International comfort products F8MVL 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 2122 01 5/2/2016
INSTALLATION INSTRUCTIONS
80% Two−Stage, Variable Speed
Category I, Gas Furnace
F8MVL & G8MVL 'B2' Series
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..............................................
LOCATION 5.............................................
MINIMUM FREE AREA REQUIRED 7........................
AIR FOR COMBUSTION AND VENTILATION 8................
INSTALLATION 10..........................................
OPENING DIMENSIONS 12.................................
AIR DUCTS 13.............................................
GAS PIPING 17............................................
ELECTRICAL CONNECTIONS 18............................
24−V WIRING 20...........................................
ACCESSORIES 20.........................................
VENTING 20..............................................
CHIMNEY INSPECTION CHART 25...........................
START−UP, ADJUSTMENT, AND SAFETY CHECK 31...........
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 .
!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, and National standards of Canada
CAN/CSA−B149.1 and .2 Natural Gas and Propane
Installation Codes.
INSTALLER: Affix these instructions on or adjacent to the furnace.
CONSUMER: Retain these instructions for future reference.

2441 01 2122 01
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 −In. (mm)
FURNACE SIZE
A B C E VENT
CABINET
WIDTH
IN. (mm)
OUTLET
WIDTH
IN. (mm)
TOP AND BOTTOM
FLUE COLLAR
IN. (mm)
BOTTOM INLET
WIDTH
IN. (mm)
VENT
CONNECTION
SIZE
IN. (mm)
SHIP WT.
LB (KG)
0451412B 14−3/16 (360) 12−9/16 (319) 9−5/16 (237) 12−11/16 (322) 4 (102) 107 (49)
0701716B 17−1/2 (445) 15−7/8 (403) 11−9/16 (294) 16 (406) 4 (102) 126 (57)
0902116B 21 (533) 19−3/8 (492) 13−5/16 (338) 19−1/2 (495) 4 (102) 140 (64)
1102122B 21 (533) 19−3/8 (492) 13−5/16 (338) 19−1/2 (495) 4 (102) 152 (69)
1352422B 24−1/2 (622) 22−7/8 (581) 15−1/16 (383) 23 (584) 4 (102)* 163 (74)
* 135 size furnace require a 5 in. or 6 in. (127 or 152 mm) vent. Use a vent adapter between furnace and vent stack.

3441 01 2122 01 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, personal injury, death, or property damage.
Improper installation, adjustment, alteration, service,
maintenance, or use can 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
Failure to follow this caution may result in unit
component damage.
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
!
Installing and servicing heating equipment can be hazardous
due to gas and electrical components. Only trained and
qualified personnel should install, repair, or service
heating equipment. Untrained personnel can perform basic
maintenance functions such as cleaning and replacing air
filters. All other operations must be performed by trained
service personnel. When working on heating equipment,
observe precautions in literature, on tags, and on labels
attached to or shipped with furnace and other safety
precautions that may apply.
These instructions cover minimum requirements and conform
to existing national standards and safety codes. In some
instances, these instructions exceed certain local codes and
ordinances, especially those that may not have kept up with
changing residential construction practices. We require these
instructions as a minimum for a safe installation.
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
!
Wear safety glasses, protective clothing and work gloves.
Have fire extinguisher available during start−up and
adjustment procedures and service calls.
This is the safety−alert symbol . When you see this symbol
on the furnace 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 a hazard which could result in personal injury or
death. CAUTION is used to identify hazards 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.
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 fur-
nace space as specified in “Air for Combustion and Ventil-
ation” 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 inten-
ded 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 in-
stallation in alcoves, attics, basements, closets, utility
rooms, crawlspaces, and garages. The furnace is factory−
shipped for use with natural gas. A CSA (A.G.A. and
C.G.A.) listed accessory gas conversion kit is required to
convert furnace for use with propane gas.
11. See Figure 2 for required clearances to combustible con-
struction.
12. Maintain a 1−in. (25 mm) clearance from combustible ma-
terials 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.
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 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 manufacturer’s coil model
numbers END4X, ENW4X or coil casing model number
NAEA. See Figure 2 for clearance to combustible con-
struction information.

