International comfort products N8MXL User manual

441 01 1421 02 9/11/2017
INSTALLATION INSTRUCTIONS
80% Single Stage, ECM Motor
Category I, Gas Furnace
N8MXL
SAFETY CONSIDERATIONS 2........................
INTRODUCTION 2..................................
CODES AND STANDARDS 5..........................
Safety 5........................................
General Installation 5...............................
Combustion and Ventilation Air 5.....................
Duct Systems 5...................................
Acoustical Lining and Fibrous Glass Duct 5.............
Gas Piping and Gas Pipe Pressure Testing 5.............
Electrical Connections 5............................
Venting 5........................................
ELECTROSTATIC DISCHARGE PRECAUTIONS
PROCEDURE 5.....................................
LOCATION 6.......................................
INSTALLATION 10..................................
Upflow Installation 10..............................
Downflow Installation 11...........................
Horizontal Installation 13...........................
Filter Arrangement 13..............................
Air Ducts 13.....................................
Gas Piping 16....................................
Electrical Connection 20............................
115−V Wiring 20..................................
J−Box Relocation 20...............................
24 Volt Wiring 21.................................
Accessories 21....................................
VENTING 23.......................................
General 23......................................
Masonry Chimney Requirements 23...................
Appliance Application Requirements 24................
Additional Venting Requirements 26...................
Sidewall Venting 26................................
START−UP, ADJUSTMENT, AND SAFETY CHECK 30.....
General 30.......................................
Start−up Procedures 30.............................
Adjustments 30...................................
Check Safety Controls 32...........................
Checklist 33......................................
SERVICE AND MAINTENANCE PROCEDURES 39.......
Introduction 39...................................
Electrical Controls and Wiring 39.....................
Care and Maintenance 40...........................
Cleaning and/or Replacing Filter 41...................
Blower Motor and Wheel 41
.........................
Cleaning Heat Exchanger 42.........................
Sequence of Operation 43...........................
Wiring Diagrams 44...............................
Troubleshooting 44................................
PARTS REPLACEMENT INFORMATION GUIDE 48.......
Use of the AHRI Certified TM Mark indicates a
manufacturer’s participation in the program. For
verification of certification for individual products,
go to www.ahridirectory.org.
NOTE: Read the entire instruction manual before starting the
installation.
Portions of the text and tables are reprinted from current edition
of NFPA 54/ANSI Z223.1E, with permission of National Fire
Protection Association, Quincy, MA 02269 and American Gas
Association, Washington DC 20001. This reprinted material is
not the complete and official position of the NFPA or ANSI on
the referenced subject, which is represented only by the standard
in its entirety.

Specifications are subject to change without notice.
2441 01 1421 02
SAFETY CONSIDERATIONS
FIRE, EXPLOSION, ELECTRICAL SHOCK, AND
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in dangerous
operation, serious injury, death, or property damage.
Improper installation, adjustment, alteration, service,
maintenance, or use could cause carbon monoxide
poisoning, explosion, fire, electrical shock, or other
conditions which may cause personal injury or property
damage. Consult a qualified service agency, local gas
supplier, or your distributor or branch for information or
assistance. The qualified service agency must use only
factory−authorized and listed kits or accessories when
modifying this product.
!WARNING
FURNACE RELIABILITY HAZARD
Improper installation or misapplication of furnace may
require excessive servicing or cause premature component
failure.
Application of this furnace should be indoors with special
attention given to vent sizing and material, gas input rate,
air temperature rise, unit leveling, and unit sizing.
CAUTION
!
Improper installation, adjustment, alteration, service,
maintenance, or use can cause explosion, fire, electrical shock, or
other conditions which may cause death, personal injury, or
property damage. Consult a qualified installer, service agency, or
your distributor or branch for information or assistance. The
qualified installer or agency must use factory−authorized kits or
accessorieswhen modifying this product. Refer to the individual
instructions packaged with the kits or accessories when installing.
Follow all safety codes. Wear safety glasses, protective clothing,
and work gloves. Have a fire extinguisher available. Read these
instructions thoroughly and follow all warnings or cautions
include in literature and attached to the unit. Consult local
building codes, the current editions of the current edition of
National Fuel Gas Code (NFGC) NFPA 54/ANSI Z223.1 and the
current edition of National Electrical Code (NEC) NFPA 70.
Recognize safety information. This is the safety−alert symbol .
When you see this symbol on the unit and in instructions or
manuals, be alert to the potential for personal injury.
Understand the signal words DANGER, WARNING, and
CAUTION. These words are used with the safety−alert symbol.
DANGER identifies the most serious hazards which will result in
severe personal injury or death. WARNING signifies hazards
which could result in personal injury or death. CAUTION is
used to identify unsafe practices which may result in minor
personal injury or product and property damage. NOTE is used
to highlight suggestions which will result in enhanced
installation, reliability, or operation.
CUT HAZARD
Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care
and wear appropriate protective clothing, safety glasses and
gloves when handling parts and servicing furnaces.
CAUTION
!
1. Use only with type of gas approved for this furnace. Refer
to the furnace rating plate.
2. Install this furnace only in a location and position as spe-
cified in the “Location” section of these instructions.
3. Provide adequate combustion and ventilation air to the
furnace space as specified in “Air for Combustion and
Ventilation” section.
4. Combustion products must be discharged outdoors. Con-
nect this furnace to an approved vent system only, as spe-
cified in the “Venting” section of these instructions.
5. Never test for gas leaks with an open flame. Use a com-
mercially available soap solution made specifically for the
detection of leaks to check all connections, as specified in
the “Gas Piping” section.
6. Always install furnace to operate within the furnace’s in-
tended temperature−rise range with a duct system which
has an external static pressure within the allowable range,
as specified in the “Start−Up, Adjustments, and Safety
Check” section. See furnace rating plate.
7. When a furnace is installed so that supply ducts carry air
circulated by the furnace to areas outside the space con-
taining the furnace, the return air shall also be handled by
duct(s) sealed to the furnace casing and terminating out-
side the space containing the furnace. See “Air Ducts” sec-
tion.
8. A gas−fired furnace for installation in a residential garage
must be installed as specified in the warning box in the
“Location” section.
9. The furnace may be used for construction heat provided
that the furnace installation and operation complies with
the first CAUTION in the LOCATION section of these in-
structions.
10. These Multipoise Gas−Fired Furnaces are CSA (formerly
A.G.A. and C.G.A). design−certified for use with natural
and propane gases (see furnace rating plate) and for install-
ation in alcoves, attics, basements, closets, utility rooms,
crawlspaces, and garages. The furnace is factory−shipped
for use with natural gas. A CSA listed accessory gas con-
version kit is required to convert furnace for use with pro-
pane gas.
11. See Fig. 2 for required clearances to combustible construc-
tion.
12. Maintain a 1−in. (25 mm) clearance from combustible ma-
terials to supply air ductwork for a distance of 36 inches
(914 mm) horizontally from the furnace. See current edi-
tion of NFPA 90B or local code for further requirements.
13. These furnaces SHALL NOT be installed directly on car-
peting, tile, or any other combustible material other than
wood flooring. In downflow installations, factory access-
ory floor base MUST be used when installed on combust-
ible materials and wood flooring. Special base is not re-
quired when this furnace is installed on manufacturer’s
coil model numbers END4X, ENW4X or coil casing mod-
el number NAEAis used. See Fig. 2 for clearance to com-
bustible construction information.
INTRODUCTION
This 4−way multipoise Category I fan−assisted furnace is CSA
design−certified. A Category I fan−assisted furnace is an
appliance equipped with an integral mechanical means to either
draw or force products of combustion through the combustion
chamber and/or heat exchanger. The furnace is factory−shipped
for use with natural gas.
This furnace is not approved for installation in mobile homes,
recreational vehicles, or outdoors. This furnace is designed for
minimum continuous return−air temperature of 60_F (16_C)db
or intermittent operation down to 55_F (13_C) db such as when

