International comfort products F8MXN User manual

Portions of the text and tables are reprinted from NFPA 54 /ANSI Z223.1−2012©, with permission of National Fire Protection Association, Quincy, MA 02269 and American Gas Association, Washing-
ton, 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.
Printed in U.S.A. 441 01 1411 04 July 2013
INSTALLATION INSTRUCTIONS
80% Single Stage, ECM Motor
Category I, Gas Furnace
F8MXN, G8MXN, F8MXL, G8MXL
These instructions must be read and understood completely before attempting installation.
Safety Labeling and Signal Words
DANGER, WARNING, CAUTION, and NOTE Signal Words in Manuals
The signal words DANGER, WARNING,CAUTION,and NOTE
are used to identify levels of hazard seriousness. The signal word
DANGER is only used on product labels to signify an immediate
hazard. The signal words WARNING, CAUTION, and NOTE will
be used on product labels and throughout this manual and other
manual that may apply to the product.
The signal word WARNING is used throughout this manual in
the following manner:
The signal word CAUTION is used throughout this manual in
the following manner:
!WARNING
DANGER −Immediate hazards which will result in severe person-
al injury or death.
WARNING −Hazards or unsafe practices which could result in
severe personal injury or death.
CAUTION −Hazards or unsafe practices which may result in
minor personal injury or product or property damage.
NOTE −Used to highlight suggestions which will result in en-
hanced installation, reliability, or operation.
!CAUTION
Signal Words on Product Labeling
Signal words are used in combination with colors and/or pictures
or product labels.
Safety−alert symbol
When you see this symbol on the unit and in instructions or manu-
als, be alert to the potential for personal injury.
TABLE OF CONTENTS
SAFETY CONSIDERATIONS 3...............................
INTRODUCTION 4.........................................
CODES AND STANDARDS 4................................
SAFETY 4.................................................
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 (ESD)
PRECAUTIONS PROCEDURE 5.............................
LOCATION 6..............................................
AIR FOR COMBUSTION AND VENTILATION 8.................
INSTALLATION 10..........................................
UPFLOW INSTALLATION 10.................................
DOWNFLOW INSTALLATION 11.............................
HORIZONTAL INSTALLATION 12.............................
FILTER ARRANGEMENT 13.................................
AIR DUCTS 13.............................................
GAS PIPING 16............................................
ELECTRICAL CONNECTIONS 19............................
SERVICE AND MAINTENANCE PROCEDURES 40.............
SEQUENCE OF OPERATION 44.............................
WIRING DIAGRAM 46......................................
TROUBLESHOOTING GUIDE 47.............................
Use of the AHRI Certified TM Mark indic-
ates a manufacturer’s participation in the
program. For verification of certification for
individual products, go to www.ahridirect-
ory.org .
!WARNING
PERSONAL INJURY, AND/OR PROPERTY
DAMAGE HAZARD
Failure to carefully read and follow this warning could
result in equipment malfunction, property damage,
personal injury and/or death.
Installation or repairs made by unqualified persons
could result in equipment malfunction, property
damage, personal injury and/or death.
The information contained in this manual is intended for
use by a qualified service technician familiar with safety
procedures and equipped with proper tools and test
instruments.
Installation must conform with local building codes and
with the Natural Fuel Gas Code (NFCG) NFPA
54/ANSI Z223.1
INSTALLER: Affix these instructions on or adjacent to the furnace.
CONSUMER: Retain these instructions for future reference.

2441 01 1411 04
Specifications are subject to change without notice.
Figure 1 −Dimensional Drawing
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 Product Data 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.....
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)
0451408 14−3/16 (360) 12−9/16 (319) 9−5/16 (237) 12−11/16 (322) 4 (102) 104 (47)
0701716 17−1/2 (445) 15−7/8 (403) 11−9/16 (294) 16 (406) 4 (102) 126 (57)
0902116 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 furnaces require a 5 in. or 6 in. (127 or 152 mm) vent. Use a vent adapter between furnace and vent stack.