4441 01 2122 01
Specifications are subject to change without notice.
Figure 2 −Clearances to Combustibles
INTRODUCTION
F8MVL & G8MVL 4−way multipoise Category I fan−assisted
furnace is CSA (formerly A.G.A. and C.G.A.) 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.
Figure 3 −Return Air Temperature
A06745
80F/27C
60F/16C
This furnace is designed for minimum continuous return−air
temperature of 60F (15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 80F
(27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.
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
NFPA 54/ANSI Z223.1−2012 and the Installation Standards,
Warm Air Heating and Air Conditioning Systems ANSI/NFPA
90B .

5441 01 2122 01 Specifications are subject to change without notice.
General Installation
Current 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
Section 9.3 NFPA 54/ANSI Z223.1−2012 , Air for Combustion
and Ventilation .
Duct Systems
Air Conditioning Contractors Association (ACCA) Manual D,
Sheet Metal and Air Conditioning Contractors National
Association (SMACNA), or American Society of Heating,
Refrigeration, and Air Conditioning Engineers (ASHRAE) 2001
Fundamentals Handbook Chapter 34 or 2000 HVAC Systems
and Equipment Handbook Chapters 9 and 16.
Acoustical Lining and Fibrous Glass Duct
Current 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
NFPA 54/ANSI Z223.1−2012 ; chapters 5, 6, and 7 and
National Plumbing Codes .
Electrical Connections
National Electrical Code (NEC) NFPA 70−2011.
Venting
NFPA 54/ANSI Z223.1−2012; chapters 12 and 13.
ELECTROSTATIC DISCHARGE (ESD)
PRECAUTIONS PROCEDURE
FURNACE RELIABILITY HAZARD
Failure to follow this caution may result in unit component
damage.
Electrostatic discharge can affect electronic components.
Take precautions 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
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 fur-
nace chassis which is close to the control. Tools held in a
person’s hand during grounding will be satisfactorily dis-
charged.
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 ungrounded
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 installed
in a furnace, follow items 1 through 4 before bringing the
control or yourself in contact with the furnace. Put all used
and new controls into containers before touching ungroun-
ded objects.
7. An ESD service kit (available from commercial sources)
may also be used to prevent ESD damage.
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.
NOTE: For high−altitude installations, the high−altitude
conversion kit MUST be installed at or above 5500 ft. (1676 M)
above sea level. Obtain high−altitude conversion kit from your
area authorized distributor.
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

6441 01 2122 01
Specifications are subject to change without notice.
This furnace must:
be installed so the electrical components are protec-
ted from water.
not 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).
be located close to the chimney or vent and attached
to an air distribution system. Refer to Air Ducts sec-
tion.
be provided ample space for servicing and cleaning.
Always comply with minimum fire protection clear-
ances shown on the furnace clearance to combust-
ible construction label.
The following types of furnace installations may require
OUTDOOR AIR for combustion due to chemical exposures:
Commercial buildings
Buildings with indoor pools
Laundry rooms
Hobby or craft rooms, and
Chemical 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:
Permanent wave solutions
Chlorinated waxes and cleaners
Chlorine based swimming pool chemicals
Water softening chemicals
De−icing salts or chemicals
Carbon tetrachloride
Halogen type refrigerants
Cleaning solvents (such as perchloroethylene)
Printing inks, paint removers, varnishes, etc.
Hydrochloric acid
Cements and glues
Antistatic fabric softeners for clothes dryers
Masonry acid washing materials
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.
FIRE, INJURY OR DEATH 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
in. (457 mm) 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 NFPA 54/ANSI Z223.1−2012 . (See
Figure 5)
!WARNING
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.
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
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.