Specifications are subject to change without notice. 3441 01 1421 02
used with a night setback thermostat. Return−air temperature
must not exceed 80_F (27_C) db. Failure to follow these
return−air temperature limits may affect reliability of heat
exchangers, motors, and controls. (See Fig. 3).
For accessory installation details, refer to the applicable
instruction literature.
NOTE: Remove all shipping brackets and materials before
operating the furnace.
A
A
B
[736.9]
[736.9]
29
29
Ø7/8
Ø7/8
[22.2]
[22.2]
ACCESSORY
ACCESSORY
5 15/16
5 15/16
[150.7]
[150.7]
28.39
28.39
[721.2]
[721.2]
Ø7/8
Ø7/8
[22.2]
[22.2]
ACCESSORY
ACCESSORY
14 7/8
14 7/8
[337.3]
[337.3]
(BOTH SIDES)
(BOTH SIDES)
Ø7/8
Ø7/8
[22.2]
[22.2]
ACCESSORY
ACCESSORY
Ø7/8
Ø7/8
[22.2]
[22.2]
ACCESSORY
ACCESSORY
Ø1 3/4
Ø1 3/4
[44.5]
[44.5]
GAS ENTRY
GAS ENTRY
Ø1/2
Ø1/2
[12.7]
[12.7]
THERMOSTAT WIRE ENTRY
THERMOSTAT WIRE ENTRY
22 1/16
22 1/16
[560]
[560]
SIDE INLET
SIDE INLET
(BOTH SIDES)
(BOTH SIDES)
11 7/16
11 7/16
[290.7]
[290.7]
9 11/16
9 11/16
[245.4]
[245.4]
[197.8]
[197.8]
7 13/16
7 13/16
Ø7/8
Ø7/8
[22.2]
[22.2]
J.BOX PROVISION
J.BOX PROVISION
Ø7/8
Ø7/8
[22.2]
[22.2]
JUNCTION BOX
JUNCTION BOX
LOCATION
LOCATION
Ø1 3/4
Ø1 3/4
[44.5]
[44.5]
GAS ENTRY
GAS ENTRY
1 15/16
1 15/16
[49.2]
[49.2]
1
[25.4]
[25.4]
1 1/4
1 1/4
[31.8]
[31.8]
29 9/16
29 9/16
[750.7]
[750.7]
1 15/16
1 15/16
[49.2]
[49.2]
5 5/8
5 5/8
[143.3]
[143.3]
5 7/16
5 7/16
[138.5]
[138.5]
6 13/16
6 13/16
[172.3]
[172.3]
Ø1/2
Ø1/2
[12.7]
[12.7]
THERMOSTAT WIRE ENTRY
THERMOSTAT WIRE ENTRY
19
19
[481.7]
[481.7]
OUTLET
OUTLET
D
21.6
21.6
[549.5]
[549.5]
BOTTOM INLET
BOTTOM INLET
C
33 1/4
33 1/4
[843.9]
[843.9]
9 9/16
9 9/16
[243.3]
[243.3]
3/4
3/4
[19.1]
[19.1]
5 7/8
5 7/8
[148.5]
[148.5]
3 7/16
3 7/16
[86.8]
[86.8]
9 7/8
9 7/8
[250.7]
[250.7]
27 3/4
27 3/4
[704.7]
[704.7]
2 5/16
2 5/16
[59]
[59]
FRONT OF CASING
FRONT OF CASING
TOP OF CASING
TOP OF CASING
4 13/16
4 13/16
[122.2]
[122.2]
27 3/4
27 3/4
[704.7]
[704.7]
5 7/8
5 7/8
[148.5]
[148.5]
8 5/8
8 5/8
[219]
[219]
5 1/2
5 1/2
[140.3]
[140.3]
8 7/16
8 7/16
[213.5]
[213.5]
FRONT OF CASING
FRONT OF CASING
TOP OF CASING
TOP OF CASING
6.1
6.1
[155.7]
[155.7]
2 1/16
2 1/16
[51.6]
[51.6]
5.1
5.1
[130.5]
[130.5]
1.7
1.7
[43.5]
[43.5]
Ø7/8
Ø7/8
[22.2]
[22.2]
ACCESSORY (2)
ACCESSORY (2)
AIR FLOW
AIR FLOW
AIR FLOW
AIR FLOW
BOTTOM RETURN
BOTTOM RETURN
WIDTH
WIDTH
AIR FLOW
AIR FLOW
KNOCK OUTS FOR
KNOCK OUTS FOR
VENTING(5
VENTING(5
PLACES)
PLACES)
A10290
NOTES:
1. Two additional 7/8-in. (22 mm) diameter holes are located in the top plate.
2. Minimum return-air openings at furnace, based on metal duct. If flex duct is used, see flex duct manufacturer's recommendations for equivalent diameters.
a. For 800 CFM-16-in. (406 mm) round or 14 1/2 x 12-in. (368 x 305 mm) rectangle.
b. For 1200 CFM-20-in. (508 mm) round or 14 1/2 x 19 1/2-in. (368 x 495 mm) rectangle.
c. For 1600 CFM-22-in. (559 mm) round or 14 1/2 x 22 1/16-in. (368 x 560mm) rectangle.
d. For airflow requirements above 1800 CFM, see Air Delivery table in Specification Sheet literature for specific use of single side inlets. The use of both side
inlets, a combination of 1 side and the bottom, or the bottom only will ensure adequate return air openings for airflow requirements above 1800 CFM.
Fig. 1 −Dimensional Drawing
Table 1 – Dimensions
FURNACE SIZE
A B C D VENT
CABINET
WIDTH
IN. (MM)
OUTLET WIDTH
IN. (MM)
TOP AND BOTTOM
FLUE COLLAR
IN. (MM)
BOTTOM WIDTH
IN. (MM)
VENT
CONNECTION
SIZE*
IN. (MM)
SHIP WT
(LB / KG)
0451412 14−3/16 (360) 12−9/16 (319) 9−5/16 (237) 12−11/16 (322) 4 (102) 104 (47)
0701712 17−1/2 (445) 15−7/8 (403) 11−9/16 (294) 16 (406) 4 (102) 126 (57)
0701716 17−1/2 (445) 15−7/8 (403) 11−9/16 (294) 16 (406) 4 (102) 126 (57)
0901714 17−1/2 (445) 15−7/8 (403) 11−9/16 (294) 16 (406) 4 (102) 127 (58)
0902116 21 (533) 19−3/8 (492) 13−5/16 (338) 19−1/2 (495) 4 (102) 140 (64)
0902120 21 (533) 19−3/8 (492) 13−5/16 (338) 19−1/2 (495) 4 (102) 140 (64)
1102120 21 (533) 19−3/8 (492) 13−5/16 (338) 19−1/2 (495) 4 (102) 152 (69)
1352420 24−1/2 (622) 22−7/8 (581) 15−1/16 (383) 23 (584) 4 (102)* 163 (74)
*135 size furnace requires a 5 or 6-in. (127 or 152 mm) vent. Use a vent adapter between furnace and vent stack. See Installation Instructions for complete
installation requirements.

Specifications are subject to change without notice.
4441 01 1421 02
A10269
Fig. 2 −Clearances to Combustibles

Specifications are subject to change without notice. 5441 01 1421 02
A02055
Fig. 3 −Return Air Temperature
CODES AND STANDARDS
Follow all national and local codes and standards in addition to
these instructions. The installation must comply with regulations
of the serving gas supplier, local building, heating, plumbing, and
other codes. In absence of local codes, the installation must
comply with the national codes listed below and all authorities
having jurisdiction.
In the United States, follow all codes and standards for the
following:
Safety
SUSA: Current edition of National Fuel Gas Code
(NFGC) NFPA 54/ANSI Z223.1 and the Installation
Standards, Warm Air Heating and Air Conditioning
Systems ANSI/NFPA 90B
General Installation
SCurrent edition of the NFGC and the NFPA 90B. For
copies, contact the National Fire Protection Association
Inc., Batterymarch Park, Quincy, MA 02269;
(www.NFPA.org) or for only the NFGC, contact the
American Gas Association, 400 N. Capitol Street,
N.W., Washington, DC 20001 (www.AGA.org).
Combustion and Ventilation Air
SCurrent edition of NFGC NFPA54/ANSI Z223.1 Sec-
tion 9.3, Air for Combustion and Ventilation.
Duct Systems
SAir Conditioning Contractors Association (ACCA)
Manual D, Sheet Metal and Air Conditioning Contract-
ors National Association (SMACNA), or American
Society of Heating, Refrigeration, and Air Condition-
ing Engineers (ASHRAE) 2005 Fundamentals Hand-
book Chapter 35 or 2004 HVAC Systems and Equip-
ment Handbook Chapters 9 and 16.
Acoustical Lining and Fibrous Glass Duct
SCurrent edition of SMACNA and NFPA 90B as tested
by UL Standard 181 for Class I Rigid Air Ducts
Gas Piping and Gas Pipe Pressure Testing
SCurrent edition of NFGC NFPA54/ANSI Z223.1;
chapters 5, 6, 7, and 8 and National Plumbing Codes.
Electrical Connections
SCurrent edition of National Electrical Code (NEC) NF-
PA 70.
Venting
SCurrent edition of NFGC NFPA 54 / ANSI Z223.1;
Chapters 12 and 13.
ELECTROSTATIC DISCHARGE (ESD)
PRECAUTIONS PROCEDURE
FURNACE RELIABILITY HAZARD
Improper installation or service of furnace may cause
premature furnace component failure.
Electrostatic discharge can affect electronic components.
Follow the Electrostatic Discharge Precautions Procedure
listed below during furnace installation and servicing to
protect the furnace electronic control. Precautions will
prevent electrostatic discharges from personnel and hand
tools which are held during the procedure. These
precautions will help to avoid exposing the control to
electrostatic discharge by putting the furnace, the control,
and the person at the same electrostatic potential.
CAUTION
!
1. Disconnect all power to the furnace. Multiple disconnects
maybe required. DO NOT TOUCH THE CONTROL OR
ANY WIRE CONNECTED TO THE CONTROL PRIOR
TO DISCHARGING YOUR BODY’S
ELECTROSTATIC CHARGE TO GROUND.
2. Firmly touch the clean, unpainted, metal surface of the fur-
nace chassis which is close to the control. Firmly touch
the clean, unpainted, metal surface of the furnace chassis
which is close to the control. Tools held in a person’s hand
during grounding will be satisfactorily discharged.
3. After touching the chassis, you may proceed to service the
control or connecting wires as long as you do nothing to
recharge your body with static electricity (for example;
DO NOT move or shuffle your feet, do not touch un-
grounded objects, etc.).
4. If you touch ungrounded objects (and recharge your body
with static electricity), firmly touch a clean, unpainted
metal surface of the furnace again before touching control
or wires.
5. Use this procedure for installed and uninstalled (ungroun-
ded) furnaces.
6. Before removing a new control from its container, dis-
charge your body’s electrostatic charge to ground to pro-
tect the control from damage. If the control is to be in-
stalled in a furnace, follow items 1 through 4 before
bringing the control or yourself in contact with the fur-
nace. Put all used and new controls into containers before
touching ungrounded objects.
7. An ESD service kit (available from commercial sources)
may also be used to prevent ESD damage.

