicable provisions of the local  
building code and these instructions.  
Single-Wire Staging  
The single-wire twinning feature of this board can also be used for stag-  
ing of two furnaces. With this feature, a single wire is connected  
between the TWIN terminal on one furnace board to the TWIN terminal  
on the second furnace board. The board then communicates the blower  
status from one furnace to the other along this wire. This communica-  
tion makes the second furnace blower come on at the same time, and  
on the same speed, as the first furnace blower.  
IMPORTANT: The “VENT SYSTEM” must be installed as specified in  
these instructions for Residential and Non HUD Modular Homes. The  
sealed combustion air / vent system is the only configuration that can  
be installed in a Non HUD Modular Home.  
14  
Unitary Products Group  
268890-UIM-B-0607  
TABLE 8: Maximum Equivalent Pipe Length  
Maximum  
Equivalent  
length feet (m)  
Model Input  
BTUH (kW)  
Pipe Size  
Inches (cm)  
This furnace may not be common vented with any other appliance,  
since it requires separate, properly sized air intake and vent lines.  
The furnace shall not be connected to any type of B, BW or L vent  
or vent connector, and not connected to any portion of a factory-  
built or masonry chimney  
40,000 (11.7)  
40,000 (11.7)  
60,000 (17.6)  
60,000 (17.6)  
80,000 (23.4)  
80,000 (23.4)  
100,000 (29.3)  
100,000 (29.3)  
120,000 (29.3)  
2 (5.1)  
3 (7.6)  
2 (5.1)  
3 (7.6)  
2 (5.1)  
3 (7.6)  
2 (5.1)  
3 (7.6)  
3 (7.6)  
65 (19.8)  
90 (27.4)  
65 (19.8)  
90 (27.4)  
65 (19.8)  
90 (27.4)  
30 (9.2)  
The furnace shall not be connected to a chimney flue serving a sep-  
arate appliance designed to burn solid fuel.  
When combustion air pipe is installed above a suspended ceiling or  
when it passes through a warm and humid space, the pipe must be  
insulated with 1/2” Armaflex or other heat resistant type insulation.  
Vent piping must be insulated with 1/2” insulation if it will be sub-  
jected to freezing temperatures such as routing through unheated  
areas or through an unused chimney.  
85 (25.9)  
60 (18.3)  
TABLE 9: Equivalent Length of Fittings  
Fitting  
Equivalent Length  
5 feet of 2" pipe  
2-1/2 feet of 2" pipe  
10 feet of 2" pipe  
5 feet of 2" pipe  
5 feet of 3" pipe  
2-1/2 feet of 3" pipe  
10 feet of 3" pipe  
5 feet of 3" pipe  
10 feet of 2" pipe  
10 feet of 3" pipe  
COMBUSTION AIR/VENT PIPE SIZING  
The size of pipe required will be determined by the furnace model, the  
total length of pipe required and the number of elbows required.  
2" 90º sweep elbow  
2" 45º sweep elbow  
2" 90º standard elbow  
2" 45º standard elbow  
3" 90º sweep elbow  
3" 45º sweep elbow  
3" 90º standard elbow  
3" 45º standard elbow  
2" corrugated connector  
3" corrugated connector  
Table 8 lists the maximum equivalent length of pipe allowed for each  
model of furnace. The equivalent length of elbows is shown in Table 9.  
The equivalent length of the vent system is the total length of straight  
pipe PLUS the equivalent length of all of the elbows.  
The following rules must also be followed:  
1. Long radius (sweep) elbows are recommended. Standard elbows  
may be used, but since they have a longer equivalent length, they  
will reduce the total length of pipe that will be allowed. Short radius  
(plumbing vent) elbows are not allowed. The standard dimensions  
of the acceptable elbows are shown below.  
Example:  
An 80,000 BTUH furnace requires 32 feet of pipe and four 90º elbows.  
Using 2" pipe and standard elbows, the total equivalent length will be:  
2. The maximum equivalent length listed in Table 8 is for the vent pip-  
ing and the air intake piping separately. For example, if the table  
allows 65 equivalent feet for a particular model, then the vent can  
have 65 equivalent feet of pipe, AND the combustion air intake can  
have another 65 equivalent feet of pipe.  
32 feet of 2" pipe =  
4 - 90º standard 2" elbows = (4x10) =  
Total =  
32 equivalent feet  
40 equivalent feet  
72 equivalent feet of 2" pipe  
3. Three vent terminal elbows (two for the vent and one for the com-  
bustion air intake) are already accounted for and need not be  
included in the equivalent length calculation.  
This exceeds the 65 foot maximum equivalent length of 2" pipe allowed  
for that model and is thus not acceptable.  
4. All combustion air and vent pipe must conform to American  
National Standards Institute (ANSI) and American Society for Test-  
ing and Materials (ASTM) standards D1785 (Schedule 40 PVC),  
D2665 (PVC-DWV), F891 (PVC-DWV Cellular Core), D2261  
(ABS-DWV) or F628 (Schedule 40 ABS). Pipe cement and primer  
must conform to ASTM Standard D2546 (PVC) or D2235 (ABS). If  
ABS pipe is to be used, any joint where ABS pipe is joined to PVC  
pipe must be glued with cement that is approved for use with  
BOTH materials. Metallic materials must not be used for venting or  
air intake.  
By using sweep elbows, the total equivalent length will be:  
32 feet of 2" pipe =  
4 - 90º standard 2" elbows = (4x5) =  
Total =  
32 equivalent feet  
20 equivalent feet  
52 equivalent feet of 2" pipe  
This is less than the 65 foot maximum equivalent length of 2" pipe  
allowed for that model and is thus acceptable.  
Alternatively, using 3" pipe and standard elbows, the total equivalent  
length will be:  
5. If a flexible connector is used in the vent system, it must be made  
of a material that is resistant to acidic exposure and to at least  
225° F temperature. Flexible connectors are also allowed in the  
combustion air pipe.  
32 feet of 3" pipe =  
4 - 90º standard 2" elbows = (4x5) =  
Total =  
32 equivalent feet  
40 equivalent feet  
72 equivalent feet of 3" pipe  
6. All models are supplied with 2" vent connections. When the pipe  
must be increased to 3" diameter, the transition from 2" to 3" must  
be done as close to the furnace as possible. For upflow models,  
the transition from 2" to 3" should be done immediately above the  
furnace. For downflow or horizontal models, the transition from 2"  
to 3" pipe should be done immediately after the drain tee or drain  
elbow.  
This is less than the 90 foot maximum equivalent length of 3" pipe  
allowed for that model and is thus acceptable.  
7. In Canada, vents shall be certified to ULC S636, Standard for Type  
BH Gas Venting Systems. IPEX System 636 PVC is certified to  
this standard.  
8. In Canada, the first three feet (900 mm) of the vent must be readily  
accessible for inspection.  
Unitary Products Group  
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268890-UIM-B-0607  
COMBUSTION AIR AND VENT PIPING ASSEMBLY  
The final assembly procedure for the combustion air and vent piping is  
as follows:  
A
A
1. Cut piping to the proper length beginning at the furnace.  
2. Deburr the piping inside and outside.  
3. Chamfer (bevel) the outer edges of the piping.  
4. Dry-fit the vent piping assembly from the furnace to the outside ter-  
mination checking for proper fit support and slope.  
5. Dry-fit the combustion air piping assembly checking for proper fit,  
support and slope on the following systems:  
STANDARD ELBOW  
LONG (SWEEP) ELBOW  
A. Sealed combustion air systems from the furnace to the out-  
side termination.  
FIGURE 16: Dimensions  
B. Ventilated combustion air systems from the furnace to the  
attic or crawl space termination.  
TABLE 10: Elbow Dimensions  
Elbow  
"A" Dimension  
2" Standard  
3" Standard  
2" Sweep  
3" Sweep  
2-5/16"  
3-1/16"  
3-1/4"  
Solvent cements are flammable and must be used in well-ventilated  
areas only. Keep them away from heat, sparks and open flames.  
Do not breathe vapors and avoid contact with skin and eyes.  
4-1/16"  
6. Disassemble the combustion air and vent piping, apply cement  
primer and the cement per the manufactures instructions. Primer  
and cement must conform to ASTM D2564 for PVC, or ASTM  
D2235 for ABS piping.  
Dimensions are those required in Standard ASTM D-3311.  
NOTE: Sidewall vent terminal may be used for sidewall vent termina-  
tions. Refer to part list in the back of the USERS INFORMATION AND  
SERVICE AND MAINTENANCE MANUAL for the terminal part number.  
7. All joints must provide a permanent airtight and watertight seal.  
TABLE 11: Combustion Air Intake and Vent Connection Size at Furnace  
8. Support the combustion air and vent piping such that it is angled a  
minimum of 1/4” per foot (0.635 cm/m) so that condensate will flow  
back towards the furnace. Piping should be supported with pipe  
hangers to prevent sagging.  
(All Models)  
FURNACE VENT CONNECTION SIZES  
40 - 100 MBH  
(17.5 - 29.3 kW)  
120 MBH  
(35.2 kW)  
9. Seal around the openings where the combustion air and / or vent  
piping pass through the roof or sidewalls.  
Furnace Input  
Intake Pipe Size  
Vent Pipe Size  
2” (5.1 cm)  
2” (5.1 cm)  
3” (7.6 cm)  
2” (5.1 cm)  
COMBUSTION AIR / VENT CLEARANCES  
IMPORTANT: The vent must be installed with the minimum clearances  
as shown in Figure 17, and must comply with local codes and require-  
ments.  
*. Vent pipe size must be increased to 3” diameter after connection to furnace  
on this model.  
IMPORTANT: Accessory concentric vent  
/
intake termination kits  
1CT0302 and 1CT0303 are available and approved for use with these  
furnaces. Horizontal sidewall vent terminations kits 1HT0901  
1HT0902 are also approved for use with these furnaces.  
&
IMPORTANT: Furnace vent pipe connections are sized for 2” (5.1 cm).  
pipe. Any pipe size change must be made outside the furnace casing in  
a vertical pipe section to allow proper drainage of condensate. An offset  
using two 45º (degree) elbows will be required for plenum clearance  
when the vent is increased to 3” (7.6 cm).  
16  
Unitary Products Group  
268890-UIM-B-0607  
VENT CLEARANCES  
G
V
A
V
VENT TERMINAL  
AIR SUPPLY  
H
D
FIXED  
CLOSED  
X
E
B
V
B
B
I
AREA WHERE TERMINAL IS NOT PERMITTED  
X
B
M
V
V
V
L
C
V
K
V
X
V
J
FIXED  
CLOSED  
V
F
B
B
OPERABLE  
FIGURE 17: Home Layout  
Canadian Installations1,3  
US Installation2,3  
Direct Vent Terminal Clearances  
A. Clearance above grade, veranda, porch, deck, or  
balcony  
12 inches (30 cm)  
12 inches (30 cm)  
Two-pipe (direct vent) applications: 9 inches (23 cm)  
for models 50,000 BTUH (15 kW), 12 inches (30 cm)  
for models >50,000 BTUH (15 kW). ††  
12 inches (30 cm) for models 100,000 BTUH (30 kW),  
36 inches (91 cm) for models >100,000 BTUH (30 kW)  
B. Clearance to window or door that may be opened  
C. Clearance to permanently closed window  
12 inches (30 cm)  
12 inches (30 cm)  
D. Vertical clearance to ventilated soffit located  
above the terminal within a horizontal distance  
12 inches (30 cm) or in accordance with local  
installation codes and the requirements of the gas  
12 inches (30 cm) or in accordance with local  
installation codes and the requirements of the gas sup-  
plier  
of 2 feet (61 cm) from the center line of the terminal supplier.  