7441 01 2122 01 Specifications are subject to change without notice.
PERSONAL INJURY AND/OR PROPERTY
DAMAGE HAZARD
Improper use or installation of this furnace may result in
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
!Figure 6 −Prohibit Installation on Back
A02054
Table 2 – Minimum Free Area Required for Each Combustion Air opening of Duct to Outdoors
FURNACE
INPUT
(BTUH)
TWO HORIZONTAL DUCTS SINGLE DUCT OR OPENING TWO OPENINGS OR VERTICAL DUCTS
(1 SQ. IN./2,000 BTUH) (1,100 SQ. MM/KW) (1 SQ. IN./3,000 BTUH) (734 SQ. MM/KW) (1 SQ. IN./4,000 BTUH) (550 SQ. MM/KW)
Free Area of Opening
and Duct
Sq. In. (Sq. mm)
Round Duct
Dia.
In. (mm)
Free Area of Opening
and Duct
Sq. In. (Sq. mm)
Round Duct
Dia.
In. (mm)
Free Area of Opening
and Duct
Sq. In. (Sq. mm)
Round Duct
Dia.
In. (mm)
44,000 22 (14194) 6 (152) 14.7 (9484) 5 (127) 11 (7096) 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 (42580) 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 2122 01
Specifications are subject to change without notice.
Table 3 – Minimum Space Volumes for 100% Combustion, Ventilation, and Dilution from Indoors
OTHER THAN FAN‐ASSISTED TOTAL
(1,000'S BTUH GAS INPUT RATE)
FAN‐ASSISTED TOTAL
(1,000'S BTUH GAS INPUT RATE)
ACH 30 40 50 44 66 88 110 132
Space Volume Ft3(M3)
0.60 1,050 (29.7) 1,400 (39.6) 1,750 (49.5) 1,100 (31.1) 1,650 (46.7) 2,200 (62.2) 2,750 (77.8) 3,300 (93.4)
0.50 1,260 (35.6) 1,680 (47.5) 2,100 (59.4) 1,320 (37.3) 1,980 (56.0) 2,640 (74.7) 3,300 (93.4) 3,960 (112.1)
0.40 1,575 (44.5) 2,100 (59.4) 2,625 (74.3) 1,650 (46.7) 2,475 (70.0) 3,300 (93.4) 4,125 (116.8) 4,950 (140.1)
0.30 2,100 (59.4) 2,800 (79.2) 3,500 (99.1) 2,200 (62.2) 3,300 (93.4) 4,400 (124.5) 5,500 (155.7) 6,600 (186.8)
0.20 3,150 (89.1) 4,200 (118.9) 5,250 (148.6) 3,300 (93.4) 4,950 (140.1) 6,600 (186.8) 8,250 (233.6) 9,900 (280.3)
0.10 6,300 (178.3) 8,400 (237.8) 10,500 (297.3) 6,600 (186.8) 9,900 (280.3) 13,200 (373.7) 16,500 (467.2) 19,800 (560.6)
0.00 NP NP NP NP NP NP NP NP
NP = Not Permitted
AIR FOR COMBUSTION AND
VENTILATION
Provisions for adequate combustion, ventilation, and dilution
air must be provided in accordance with:
U.S. Installations: Section 9.3 of the NFPA 54/ANSI
Z223.1−2012 , Air for Combustion and Ventilation
and applicable provisions of the local building codes.
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
!
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 the Carbon Monoxide Poisoning Hazard
warning in the venting section of these instructions to
determine if an adequate amount of make−up air is
available.
!WARNING
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.
Spaces having less than 50 cubic feet per 1,000 Btuh
require the OUTDOOR COMBUSTION AIR METH-
OD.
Figure 7 −Air for Combustion, Ventilation, and Dilution
for 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
Spaces having at least 50 cubic feet per 1,000 Btuh
may use the INDOOR COMBUSTION AIR, STAND-
ARD or KNOWN AIR INFILTRATION METHOD.
Outdoor Combustion Air Method
1. Provide the space with sufficient air for proper combustion,
ventilation, and dilution of flue gases using permanent hori-
zontal or vertical duct(s) or opening(s) directly communic-
ating 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 vent-
ilation 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.