3
441 01 1411 04 Specifications are subject to change without notice.
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 accessories when 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 National Fuel
Gas Code (NFGC) NFPA 54/ANSI Z223.1 and the 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
specified 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.
Connect this furnace to an approved vent system only,
as specified in the “Venting” section of these instruc-
tions.
5. 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, as
specified in the “Gas Piping” section.
6. Always install furnace to operate within the furnace’s
intended temperature−rise range with a duct system
which has an external static pressure within the allow-
able 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
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.
See “Air Ducts” section.
8. A gas−fired furnace for installation in a residential gar-
age 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 sec-
tion of these instructions.
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 installation 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 conversion kit is required to
convert furnace for use with propane gas.
11. See Figure 2 for required clearances to combustible
construction.
12. Maintain a 1−in. (25 mm) clearance from combustible
materials to supply air ductwork for a distance of 36
inches (914 mm) horizontally from the furnace. See
NFPA 90B or local code for further requirements.
13. These furnaces SHALL NOT be installed directly on
carpeting, tile, or any other combustible material other
than wood flooring. In downflow installations, factory
accessory floor base MUST be used when installed on
combustible materials and wood flooring. Special base
is not required when this furnace is installed on manu-
facturer’s coil model numbers END4X, ENW4X or coil
casing model number NAEA. See Figure 2 for clear-
ance to combustible construction information.

4441 01 1411 04
Specifications are subject to change without notice.
INTRODUCTION
F8MXN, G8MXN, F8MXL, and G8MXL, 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 used with a night setback thermostat.
Return−air temperature must not exceed 85_F (29_C) db.
Failure to follow these return−air temperature limits may affect
reliability of heat exchangers, motors, and controls. (See
Figure 3).
For accessory installation details, refer to the applicable
instruction literature.
NOTE: Remove all shipping brackets and materials before
operating the furnace.
Figure 2 −Clearances to Combustibles
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: National Fuel Gas Code (NFGC) NFPA
54−2012/ANSI Z223.1−2012 and the Installation
Standards, Warm Air Heating and Air Conditioning
Systems ANSI/NFPA 90B

5
441 01 1411 04 Specifications are subject to change without notice.
Figure 3 −Return Air Temperature
A06745
80_F/27_C
60_F/16_C
General Installation
SCurrent edition of the NFGC and the NFPA 90B. For
copies, contact the National Fire Protection Associ-
ation 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
SNFGC NFPA54/ANSI Z223.1−2012 Section 9.3, Air
for Combustion and Ventilation.
Duct Systems
SAir Conditioning Contractors Association (ACCA)
Manual D, Sheet Metal and Air Conditioning Con-
tractors National Association (SMACNA), or Americ-
an Society of Heating, Refrigeration, and Air Condi-
tioning Engineers (ASHRAE) 2005 Fundamentals
Handbook Chapter 35 or 2004 HVAC Systems and
Equipment 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
SNFGC NFPA54/ANSI Z223.1−2012; chapters 5, 6,
7, and 8 and National Plumbing Codes.
Electrical Connections
SNational Electrical Code (NEC) ANSI/NFPA
70−2011.
Venting
SNFGC NFPA 54 / ANSI Z223.1−2012; 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 discon-
nects may be 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
furnace chassis which is close to the control. Firmly
touch the clean, unpainted, metal surface of the fur-
nace 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 noth-
ing to recharge your body with static electricity (for ex-
ample; DO NOT move or shuffle your feet, do not touch
ungrounded objects, etc.).
4. If you touch ungrounded objects (and recharge your
body with static electricity), firmly touch a clean, un-
painted metal surface of the furnace again before
touching control or wires.
5. Use this procedure for installed and uninstalled (un-
grounded) furnaces.
6. Before removing a new control from its container, dis-
charge your body’s electrostatic charge to ground to
protect the control from damage. If the control is to be
installed 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 be-
fore touching ungrounded objects.
7. An ESD service kit (available from commercial
sources) may also be used to prevent ESD damage.

6441 01 1411 04
Specifications are subject to change without notice.
Figure 4 −Multipoise Orientations
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
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 Figure 4.
This furnace must:
Sbe installed so the electrical components are protec-
ted 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 model numbers END4X,
ENW4X or coil casing model number NAEA when
installed on combustible materials or wood flooring
(refer to SAFETY CONSIDERATIONS).
Sbe located as close to the chimney or vent and at-
tached 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 combust-
ible label.
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
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
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

7
441 01 1411 04 Specifications are subject to change without notice.
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.
Figure 5 −Installation in a Garage
18−IN. (457.2 mm)
MINIMUM TO BURNERS
A93044
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

8441 01 1411 04
Specifications are subject to change without notice.
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
ACH = Air Changes/Hour
NP = Not Permitted
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 Figure 6)
!WARNING
Figure 6 −Prohibit Installation on Back
A02054
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 NFGC
NFPA54/ANSI Z223.1−2012, 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 per-
manent horizontal or vertical duct(s) or opening(s) dir-
ectly communicating with the outdoors or spaces that
freely communicate with the outdoors.
2. Figure 7 illustrates how to provide TWO OUTDOOR
OPENINGS, one inlet and one outlet combustion and
ventilation air opening, to the outdoors.
a. 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.
b. Size openings and ducts per Figure 7 and Table 2.