12 inches (30 cm) or in accordance with local  
installation codes and the requirements of the gas  
supplier  
12 inches (30 cm) or in accordance with local  
installation codes and the requirements of the gas  
supplier  
E. Clearance to unventilated soffit  
12 inches (30 cm) or in accordance with local  
installation codes and the requirements of the gas  
supplier  
12 inches (30 cm) or in accordance with local  
installation codes and the requirements of the gas  
supplier  
F. Clearance to outside corner  
G. Clearance to inside corner  
3 feet (91 cm)  
3 feet (91 cm)  
Above a meter/regulator assembly within 3 feet (91 cm) Above a meter/regulator assembly within 3 feet (91  
H. Clearance to each side of center line  
extended above meter/regulator assembly  
horizontally of the vertical center-line of the regulator  
vent outlet to a maximum vertical distance of 15 feet  
(4.5 cm) above the meter/regulator assembly.  
cm) horizontally of the vertical center-line of the regula-  
tor vent outlet to a maximum vertical distance of 15  
feet (4.5 cm) above the meter/regulator assembly.  
3 feet (91 cm) or in accordance with local installation  
codes and the requirements of the gas supplier.  
I. Clearance to service regulator vent outlet  
3 feet (91 cm)  
J. Clearance to nonmechanical air supply inlet to  
building or the combustion air inlet to any other  
appliance  
Two-pipe (direct vent) applications: 9 inches (23 cm)  
for models 50,000 BTUH (15 kW), 12 inches (30 cm)  
for models >50,000 BTUH (15 kW).  
12 inches (30 cm) for models 100,000 BTUH (30 kW),  
36 inches (91 cm) for models >100,000 BTUH (30 kW)  
3 feet (91 cm) above if within 10 feet (3 cm)  
horizontally  
K. Clearance to a mechanical supply inlet  
6 feet (1.83 m)  
7 feet (2.13 m)†  
L. Clearance above paved sidewalk or paved  
driveway located on public property  
7 feet (2.13 m) or in accordance with local installation  
codes and the requirements of the gas supplier.  
12 inches (30 cm) or in accordance with local installa-  
tion codes and the requirements of the gas supplier.  
M. Clearance under veranda, porch, deck, or balcony 12 inches (30 cm)‡  
1. In accordance with the current CSA B149.1-00, Natural Gas and Propane Installation Code.  
2. In accordance with the current ANSI Z223.1 / NFPA 54, National Gas Code.  
3. In accordance with the current ANSI Z21.47 * CSA 2.3 American National Standard.  
A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.  
†† 12 inches (30 cm) up from the bottom edge of the structure for Two-pipe (direct vent) applications per ANSI Z223.1 / NFPA 54, National Gas Code.  
Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor and the distance between the top of the vent termina-  
tion and the underside of the veranda, porch, or deck is greater than 1 foot (30 cm) as specified in CSA B149.1-00.  
A vent shall not terminate less than 1 foot (30 cm) above a grade level.  
Any fresh air or make up inlet for dryer or furnace area is considered to be forced air inlet.  
Avoid areas where condensate drippage may cause problems such as above planters, patios, or adjacent to windows where steam may cause fogging.  
A terminus of a vent shall be fitted with a cap in accordance with the vent manufacturer’s installation instructions, or in accordance with the installation instructions for a  
special venting system.  
IMPORTANT: Consideration must be given for degradation of building materials by flue gases. Sidewall termination may require sealing or shielding of building surfaces  
with a corrosion resistant material to protect against combustion product corrosion. Consideration must be given to wind direction in order to prevent flue products and/or  
condensate from being blown against the building surfaces. If a metal shield is used it must be a stainless steel material at a minimum dimension of 20 inches. It is rec-  
ommended that a retaining type collar be used that is attached to the building surface to prevent movement of the vent pipe.  
Responsibility for the provision of proper adequate venting and air supply for application shall rest with the installer.  
Vent shall extend high enough above building, or a neighboring obstruction, so that wind from any direction will not create a positive pressure in the vicinity of the vent.  
Unitary Products Group  
17  
268890-UIM-B-0607  
VENT SYSTEM  
HORIZONTAL VENT ASSEMBLY  
This furnace is certified to be installed with one of two possible vent  
configurations.  
Horizontal Left Vent Assembly  
1. Place the 2” (5.08 cm) 45° PVC street elbow on the vent connec-  
tion shown in Figure 18.  
1. Horizontal vent system. This vent system can be installed com-  
pletely horizontal or combinations of horizontal, vertical, or offset  
using elbows.  
2. Place the 2” (5.08 cm) PVC WYE (“Y”) assembly on the 2” (5.08  
cm) 45° PVC street elbow as shown in Figure 18.  
2. Vertical vent system. This vent system can be installed completely  
vertical or a combination of horizontal, vertical, or offset using  
elbows.  
3. Refer to the “DOWNFLOW/HORIZONTAL CONDENSATE INTER-  
NAL DRAIN CONFIGURATIONS” for futher details.  
Horizontal Right Vent Assembly  
HORIZONTAL VENT APPLICATIONS AND  
TERMINATION  
When selecting the location for a horizontal combustion air / vent termi-  
nation, the following should be considered:  
1. Place the 2” (5.08 cm) 45° PVC street elbow on the vent connec-  
tion shown in Figure 18.  
2. Place the 2” (5.08 cm) PVC WYE (“Y”) assembly on the 2” (5.08  
cm) 45° PVC street elbow as shown in Figure 18.  
3. Refer to the “DOWNFLOW/HORIZONTAL CONDENSATE INTER-  
NAL DRAIN CONFIGURATIONS” for futher details.  
1. Observe all clearances listed in vent clearances in these instruc-  
tions.  
MAINTAIN 12” MINIMUM CLEARANCE  
ABOVE HIGHEST ANTICIPATED SNOW  
LEVEL. MAXIMUM 24” ABOVE ROOF.  
2. Termination should be positioned where vent vapors will not dam-  
age plants or shrubs or air conditioning equipment.  
3. Termination should be located where it will not be affected by wind  
gusts, light snow, airborne leaves or allow recirculation of flue  
gases.  
12” MIN.  
4. Termination should be located where it will not be damaged or  
exposed to flying stones, balls, etc.  
12” MIN.  
5. Termination should be positioned where vent vapors are not objec-  
tionable.  
6. Horizontal portions of the vent system must slope upwards and be  
supported to prevent sagging. The vent system may be supported  
by the use of clamps or hangers secured to a permanent part of  
the structure every 4 ft. (1.22 m).  
7. Sealed combustion air systems must be installed so the vent and  
the combustion air pipes terminate in the same atmospheric zone.  
Refer to Figures 19, 20, & 21.  
FIGURE 19: Termination Configuration - 1 Pipe  
12” VERTICAL SEPARATION  
BETWEEN COMBUSTION AIR  
AND VENT  
DOWNFLOW VENT ASSEMBLY  
1. Place the 2” (5.08 cm) 45° PVC street elbow on the vent connec-  
tion shown in Figure 18.  
12” MINIMUM  
BELOW  
OVERHANG  
MAINTAIN 12”  
MINIMUM  
CLEARANCE  
ABOVE HIGHEST  
ANTICIPATED  
SNOW LEVEL.  
12” MINIMUM  
SEPARATION  
BETWEEN BOTTOM  
OF COMBUSTION  
AIR PIPE AND  
2. Place the 2” (5.08 cm) PVC WYE (“Y”) assembly on the 2” (5.08  
cm) 45° PVC street elbow as shown in Figure 18.  
3. Locate the rubber condensate hose in front of the blower access  
panel.  
BOTTOM OF VENT  
MAINTAIN 12”  
4. Slide the hose through the hole in the top cover, and insert the  
hose on to the barbed fitting on the bottom of the 2” (5.08 cm) PVC  
WYE (“Y”) assembly as shown in Figure 18.  
MINIMUM CLEARANCE  
ABOVE HIGHEST  
ANTICIPATED SNOW  
LEVEL OR GRADE,  
WHICHEVER IS  
HIGHER  
RETURN  
AIR  
2” (5.08 cm)  
VENT PIPE  
RETURN  
AIR  
2” PVC  
WYE  
2” PVC  
45°  
STELL  
FURNACE  
VENT PIPE  
HORIZONTAL LEFT  
FIGURE 20: Termination Configuration - 2 Pipe  
12” MINIMUM SEPARATION BETWEEN BOTTOMOF  
COMBUSTION AIR PIPE AND TOP OF VENT.  
MAINTAIN 12” MIN. CLEARANCE ABOVE  
HIGHEST ANTICIPATED SNOW LEVEL.  
DOWNFLOW  
RETURN  
AIR  
12” MIN.  
BARBED  
FITTING  
12” MIN.  
HORIZONTAL RIGHT  
FIGURE 18: Downflow/Horizontal Vent Assembly  
FIGURE 21: Termination Configuration - 2 Pipe Horizontal  
18  
Unitary Products Group  
268890-UIM-B-0607  
12” MINIMUM  
BELOW  
OVERHANG  
MIN.  
6”  
12” MINIMUM  
SEPARATION  
BETWEEN BOTTOM  
OF COMBUSTION  
AIR PIPE AND  
BOTTOM OF VENT  
MAINTAIN 12”  
MINIMUM CLEARANCE  
ABOVE HIGHEST  
ANTICIPATED SNOW  
LEVEL OR GRADE,  
WHICHEVER IS  
HIGHER  
FIGURE 24: Double Vertical Sealed Combustion Air and Vent  
Termination  
VENT DRAIN  
COMBUSTION AIR SUPPLY  
FIGURE 22: Crawl Space Termination Configuration - 2Pipe  
All installations must comply with Section 5.3, Air for Combustion and  
Ventilation of the National Fuel Gas Code, ANSI Z223.1 or Sections  
7.2, 7.3 or 7.4 of CAN/CGA B149.1 or .2 Installation Code - latest edi-  
tions.  
VERTICAL VENT APPLICATIONS AND  
TERMINATION  
Roof mounted vertical terminals may be field fabricated. Standard PVC/  
SRD fittings may be used. If installing a vertical venting system through  
any unconditioned space such as an attic or crawl space it must be  
insulated.  
This furnace is certified to be installed with one of three possible com-  
bustion air intake configurations.  
1. OUTDOOR COMBUSTION AIR: This is a sealed combustion air  
configuration where the combustion air is supplied through a PVC  
or ABS pipe that is connected to the PVC coupling attached to the  
burner box and is terminated in the same atmospheric zone as the  
vent. This type of installation is approved on all models. Refer to  
Figures 25 & 27.  
1. Observe all clearances listed in vent clearances in these instruc-  
tions.  
2. Termination should be positioned where vent vapors are not objec-  
tionable.  
3. Termination should be located where it will not be affected by wind  
gusts, light snow, or allow recirculation of flue gases.  