Specifications are subject to change without notice.
6441 01 1421 02
THE BLOWER IS LOCATED
TO THE RIGHT OF THE
BURNER SECTION, AND
AIR CONDITIONED AIR IS
DISCHARGED TO THE LEFT.
THE BLOWER IS
LOCATED BELOW THE
BURNER SECTION, AND
CONDITIONED AIR IS
DISCHARGED UPWARD.
THE BLOWER IS
LOCATED ABOVE THE
BURNER SECTION, AND
CONDITIONED AIR IS
DISCHARGED DOWNWARD
THE BLOWER IS
LOCATED TO THE LEFT
OF THE BURNER SECTION,
AND CONDITIONED AIR IS
DISCHARGED TO THE RIGHT.
A02097
Fig. 4 −Multipoise Orientations
LOCATION
GENERAL
This multipoise furnace is shipped in packaged configuration.
Some assembly and modifications are required when used in any
of the four applications shown in Fig. 4.
This furnace must:
Sbe installed so the electrical components are protected
from water.
Snot be installed directly on any combustible material
other than wood flooring for upflow applications.
Downflow installations require use of a factory−ap-
proved floor base or coil assembly when installed on
combustible materials or wood flooring (refer to
SAFETY CONSIDERATIONS).
Sbe located as close to the chimney or vent and attached
to an air distribution system. Refer to Air Ducts section.
Sbe provided ample space for servicing and cleaning.
Always comply with minimum fire protection clear-
ances shown on the furnace clearance to combustible
label.
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal
injury or death, and unit component damage.
Corrosive or contaminated air may cause failure of parts
containing flue gas, which could leak into the living space.
Air for combustion must not be contaminated by halogen
compounds, which include fluoride, chloride, bromide, and
iodide. These elements can corrode heat exchangers and
shorten furnace life. Air contaminants are found in aerosol
sprays, detergents, bleaches, cleaning solvents, salts, air
fresheners, and other household products. Do not install
furnace in a corrosive or contaminated atmosphere. Make
sure all combustion and circulating air requirements are met,
in addition to all local codes and ordinances.
!WARNING
The following types of furnace installations may require
OUTDOOR AIR for combustion due to chemical exposures:
SCommercial buildings
SBuildings with indoor pools
SLaundry rooms
SHobby or craft rooms, and
SChemical storage areas
If air is exposed to the following substances, it should not be used
for combustion air, and outdoor air may be required for
combustion:
SPermanent wave solutions
SChlorinated waxes and cleaners
SChlorine based swimming pool chemicals
SWater softening chemicals
SDe−icing salts or chemicals
SCarbon tetrachloride
SHalogen type refrigerants
SCleaning solvents (such as perchloroethylene)
SPrinting inks, paint removers, varnishes, etc.
SHydrochloric acid
SCements and glues
SAntistatic fabric softeners for clothes dryers
SMasonry acid washing materials

Specifications are subject to change without notice. 7441 01 1421 02
All fuel−burning equipment must be supplied with air for fuel
combustion. Sufficient air must be provided to avoid negative
pressure in the equipment room or space. A positive seal must be
made between the furnace cabinet and the return−air duct to
prevent pulling air from the burner area and from draft safeguard
opening.
18-IN. (457.2 mm)
MINIMUM TO BURNERS
A93044
Fig. 5 −Installation in a Garage
FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
When the furnace is installed in a residential garage, the
burners and ignition sources must be located at least 18
inches above the floor. The furnace must be located or
protected to avoid damage by vehicles. When the furnace is
installed in a public garage, airplane hangar, or other
building having a hazardous atmosphere, the furnace must
be installed in accordance with the NFGC.
!WARNING
PERSONAL INJURY AND/OR PROPERTY
DAMAGE HAZARD
Improper use or installation of this furnace may cause
premature furnace component failure.
This gas furnace may be used for heating buildings under
construction provided that:
−The furnace is permanently installed with all electrical
wiring, piping, venting and ducting installed according to
these installation instructions. A return air duct is provided,
sealed to the furnace casing, and terminated outside the
space containing the furnace. This prevents a negative
pressure condition as created by the circulating air blower,
causing a flame rollout and/or drawing combustion
products into the structure.
−The furnace is controlled by a thermostat. It may not be
“hot wired” to provide heat continuously to the structure
without thermostatic control.
−Clean outside air is provided for combustion. This is to
minimize the corrosive effects of adhesives, sealers and
other construction materials. It also prevents the
entrainment of drywall dust into combustion air, which can
cause fouling and plugging of furnace components.
−The temperature of the return air to the furnace is
maintained between 55_F (13_C) and 80_F (27_C), with
no evening setback or shutdown. The use of the furnace
while the structure is under construction is deemed to be
intermittent operation per our installation instructions.
−The air temperature rise is within the rated rise range on
the furnace rating plate, and the gas input rate has been set
to the nameplate value.
−The filters used to clean the circulating air during the
construction process must be either changed or thoroughly
cleaned prior to occupancy.
−The furnace, ductwork and filters are cleaned as necessary
to remove drywall dust and construction debris from all
HVAC system components after construction is completed.
−Verify proper furnace operating conditions including
ignition, gas input rate, air temperature rise, and venting
according to these installation instructions.
CAUTION
!
Table 2 – Minimum Free Area Required for Each Combustion Air Opening or Duct to Outdoors
FURNACE
INPUT
(BTUH)
TWO HORIZONTAL DUCTS
(1 SQ. IN./2,000 BTUH)
(1,100 SQ. MM/KW)
SINGLE DUCT OR OPENING
(1 SQ. IN./3,000 BTUH)
(734 SQ. MM/KW)
TWO OPENINGS OR VERTICAL
DUCTS
(1 SQ. IN./4,000 BTUH)
(550 SQ. MM/KW)
Free Area of Open
ing and Duct
(sq. in. / sq. mm)
Round Duct
Diameter
(in./mm)
Free Area of Open
ing and Duct
(sq. In. / sq. mm)
Round Duct
Diameter
(in. / mm)
Free Area of
Opening and Duct
(sq. In. / sq. mm)
Round Duct
Diameter
(In./mm)
44,000 22 (14193) 6 (152) 14.7 (9484) 5 (127) 11 (7097) 4 (102)
66,000 33 (21290) 7 (178) 22 (14193) 6 (152) 16.5 (10645) 5 (127)
88,000 44 (28387) 8 (203) 29.3 (18903) 7 (178) 22 (14193) 6 (152)
110,000 55 (35484) 9 (229) 36.7 (23677) 7 (178) 27.5 (17742) 6 (152)
132,000 66 (42581) 10 (254) 44 (28387) 8 (203) 33 (21290) 7 (178)
EXAMPLES: Determining Free Area
FURNACE WATER HEATER TOTAL INPUT
110,000 + 30,000 = (140,000 divided by 4,000) = 35.0 Sq. In. for each two Vertical Ducts or Openings
66,000 + 40,000 = (106,000 divided by 3,000) = 35.3 Sq. In. for a Single Duct or Opening
88,000 + 30,000 = (118,000 divided by 2,000) =59.0 Sq. In. for each of two Horizontal Ducts