9
441 01 1411 04 Specifications are subject to change without notice.
c. 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 Figure 7
and Table 2.
d. 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 Figure 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 connect-
ors 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.
Figure 7 −Air for Combustion, Ventilation, and Dilution
from Outdoors
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
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
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 ap-
pliances 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 National Fuel Gas
Code ANSI Z223.1−2012/NFPA 54−2012, 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
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
ceiling and the second opening shall commence with-

10 441 01 1411 04
Specifications are subject to change without notice.
in 12” (300 mm) of the floor. The minimum dimension
of air openings shall be at least 3 in. (80 mm). (See
Figure 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 permanent 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.
Figure 8 −Air for Combustion, Ventilation, and Dilution
from Indoors
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 LEAST 3 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
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 outdoors 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 Meth-
od, infiltration should be adequate to provide air for
combustion, permanent ventilation and dilution of flue
gases. However, in buildings with unusually tight con-
struction, additional air MUST be provided using the
methods described 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
continuous, sealed vapor barrier. Openings are gas-
keted 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
Outdoor Combustion Air Method mentioned previ-
ously 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.
Figure 9 −Removing Bottom Closure Panel
BOTTOM
FILLER PANEL
BOTTOM
CLOSURE
PANEL
b. Outdoor opening size reduction Factor is 1 minus the
Ratio in a. above.
c. Minimum size of Outdoor openings shall be the size
required in Outdoor Combustion Air Method above
multiplied by reduction Factor in b. above. The minim-
um dimension 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
bottom filler panel. (See Figure 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
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 Figure 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

11
441 01 1411 04 Specifications are subject to change without notice.
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 Figure 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. (In-
stall flat washer if desired.)
Figure 10 −Leveling Legs
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
4. Adjust outside nut to provide desired height, and tight-
en 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
two accessories are used:
SDownflow combustible floor subbase
SCoil model 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 Figure 11.
3. Construct plenum to dimensions specified in Table 4
and Figure 11.
4. If downflow subbase is used, install as shown in
Figure 12. If coil model numbers END4X, ENW4X or
coil casing model number NAEA are used, install as
shown in Figure 13.
NOTE: It is recommended 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 casing. 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 Figure 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
bottom filler panel. (See Figure 9)
2. Rotate bottom filler panel downward to release holding
tabs.
3. Remove bottom closure panel.
4. Reinstall bottom filler panel and screws
Figure 11 −Floor and Plenum Opening Dimensions
C
A
B D
A96283
Figure 12 −Furnace, Plenum, and Subbase Installed
on a Combustible Floor
DOWNFLOW
SUBBASE
SHEET METAL
PLENUM
FLOOR
OPENING
FURNACE
(OR COIL CASING
WHEN USED)
COMBUSTIBLE
FLOORING
A96285
Figure 13 −Furnace, Plenum, and Coil or
Coil Casing Installed on a Combustible Floor
APPROVED
COIL ASSEMBLY
OR
COIL BOX
FURNACE
SHEET METAL
PLENUM
FLOOR
OPENING
COMBUSTIBLE
FLOORING
A08556

12 441 01 1411 04
Specifications are subject to change without notice.
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 Flooring
(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 Flooring
(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 Flooring
(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 Flooring
(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)
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
Figure 15 and Figure 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 Figure 15 and Figure 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 Figure 2 and Figure 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 Figure 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
bottom filler panel. (See Figure 9)

13
441 01 1411 04 Specifications are subject to change without notice.
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 Figure 20).
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.
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
Figure 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 Figure 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 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.