9441 01 2122 01 Specifications are subject to change without notice.
c. TWO HORIZONTAL DUCTS require 1 sq. in. (645
sq. mm) 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
sq. in. (645 sq. mm) 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 sq. in. (645 sq. mm) of free area per 3,000 Btuh
(734 mm2/kW) for combined input of all gas appli-
ances in the space per Table 2 and
b. Not less than the sum of the areas of all vent con-
nectors in the space.
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 sq in. (64516 sq. mm)with minimum dimensions of 3
in. (76 mm)
† Minimum of 3 in. (76 mm) when type‐B1 vent is used.
A03175
The opening shall commence within 12 in. (300 mm) of the
ceiling. Appliances in the space shall have clearances of at
least 1 in. (25 mm) from the sides and back and 6 in. (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 personal
injury or death.
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 appli-
ances 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
A04003
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 open-
ing 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
in. (300 mm) of the ceiling and the second opening
shall commence within 12 in. (300 mm) of the floor.
The minimum dimension of air openings shall be at
least 3 in. (80 mm). (See Figure 8)

10 441 01 2122 01
Specifications are subject to change without notice.
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 appli-
ances.
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, ad-
ditional air MUST be provided using the methods de-
scribed in the Outdoor Combustion Air Method section.
4. 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 in-
clude 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 di-
vided by required volume for Indoor Combustion
Air Method below.
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 min-
imum 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 2 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.
Figure 9 −Removing Bottom Closure Panel
BOTTOM
FILLER PANEL
BOTTOM
CLOSURE
PANEL
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
closure panel to install leveling legs. To remove bottom closure
panel, see Item 1 in Bottom Return Air Inlet section in Step 1
above.
To install leveling legs:
1. Position furnace on its back. Locate and drill a hole in each
bottom corner of furnace. (See Figure 10)
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
2. For each leg, install nut on bolt and then install bolt with
nut in hole. (Install flat washer if desired.)
3. Install another nut on other side of furnace base. (Install
flat washer if desired.)
4. Adjust outside nut to provide desired height, and tighten
inside nut to secure arrangement.

11441 01 2122 01 Specifications are subject to change without notice.
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:
Downflow combustible floor subbase
Coil model numbers END4X or ENW4X
Coil 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 2 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.
HORIZONTAL INSTALLATION
FIRE, EXPLOSION, AND CARBON MONOXIDE
POISONING HAZARD
Failure to follow this warning could result in personal
injury, death, 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
crawlspace 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 in. screws into the side and 2 #8 x in. 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 3 and Figure 17) For
furnaces with 1−in. (25 mm) clearance requirement on side,
set furnace on non−combustible blocks, bricks or angle iron.
For crawlspace 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.
Figure 11 −Floor and Plenum Opening Dimensions
C
A
B D
A96283
Roll−Out Protection
Provide a minimum 17−3/4−in. X 22−in. (451 X 559 mm) piece
of sheet metal for flame roll−out protection in front of burner
area for furnaces closer than 12−in. (305 mm) above the
combustible deck or suspended furnaces closer than 12−in.
(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)
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 side return air inlet(s) are used without a bottom
return air inlet.
Not all horizontal furnaces are approved for side return air
connections (See Figure 20)

12 441 01 2122 01
Specifications are subject to change without notice.
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 In-
stalled on a Combustible Floor
APPROVED
COIL ASSEMBLY
OR
COIL BOX
FURNACE
SHEET METAL
PLENUM
FLOOR
OPENING
COMBUSTIBLE
FLOORING
A08556
Table 4 – Opening Dimensions −In. (mm)
FURNACE
CASING
WIDTH
IN. (mm)
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
(319)
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 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)

13441 01 2122 01 Specifications are subject to change without notice.
Filter Arrangement
CARBON MONOXIDE 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 rack 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
10 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 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 air stream. 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 to allow the evaporator coil to hang on the
flange temporarily while the remaining attachment and sealing
of the coil are performed.
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

14 441 01 2122 01
Specifications are subject to change without notice.
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
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

15441 01 2122 01 Specifications are subject to change without notice.
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
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.
Figure 18 −Upflow Return Air Configurations and Restrictions
5TONS AND
GREATER *
*2000 CFM AND GREATER AT .6 ESP HI COOLING SPEED
UPFLOW RETURN AIR CONFIGURATIONS AND RESTRICTIONS