2. AMBIENT COMBUSTION AIR: Combustion air is supplied from  
the area surrounding the furnace through the combustion air pipe  
in the furnace casing. The combustion air and the vent pipes are  
not terminated in the same atmospheric zone. Refer to Figures 19  
& 26 for vent terminations. Refer to “AMBIENT COMBUSTION  
AIR SUPPLY” and “VENT AND SUPPLY OUTSIDE AIR SAFETY  
CHECK PROCEDURE” for proper installation.  
4. Termination should be located where it cannot be damaged,  
plugged or restricted by tree limbs, leaves and branches.  
5. Horizontal portions of the vent system must slope upwards and be  
supported to prevent sagging. The vent system may be supported  
by the use of clamps or hangers secured to a permanent part of  
the structure every 4 ft. (1.22 m).  
3. VENTILATED COMBUSTION AIR: Combustion air is supplied  
through a PVC or ABS pipe that is connected to the PVC coupling  
attached to the burner box and is terminated in a ventilated attic or  
crawl space. The combustion air and the vent pipes are not termi-  
nated in the same atmospheric zone. Refer to Figure 28 for crawl  
space and attic termination. Only the combustion air intake may  
terminate in the attic. The vent must terminate outside.  
VENTING MULTIPLE UNITS  
Only the sealed combustion system can be used for installations requir-  
ing more than one furnace in a structure. A separate sealed combustion  
air pipe and a separate vent pipe must be installed for each furnace. Do  
not connect more than one furnace to a combustion air pipe or a vent  
pipe. The combustion air and vent termination must be located as  
shown in Figures 23 or 24.  
Outdoor Combustion Air  
Combustion Air Intake/Vent Connections  
This installation requires combustion air to be brought in from outdoors.  
This requires a properly sized pipe (shown in Figures 31, 33, or 35) that  
will bring air in from the outdoors to the furnace combustion air intake  
collar on the burner box. The second pipe (shown in Figures 31, 33 or  
35) is the furnace vent pipe.  
VENT  
2” (5.08 cm)  
VENT  
CONNECTION  
COMBUSTION AIR  
2”  
MIN.  
FIGURE 23: Double Horizontal Sealed Combustion Air and Vent  
Termination  
AIR INTAKE  
FIGURE 25: Sealed Combustion Air Intake Connection and Vent  
Connection  
Unitary Products Group  
19  
268890-UIM-B-0607  
The combustion air intake pipe should be located either through the  
wall (horizontal or side vent) or through the roof (vertical vent). Care  
should be taken to locate side vented systems where trees or shrubs  
will not block or restrict supply air from entering the terminal.  
Combustion Air Source From Outdoors  
The blocking effects of louvers, grilles and screens must be given con-  
sideration in calculating free area. If the free area of a specific louver or  
grille is not known, refer to Table 12, to estimate free area.  
Also, the terminal assembly should be located as far as possible from a  
swimming pool or a location where swimming pool chemicals might be  
stored. Be sure the terminal assembly follows the outdoor clearances  
listed in Section #1 “COMBUSTION AIR QUALITY (LIST OF CONTAM-  
INANTS).”  
TABLE 12: Estimated Free Area  
Wood or Metal  
Louvers or Grilles  
Wood 20-25%*  
Metal 60-70% *  
1/4” (0.635 cm)  
Screens+  
mesh or larger 100%  
Fresh air pipe can either be routed through the furnace or routed out-  
side the furnace.  
*
+
Do not use less than 1/4” (0.635 cm) mesh  
Free area or louvers and grilles varies widely; the installer should follow lou-  
ver or grilles  
manufacturer’s instructions.  
Ambient Combustion Air Supply  
This type installation will draw the air required for combustion from  
within the space surrounding the appliance and from areas or rooms  
adjacent to the space surrounding the appliance. This may be from  
within the space in a non-confined location or it may be brought into the  
furnace area from outdoors through permanent openings or ducts. It is  
not piped directly into the burner box. A single, properly sized pipe from  
the furnace vent connector to the outdoors must be provided. For down-  
flow models combustion air is brought into the furnace through the unit  
top panel opening. Do not install a pipe into the combustion air pipe at  
the top of the furnace. Refer to Figures 19 & 26.  
Dampers, Louvers and Grilles (Canada Only)  
1. The free area of a supply air opening shall be calculated by sub-  
tracting the blockage area of all fixed louvers grilles or screens  
from the gross area of the opening.  
2. Apertures in a fixed louver, a grilles, or screen shall have no  
dimension smaller than 0.25” (0.64 cm).  
3. A manually operated damper or manually adjustable louvers are  
not permitted for use.  
4. A automatically operated damper or automatically adjustable lou-  
vers shall be interlocked so that the main burner cannot operate  
unless either the damper or the louver is in the fully open position.  
TABLE 13: Free Area - Outdoor Air  
Minimum Free Area Required for Each Opening  
This type of installation requires that the supply air to the appli-  
ance(s) be of a sufficient amount to support all of the appliance(s)  
in the area. Operation of a mechanical exhaust, such as an exhaust  
fan, kitchen ventilation system, clothes dryer or fireplace may cre-  
ate conditions requiring special attention to avoid unsatisfactory  
operation of gas appliances. A venting problem or a lack of supply  
air will result in a hazardous condition, which can cause the appli-  
ance to soot and generate dangerous levels of CARBON MONOX-  
IDE, which can lead to serious injury, property damage and / or  
death.  
BTUH Input  
Rating  
Vertical Duct or  
Opening to Outside  
(4,000 BTUH)  
Round Duct  
(4,000  
BTUH)  
Horizontal Duct  
(2,000 BTUH)  
20 sq. in. (129 cm2) 10 sq. in. (65 cm2)  
30 sq. in. (194 cm2) 15 sq. in. (97 cm2)  
40 sq. in. (258 cm2) 20 sq. in. (129 cm2)  
50 sq. in. (323 cm2) 25 sq. in. (161 cm2)  
60 sq. in. (387 cm2) 30 sq. in. (194 cm2)  
40,000  
60,000  
80,000  
100,000  
120,000  
4” (10 cm)  
5” (13 cm)  
5” (13 cm)  
6” (15 cm)  
7” (18 cm)  
An unconfined space is not less than 50 cu.ft (1.42 m3) per 1,000 Btu/  
hr. (0.2928 kW) input rating for all of the appliances installed in that  
area.  
EXAMPLE: Determining Free Area.  
Appliance 1Appliance  
100,000 + 30,000 = (130,000 ÷ 4,000) = 32.5 Sq. In. Vertical  
Appliance 1Appliance 2Total Input  
2Total Input  
Rooms communicating directly with the space containing the appli-  
ances are considered part of the unconfined space, if openings are not  
furnished with doors.  
100,000 + 30,000 = (130,000 ÷ 2,000) = 65 Sq. In. Horizontal  
A confined space is an area with less than 50 cu.ft (1.42 m3) per 1,000  
Btu/hr. (0.2928 kW) input rating for all of the appliances installed in that  
area. The following must be considered to obtain proper air for combus-  
tion and ventilation in confined spaces.  
TABLE 14: Unconfined Space Minimum Area in Square Inches  
BTUH Input Rating Minimum Free Area Required for Each Opening  
40 (258 cm2)  
40,000  
60 (387 cm2)  
60,000  
80 (516 cm2)  
80,000  
VENT PIPE PASSES  
THROUGH TOP PANEL  
COMBUSTION  
AIRFLOW  
100 (645 cm2)  
100,000  
120 (774 cm2)  
120,000  
COMBUSTION AIRFLOW  
3-WAY TRANSITION  
FIGURE 26: Combustion Airflow Path Through The Furnace Casing to  
the Burner Box  
20  
Unitary Products Group  
268890-UIM-B-0607  
GAS  
VENT  
AIR SUPPLY OPENINGS AND DUCTS  
GAS  
VENT  
GABLE  
VENT  
An opening may be used in lieu of a duct to provide to provide the outside air  
supply to an appliance unless otherwise permitted by the authority having  
jurisdiction. The opening shall be located within 12” (30.5 cm) horizontally from,  
the burner level of the appliance. Refer to “AIR SOURCE FROM OUTDOORS  
AND VENT AND SUPPLY AIR SAFETY CHECK” in these instructions for  
additional information and safety check procedure.  
1.  
VENTILATED  
ATTIC  
TOP ABOVE  
INSULATION  
OPTIONAL  
INLET (a)  
OUTLET  
AIR (b)  
OUTLET  
AIR (a)  
The duct shall be either metal, or a material meeting the class 1  
requirements of CAN4-S110 Standard for Air Ducts.  
OUTLET  
AIR (a)  
SOFFIT  
VENT  
2.  
3.  
The duct shall be least the same cross-sectional area as the free  
area of the air supply inlet opening to which it connects.  
GAS  
WATER  
HEATER  
The duct shall terminate within 12 in (30.5 cm) above, and  
within 24 in (61 cm) horizontally from, the burner level of  
the appliance having the largest input.  
4.  
GAS  
WATER  
HEATER  
INLET  
AIR (b)  
INLET  
AIR (a)  
COMBUSTION AIR SOURCE FROM OUTDOORS  
1. Two permanent openings, one within 12 in (30.5 mm) of the top and  
one within 12 in (30.5 mm) of bottom of the confined space, Two  
permanent openings, shall communicate directly or by means of ducts  
with the outdoors, crawl spaces or attic spaces.  
VENTILATED  
CRAWL SPACE  
GAS  
GABLE  
VENT  
VENT  
5. A square or rectangular shaped duct shall only be used  
when the required free area of the supply opening is  
9 in2 (58.06 cm2) or larger. When a square or rectangular  
duct is used, its small dimensionshall not be less than  
3 in (7.6 cm).  
VENTILATED  
ATTIC  
TOP ABOVE  
INSULATION  
2. One permanent openings, commencing within 12 in (30.5 mm)of the  
top of the enclosure shall be permitted where the equipment has  
clearances of at least 1 in (2.54 cm) from the sides and back and  
6 in (15.24 cm) from the front of the appliance. The opening shall  
communicate directly with the outdoors and shall have a minimum  
free area of:  
6. An air inlet supply from outdoors shall be equipped with  
a means to prevent the direct entry of rain and wind.  
Such means shall not reduce the required free area of  
the air supply opening.  
SOFFIT  
VENT  
1 square in per 3000 Btu per hour (6.45 cm2 0.879 kW) of the total  
a.  
input rating of all equipment located in the enclosure.  
Not less than the sum of all vent connectors in the confined space.  
b.  
7. An air supply inlet opening from the outdoors shall  
be located not less than 12” (30.5 cm) above the  
outside grade level.  
GAS  
WATER  
HEATER  
3. The duct shall be least the same cross-sectional area as the free  
area of the air supply inlet opening to which it connects.  
4. The blocking effects of louvers, grilles and screens must be given  
consideration in calculating free area. If the free area of a specific  
louver aor grille is not known.  
INLET  
AIR (b)  
INLET  
AIR (a)  
FIGURE 27: Outside and Ambient Combustion Air  
NOTE: An unsafe condition exists when the CO reading exceeds 40  
ppm and the draft reading is not in excess of - 0.1 in. W.C. (-25 kPa)  
with all of the appliance(s) operating at the same time.  