14 441 01 1411 04
Specifications are subject to change without notice.
Figure 14 −Duct Flanges
UPFLOW DOWNFLOW HORIZONTAL
YES
NO NO
YES
YES
YES
NO
120°
MIN
YES 120°
MIN
YES
120°
MIN
90°90°
A02020
Figure 15 −Horizontal Unit Suspension
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

15
441 01 1411 04 Specifications are subject to change without notice.
Figure 16 −Horizontal Suspension with Straps
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
Figure 17 −Typical Attic Installation
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
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. Refer to the following instructions.
!WARNING
Downflow Furnaces
The return−air duct must be connected to return−air opening
(bottom inlet) as shown in Figure 21. DO NOT cut into casing
sides (left or right). Side opening is permitted for only upflow
and most horizontal furnaces. (See Figure 21) 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

16 441 01 1411 04
Specifications are subject to change without notice.
furnace casing as shown in Figure 20 and Figure 22. Bypass
humidifier may be attached into unused return air side of the
furnace casing. (See Figure 20 and Figure 22)
Not all horizontal furnaces are approved for side return air
connections. (See Figure 22)
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. A fire or explosion may result causing
property damage, personal injury or loss of life.
!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 ap-
proved 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 Figure 48)
Some installations require gas entry on right side of furnace
(as viewed in upflow). (See Figure 18)
Install a sediment trap in riser leading to furnace as shown in
Figure 19. 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.
Figure 18 −Burner and Manifold
2” (51mm)
Street Elbow
A08551
Figure 19 −Typical Gas Pipe Arrangement
UNION
SEDIMENT
TRAP
MANUAL
SHUTOFF
VALVE
(REQUIRED)
GAS
SUPPLY
A02035

17
441 01 1411 04 Specifications are subject to change without notice.
Table 5 – Air Delivery −CFM (With Filter)*
UNIT SIZE COLOR SPEED EXTERNAL STATIC PRESSURE (in. w.c.)
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0451408
Gray 5 1185 1145 1115 1075 1035 980 905 820 720 580
Yellow 4 920 880 835 800 755 720 680 645 605 540
Blue 3 735 685 625 585 530 490 435 395 345 295
Orange 2 820 765 725 670 630 580 545 490 455 405
Red 1 650 595 535 490 430 390 330 280 235 --
0701716
Gray 5 1625 1585 1535 1495 1460 1415 1365 1295 1220 1125
Yellow 4 1405 1360 1320 1280 1240 1195 1155 1115 1070 1030
Blue 3 1240 1200 1155 1110 1065 1020 975 935 895 850
Orange 2 1190 1140 1095 1050 1000 955 915 870 830 790
Red 1 1035 985 930 885 835 785 745 695 650 600
0902116
Gray 5 1845 1800 1755 1710 1665 1595 1500 1400 1275 1105
Yellow 4 1590 1545 1500 1455 1410 1365 1315 1270 1180 1000
Blue 3 1365 1320 1270 1215 1170 1125 1070 1025 955 900
Orange 2 1225 1160 1110 1060 1010 950 895 830 770 710
Red 1 1100 1030 960 875 805 730 645 570 505 425
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 2295 2240 2185 2125 2070 2005 1925 1805 1670 1545
Yellow 4 1725 1660 1605 1545 1460 1395 1340 1285 1230 1170
Blue 3 1910 1865 1800 1745 1685 1610 1545 1485 1435 1380
Orange 2 1630 1575 1510 1435 1365 1300 1245 1185 1130 1065
Red 1 1430 1355 1285 1200 1125 1075 1015 945 855 800
*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.
−− Indicates unstable operating conditions.
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 ANSI Z223−2012/NFPA 54−2012.
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.

18 441 01 1411 04
Specifications are subject to change without notice.
Figure 20 −Upflow Return Air Configurations and Restrictions
5TONS AND
GREATER *
*2000 CFM AND GREATER AT .6 ESP HI COOLING SPEED
Figure 21 −Downflow Return Air Configurations and Restrictions
5TONS AND
GREATER *
*2000 CFM AND GREATER AT .6 ESP HI COOLING SPEED
Figure 22 −Horizontal Return Air Configurations and Restrictions
5TONS AND
GREATER *
*2000 CFM AND GREATER AT .6 ESP HI COOLING SPEED