Specifications are subject to change without notice.
8441 01 1421 02
Table 3 – Minimum Space volumes for 100% combustion, Ventilation, and Dilution from Indoors
ACH*
OTHER THAN FAN-ASSISTED TOTAL
(1,000'S BTUH GAS INPUT RATE
FAN-ASSISTED TOTAL
(1,000'S BTUH GAS INPUT RATE)
30 40 50 44 66 88 110 132
Space Volume (ft.3)
0.60 1,050 1,400 1,750 1,100 1,650 2,200 2,750 3,300
0.50 1,260 1,680 2,100 1,320 1,980 2,640 3,300 3,960
0.40 1,575 2,100 2,625 1,650 2,475 3,300 4,125 4,950
0.30 2,100 2,800 3,500 2,200 3,300 4,400 5,500 6,600
0.20 3,150 4,200 5,250 3,300 4,950 6,600 8,250 9,900
0.10 6,300 8,400 10,500 6,600 9,900 13,200 16,500 19,800
0.00 NP NP NP NP NP NP NP NP
*Air Changes/Hour
FIRE HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
Do not install the furnace on its back or hang furnace with
control compartment facing downward. Safety control
operation will be adversely affected. Never connect
return−air ducts to the back of the furnace. (See Fig. 6.)
!WARNING
A02054
Fig. 6 −Prohibit Installation on Back
FURNACE CORROSION HAZARD
Failure to follow this caution may result in furnace damage.
Air for combustion must not be contaminated by halogen
compounds, which include fluoride, chloride, bromide, and
iodide. These elements can corrode heat exchangers and
shorten furnace life. Air contaminants are found in aerosol
sprays, detergents, bleaches, cleaning solvents, salts, air
fresheners, and other household products.
CAUTION
!
LOCATION RELATIVE TO COOLING EQUIPMENT
The cooling coil must be installed parallel with, or on the
downstream side of the unit to avoid condensation in the heat
exchangers. When installed parallel with the furnace, dampers or
other flow control must prevent chilled air from entering the
furnace. If the dampers are manually operated, they must be
equipped with means to prevent operation of either unit unless
the damper is in the full−heat or full−cool position.
AIR FOR COMBUSTION AND
VENTILATION
Provisions for adequate combustion, ventilation, and dilution air
must be provided in accordance with:
SU.S. installations: Section 9.3 of the current edition of
NFGC NFPA54/ANSI Z223.1, Air for Combustion
and Ventilation, and applicable provisions of the local
building codes.
!WARNING
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury
or death.
The operation of exhaust fans, kitchen ventilation fans,
clothes dryers, attic exhaust fans or fireplaces could create a
NEGATIVE PRESSURE CONDITION at the furnace.
Make−up air MUST be provided for the ventilation devices,
in addition to that required by the furnace. Refer to Carbon
Monoxide Poisoning Hazard warning in venting section of
these instructions to determine if an adequate amount of
make−up air is available.
The requirements for combustion and ventilation air depend upon
whether or not the furnace is located in a space having a volume
of at least 50 cubic feet per 1,000 Btuh input rating for all gas
appliances installed in the space.
SSpaces having less than 50 cubic feet per 1,000 Btuh
require the OUTDOOR COMBUSTION AIR
METHOD.
SSpaces having at least 50 cubic feet per 1,000 Btuh
may use the INDOOR COMBUSTION AIR,
STANDARD or KNOWN AIR INFILTRATION
METHOD.
Outdoor Combustion Air Method
1. Provide the space with sufficient air for proper combus-
tion, ventilation, and dilution of flue gases using perman-
ent horizontal or vertical duct(s) or opening(s) directly
communicating with the outdoors or spaces that freely
communicate with the outdoors.
2. Fig. 7 illustrates how to provide TWO OUTDOOR
OPENINGS, one inlet and one outlet combustion and
ventilation air opening, to the outdoors.
e. One opening MUST commence within 12−in. (300 mm)
of the ceiling and the second opening MUST commence
within 12−in. (300 mm) of the floor.
f. Size openings and ducts per Fig. 7 and Table 2.

Specifications are subject to change without notice. 9441 01 1421 02
1 SQ IN.
PER
4000
BTUH*
DUCTS
TO
OUTDOORS
1 SQ IN.
PER 4000
BTUH*
CIRCULATING
AIR DUCTS
VENT
THROUGH
ROOF
D
B
A
C
E
1 SQ IN.
PER 4000
BTUH*
DUCT
TO
OUTDOORS
CIRCULATING AIR DUCTS
1 SQ IN.
PER 2000
BTUH*
1 SQ IN.
PER 2000
BTUH*
DUCTS
TO
OUTDOORS
12″MAX
12″MAX
12″MAX
12″
MAX
12″
MAX
OUTDOORS
1 SQ IN.
PER
4000
BTUH*
F
G
CLEARANCE IN FRONT
OF COMBUSTION AIR
OPENINGS SHALL BE
AT LEAST 3 IN.
(305mm)
(305mm)
(305mm)
(305mm)
(305mm)
(76mm)
*Minimum dimensions of 3 in. (76 mm).
NOTE: Use any of the following combinations of openings:
A&B, C&D, D&E, F&G
A03174
Fig. 7 −Air for Combustion, Ventilation, and Dilution from
Outdoors
g. TWO HORIZONTAL DUCTS require 1 square inch of
free area per 2,000 Btuh (1,100 mm2/kW) of combined
input for all gas appliances in the space per Fig. 7 and
Table 2.
h. TWO OPENINGS OR VERTICAL DUCTS require 1
square inch of free area per 4,000 Btuh (550 mm2/kW)
for combined input of all gas appliances in the space per
Fig. 7 and Table 2.
3. ONE OUTDOOR OPENING requires:
a. 1 square inch of free area per 3,000 Btuh (734 mm2/kW)
for combined input of all gas appliances in the space per
Table 2 and
b. Not less than the sum of the areas of all vent connectors
in the space.
The opening shall commence within 12” (300 mm) of the ceiling.
Appliances in the space shall have clearances of at least 1” (25
mm) from the sides and back and 6” (150 mm) from the front.
The opening shall directly communicate with the outdoors or
shall communicate through a vertical or horizontal duct to the
outdoors or spaces (crawl or attic) that freely communicate with
the outdoors.
Indoor Combustion Air −NFPA & AGA
Standard and Known−Air−Infiltration Rate Methods
Indoor air is permitted for combustion, ventilation, and dilution,
if the Standard or Known−Air−Infiltration Method is used.
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in death and/or
personal injury.
Many homes require air to be supplied from outdoors for
furnace combustion, ventilation, and dilution of flue gases.
The furnace combustion air supply must be provided in
accordance with this instruction manual.
!WARNING
CIRCULATING AIR
DUCTS
6" MIN
(FRONT)Ü
CIRCULATING AIR DUCTS
VENT THROUGH ROOF
1 SQ IN.
PER 1000
BTUH* IN DOOR
OR WALL
12" MAX
1 SQ IN.
PER 1000
BTUH* IN DOOR
OR WALL
12" MAX
UNCONFINED
SPACE
INTERIOR
HEATED
SPACE
CLEARANCE IN FRONT OF COMBUSTION AIR
OPENINGS SHALL BE AT LEAST3 IN.
(305mm)
(152mm)
(305mm)
*Minimum opening size is 100 in.2with minimum dimensions of 3 in. (76
mm).
*Minimum of 3 in. (76 mm), when type -B1 vent is used.
A03175
Fig. 8 −Air for Combustion, Ventilation, and Dilution from
Indoors
The Standard Method:
1. The space has no less volume than 50 cubic feet per 1,000
Btuh of the maximum input ratings for all gas appliances
installed in the space and
2. The air infiltration rate is not known to be less than 0.40
air changes per hour (ACH).
The Known Air Infiltration Rate Method shall be used, if the
infiltration rate is known to be:
1. Less than 0.40 ACH and
2. Equal to or greater than 0.10 ACH
Infiltration rates greater than 0.60 ACH shall not be used. The
minimum required volume of the space varies with the number of
ACH and shall be determined per Table 3 or Equations 1 and 2.
Determine the minimum required volume for each appliance in
the space and add the volumes together to get the total minimum
required volume for the space.
Table 3 −Minimum Space Volumes were determined by using
the following equations from the current edition of National Fuel
Gas Code ANSI Z223.1/NFPA 54, 9.3.2.2:
1. For other than fan−assisted appliances, such as a draft
hood−equipped water heater:
Volume
Other
=21ft
3
ACH
I
other
1000 Btu/hr
A04002
2. For fan−assisted appliances such as this furnace:
Volume
Fan
=15ft
3
ACH
I
fan
1000 Btu/hr
A004003
If:
Iother = combined input of all other than fan−assisted appliances
in Btuh/hr