Vent and Supply (Outside) Air Safety Check Procedure  
Follow the procedure in ANSI Z223.1 National Fuel Gas Code. Refer to  
the section on the “Recommended Procedure for Safety Inspection of  
an Existing Appliance” or in Canada B149.1-00 Natural Gas and Pro-  
pane Installation Code section on “Venting Systems and Air Supply for  
Appliances” and all local codes. In addition to the procedure specified in  
ANSI Z223.1, it is recommended that you follow the venting safety pro-  
cedure below. This procedure is designed to detect an inadequate ven-  
tilation system that can cause the appliances in the area to operate  
improperly causing unsafe levels of Carbon Monoxide or an unsafe  
condition to occur.  
8. Any corrections to the venting system and / or to the supply (out-  
side) air system must be in accordance with the National Fuel Gas  
Code Z223.1 or CAN/CGA B149.1-00 Natural Gas and Propane  
Installation Code (latest editions). If the vent system must be  
resized, follow the appropriate tables in Appendix G of the above  
codes or for this appliance, refer to Table 8 of these instructions.  
Ventilated Combustion Air  
The ventilated attic space or a crawl space from which the combustion  
air is taken must comply with the requirements specified in “COMBUS-  
TION AIR SOURCE FROM OUTDOORS” in this instruction or in Sec-  
tion 5.3, Air for Combustion and Ventilation of the National Fuel Gas  
Code, ANSI Z223.1 (latest edition). This type installation requires two  
properly sized pipes. One brings combustion air from a properly venti-  
lated attic space or crawl space and a second pipe that extends from  
the furnace vent connection (top right of unit) to the exterior of the build-  
ing. Refer to Table 8 for intake pipe sizing, allowable length and elbow  
usage. Follow all notes, procedures and required materials in the  
SEALED COMBUSTION AIR SUPPLY section in these instructions  
when installing the combustion air pipe from the unit and into a venti-  
lated attic space or crawl space. DO NOT terminate vent pipe in an Attic  
or Crawl Space.  
1. Inspect the venting system for proper size and horizontal pitch.  
Determine that there is no blockage, restriction, leakage, corrosion  
or other deficiencies, which could cause an unsafe condition  
2. Close all building doors and windows and all doors.  
3. Turn on clothes dryers and TURN ON any exhaust fans, such as  
range hoods and bathroom exhausts, so they shall operate at  
maximum speed. Open the fireplace dampers. Do not operate a  
summer exhaust fan.  
4. Follow the lighting instructions. Place the appliance being  
inspected in operation. Adjust thermostat so the appliance shall  
operate continuously.  
5. Test each appliance (such as a water heater) equipped with a draft  
hood for spillage (down-draft or no draft) at the draft hood relief  
opening after 5 minutes of main burner operation. Appliances that  
do not have draft hoods need to be checked at the vent pipe as  
close to the appliance as possible. Use a combustion analyzer to  
check the CO2 and CO levels of each appliance. Use a draft  
gauge to check for a downdraft or inadequate draft condition.  
Ventilated Combustion Air Termination  
Refer to Figure 28 for required attic termination for the combustion air  
intake pipe. For attic termination, use two 90 elbows with the open end  
in a downward position. Be sure to maintain 12” (30.5 cm) clearance  
above any insulation, flooring or other material.  
6. After it has been determined that each appliance properly vents  
when tested as outlined above, return doors, windows, exhaust  
fans, fireplace dampers and any other gas burning appliance to  
their normal condition.  
A crawl space combustion air installation consists of a straight pipe from  
the PVC coupling on the burner box that extends into the crawl space  
and terminates with a 1/4” (0.63 cm) mesh screen and no elbows.  
7. If improper venting is observed during any of the above tests, a  
problem exists with either the venting system or the appliance  
does not have enough combustion air (Supply Air from outside) to  
complete combustion. This condition must be corrected before the  
appliance can function safely.  
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IMPORTANT: Condensate must be disposed of properly. Follow local  
plumbing or wastewater codes. The drain line must maintain a 1/4" per  
foot (0.635 cm per meter) slope to the drain.  
12” MINIMUM BETWEEN  
BOTTOM OF BELOW AND  
ANY MATERIAL  
12”  
MIN.  
CONDENSATE DRAIN TRAP AND DRAIN FREEZE  
PROTECTION  
Special precautions MUST be made if installing furnace in an area,  
which may drop below freezing. This can cause improper operation or  
damage to the equipment. If the furnace is installed in an area that has  
the potential of freezing, the drain line and the drain trap must be pro-  
tected. Use a 3 to 6 watt per foot at 115 vac, 40º F (4.4° C) self-regulat-  
ing, shielded and waterproof heat tape. Wrap the drain trap and the  
drain line with the heat tape and secure with ties. Follow the heat tape  
manufacturer's recommendations.  
FIGURE 28: Attic Combustion Air Termination  
Specially Engineered Installations  
CONDENSATE DRAIN HOSE PART NUMBERS  
TABLE 15: Condensate Drain Hose  
The above requirements shall be permitted to be waived where special  
engineering, approved by the authority having jurisdiction, provides an  
adequate supply of air for combustion, ventilation and dilution of flue  
gases.  
Hose  
Part  
Number  
Numb  
er  
Description  
028-15156-000  
028-15176-000  
#1  
#2  
Drain tube - Condensate pan (Down flow)  
Drain tube - Inducer (Horizontal RT.)  
-Vent system Down flow)  
Be sure to instruct the owner not to block this intake pipe.  
SECTION VIII: CONDENSATE PIPING  
028-15168-000  
028-15176-000  
028-15176-000  
028-15196-000  
028-15169-001  
028-13309-004  
028-15158-000  
#3  
#4  
#5  
#6  
#7  
#8  
#9  
Drain tube - Inducer (Down flow)  
Drain tube - Rain gutter (Down flow & Horizontal RT.)  
Drain tube - After Tee (Down flow)  
Drain tube – Upper rain gutter (Horizontal LT.)  
Drain tube - After Tee (Horizontal RT.)  
Drain tube - P-trap (All models)  
Drain tube - Vent system (Horizontal LT.)  
- Before Tee (Horizontal RT.)  
Drain tube – Condensate pan (Horizontal –  
drain closer to the front of the furnace, both LT & RT)  
028-15197-000  
#10  
CONDENSATE DRAIN TUBE 5/8” (1.59 cm)  
FIGURE 29: Condensate Drain Internal Hose Routing  
CONDENSATE DRAIN  
The condensate drain connection is provided in the furnace for field  
installation. It consists of the hoses shown below, a NPT male connec-  
tion, and a 1/2” (1.27 cm) female x 3/4” (1.9 cm) PVC slip coupling.  
Some of the drain hoses will be needed to convert the condensate drain  
system when the furnace is installed in a horizontal left or right configu-  
ration. Refer to Figures 30 - 36 for the condensate hose sizes for con-  
densate drain connections.  
Hoses #2, #4, #5, along with a barbed nipple, and a barbed tee are part of  
condensate hose assembly 028-15176-000.  
DOWNFLOW/HORIZONTAL CONDENSATE  
INTERNAL DRAIN CONFIGURATIONS  
Downflow - Refer to Figure 30  
Furnace is shipped with one end of condensate hose #2 left open in the  
furnace. If the provided Wye's drain is aligned with the opening in the  
top of the furnace, hose #2 can be used. If it is desired that the Wye and  
street elbow assembly point away from the opening in the casing top,  
then the #2 hose will have to be replaced with provided #9 hose. The  
dogleg end of hose #9 hose should be installed on the drain of the Wye.  
IMPORTANT: The condensate drain from the furnace may be con-  
nected in common with the drain from an air conditioning coil if allowed  
by local code.  
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SPRING CLAMP  
1”  
HOSE #5  
HOSE #1  
2-3/4”  
CUT  
4-1/2”  
PIECE  
3/4”  
3/4”  
SPRING CLAMP  
-
DOGLEG  
8-1/8”  
9”  
HOSE #3  
SPRING CLAMP  
HOSE #2 (if drain aligned  
above the hole in  
furnace top)  
5/8”  
1-1/8”  
3-3/8”  
HOSE #4 (with 3/8”  
barbed nipple)  
HOSE #2  
17-1/2”  
3/8”  
3/8” Barbed Tee  
SPRING CLAMP  
3/4”  
DOG  
LEG  
HOSE #5  
HOSE #1  
* USED AFTER  
CONDENSATE  
TRAP  
1”  
HOSE #8  
2-3/4”  
HOSE #3  
SPRING CLAMP  
1”  
DOG  
LEG  
HOSE #4  
22-1/8”  
2”  
3/4”  
SPRING CLAMP  
1/2”  
HOSE #9  
3/4”  
1-5/8”  
3/4”  
33”  
FIGURE 30: Downflow Condensate Drain Hose Configuration  
7. Switch the blocked condensate hose to the condensate tap on the  
bottom of the condensate pan (close to the inducer).  
Horizontal Left Air Flow (Inducer Low) -  
Refer to Figures 31 & 32  
8. Install hose #9 between the external drain on the Wye and the  
condensate trap; with the dogleg end installed on the protruded  
(stub) drain of the condensate trap. The length of hose #9 may  
have to be trimmed to ensure proper condensate drainage.  
1. Remove all the condensate hoses inside the furnace, leaving the  
3/8" barbed nipple and hose # 4, both factory installed, in the rain  
gutter.  
2. Remove the condensate trap and its bracket from inside the fur-  
nace, saving the screws for use later.  
9. Remove all condensate hoses off the 3/8" barbed tee.  
10. Cut 1-1/2" length of straight 3/8" hose off of hose #5 and install it  
on the 3/8" barbed tee. The other end of the 1-1/2" hose should be  
installed on the welled opening on the condensate trap.  
3. Remove the yellow cap from the top drain of the rain gutter and  
install loosely packed 3/8" barbed nipple in it.  
4. Remove the large condensate cap from the side of the condensate  
pan and install it on the middle drain of the condensate pan, from  
where #1 hose was removed.  
11. Install one end of the 3/8" barbed tee on hose #4 as shown.  
Ensure that hose #4 follows a gradual downward slope all the way  
to the barbed tee.  
5. Install longer dogleg end of hose #10 through the casing hole on to  
the side drain of the condensate pan, where cap was removed in  
step #4. Some lubricant may have to be used to facilitate this  
installation as the hose is designed as a tight fit over the conden-  
sate drain. The other, shorter, dogleg end of hose #10 should be  
installed into the large recessed drain in the condensate trap.  
12. Install hose #6 between the top drain of the rain gutter of the  
inducer and the remaining open end of 3/8" barbed tee.  
13. Ensure that all hoses are properly installed, have no kinks, and are  
draining properly. All hoses on the condensate trap should be  
pushed all the way down to ensure against leakage.  
6. Install the condensate trap bracket, with the condensate trap, on to  
the front side of the furnace, using the screws removed in step #1.  
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FIGURE 31: Horizontal Left Condensate Drain Hose Configuration  
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FIGURE 32: Horizontal Left Condensate Drain Hose Configuration  
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Horizontal Right Air Flow (Inducer High)  
Refer to Figures 33-36  
Installation with condensate trap bracket (Front of casing):  
Refer to Figure 33 & 34  
Ensure all condensate hoses are pushed all the way down on the  
condensate trap, barbed fittings, and condensate pan drains.  
1. Remove the 2" knockout on the casing side, away from the  
inducer motor.  
2. Remove all the condensate hoses inside the furnace, including the  
3/8" barbed nipple, factory installed, in the rain gutter.  