19
441 01 1411 04 Specifications are subject to change without notice.
Table 7 – Electrical Data
FURNACE
MODEL
VOLTS-
HERTZ-
PHASE
OPERATING
VOLTAGE*
(VOLTS)
MAX UNIT
(AMPS)
UNIT
AMPACITY#
(AMPS)
MAX WIRE
LENGTH}
FT. (M)
MAX FUSE/
CKT BKR{
(AMPS)
MIN WIRE
GAGE
MAX MIN
0451408A 115-60-1 127 104 8.1 10.9 34 (10) 15 14
0701716A 115-60-1 127 104 10.8 14.2 26 (8) 15 14
0902116A 115-60-1 127 104 11.4 14.8 25 (7) 15 14
1102120A 115-60-1 127 104 14.2 18.2 31 (9) 20 12
1352420A 115-60-1 127 104 14.2 18.2 31 (9) 20 12
* 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 1 way along wire path between unit and service panel for maximum 2 percent voltage drop.
ELECTRICAL CONNECTIONS
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 Figure 26 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 NEC ANSI/NFPA
70−2011 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 electrical specifications.
Make all electrical connections in accordance with National
Electrical Code (NEC) ANSI/NFPA 70−2011 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 electrical disconnect 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.
NOTE: The J−Box cover need not be removed from the
J−Box in order to move the J−Box. Do NOT remove green
ground screw inside J−Box.
2. Cut wire tie on loop in furnace wires attached to J−box.
3. Move J−Box to desired location.
4. Fasten J−Box to casing with two screws removed in
Step 1.
5. Route J−Box wires within furnace away from sharp
edges, rotating parts and hot surfaces.

20 441 01 1411 04
Specifications are subject to change without notice.
ELECTRICAL CONNECTION TO J−BOX
Electrical Box on Furnace Casing Side
FIRE OR ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury, death, or property damage.
If field−supplied manual disconnect switch is to be
mounted on furnace casing side, select a location
where a drill or fastener cannot damage electrical or
gas components.
!WARNING
1. Select and remove a hole knockout in the casing
where the electrical box is to be installed.
NOTE: Check that duct on side of furnace will not interfere
with installed electrical box.
2. Remove the desired electrical box hole knockout and
position the hole in the electrical box over the hole in
the furnace casing.
3. Fasten the electrical box to casing by driving two field
supplied screws from inside electrical box into casing
steel.
4. Remove and save two screws holding J−Box.
5. Pull furnace power wires out of 1/2−in. (12 mm) diamet-
er hole in J−Box. Do not loosen wires from strain−relief
wire−tie on outside of J−Box.
6. Route furnace power wires through holes in casing and
electrical box and into electrical box.
7. Pull field power wires into electrical box.
8. Remove cover from furnace J−Box.
9. Route field ground wire through holes in electrical box
and casing, and into furnace J−Box.
10. Reattach furnace J−Box to furnace casing with screws
removed in Step 4.
11. Secure field ground wire to J−Box green ground screw.
12. Complete electrical box wiring and installation. Connect
line voltage leads as shown in Figure 26. Use best
practices (NEC in U.S. for wire bushings, strain relief,
etc.
13. Reinstall cover to J−Box. Do not pinch wires between
cover and bracket.
Figure 23 −Relocating J−Box
FACTORY
INSTALLED
LOCATION ALTERNATE
FIELD
LOCATION
Figure 24 −Field−Supplied Electrical Box on Furnace
Casing
A10141
POWER CORD INSTALLATION IN FURNACE J−BOX
NOTE: Power cords must be able to handle the electrical
requirements listed in Table 7. Refer to power cord
manufacturer’s listings.
1. Remove cover from J−Box.
2. Route listed power cord through 7/8−in. (22 mm) dia-
meter hole in J−Box.
3. Secure power cord to J−Box bracket with a strain relief
bushing or a connector approved for the type of cord
used.
4. Secure field ground wire to green ground screw on
J−Box bracket.
5. Connect line voltage leads as shown in Figure 26.
6. Reinstall cover to J−Box. Do not pinch wires between
cover and bracket.
BX CABLE INSTALLATION IN FURNACE J−BOX
1. Remove cover from J−Box.
2. Route BX cable into 7/8−inch diameter hole in J−Box.
3. Secure BX cable to J−Box bracket with connectors ap-
proved for the type of cable used.
4. Secure field ground wire to green ground screw on
J−Box bracket.
5. Connect line voltage leads as shown in Figure 26 .
6. Reinstall cover to J−Box. Do not pinch wires between
cover and bracket.
24−V WIRING
Make field 24−v connections at the 24−v terminal strip. (See
Figure 24) Connect terminal Y/Y2 as shown in Figure 25 for
proper cooling operation. Use only AWG No. 18,
color−coded, copper thermostat wire.
The 24−v circuit contains an automotive−type, 3−amp. fuse
located on the control. Any direct shorts during installation,
service, or maintenance could cause this fuse to blow. If fuse
replacement is required, use ONLY a 3−amp. fuse of identical
size.