Specifications are subject to change without notice.
10 441 01 1421 02
Ifan = combined input of all fan−assisted appliances in Btuh/hr
ACH = air changes per hour (ACH shall not exceed 0.60.)
The following requirements apply to the Standard Method and to
the Known Air Infiltration Rate Method.
1. Adjoining rooms can be considered part of a space if:
a. There are no closeable doors between rooms.
b. Combining spaces on same floor level. Each opening
shall have free area of at least 1 in.2/1,000 Btuh (2,000
mm2/kW) of the total input rating of all gas appliances
in the space, but not less than 100 in.2(0.06 m2). One
opening shall commence within 12” (300 mm) of the ceil-
ing and the second opening shall commence within 12”
(300 mm) of the floor. The minimum dimension of air
openings shall be at least 3 in. (80 mm). (See Fig. 8.)
c. Combining space on different floor levels. The volumes
of spaces on different floor levels shall be considered as
communicating spaces if connected by one or more per-
manent openings in doors or floors having free area of
at least 2 in.2/1,000 Btuh (4,400 mm2/kW) of total input
rating of all gas appliances.
2. An attic or crawlspace may be considered a space that
freely communicates with the outdoors provided there are
adequate permanent ventilation openings directly to out-
doors having free area of at least 1−in.2/4,000 Btuh of total
input rating for all gas appliances in the space.
3. In spaces that use the Indoor Combustion Air Method,
infiltration should be adequate to provide air for combus-
tion, permanent ventilation and dilution of flue gases.
However, in buildings with unusually tight construction,
additional air MUST be provided using the methods de-
scribed in the Outdoor Combustion Air Method section.
Unusually tight construction is defined as construction with:
a. Walls and ceilings exposed to the outdoors have a con-
tinuous, sealed vapor barrier. Openings are gasketed or
sealed and
b. Doors and openable windows are weatherstripped and
c. Other openings are caulked or sealed. These include
joints around window and door frames, between sole
plates and floors, between wall−ceiling joints, between
wall panels, at penetrations for plumbing, electrical and
gas lines, etc.
Combination of Indoor and Outdoor Air
1. Indoor openings shall comply with the Indoor Combus-
tion Air Method below and,
2. Outdoor openings shall be located as required in the Out-
door Combustion Air Method mentioned previously and,
3. Outdoor openings shall be sized as follows:
a. Calculate the Ratio of all Indoor Space volume divided
by required volume for Indoor Combustion Air Meth-
od below.
b. Outdoor opening size reduction Factor is 1 minus the Ra-
tio in a. above.
c. Minimum size of Outdoor openings shall be the size re-
quired in Outdoor Combustion Air Method above multi-
plied by reduction Factor in b. above. The minimum di-
mension of air openings shall be not less than 3 in. (80
mm).
INSTALLATION
UPFLOW INSTALLATION
Bottom Return Air Inlet
These furnaces are shipped with bottom closure panel installed in
bottom return−air opening. Remove and discard this panel when
bottom return air is used. To remove bottom closure panel,
perform the following:
1. Tilt or raise furnace and remove two screws holding bot-
tom filler panel. (See Fig. 9.)
Bottom
Closure Panel
Bottom Filler Panel
A10273
Fig. 9 −Removing Bottom Closure Panel
2. Rotate bottom filler panel downward to release holding
tabs.
3. Remove bottom closure panel.
4. Reinstall bottom filler panel and screws.
Side Return Air Inlet
These furnaces are shipped with bottom closure panel installed in
bottom return−air opening. This panel MUST be in place when
only side return air is used.
NOTE: Side return−air openings can be used in UPFLOW and
most HORIZONTAL configurations. Do not use side return−air
openings in DOWNFLOW configuration.
Leveling Legs (If Desired)
In upflow position with side return inlet(s), leveling legs may be
used. (See Fig. 10.) Install field−supplied, 5/16 x 1−1/2 in. (8 x
38 mm) (max) corrosion−resistant machine bolts, washers and
nuts.
NOTE: Bottom closure must be used when leveling legs are
used. It may be necessary to remove and reinstall bottom closure
panel to install leveling legs. To remove bottom closure panel, see
Item 1. in Bottom Return Air Inlet section.
To install leveling legs:
1. Position furnace on its back. Locate and drill a hole in
each bottom corner of furnace. (See Fig. 10.)
2. For each leg, install nut on bolt and then install bolt and
nut in hole. (Install flat washer if desired.)
3. Install another nut on other side of furnace base. (Install
flat washer if desired.)

Specifications are subject to change without notice. 11441 01 1421 02
1
3
/ 4 
1
3
/ 4 
1
3/
4 
1
3/
4 
5/
16 
5
/ 16 
5/
16 
5/
16 
(44mm)
(8mm)
(44mm)
(8mm)
(8mm)
(8mm)
(44mm)
(44mm)
A89014
Fig. 10 −Leveling Legs
4. Adjust outside nut to provide desired height, and tighten
inside nut to secure arrangement.
5. Reinstall bottom closure panel if removed.
DOWNFLOW INSTALLATION
NOTE: For downflow applications, this furnace is approved for
use on combustible flooring when any one of the following 3
accessoriesare used:
SDownflow combustible floor subbase
SCased Coil numbers END4X, ENW4X
SCoil casing model number NAEA
1. Determine application being installed from Table 4.
2. Construct hole in floor per Table 4 and Fig. 11.
3. Construct plenum to dimensions specified in Table 4 and
Fig. 11.
4. If downflow subbase is used, install as shown in Fig. 12. If
Coil model number END4X, ENW4X or Coil Casing
model number NAEA is used, install as shown in Fig. 13.
NOTE: It is required that the perforated supply−air duct flanges
be completely folded over or removed from furnace when
installing the furnace on a factory−supplied cased coil or coil box.
To remove the supply−air duct flange, use wide duct pliers or
hand seamers to bend flange back and forth until it breaks off. Be
careful of sharp edges. (See Fig. 14.)
Bottom Return Air Inlet
These furnaces are shipped with bottom closure panel installed in
bottom return−air opening. Remove and discard this panel when
bottom return air is used. To remove bottom closure panel,
perform the following:
1. Tilt or raise furnace and remove two screws holding bot-
tom filler panel. (See Fig. 9.)
2. Rotate bottom filler panel downward to release holding
tabs.
3. Remove bottom closure panel.
4. Reinstall bottom filler panel and screws
PLENUM
OPENING
C
A
BD
FLOOR
OPENING
A96283
Fig. 11 −Floor and Plenum Opening Dimensions
DOWNFLOW
SUBBASE
SHEET METAL
PLENUM
FLOOR
OPENING
FURNACE
(OR COIL CASING
WHEN USED)
COMBUSTIBLE
FLOORING
A96285
Fig. 12 −Furnace, Plenum, and Subbase Installed
on a Combustible Floor