Plug all unused condensate trap, condensate pan and inducer drain  
connection points using plugs provided.  
3. Remove the drain cap from the bottom rain gutter drain and insert  
the 3/8” barbed nipple removed above in the bottom rain gutter  
drain. Place the cap, just removed, to the other side of the rain gut-  
ter on the inducer.  
Installation with condensate trap bracket (Back of casing):  
Refer to Figure 35 & 36  
4. Remove the condensate trap and its bracket from inside the fur-  
nace, saving the screws for later use.  
1. Remove the 2" knockout on the casing side, away from the  
inducer motor.  
5. Remove the large condensate cap from the side of the condensate  
pan and install it on the middle drain of the condensate pan, from  
where #1 hose was removed.  
2. Remove all the condensate hoses inside the furnace, including the  
3/8" barbed nipple, factory installed, in the rain gutter.  
3. Remove the drain cap from the bottom rain gutter drain and insert  
the 3/8” barbed nipple removed above in the bottom rain gutter  
drain. Place the cap, just removed, to the other side of the rain gut-  
ter on the inducer.  
6. Install longer dogleg end of hose #10 through the casing hole on to  
the side drain of the condensate pan, where cap was removed in  
step #3. Some lubricant may have to be used to facilitate this  
installation as the hose is designed to be a tight fit over the con-  
densate drain. The other, smaller, dogleg end of hose #10 should  
be installed into the large recessed drain in the condensate trap.  
4. Remove the condensate trap and it's bracket from inside the fur-  
nace, saving the screws for later, use.  
7. Install the condensate trap bracket, with the condensate trap, on to  
the front side of the furnace, using the screws removed in step #1.  
5. Remove the large condensate cap from the side of the condensate  
pan and install it on the middle drain of the condensate pan, from  
where #1 hose was removed.  
8. Install the dogleg end of hose #9 on the Wye drain and route the  
hose through the opening on top of the furnace, as shown. Install  
the other end of the #9 hose to the barbed tee, inside the furnace.  
6. Do not remove condensate trap from the condensate trap bracket.  
7. Cut 2-1/2" straight piece from hose #1 and install it through the  
knockout opening in the casing on the side of the condensate pan,  
from where the cap was previously removed. Insert the other end  
of the hose into the large recessed drain on the condensate trap.  
9. Install the dogleg end of hose #4 to the rain gutter on the inducer.  
The other end of hose #4 should be installed on the 3/8" barbed  
tee.  
8. Install the condensate trap bracket to the 2” inch hole on the side  
of casing, using existing holes, lining up the condensate pan open-  
ing with the larger opening on the condensate trap.  
10. Install one end of hose #7 on the 3/8" barbed tee inside the fur-  
nace. Guide the other end of hose #7 towards the condensate  
trap, and install it on the tap on the condensate trap.  
9. Install the dogleg end of hose #9 on the Wye drain and route the  
hose through the opening on top of the furnace. Install the other  
end of the #9 hose to the barbed tee, inside the furnace.  
11. Install the dogleg end of hose #2 on the bottom drain of the  
inducer. Guide the other end of hose #2 towards the condensate  
trap, and install it on the small recessed drain in the condensate  
trap.  
10. Install the dogleg end of hose #4 on 3/8" barbed nipple, in the rain  
gutter. The other end of hose #4 should be installed on the 3/8"  
barbed tee.  
12. Ensure that all hoses are properly installed, have no kinks, and are  
draining properly. All hoses on the condensate trap and conden-  
sate pan should be pushed all the way down to ensure against  
leakage and performance. Some hoses may have to be trimmed  
for proper fit.  
11. Install one end of hose #7 on the 3/8" barbed tee inside the fur-  
nace. Guide the other end of hose #7 towards the condensate  
trap, and install it on the tap on the condensate trap  
NOTE: The condensate trap can also be installed on the 2" knockout  
opening, in this configuration, using the provided condensate trap  
bracket. Some modifications may, however, have to be made to the  
condensate hoses.  
12. Install the dogleg end of hose #2 on the bottom drain of the  
inducer. Guide the other end of hose #2 towards the condensate  
trap, and install it on the small recessed drain in the condensate  
trap.  
13. Ensure that all hoses are properly installed, have no kinks, and are  
draining properly. All hoses on the condensate trap should be  
pushed all the way down to ensure against leakage. All hoses on  
the condensate pan should be pulled all the way up to ensure  
proper operation.  
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FIGURE 33: Horizontal Right Condensate Drain Hose Configuration (Option 1 - Front of Casing)  
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FIGURE 34: Horizontal Right Condensate Drain Hose Configuration (Option 1 - Front of Casing)  
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FIGURE 35: Horizontal Right Condensate Drain Hose Configuration (Option 2 - Back of Casing)  
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FIGURE 36: Horizontal Right Condensate Drain Hose Configuration (Option 2 - Back of Casing)  
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CONDENSATE DRAIN TERMINATION  
DO NOT terminate condensate drain in a chimney, or where the drain  
line may freeze. The line must terminate at an inside drain to prevent  
freezing of the condensate and possible property damage. DO NOT  
trap the drain line at any other location than at the condensate drain  
trap supplied with the furnace. A condensate sump pump MUST be  
used if required by local codes, or if no indoor floor drain is available.  
The condensate sump pump must be approved for use with acidic con-  
densate.  
DOWNFLOW/HORIZONTAL  
FIGURE 37: Pressure Switch Tubing Routing  
LIMIT CONTROLS  
There is high temperature limit control located on the furnace vestibule  
panel near the gas valve. This is an automatic reset control that pro-  
vides over-temperature protection due to reduced airflow. This may be  
caused by  
CONDENSATE DRAIN PRE-START UP PROCEDURE  
The condensate trap must be filled with water before putting the furnace  
into operation. Perform the following procedures only after the conden-  
sate trap has been properly piped to a drain connection using the pro-  
cedure in this instruction. The recommended procedure is as follows:  
1. Disconnect the condensate drain hose from the induced draft  
blower discharge.  
2. Elevate this hose and fill with water using a funnel.  
3. Replace the condensate drain hose and clamps. If this procedure  
is not followed, the unit may not properly drain on initial start up.  
1. Dirty filter,  
2. If the indoor fan motor should fail, or  
3. Too many supply or return registers closed or blocked off.  
SECTION IX: SAFETY CONTROLS  
CONTROL CIRCUIT FUSE  
A 3-amp fuse is provided on the control circuit board to protect the 24-  
volt transformer from overload caused by control circuit wiring errors.  
This is an ATO 3, automotive type fuse and is located on the control  
board.  
The control module will lockout if the limit trips 5 consecutive times  
within a single call for heat. Control will reset and try ignition again after  
1 hour.  
SECTION X: START-UP AND  
ADJUSTMENTS  
The initial start-up of the furnace requires the following additional  
procedures:  
BLOWER DOOR SAFETY SWITCH  
This unit is equipped with an electrical interlock switch mounted in the  
blower compartment. This switch interrupts all power at the unit when  
the panel covering the blower compartment is removed.  
IMPORTANT: All electrical connections made in the field and in the fac-  
tory should be checked for proper tightness.  
When the gas supply is initially connected to the furnace, the gas piping  
may be full of air. In order to purge this air, it is recommended that the  
ground union be loosened until the odor of gas is detected. When gas is  
detected, immediately retighten the union and check for leaks. Allow  
five minutes for any gas to dissipate before continuing with the start-up  
procedure.  
Electrical supply to this unit is dependent upon the panel that covers the  
blower compartment being in place and properly positioned.  
Main power to the unit must still be interrupted at the main power  
disconnect switch before any service or repair work is to be done to  
the unit. Do not rely upon the interlock switch as a main power dis-  
connect.  
Blower and burner must never be operated without the blower  
panel in place.  
Perform the following procedures only after the condensate trap  
has been properly piped to a drain connection using the procedure  
in this instruction. Be sure proper ventilation is available to dilute  
and carry away any vented gas.  
ROLLOUT SWITCH CONTROLS  
These controls are mounted on the burner box assembly. If the temper-  
ature in the burner box exceeds its set point, the ignition control and the  
gas valve are de-energized. The operation of this control indicates a  
malfunction in the combustion air blower, heat exchanger or a blocked  
vent pipe connection. Corrective action is required. These are manual  
reset controls that must be reset before operation can continue.  
TOOLS AND INFORMATION THAT WILL BE  
REQUIRED IN ORDER TO PROPERLY PERFORM THE  
FURNACE STARTUP PROCEDURE.  
1. Call the local gas supplier to obtain heating value of the natural  
gas. If you cannot obtain the heating valve of the gas from the gas  
supplier, you may use a default value of 1030 BTU/SCF (38.4 MJ /  
m³).  
PRESSURE SWITCHES  
2. You will need a thermometer or portable digital thermometer to  
read the supply and return air temperatures.  
This furnace is supplied with a pressure switch which monitors the flow  
through the combustion air/vent piping system. This switch de-ener-  
gizes the ignition control module and the gas valve if any of the follow-  
ing conditions are present. Refer to Figure 37 for tubing connections.  
3. You will need a U-tube manometer or digital equipment that has  
the ability to read pressures between 0 – 15” in.w.c (0 - 3.73 kPa)  
in order to measure the gas line and the manifold pressures.  
1. Blockage of combustion air piping or terminal.  
2. Blockage of vent piping or terminal.  
3. Failure of combustion air blower motor.  
4. Blockage of condensate drain piping.  
4. You will need a 3/32” Allen wrench for the pressure port plugs in  
the gas valve.  
5. You will need 2 pieces of 1/8” (0.3 cm) ID flexible tubing that is 12”  
(30 cm) in length, 2 – pieces of 1/8” (0.3 cm) tubing that are 4”  
(10.1 cm) in length, a 1/8” (0.3 cm) tee and a 1/8” (0.3 cm) adapter  
to connect the U-tube manometer or the digital pressure measur-  
ing equipment to the gas valve pressure ports.  
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There is an accessory kit (1PK0601) available from Source 1, which  
has the following items:  
IMPORTANT: Burner ignition may not be satisfactory on first startup  
due to residual air in the gas line or until gas manifold pressure is  
adjusted. The ignition control will make 3 attempts to light before lock-  
ing out.  
1 - 12” (30 cm) length x 1/8” (0.3 cm) diameter tubing  
2 – pieces of 4” (10 cm) length x 1/8” (0.3 cm) diameter tubing  
1 - 5/16” (0.8 cm) tee  
1 – 5/16” (0.8 cm) x 1/8” (3.175 mm) reducing coupling  
1 – 1/8” (0.3 cm) adapter  
With furnace in operation, check all of the pipe joints, gas valve connec-  
tions and manual valve connections for leakage using an approved gas  
detector, a non-corrosive leak detection fluid, or other leak detection  
methods. Take appropriate steps to stop any leak. If a leak persists,  
replace the component.  
There is a accessory kit (1PK0602) available from Source 1, which has  
the following items:  
The furnace and its equipment shutoff valve must be disconnected from  
the gas supply piping system during any pressure testing of that system  
at test pressures in excess of 1/2 PSI (3.45 kPa).  