Specifications are subject to change without notice.
12 441 01 1421 02
APPROVED
COIL ASSEMBLY
OR
COIL BOX
FURNACE
SHEET METAL
PLENUM
FLOOR
OPENING
COMBUSTIBLE
FLOORING
A08556
Fig. 13 −Furnace, Plenum, and Coil Assembly or
Coil Box Installed on a Combustible Floor
Table 4 – Opening Dimensions −In. (mm)
FURNACE
CASING
WIDTH
APPLICATION PLENUM OPENING FLOOR OPENING
A B C D
14–3/16
(360)
Upflow Applications on Combustible or Noncombustible Floor-
ing (subbase not required)
12−11/16
(322)
21−5/8
(549)
13−5/16
(338)
22−1/4
(565)
Downflow Applications on Noncombustible Flooring
(subbase not required)
12−9/16
(319)
19
(483)
13−3/16
(335)
19−5/8
(498)
Downflow Applications on Combustible Flooring
(subbase required)
11−13/16
(284)
19
(483)
13−7/16
(341)
20−5/8
(600)
Downflow Applications on Combustible Flooring with Coil
END4X, ENW4X or Coil Casing NAEA (subbase not required)
12−5/16
(313)
19
(483)
13−5/16
(338)
20
(508)
17–1/2
(445)
Upflow Applications on Combustible or Noncombustible Floor-
ing (subbase not required)
16
(406)
21−5/8
(549)
16−5/8
(422)
22−1/4
(565)
Downflow Applications on Noncombustible Flooring
(subbase not required)
15−7/8
(403)
19
(483)
16−1/2
(419)
19−5/8
(498)
Downflow Applications on Combustible Flooring
(subbase required)
15−1/8
(384)
19
(483)
16−3/4
(425)
20−5/8
(600)
Downflow Applications on Combustible Flooring Coil with Coil
END4X, ENW4X or Coil Casing NAEA (subbase not required)
15−1/2
(394)
19
(483)
16−1/2
(419)
20
(508)
21
(533)
Upflow Applications on Combustible or Noncombustible Floor-
ing (subbase not required)
19−1/2
(495)
21−5/8
(549)
20−1/8
(511)
22−1/4
(565)
Downflow Applications on Noncombustible Flooring
(subbase not required)
19−3/8
(492)
19
(483)
20
(508)
19−5/8
(498)
Downflow Applications on Combustible Flooring
(subbase required)
18−5/8
(473)
19
(483)
20−1/4
(514)
20−5/8
(600)
Downflow Applications on Combustible Flooring with Coil
END4X, ENW4X or Coil Casing NAEA (subbase not required)
19
(483)
19
(483)
20
(508)
20
(508)
24−1/2
(622)
Upflow Applications on Combustible or Noncombustible Floor-
ing (subbase not required)
23
(584)
21−1/8
(537)
23−5/8
(600)
22−1/4
(565)
Downflow Applications on Noncombustible Flooring
(subbase not required)
22−7/8
(581)
19
(483)
23−1/2
(597)
19−5/8
(498)
Downflow Applications on Combustible Flooring
(subbase required)
22−1/8
(562)
19
(483)
23−3/4
(603)
20−5/8
(600)
Downflow Applications on Combustible Flooring with Coil
END4X, ENW4X or Coil Casing NAEA (subbase not required)
22−1/2
(572)
19
(483)
23−1/2
(597)
20
(508)

Specifications are subject to change without notice. 13441 01 1421 02
HORIZONTAL INSTALLATION
FIRE, EXPLOSION, AND CARBON MONOXIDE
POISONING HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Do not install the furnace on its back or hang furnace with
control compartment facing downward. Safety control
operation will be adversely affected. Never connect
return−air ducts to the back of the furnace.
!WARNING
The furnace can be installed horizontally in an attic or crawl space
on either the left−hand (LH) or right−hand (RH) side. The furnace
can be hung from floor joists, rafters or trusses or installed on a
non−combustible platform, blocks, bricks or pad.
Suspended Furnace Support
The furnace may be supported under each end with threaded rod,
angle iron or metal plumber’s strap as shown. (See Fig. 15 and
16.) Secure angle iron to bottom of furnace as shown.
Heavy−gauge sheet metal straps (plumber’s straps) may be used
to suspend the furnace from each bottom corner. To prevent
screws from pulling out, use 2 #8 x 3/4−in. (19 mm) screws into
the side and 2 #8 x 3/4−in. (19 mm) screws in the bottom of the
furnace casing for each strap. (See Fig. 15 and 16.) If the screws
are attached to ONLY the furnace sides and not the bottom, the
straps must be vertical against the furnace sides and not pull away
from the furnace sides, so that the strap attachment screws are not
in tension (are loaded in shear) for reliable support.
Platform Furnace Support
Construct working platform at location where all required furnace
clearances are met. (See Fig. 2 and 17.) For furnaces with 1−in.
(25 mm) clearance requirement on side, set furnace on
noncombustible blocks, bricks or angle iron. For crawl space
installations, if the furnace is not suspended from the floor joists,
the ground underneath furnace must be level and the furnace set
on blocks or bricks.
Roll−Out Protection
Provide a minimum 17−3/4 in. x 22 in. (451 mm x 559 mm)
piece of sheet metal for flame roll−out protection in front of
burner area for furnaces closer than 12 inches (305 mm) above
the combustible deck or suspended furnaces closer than 12 inches
(305 mm) to joists. The sheet metal MUST extend underneath the
furnace casing by 1 in. (25 mm) with the door removed.
The bottom closure panel on furnaces of widths 17−1/2 in. (445
mm) and larger may be used for flame roll−out protection when
bottom of furnace is used for return air connection. See Fig. 17
for proper orientation of roll−out shield.
Bottom Return Air Inlet
These furnaces are shipped with bottom closure panel installed in
bottom return−air opening. Remove and discard this panel when
bottom return air is used. To remove bottom closure panel,
perform the following:
1. Tilt or raise furnace and remove two screws holding bot-
tom filler panel. (See Fig. 9.)
2. Rotate bottom filler panel downward to release holding
tabs.
3. Remove bottom closure panel.
4. Reinstall bottom filler panel and screws. Side Return Air
Inlet
Side Return Air Inlet
These furnaces are shipped with bottom closure panel installed in
bottom return−air opening. This panel MUST be in place when
side return air inlet(s) is used without a bottom return air inlet.
Not all horizontal furnaces are approved for side return air
connections. (See Fig. 21.)
FILTER ARRANGEMENT
CARBON MONOXIDE AND POISONING
HAZARD
Failure to follow this warning could result in personal
injury, or death.
Never operate a furnace without a filter or with filter access
door removed.
!WARNING
There are no provisions for an internal filter rack in these
furnaces.
A field−supplied accessory external filter is required.
Refer to the instructions supplied with the external filter rack for
assembly and installation options.
AIR DUCTS
General Requirements
The duct system should be designed and sized according to
accepted national standards such as those published by: Air
Conditioning Contractors Association (ACCA), Sheet Metal and
Air Conditioning Contractors National Association (SMACNA)
or American Society of Heating, Refrigerating and Air
Conditioning Engineers (ASHRAE) or consult The Air Systems
Design Guidelines reference tables available from your local
distributor. The duct system should be sized to handle the
required system design CFM at the design external static pressure.
The furnace airflow rates are provided in Table 5 −AIR
DELIVERY−CFM (With Filter).
When a furnace is installed so that the supply ducts carry air
circulated by the furnace to areas outside the space containing the
furnace, the return air shall also be handled by duct(s) sealed to
the furnace casing and terminating outside the space containing
the furnace.
Secure ductwork with proper fasteners for type of ductwork used.
Seal supply−and return−duct connections to furnace with code
approved tape or duct sealer.
NOTE: Flexible connections should be used between ductwork
and furnace to prevent transmission of vibration. Ductwork
passing through unconditioned space should be insulated and
sealed to enhance system performance. When air conditioning is
used, a vapor barrier is recommended.
Maintain a 1−in. (25 mm) clearance from combustible materials
to supply air ductwork for a distance of 36 in. (914 mm)
horizontally from the furnace. See NFPA 90B or local code for
further requirements.
Ductwork Acoustical Treatment
NOTE: Metal duct systems that do not have a 90 degree elbow
and 10 ft. (3 M) of main duct to the first branch take−off may
require internal acoustical lining. As an alternative, fibrous
ductwork may be used if constructed and installed in accordance
with the latest edition of SMACNA construction standard on
fibrous glass ducts. Both acoustical lining and fibrous ductwork
shall comply with NFPA 90B as tested by UL Standard 181 for
Class 1 Rigid air ducts.
Supply Air Connections
For a furnace not equipped with a cooling coil, the outlet duct
shall be provided with a removable access panel. This opening
shall be accessible when the furnace is installed and shall be of
such a size that the heat exchanger can be viewed for possible
openings using light assistance or a probe can be inserted for
sampling the airstream. The cover attachment shall prevent leaks.