12” (30 cm) length x 1/8” (0.3 cm) diameter tubing  
2 – pieces of 4” (10 cm) length x 1/8” (0.3 cm) diameter tubing  
1 - 5/16” (0.8 cm) tee  
1 – 5/16” (0.8 cm) x 1/8” (0.3 cm) reducing coupling  
1 – 1/8” (0.3 cm) adapter  
The furnace must be isolated from the gas supply piping system by  
closing the equipment shutoff valve during any pressure testing of the  
gas supply piping system.  
1 - Dwyer – Manometer  
CALCULATING THE FURNACE INPUT  
(NATURAL GAS)  
These items are required in order to properly perform the required star-  
tup procedure.  
NOTE: Burner orifices are sized to provide proper input rate using natu-  
ral gas with a heating value of 1030 BTU/Ft3 (38.4 MJ/m3). If the heat-  
ing value of your gas is significantly different, it may be necessary to  
replace the orifices.  
IGNITION SYSTEM SEQUENCE  
1. Turn the gas supply ON at external valve and main gas valve.  
2. Set the thermostat above room temperature to call for heat.  
3. System start-up will occur as follows:  
NOTE: Front door of burner box must be secured when checking gas  
input.  
a. The induced draft blower motor will start and come up to  
speed. Shortly after inducer start-up, the hot surface igniter  
will glow for about 17 seconds.  
1. Turn off all other gas appliances connected to the gas meter.  
2. At the gas meter, measure the time (with a stop watch) it takes to  
use 2 cubic ft. (0.0566 m3.) of gas.  
b. After this warm up, the ignition module will energize (open)  
the main gas valve.  
3. Calculate the furnace input by using one of the following equa-  
tions.  
c. After flame is established, the supply air blower will start in  
about 30 seconds.  
FIRE OR EXPLOSION HAZARD  
Failure to follow the safety warnings exactly could result in serious  
injury, death or property damage.  
Never test for gas leaks with an open flame. Use a commercially  
available soap solution made specifically for the detection of leaks  
to check all connections. A fire or explosion may result causing  
property damage, personal injury or loss of life.  
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In the USA use the following formula to calculate the furnace input.  
For natural gas multiply the heat content of the gas BTU/SCF or Default 1030 BTU/SCF (38.4 MJ/m3), times 2 cubic ft. (0.056 m) of gas measured at  
the gas meter, times a barometric pressure and temperature correction factor of 0.960; times 3600, then divided by the time (In seconds) it took to  
measure 2 cubic ft. (0.056 m) of gas from the gas meter.  
For propane (LP) gas multiply the heat content of the gas BTU/SCF or Default 2500 BTU/SCF (93.15 MJ/m3), times 1 cubic ft. (0.028 m) of gas mea-  
sured at the gas meter, times a barometric pressure and temperature correction factor of 0.960; times 3600, then divided by the time (In seconds) it  
took to measure 1 cubic ft. (0.028 m) of gas from the gas meter.  
The formula for US input calculation using a cubic foot gas meter:  
3
3
BTU/ft x 2 cu.ft. x 0.960 x 3600  
BTU/ft x 1 cu.ft. x 0.960 x 3600  
=
=
BTU/H  
=
=
BTU/H  
Seconds it took to measure the 2 cu.ft. of gas  
NATURAL GAS INPUT CALCULATION  
EXAMPLE:  
Seconds it took to measure the 1 cu.ft. of gas  
PROPANE (LP) GAS INPUT CALCULATION  
EXAMPLE:  
1030 x 2 x 0.960 x 3600  
90.5  
2500 x 1 x 0.960 x 3600  
108  
78,666.90  
80,000.00  
Natural Gas  
Propane Gas  
2500 BTU/SCF  
1030 BTU/SCF  
In Canada you will use the following formula to calculate the furnace input if you are using a cubic foot gas meter.  
For Natural Gas multiply the Heat content of the gas MJ/m3 (or Default 38.4), times 2 cubic ft. of gas x 0.028 to convert from cubic feet to cubic  
meters measured at the gas meter, times a barometric pressure and temperature correction factor of 0.960; times 3600, then divided by the time it  
took to measure 2 cubic ft. (0.056 m) of gas from the gas meter.  
For Propane (LP) Gas multiply the Heat content of the gas MJ/m3 (or Default 93.15), times 1 cu. ft. of gas x 0.028 to convert from cubic feet to cubic  
meters measured at the gas meter, times a barometric pressure and temperature correction factor of 0.960; times 3600, then divided by the time it  
took to measure 1 cubic ft. (0.028 m) of gas from the gas meter.  
The formula for metric input calculation using a cubic foot gas meter:  
3
MJ/m x 2 cu.ft. x 0.028 x 0.960 x 3600  
=
=
MJ/H  
82.12  
x
x
0.2777  
0.2777  
=
=
kW  
x
x
3412.14  
3412.14  
=
=
BTU/H  
Seconds it took to measure the 2 cu.ft. of gas  
NATURAL GAS INPUT CALCULATION  
EXAMPLE:  
38.4 x 2 x 0.028 x 0.960 x 3600  
90.5  
22.80  
77,796.80  
Natural Gas  
3
1030 BTU/SCF = 38.4 MJ/m  
PROPANE (LP) GAS INPUT CALCULATION  
EXAMPLE:  
93.15 x 1 x 0.028 x 0.960 x 3600  
=
83.46  
x
0.2777  
=
23.18  
x
3412.14  
=
79,093.4  
108  
Propane Gas  
3
2500 BTU/SCF = 93.15 MJ/m  
In Canada use the following formula to calculate the furnace input if you are using a gas meter that measures cubic meters.  
For Natural Gas multiply the Heat content of the gas MJ/m3 (or Default 38.4), times 0.10 m3 of gas measured at the gas meter, times a barometric  
pressure and temperature correction factor of 0.960; times 3600, then divided by the time it took to measure 0.10 m3 of gas from the gas meter.  
For Propane (LP) Gas multiply the Heat content of the gas MJ/m3 (or Default 93.15), times 0.10 m3 of gas measured at the gas meter, times a baro-  
metric pressure and temperature correction factor of 0.960; times 3600, then divided by the time it took to measure 0.10 m3 of gas from the gas  
meter.  
The formula for metric input calculation using a cubic meter gas meter:  
3
3
MJ/m x m x 0.960 x 3600  
=
=
MJ/H  
82.94  
x
x
0.2777  
0.2777  
=
=
kW  
x
x
3412.14  
3412.14  
=
=
BTU/H  
Seconds it took to measure the 0.10 m3 of gas  
NATURAL GAS INPUT CALCULATION  
EXAMPLE:  
38.4 x 0.1 x 0.960 x 3600  
160  
23.03  
78,581.60  
Natural Gas  
3
1030 BTU/SCF = 38.4 MJ/m  
PROPANE (LP) GAS INPUT CALCULATION  
EXAMPLE:  
93.15 x 0.1 x 0.960 x 3600  
387  
=
83.19  
x
0.2777  
=
23.10  
x
3412.14  
=
78,826.3  
Propane Gas  
3
2500 BTU/SCF = 93.15 MJ/m  
DO NOT ADJUST the manifold pressure regulator if the actual input is equal to or within 8% less than the furnace input specified on the rating plate  
or if the furnace rise is above the specified rise range on the rating plate.  
If the actual input is significantly higher than the furnace input specified on the rating plate then replace the gas orifices with the gas orifices  
of the proper size for the type of gas you are using.  
Unitary Products Group  
33  
268890-UIM-B-0607  
Reading the gas pressure with the burner box cover removed -  
Remove the screws securing the burner box front cover plate. Remove  
the cover. The gasket and may stick in place. Connect the positive side  
of the manometer to the gas valve as described in E above. There will  
be no second connection to the manometer, as it will reference atmo-  
spheric pressure. Refer to Figure 39 for connection details.  
Be sure to relight any gas appliances that were turned off at the  
start of this input check.  
TABLE 16: Inlet Gas Pressure Range  
IMPORTANT: The cap for the pressure regulator must be removed  
entirely to gain access to the adjustment screw. Loosening or tightening  
the cap does not adjust the flow of gas.  
INLET GAS PRESSURE RANGE  
Natural Gas  
Propane (LP)  
1. Refer to Figure 38 for location of pressure regulator adjustment  
cap and adjustment screw on main gas valve.  
Minimum  
Maximum  
4.5” W.C. (1.12 kPa)  
10.5” W.C. (2.61 kPa)  
8.0” W.C. (1.99 kPa)  
13.0” (3.24 kPa) W.C.  
2. Turn gas and electrical supplies on and follow the operating  
instructions to place the unit back in operation.  
IMPORTANT: The inlet gas pressure operating range table specifies  
what the minimum and maximum gas line presures must be for the fur-  
nace to operate safely. The gas line pressure MUST BE  
3. Adjust manifold pressure by adjusting gas valve regulator screw  
for the appropriate gas per the following:  
7” W.C. (1.74 kPA) for Natural Gas  
11” W.C. (2.74 kPA) for Propane (LP) Gas  
TABLE 17: Nominal Manifold Pressure  
NOMINAL MANIFOLD PRESSURE  
in order to obtain the BTU input specified on the rating plate and/or the  
nominal manifold pressure specified in these instructions and on the  
rating plate.  
Natural Gas  
3.5" w.c. (0.87 kPa)  
Propane (LP) Gas  
10.0" w.c. (2.488 kPa)  
ADJUSTMENT OF MANIFOLD GAS PRESSURE  
OUTLET  
PRESSURE  
PORT  
VENT PORT  
Manifold gas pressure may be measured by two different procedures. It  
may be measured with the burner box cover in place or it may be mea-  
sured with the burner box cover removed. Follow the appropriate sec-  
tion in the instructions below. Refer to Figure 38 for a drawing of the  
locations of the pressure ports on the gas valve.  
INLET  
OUTLET  
WRENCH  
BOSS  
Turn gas off at the ball valve or gas cock on gas supply line  
before the gas valve. Find the pressure ports on the gas  
valve marked OUT P and IN P.  
INLET  
PRESSURE  
PORT  
MAIN REGULATOR  
ADJUSTMENT  
ON/OFF SWITCH  
(Shown in ON position)  
1. The manifold pressure must be taken at the port marked OUT P.  
2. The gas line pressure must be taken at the port marked IN P.  
FIGURE 38: Gas Valve  
IMPORTANT: If gas valve regulator is turned in (clockwise), manifold  
pressure is increased. If screw is turned out (counterclockwise), mani-  
fold pressure will decrease.  
3. Using a 3/32” (2.4 mm) Allen wrench, loosen the setscrew by turn-  
ing it 1 turn counter clockwise. DO NOT REMOVE THE SET  
SCREW FROM THE PRESSURE PORT.  
4. After the manifold pressure has been adjusted, re-calculate the  
furnace input to make sure you have not exceeded the specified  
input on the rating plate. Refer to “CALCULATING THE FURNACE  
INPUT (NATURAL GAS)”.  
Read the inlet gas pressure using either of the two meth-  
ods below.  
Reading the gas pressure with the burner box cover in place:  
5. Once the correct BTU (kW) input has been established, turn the  
gas valve to OFF and turn the electrical supply switch to OFF; then  
remove the flexible tubing and fittings from the gas valve pressure  
tap and the pressure reference hose from the right side of the  
burner box and tighten the pressure tap plug using the 3/32”  
Allen wrench. Replace the burner box front cover (if it was  
removed) and place the pressure reference hose back on the gas  
valve.  