Specifications are subject to change without notice.
14 441 01 1421 02
Upflow and Horizontal Furnaces
Connect supply−air duct to flanges on furnace supply−air outlet.
Bend flange upward to 90_with wide duct pliers. (See Fig. 14.)
The supply−air duct must be connected to ONLY the furnace
supply−outlet−air duct flanges or air conditioning coil casing
(when used). DO NOT cut main furnace casing side to attach
supply air duct, humidifier, or other accessories. All accessories
MUST be connected to duct external to furnace main casing.
NOTE: For horizontal applications, the top−most flange may be
bent past 90 degrees to allow the evaporator coil to hang on the
flange temporarily while the remaining attachment and sealing of
the coil are performed.
Downflow Furnaces
Connect supply−air duct to supply−air outlet on furnace. Bend
flange inward past 90_with wide duct pliers. (See Fig. 14.) The
supply−air duct must be connected to ONLY the furnace supply
outlet or air conditioning coil casing (when used). When installed
on combustible material, supply−air duct must be connected to
ONLY the factory−approved accessory subbase or a factory−
approved air conditioning coil casing. DO NOT cut main furnace
casing to attach supply side air duct, humidifier, or other
accessories.All accessories MUST be connected to duct external
to furnace casing.
UPFLOW DOWNFLOW HORIZONTAL
YES
NO NO
YES
YES
YES
NO
120
MIN
YES 120
MIN
YES
120
MIN
9090
A02020
Fig. 14 −Duct Flanges
1
/ 4" (6mm) THREADED ROD
4 REQ.
SECURE ANGLE
IRON TO BOTTOM
OF FURNACE WITH
3 #8 x
3
/ 4 " (19mm) SCREWS
TYPICAL FOR 2 SUPPORTS
1” (25mm) SQUARE, 1-1/4”x1-1/4”x1/8” (32x32x3mm)
ANGLE IRON OR UNI-STRUT MAY BE USED
(2) HEX NUTS, (2) WASHERS & (2) LOCK WASHERS
REQ. PER ROD
8" (203mm)
MIN
FOR DOOR REMOVAL
OUTER DOOR
ASSEMBLY
A10130
Fig. 15 −Horizontal Unit Suspension

Specifications are subject to change without notice. 15441 01 1421 02
METHOD 2
USE (4) #8 x 3/4 (19 mm) SHEET
METAL SCREWS FOR EACH
STRAP. THE STRAPS
SHOULD BE VERTICAL
AGAINST THE FURNACE
SIDES AND NOT PULL AWAY
FROM THE FURNACE
SIDES.
METHOD 1
FOLD ALL STRAPS UNDER
FURNACE AND SECURE WTH
(4) #8 x 3/4 (19 mm) SHEET METAL SCREWS
(2 SCREWS IN SIDE AND 2 SCREWS
IN BOTTOM).
A10131
Fig. 16 −Horizontal Suspension with Straps
30-IN. (762mm)
MIN WORK AREA
6″ MIN
*
TYPE-B
VENT
17
3
/ 4 ″
22 ″
SHEET
METAL
SEDIMENT
TRAP
EQUIPMENT MANUAL
SHUT-OFF GAS VALVE
LINE CONTACT ONLY PERMISSIBLE BETWEEN
LINES FORMED BY INTERSECTIONS OF
THE TOP AND TWO SIDES OF THE FURNACE
JACKET AND BUILDING JOISTS,
STUDS, OR FRAMING.
GAS
ENTRY
17
3
/ 4 ″ (451mm) OVERALL
4
3
/ 4 ″ (121mm) UNDER DOOR
1″
(25mm) UNDER FURNACE
EXTEND OUT 12″
(305mm)
FROM FACE OF DOOR
* WHEN USED WITH
SINGLE WALL VENT
CONNECTIONS
UNION
(152mm)
(451mm)
(559mm)
A10164
Fig. 17 −Typical Attic Installation

Specifications are subject to change without notice.
16 441 01 1421 02
Return Air Connections
FIRE HAZARD
Failure to follow this warning could cause personal injury,
death and/or property damage.
Never connect return−air ducts to the back of the furnace.
Follow instructions below
!WARNING
Downflow Furnaces
The return−air duct must be connected to return−air opening
(bottom inlet) as shown in Fig. 20. DO NOT cut into casing sides
(left or right). Side opening is permitted for only upflow and most
horizontal furnaces. (See Fig. 20.) Bypass humidifier connections
should be made at ductwork or coil casing sides exterior to
furnace.
Upflow and Horizontal Furnaces
The return−air duct must be connected to bottom, sides (left or
right), or a combination of bottom and side(s) of main furnace
casing as shown in Fig. 19 and 21. Bypass humidifier may be
attached into unused return air side of the furnace casing. (See
Fig. 19 and 21.)
Not all horizontal furnaces are approved for side return air
connections. (See Fig. 21.)
GAS PIPING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Never purge a gas line into a combustion chamber. 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.
!WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury,death, and/or property damage.
Use proper length of pipe to avoid stress on gas control
manifold and a gas leak.
!WARNING
FURNACE OVERHEAT HAZARD
Failure to follow this caution may result in property
damage.
Connect gas pipe to gas valve using a backup wrench to
avoid damaging gas controls and burner misalignment.
CAUTION
!
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
If local codes allow the use of a flexible gas appliance
connector, always use a new listed connector. Do not use a
connector which has previously served another gas
appliance. Black iron pipe shall be installed at the furnace
gas control valve and extend a minimum of 2 in.(51 mm)
outside the furnace.
!WARNING
Gas piping must be installed in accordance with national and
local codes. Refer to current edition of NFGC.
Installations must be made in accordance with all authorities
having jurisdiction. If possible, the gas supply line should be a
separate line running directly from meter to furnace.
NOTE: In the state of Massachusetts:
1. Gas supply connections MUST be performed by a li-
censed plumber or gas fitter.
2. When flexible connectors are used, the maximum length
shall not exceed 36 inches (915 mm).
3. When lever handle type manual equipment shutoff valves
are used, they shall be T−handle valves.
4. The use of copper tubing for gas piping is NOT approved
by the state of Massachusetts.
Refer to Table 6 for recommended gas pipe sizing. Risers must be
used to connect to furnace and to meter. Support all gas piping
with appropriate straps, hangers, etc. Use a minimum of 1 hanger
every 6 ft. (2 M). Joint compound (pipe dope) should be applied
sparingly and only to male threads of joints. Pipe dope must be
resistant to the action of propane gas.
An accessible manual equipment shutoff valve MUST be
installed external to furnace casing and within 6 ft. (2 M) of
furnace. A 1/8−in. (3 mm) NPT plugged tapping, accessible for
test gauge connection, MUST be installed immediately upstream
of gas supply connection to furnace and downstream of manual
equipment shutoff valve.
NOTE: The furnace gas control valve inlet pressure tap
connection is suitable to use as test gauge connection providing
test pressure DOES NOT exceed maximum 0.5 psig (14−In.
W.C.) stated on gas control valve. (See Fig. 40.)
Some installations require gas entry on right side of furnace (as
viewed in upflow.) (See Fig. 22.)
Install a sediment trap in riser leading to furnace as shown in Fig.
18. Connect a capped nipple into lower end of tee. Capped nipple
should extend below level of furnace gas controls. Place a ground
joint union between furnace gas control valve and exterior
manual equipment gas shutoff valve. A 1/8−in. (3 mm) NPT
plugged tapping, accessible for test gauge connection, MUST be
installed immediately upstream of gas supply connection to
furnace and downstream of manual equipment shutoff valve.

Specifications are subject to change without notice. 17441 01 1421 02
Table 5 – Air Delivery −CFM (With Filter)*
UNIT
SIZE
WIRE−
LEAD-
COLOR
SPEED
Test Airflow Delivery @ Various External Static Pressures (in. w.c.)
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0451412
Gray 5 1230 1190 1155 1120 1080 1045 1010 975 935 895
Yellow 4 980 945 920 890 855 815 770 735 690 645
Orange 3 770 720 685 640 600 560 520 475 430 385
Blue 2 710 660 620 580 540 490 455 415 375 335
Red 1 600 540 500 455 415 385 345 305 235 −−
0701712
Gray 5 1185 1140 1095 1055 1005 960 915 865 820 780
Yellow 4 1000 940 895 850 800 750 695 650 600 555
Blue 3 990 935 895 845 790 740 690 640 590 535
Orange 2 855 775 720 660 605 560 495 435 385 335
Red 1 860 685 515 445 385 340 275 205 −− −−
0701716
Gray 5 1610 1565 1525 1475 1435 1395 1350 1305 1260 1215
Yellow 4 1385 1335 1290 1250 1205 1165 1125 1075 1025 980
Blue 3 1215 1165 1120 1075 1035 985 940 895 845 840
Orange 2 1175 1130 1085 1035 990 945 900 855 805 760
Red 1 1080 1015 955 920 875 820 780 725 670 620
0901714
Gray 5 1355 1320 1285 1245 1210 1165 1125 1080 1025 815
Yellow 4 1295 1255 1220 1185 1140 1100 1055 1005 955 815
Blue 3 1220 1185 1150 1105 1065 1025 975 915 840 740
Orange 2 1030 985 940 900 845 790 715 655 590 535
Red 1 3945 905 855 800 750 670 600 540 490 435
0902116
Gray 5 1625 1580 1535 1490 1445 1395 1340 1260 1135 995
Blue 4 1440 1395 1350 1305 1255 1200 1145 1090 1040 950
Yellow 3 1425 1380 1335 1290 1235 1185 1125 1075 1020 940
Orange 2 1260 1210 1160 1105 1050 990 935 880 820 755
Red 1 31095 1040 980 905 845 780 720 650 585 520
0902120
Gray 5 2180 2130 2080 2030 1980 1925 1870 1805 1745 1680
Yellow 4 1900 1845 1795 1740 1685 1635 1570 1500 1435 1375
Blue 3 1685 1620 1565 1505 1455 1385 1320 1260 1200 1140
Orange 2 1390 1315 1240 1175 1095 1030 970 900 825 760
Red 1 31240 1155 1075 990 915 835 765 690 615 555
1102120
Gray 5 2255 2205 2150 2100 2040 1985 1920 1835 1735 1615
Yellow 4 1600 1525 1465 1400 1335 1275 1210 1150 1080 1015
Blue 3 1945 1890 1830 1770 1715 1655 1600 1545 1480 1430
Orange 2 1420 1340 1280 1200 1140 1065 1005 925 865 790
Red 1 1280 1205 1140 1055 990 910 840 760 695 630
1352420
Gray 5 2065 2005 1940 1875 1810 1740 1670 1600 1530 1470
Blue 4 1825 1760 1695 1630 1560 1490 1420 1350 1275 1205
Yellow 3 1760 1690 1625 1555 1485 1415 1345 1275 1200 1130
Orange 2 1620 1550 1480 1405 1335 1260 1195 1130 1065 995
Red 1 31325 1260 1185 1100 1025 955 885 805 735 670
1. A filter is required for each return-air inlet. Airflow performance included 3/4-in. (19 mm) washable filter media such as contained in factory-authorized
accessory filter rack. To determine airflow performance without this filter, assume an additional 0.1 In. W.C. available external static pressure.
2. Adjust the blower speed tabs as necessary for the proper air temperature rise for each installation.
3. Highlighted areas indicate airflow range is beyond the range allowed for heating. THESE AIRFLOW RANGES MAY ONLY BE USED FOR COOLING.
4. -- Indicates unstable operating conditions.

Specifications are subject to change without notice.
18 441 01 1421 02
Table 6 – Maximum Capacity of Pipe*
NOMINAL IRON
PIPE
INTERNAL
DIAMETER LENGTH OF PIPE - FT. (M)
SIZE IN. (mm) In. (mm) 10 20 30 40 50
1/2 (13) 0.622 (16) 175 (53) 120 (37) 97 (30) 82 (25) 73 (22)
3/4 (19) 0.824 (21) 360 (110) 250 (76) 200 (61) 170 (52) 151 (46)
1 (25) 1.049 (27) 680 (207) 465 (142) 375 (114) 320 (98) 285 (87)
1-1/4 (32) 1.380 (35) 1400 (427) 950 (290) 770 (235) 660 (201) 580 (177)
1-1/2 (38) 1.610 (41) 2100 (640) 1460 (445) 1180 (360) 990 (301) 900 (274)
* Cubic ft. of natural gas per hr for gas pressures of 0.5 psig (14-In. W.C.) or less and a pressure drop of 0.5-In. W.C. (based on a 0.60 specific gravity
gas). Ref: Chapter 6 current edition of ANSI Z223/NFPA 54.
Piping should be pressure and leak tested in accordance with
NFGC in the United States, local, and national plumbing and gas
codes before the furnace has been connected. After all
connections have been made, purge lines and check for leakage at
furnace prior to operating furnace.
If pressure exceeds 0.5 psig (14−In. W.C.), gas supply pipe must
be disconnected from furnace and capped before and during
supply pipe pressure test. If test pressure is equal to or less than
0.5 psig (14−In. W.C.), turn off electric shutoff switch located on
furnace gas control valve and accessible manual equipment
shutoff valve before and during supply pipe pressure test. After
all connections have been made, purge lines and check for
leakage at furnace prior to operating furnace.
The gas supply pressure shall be within the maximum and
minimum inlet supply pressures marked on the rating plate with
the furnace burners ON and OFF.
UNION
SEDIMENT
TRAP
MANUAL
SHUTOFF
VALVE
(REQUIRED)
GAS
SUPPLY
A02035
Fig. 18 −Typical Gas Pipe Arrangement
A02075
Fig. 19 −Upflow Return Air Configurations and Restrictions

Specifications are subject to change without notice. 19441 01 1421 02
A02163
Fig. 20 −Downflow Return Air Configurations and Restrictions
A02162
Fig. 21 −Horizontal Return Air Configurations and Restrictions
2” (51mm)
Street Elbow
A08551
Fig. 22 −Burner and Manifold

Specifications are subject to change without notice.
20 441 01 1421 02
Table 7 – Electrical Data
FURNACE
MODEL
Volts−
Hertz−
Phase
Operating
Voltage* Range
Maximum
Unit Amps
Unit
Ampacit
y
#
Minimum
Wire Size
AWG
Maximum
Wire Length‡
ft (m)
Maximum
Fuse or
CKT BKR†
Amps
Maxi-
mum
Mini-
mum
0451412 115-60-1 127 104 5.6 7.8 14.0 47.0 (14.3) 15.0
0701712 115-60-1 127 104 5.6 7.8 14.0 47.0 (14.3) 15.0
0701716 115-60-1 127 104 10.0 13.3 14.0 27.0 (8.2) 15.0
0901714 115-60-1 127 104 8.2 11.0 14.0 33.0 (10.1) 15.0
0902116 115-60-1 127 104 8.2 11.0 14.0 33.0 (10.1) 15.0
0902120 115-60-1 127 104 12.9 16.9 12.0 33.9 (10.3) 20.0
1102120 115-60-1 127 104 13.4 17.4 12.0 33.0 (10.1) 20.0
1352420 115-60-1 127 104 10.7 14.0 14.0 26.0 (7.9) 15.0
* Permissible limits of the voltage range at which the unit operates satisfactorily.
# Unit ampacity = 125 percent of largest operating component's full load amps plus 100 percent of all other potential operating components' (EAC, humidifier,
etc.) full load amps.
{Time-delay type is recommended.
}Length shown is as measured one way along wire path between unit and service panel for maximum 2 percent voltage drop.
ELECTRICAL CONNECTIONS
ELECTRICAL SHOCK, FIRE OR EXPLOSION
HAZARD
Failure to follow safety warnings could result in dangerous
operation, serious injury, death or property damage.
Improper servicing could result in dangerous operation,
serious injury, death or property damage.
−Before servicing, disconnect all electrical power to
furnace.
−When servicing controls, label all wires prior to
disconnection. Reconnect wires correctly.
−Verify proper operation after servicing.
!WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Blower access panel door switch opens 115−v power to
control. No component operation can occur. Do not bypass
or close switch with panel removed.
!WARNING
See Fig. 25 for field wiring diagram showing typical field 115−v
wiring. Check all factory and field electrical connections for
tightness.
Field−supplied wiring shall conform with the limitations of 63_F
(35_C) rise.
ELECTRICAL SHOCK AND FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, or property damage.
The cabinet MUST have an uninterrupted or unbroken
ground according to current edition of NEC NFPA 70 or
local codes to minimize personal injury if an electrical fault
should occur. This may consist of electrical wire, conduit
approved for electrical ground or a listed, grounded power
cord (where permitted by local code) when installed in
accordance with existing electrical codes. Refer to the
power cord manufacturer’s ratings for proper wire gauge.
Do not use gas piping as an electrical ground.
!WARNING
FURNACE MAY NOT OPERATE
Failure to follow this caution may result in intermittent
furnace operation.
Furnace control must be grounded for proper operation or
else control will lock out. Control must remain grounded
through green/yellow wire routed to gas valve and manifold
bracket screw.
CAUTION
!
115−V WIRING
Verify that the voltage, frequency, and phase correspond to that
specified on unit rating plate. Also, check to be sure that service
provided by utility is sufficient to handle load imposed by this
equipment. Refer to rating plate or Table 7 for equipment
electricalspecifications.
Make all electrical connections in accordance with current edition
of National Electrical Code (NEC) NFPA 70 and any local codes
or ordinances that might apply.
FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, or property damage.
Do not connect aluminum wire between disconnect switch
and furnace. Use only copper wire.
!WARNING
Use a separate, fused branch electrical circuit with a properly
sized fuse or circuit breaker for this furnace. See Table 7 for wire
size and fuse specifications. A readily accessible means of
electricaldisconnect must be located within sight of the furnace.
NOTE: Proper polarity must be maintained for 115−v wiring. If
polarity is incorrect, control LED status indicator light will flash a
status code 10 and furnace will NOT operate.
J−BOX RELOCATION
NOTE: If factory location of J−Box is acceptable, go to next
section (ELECTRICAL CONNECTION TO J−BOX).
NOTE: On 14−in. (356 mm) wide casing models, the J−Box
shall not be relocated to other side of furnace casing when the
vent pipe is routed within the casing.
1. Remove and save two screws holding J−Box.