A. Disconnect the pressure reference hose from the right side of  
the burner box. Using a tee fitting and a short piece of hose,  
connect the negative side of the manometer to the burner  
box as described in below.  
B. Remove one end the 5/16” (0.8 cm) ID flexible tubing over  
the pressure port on the burner box.  
C. Insert the end of the 5/16” (0.8 cm) tubing, that has the 1/8”  
(0.3 cm) adapter at the end of the tube, in to the 1/8” (0.3 cm)  
tee.  
6. Turn the electrical and gas supplies back on, and with the burners  
in operation, check for gas leakage around the gas valve pressure  
port for leakage using an approved gas detector, a non-corrosive  
leak detection fluid, or other leak detection methods.  
D. Connect the 1/8” (0.3 cm) tee to the burner box adapter and  
to the negative side of a U-tube manometer or digital pres-  
sure measuring equipment with 2 – 1/8” (0.3 cm) tubes.  
E. Use the 5/16” (0.8 cm x 1/8” (0.3 cm) reducing coupling and a  
4” (10.2 cm) piece of 1/8” (0.3 cm) tubing to connect the posi-  
tive side of the manometer to the gas valve pressure refer-  
ence port. Refer to Figure 39 for connection details.  
The manifold pressure must be checked with the screw-off cap for  
the gas valve pressure regulator in place. If not, the manifold pres-  
sure setting could result in an over-fire condition. A high manifold  
pressure will cause an over-fire condition, which could cause pre-  
mature heat exchanger failure. If the manifold pressure is too low,  
sooting and eventual clogging of the heat exchanger could occur.  
Be sure that gas valve regulator cap is in place and burner box to  
gas valve pressure reference hose is connected.  
34  
Unitary Products Group  
268890-UIM-B-0607  
WITH BURNER BOX COVER IN PLACE  
WITH BURNER BOX COVER REMOVED  
TEE  
GAS  
GAS VALVE  
FITTING  
VALVE  
BURNER BOX  
PRESSURE  
REFERENCE  
HOSE  
BURNER BOX  
PRESSURE  
REFERENCE  
HOSE  
6
5
4
3
2
1
0
1
2
3
4
5
6
6
5
4
3
2
1
0
1
2
3
4
5
6
3.5 IN  
3.5 IN  
U-TUBE  
MANOMETER  
WATER COLUMN  
GAS PRESSURE  
SHOWN  
U-TUBE  
MANOMETER  
WATER COLUMN  
GAS PRESSURE  
SHOWN  
FIGURE 39: Reading Gas Pressure  
ADJUSTMENT OF TEMPERATURE RISE  
All direct-drive blowers have multi-speed motors. The blower motor  
speed taps are located in the control box in the blower compartment.  
Refer to Figure 40, and the unit-wiring label to change the blower  
speed. To use the same speed tap for heating and cooling, the heat ter-  
minal and cool terminal must be connected using a jumper wire and  
connected to the desired motor lead. Place all unused motor leads on  
Park terminals. Two are provided.  
The temperature rise, or temperature difference between the return  
air and the supply (heated) air from the furnace, must be within the  
range shown on the furnace rating plate and within the application  
limitations shown in Table 7 “ELECTRICAL AND PERFORMANCE  
DATA”.  
The supply air temperature cannot exceed the “Maximum Supply  
Air Temperature” specified in these instructions and on the fur-  
nace rating plate. Under NO circumstances can the furnace be  
allowed to operate above the Maximum Supply Air Temperature.  
Operating the furnace above the Maximum Supply Air Temperature  
will cause premature heat exchanger failure, high levels of Carbon  
Monoxide, a fire hazard, personal injury, property damage, and/or  
death.  
Do not energize more than one motor speed at a time or damage to  
the motor will result.  
ADJUSTMENT OF FAN CONTROL SETTINGS  
This furnace is equipped with a time-on/time-off heating fan control. The  
fan on delay is fixed at 30 seconds. The fan off delay has 4 settings (60,  
90, 120 and 180 seconds). The fan off delay is factory set to 120 sec-  
onds. The fan-off setting must be long enough to adequately cool the  
furnace, but not so long that cold air is blown into the heated space. The  
fan-off timing may be adjusted by positioning the jumper on two of the  
four pins as shown in Figure 40.  
The temperature rise, or temperature difference between the return air  
and the heated supply air from the furnace, must be within the range  
shown on the furnace rating plate and within the application limitations  
as shown in Table 7.  
After about 20 minutes of operation, determine the furnace temperature  
rise. Take readings of both the return air and the heated air in the ducts,  
about six feet (1.83 m) from the furnace where they will not be affected  
by radiant heat. Increase the blower speed to decrease the temperature  
rise; decrease the blower speed to increase the rise.  
The blower speed connections shown in Figure 40 are typical. How-  
ever, these connections may vary from model to model and may be  
changed as needed to give proper heating and cooling airflow.  
TWIN  
YELLOW-MED. LOW  
PARK PARK  
FAN OFF  
ADJUSTMENT  
JUMPER  
RED-LOW  
HI COOL  
BLACK-HI  
HEAT  
BLUE-MED. HI  
EAC-H  
L1  
XFMR  
HUM  
FIGURE 40: Furnace Control Board  
Unitary Products Group  
35  
268890-UIM-B-0607  
9 RED FLASHES: Indicates reversed line voltage polarity or grounding  
problem. Both heating and cooling operations will be affected. Check  
polarity at furnace and branch. Check furnace grounding. Check that  
flame probe is not shorted to chassis.  
FURNACE CONTROL DIAGNOSTICS  
The furnace has built-in, self-diagnostic capability. If a system problem  
occurs, a blinking LED shows a fault code. The LED can flash red,  
green or amber to indicate various conditions. It is located behind a  
clear view port in the blower compartment door.  
10 RED FLASHES: Gas valve energized with no call for heat. Check  
gas valve and gas valve wiring.  
The control continuously monitors its own operation and the operation  
of the system. If a failure occurs, the LED will indicate the failure code. If  
the failure is internal to the control, the light will stay on continuously. In  
this case, the entire control should be replaced, as the control is not  
field repairable.  
11 RED FLASHES: This indicates that a primary or auxiliary limit switch  
has opened its normally-closed contacts and has remained open for  
more than five minutes. This condition is usually caused by a failed  
blower motor or blower wheel.  
12 RED FLASHES: This code indicates an open igniter circuit, which  
could be caused by a disconnected or loose wire or by a cracked or bro-  
ken igniter.  
Flash sequence codes 1 through 10 are as follows: LED will turn “on”  
for 1/4 second and “off” for 1/4 second. This pattern will be repeated the  
number of times equal to the code. For example, six “on” flashes equals  
a number 6 fault code. All flash code sequences are broken by a 2 sec-  
ond “off” period.  
STEADY ON RED: Control failure. Replace control board.  
60-MINUTE AUTOMATIC RESET FROM LOCKOUT: This control  
includes a “watchdog” type circuit that will reset from a lockout condition  
after 60 minutes. Operational faults 6,7,8 will be reset. This provides  
protection to an unoccupied structure if a temporary condition exists  
causing a furnace malfunction. An example would be a low incoming  
gas supply pressure preventing unit operation. When the gas pressure  
is restored, at some point the “watchdog” would restart the unit and pro-  
vide heat for the house.  
SLOW GREEN FLASH: Normal operation.  
SLOW AMBER FLASH: Normal operation with call for heat.  
RAPID RED FLASH: Twinning error, incorrect 24V phasing. Check  
twinning wiring.  
RAPID AMBER FLASH: Flame sense current is below 1.5 microamps.  
Check and clean flame sensor. Check for proper gas flow.  
4 AMBER FLASHES: The control board is recieving a “Y” signal from  
the thermostat without a “G” signal, indicating improper thermostat wir-  
ing.  
NOTE: If a flame is detected the control flashes the LED for 1/8 of a  
second and then enters a flame stabilization period.  
IGNITION CONTROL  
Normal flame sense current is approximately  
3.7 microamps DC (µa)  
Low flame signal warning starts at 1.5 microamps.  
Low flame signal control lockout point is  
0.1 microamps DC (µa)  
1 RED FLASH: This indicates that flame was sensed when there was  
not a call for heat. With this fault code the control will turn on both the  
inducer motor and supply air blower. A gas valve that leaks through or  
is slow closing would typically cause this fault.  
2 RED FLASHES: This indicates that the normally open pressure  
switch contacts are stuck in the closed position. The control confirms  
these contacts are open at the beginning of each heat cycle. This would  
indicate a faulty pressure switch or miswiring.  
DIAGNOSTIC FAULT CODE STORAGE AND  
RETRIEVAL  
3 RED FLASHES: This indicates the normally open pressure switch  
contact did not close after the inducer was energized. This could be  
caused by a number of problems: faulty inducer, blocked vent pipe, bro-  
ken pressure switch hose or faulty pressure switch.  
The control in this furnace is equipped with memory that will store up to  
five error codes to allow a service technician to diagnose problems  
more easily. This memory will be retained even if power to the furnace  
is lost. This feature should only be used by a qualified service tech-  
nician.  
4 RED FLASHES: This indicates that a primary or auxiliary limit switch  
has opened its normally closed contacts. With this fault code the control  
will operate the supply air blower and inducer. This condition may be  
caused by: dirty filter, improperly sized duct system, incorrect blower  
speed setting, incorrect firing rate or faulty blower motor.  
The control stores up to five separate error codes. If more than five  
error codes have occurred since the last reset, only the five most recent  
will be retained. The furnace control board has a button, labeled "LAST  
ERROR" that is used to retrieve error codes. This function will only work  
if there are no active thermostat signals. So any call for heating, cooling  
or continuous fan must be terminated before attempting to retrieve error  
codes.  
5 RED FLASHES: This fault is indicated if the normally closed contacts  
in the rollout switch opens. The rollout control is manually reset. If it has  
opened, check for proper combustion air, proper inducer operation, and  
primary heat exchanger failure or burner problem. Be sure to reset the  
switch after correcting the failure condition.  
To retrieve the error codes, push the LAST ERROR button. The LED on  
the control will then flash the error codes that are in memory, starting  
with the most recent. There will be a two-second pause between each  
flash code. After the error codes have all been displayed, the LED will  
resume the normal slow green flash after a five second pause. To  
repeat the series of error codes, push the button again.  
6 RED FLASHES: This indicates that after the unit was operating, the  
pressure switch opened 4 times during the call for heat. If the main  
blower is in a “Delay on” mode it will complete it, and any subsequent  
delay off period. The furnace will lock out for one hour and then restart.  
If there are no error codes in memory, the LED will flash two green  
flashes. To clear the memory, push the LAST ERROR button and hold it  
for more than five seconds. The LED will flash three green flashes when  
the memory has been cleared, then will resume the normal slow green  
flash after a five-second pause.  
7 RED FLASHES: This fault code indicates that the flame could not be  
established. This no-light condition occurred 3 times (2 retries) during  
the call for heat before locking out. Low gas pressure, faulty gas valve,  
faulty hot surface ignitor or burner problem may cause this. The furnace  
will lock out for one hour and then restart.  
8 RED FLASHES: This fault is indicated if the flame is lost 5 times (4  
recycles) during the heating cycle. This could be caused by low gas  
pressure or faulty gas valve. The furnace will lock out for one hour and  
then restart.  
36  
Unitary Products Group  
268890-UIM-B-0607  
TABLE 18: Blower Performance CFM  
Airflow with Top Return - without Filters (m3min)  
External Static Pressure, Inches (kPa)  
MODELS  
Input/  
Airflow/  
Cabinet  
Airflow with Top Return - without Filters (CFM)  
External Static Pressure, Inches W.C.  
Speed  
Tap  
0.1  
0.2  
0.3  
0.4  
0.5  
0.6  
0.7  
0.8  
0.9  
1.0 0.025 0.050 0.075 0.099 0.124 0.149 0.174 0.199 0.224 0.249  
High  
1635 1590 1535 1480 1415 1340 1280 1185 NR  
NR  
NR  
NR  
NR  
46  
33  
27  
22  
48  
34  
26  
21  
48  
36  
28  
22  
59  
45  
36  
27  
56  
41  
33  
26  
68  
57  
46  
38  
71  
57  
45  
37  
45  
33  
27  
21  
47  
33  
26  
21  
47  
35  
28  
22  
57  
45  
36  
27  
56  
42  
34  
25  
66  
55  
45  
37  
69  
56  
44  
36  
43  
33  
27  
21  
46  
33  
26  
21  
46  
34  
28  
21  
56  
44  
36  
26  
55  
42  
34  
25  
63  
53  
43  
35  
67  
55  
42  
34  
42  
32  
27  
21  
45  
33  
26  
20  
44  
34  
27  
21  
55  
44  
36  
27  
54  
42  
34  
24  
61  
51  
42  
34  
64  
54  
41  
33  
40  
32  
27  
20  
44  
32  
26  
20  
43  
33  
26  
20  
53  
43  
36  
27  
52  
42  
34  
23  
58  
50  
40  
33  
61  
53  
40  
31  
38  
31  
26  
19  
43  
32  
25  
18  
41  
32  
25  
19  
51  
43  
36  
26  
50  
41  
34  
22  
54  
47  
39  
31  
58  
50  
38  
30  
36  
30  
24  
18  
41  
30  
23  
17  
39  
31  
24  
18  
48  
41  
35  
26  
48  
40  
33  
20  
51  
45  
37  
29  
55  
48  
36  
28  
34  
29  
23  
17  
39  
29  
22  
16  
37  
29  
22  
17  
46  
40  
34  
25  
46  
39  
32  
19  
48  
42  
35  
27  
51  
45  
34  
24  
NR  
NR  
NR  
NR  
37  
28  
22  
15  
34  
27  
21  
16  
43  
38  
32  
23  
43  
37  
31  
18  
44  
39  
32  
25  
48  
42  
31  
22  
NR  
NR  
NR  
NR  
34  
27  
20  
14  
31  
25  
19  
14  
40  
35  
29  
21  
40  
34  
29  
18  
40  
35  
27  
21  
43  
38  
26  
20  
Med-High 1179 1170 1160 1140 1135 1098 1048 1026 NR  
40/1200/A  
60/1200/B  
80/1200/B  
80/1600/C  
100/1600/C  
100/2000/C  
Med-Low 969  
967  
753  
967  
745  
959  
726  
938  
698  
905  
674  
860  
652  
802  
612  
NR  
NR  
Low  
774  
High  
1687 1652 1631 1595 1557 1511 1456 1382 1313 1211  
Med-High 1193 1183 1173 1162 1142 1115 1076 1036 982  
950  
712  
496  
Med-Low 933  
933  
745  
921  
731  
911  
718  
902  
698  
872  
652  
825  
602  
793  
580  
771  
536  
Low  
752  
High  
1686 1658 1623 1572 1534 1465 1391 1305 1202 1091  
Med-High 1257 1223 1218 1203 1177 1142 1094 1026 939  
874  
686  
490  
Med-Low 977  
982  
777  
976  
757  
955  
733  
934  
698  
899  
663  
843  
627  
791  
584  
738  
549  
Low  
775  
High  
2071 2026 1981 1935 1864 1796 1713 1625 1532 1401  
Med-High 1583 1590 1569 1554 1532 1502 1457 1409 1327 1221  
Med-Low 1256 1275 1275 1288 1275 1265 1232 1187 1126 1023  
Low  
937  
939  
936  
945  
942  
936  
912  
874  
810  
726  
High  
1996 1961 1938 1896 1836 1779 1707 1625 1531 1399  
Med-High 1449 1480 1495 1488 1488 1449 1417 1368 1299 1208  
Med-Low 1167 1192 1192 1187 1202 1192 1182 1140 1097 1018  
Low  
932  
900  
871  
840  
805  
761  
710  
663  
641  
623  
High  
2404 2320 2225 2138 2034 1924 1816 1692 1559 1422  
Med-High 2018 1955 1883 1815 1750 1670 1586 1497 1394 1246  
Med-Low 1626 1581 1531 1488 1418 1363 1291 1225 1123 964  
Low  
1336 1291 1249 1205 1155 1091 1018 951  
884  
759  
High  
2520 2432 2353 2251 2152 2042 1947 1815 1701 1525  
Med-High 2018 1979 1945 1911 1863 1779 1705 1599 1493 1353  
Med-Low 1586 1545 1501 1457 1407 1351 1287 1216 1081 926  
120/2000/D  
NOTES:  
Low  
1321 1266 1213 1163 1111 1071 987  
864  
763  
700  
3
1. Airflow expressed in standard cubic feet per minute (CFM) and in cubic meters per minute (m /min).  
2. Motor voltage at 115 V.  
3. NR = Operation at this static pressure is not recommended.  
NOTE: The filter pressure drop values in Table 19 are typical values for  
the type of filter listed and should only be used as a guideline. Actual  
pressure drop ratings for each filter type vary between filter manufactur-  
ers.  
FILTER PERFORMANCE  
The airflow capacity data published in Table 18 represents blower per-  
formance WITHOUT filters. To determine the approximate blower per-  
formance of the system, apply the filter drop value for the filter being  
used or select an appropriate value from the Table 19.  
TABLE 19: Filter Performance - Pressure Drop Inches W.C. and (kPa)  
Filter Type  
Minimum  
Airflow Range  
Opening Size  
Disposable  
Washable Fiber  
Pleated  
In W.C.  
m3/min  
in2  
230  
330  
330  
330  
380  
380  
463  
cm2  
1484  
2129  
2129  
2129  
2452  
2542  
2987  
CFM  
In W.C.  
kPA  
In W.C.  
kPA  
kPA  
0 - 750  
0 - 21.4  
0.01  
0.05  
0.10  
0.10  
0.15  
0.19  
0.19  
0.00249  
0.01245  
0.02491  
0.02491  
0.03736  
0.04733  
0.04733  
0.01  
0.05  
0.10  
0.10  
0.14  
0.18  
0.18  
0.00249  
0.01245  
0.02491  
0.02491  
0.03487  
0.04484  
0.04484  
0.15  
0.20  
0.20  
0.25  
0.30  
0.30  
0.30  
0.03736  
0.04982  
0.04982  
0.06227  
0.07473  
0.07473  
0.07473  
751 - 1000  
21.25 - 28.32  
28.33 - 35.40  
35.41 - 42.48  
42.49 - 49.55  
49.56 - 56.63  
56.64 - Above  
1001 - 1250  
1251 - 1500  
1501 - 1750  
1751 - 2000  
2001 & Above  
Unitary Products Group  
37  
268890-UIM-B-0607  
Example: For a 120,000 Btuh furnace operating on high speed blower,  
it is found that total system static is 0.58" w.c. To determine the system  
airflow, complete the following steps:  
APPLYING FILTER PRESSURE DROP TO  
DETERMINE SYSTEM AIRFLOW  
To determine the approximate airflow of the unit with a filter in place, fol-  
low the steps below:  
1. Obtain the airflow values at 0.50" & 0.60" ESP.  
Airflow @ 0.50": 2152 CFM  
Airflow @ 0.60": 2042 CFM  
1. Select the filter type.  
2. Determine the External System Static Pressure (ESP) without the  
filter.  
2. Subtract the airflow @ 0.50" from the airflow @ 0.60" to obtain air-  
flow difference.  
3. Select a filter pressure drop from the table based upon the number  
of return air openings or return air opening size and add to the  
ESP from Step 2 to determine the total system static.  
2042 - 2152 = -110 CFM  
3. Subtract the total system static from 0.50" and divide this differ-  
ence by the difference in ESP values in the table, 0.60" - 0.50", to  
obtain a percentage.  
4. If total system static matches a ESP value in the airflow table (i.e.  
0.20, 0.60, etc,) the system airflow corresponds to the intersection  
of the ESP column and Model/Blower Speed row.  
(0.58 - 0.50) / (0.60 - 0.50) = 0.8  
5. If the total system static falls between ESP values in the table (i.e.  
0.58, 0.75, etc.), the static pressure may be rounded to the nearest  
value in the table determining the airflow using Step 4 or calculate  
the airflow by using the following example.  
4. Multiply percentage by airflow difference to obtain airflow reduc-  
tion.  
(0.8) x (-110) = -88  
5. Subract airflow reduction value to airflow @ 0.50" to obtain actual  
airflow @ 0.58" ESP.  
2152 - 88 = 2064  
FIELD INSTALLED ACCESSORIES - NON-ELECTRICAL  
DESCRIPTION  
MODEL NO.  
1NP0347  
1CT0302  
1CT0303  
1PS0904  
1PS0901  
1PS0902  
1PS0903  
1NK0301  
1HT0901  
1HT0902  
1CB0314  
1CB0317  
1CB0321  
USED WITH  
ALL MODELS  
ALL MODELS EXCEPT 120 MBH  
ALL MODELS  
40  
PROPANE (LP) CONVERSION KIT  
CONCENTRIC INTAKE/VENT 2”  
CONCENTRIC INTAKE/VENT 3”  
60/100/120  
HIGH ALTITUDE PRESSURE SWITCH KIT  
(Does Not Include Orifices)  
80/1200  
80/1600  
CONDENSATE NEUTRALIZER KIT  
SIDEWALL VENT TERMINATION KIT 3”  
SIDEWALL VENT TERMINATION KIT 2”  
ALL MODELS  
ALL MODELS  
ALL MODELS  
14-1/2” CABINET  
17-1/2” CABINET  
21” CABINET  
COMBUSTIBLE FLOOR BASE  
These kits are required in downflow application when using G*F*  
series coils. These kits are not required with MC/FC series coils,  
but please ensure that the coil and furnace are secured and that  
there are noair leaks.  
1CB0324  
24 1/2” CABINET  
1TK0914  
1TK0917  
1TK0921  
1TK0924  
1VK0901  
14-1/2” CABINET  
17-1/2” CABINET  
21” CABINET  
COIL TRANSITION KIT  
3-WAY TRANSITION KIT  
24 1/2” CABINET  
All MODELS  
38  
Unitary Products Group  
268890-UIM-B-0607  
SECTION XI: WIRING DIAGRAM  
FIGURE 41: Wiring Diagram  
Unitary Products Group  
39  
NOTES  
Subject to change without notice. Printed in U.S.A.  
268890-UIM-B-0607  
Copyright © by York International Corp. 2007. All rights reserved.  
Supersedes: 268890-UIM-A-0407  
Unitary  
Product  
Group  
5005  
York  
Drive  
Norman  
OK  
73069  

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