16 441 01 2122 01
Specifications are subject to change without notice.
Figure 19 −Downflow Return Air Configurations and Restrictions
5TONS AND
GREATER *
*2000 CFM AND GREATER AT .6 ESP HI COOLING SPEED
DOWNFLOW RETURN AIR CONFIGURATIONS AND RESTRICTIONS
Figure 20 −Horizontal Return Air Configurations and Restrictions
5TONS AND
GREATER *
*2000 CFM AND GREATER AT .6 ESP HI COOLING SPEED
HORIZONTAL RETURN AIR CONFIGURATIONS AND RESTRICTIONS

17441 01 2122 01 Specifications are subject to change without notice.
Return Air Connections
FIRE HAZARD
A 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 Figure 1. DO NOT cut into casing
sides (left or right). Side opening is permitted for only upflow
and certain horizontal furnaces. Bypass humidifier
connections should be made at ductwork or coil casing sides
exterior to furnace. (See Figure 19)
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 Figure 1. Bypass humidifier may be
attached into unused return air side of the furnace casing.
(See Figure 18 and Figure 20) Not all horizontal furnace
models are approved for side return air connections. (See
Figure 20)
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
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Gas valve inlet and/or inlet pipe must remain capped
until gas supply line is permanently installed to protect
the valve from moisture and debris. Also, install a
sediment trap in the gas supply piping at the inlet to
the gas valve.
!WARNING
Gas piping must be installed in accordance with national and
local codes. Refer to current edition of NFGC in the U.S.
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 in. (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 5 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. (1.8 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.
Table 5 – Maximum Capacity of Pipe*
NOMINAL
IRON
PIPE SIZE
IN. (MM)
INTERNAL
DIA.
IN. (MM)
LENGTH OF PIPE −FT (M)
10
(3.0)
20
(6.0)
30
(9.1)
40
(12.1)
50
(15.2)
1/2 (12.7) 0.622 (158) 175 120 97 82 73
3/4 (19.0) 0.824 (20.9) 360 250 200 170 151
1 ( 25.4) 1.049 (26.6) 680 465 375 320 285
1-1/4
(31.8) 1.380 (35.0) 1400 950 770 660 580
1-1/2
(38.1) 1.610 (40.9) 2100 1460 1180 990 900
* Cubic ft of 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: Table 6
and 9.2 NFGC.
FIRE OR EXPLOSION HAZARD
A 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
FURNACE DAMAGE HAZARD
Failure to follow this caution may result in furnace
damage.
Connect gas pipe to furnace using a backup wrench
to avoid damaging gas controls and burner
misalignment.
CAUTION
!
An accessible manual equipment shutoff valve MUST be
installed external to furnace casing and within 6 ft. (1.8 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.

18 441 01 2122 01
Specifications are subject to change without notice.
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 49)
Some installations require gas entry on right side of furnace
(as viewed in upflow). (See Figure 21)
Install a sediment trap in riser leading to furnace as shown in
Figure 22. 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.
Piping should be pressure and leak tested in accordance with
the current addition of the 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.
Figure 21 −Burner and Manifold
2” (51mm)
Street Elbow
A08551
Figure 22 −Typical Gas Pipe Arrangement
UNION
SEDIMENT
TRAP
MANUAL
SHUTOFF
VALVE
(REQUIRED)
GAS
SUPPLY
A02035
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
disconnecting. 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 Figure 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
(33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 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 HAZARD
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 6 for
equipment electrical specifications.
U.S. Installations: Make all electrical connections in
accordance with National Electrical Code (NEC) NFPA
70−2011 and any local codes or ordinances that might apply.

19441 01 2122 01 Specifications are subject to change without notice.
Table 6 – Electrical Data
FURNACE SIZE
VOLTS−
HERTZ−
PHASE
OPERATING
VOLTAGE RANGE MAX. UNIT
AMPS
UNIT
AMPACITY
#
MAX. WIRE LENGTH
−FT (M)}
MAX. FUSE OR
CKT BKR AMPS {MAX. WIRE
SIZE AWGMax. Min.
0451412B 115-60-1 127 104 8.0 10.8 34.0 (10.4) 15.0 14
0701716B 115-60-1 127 104 11.3 15.0 24.0 (7.3) 15.0 14
0902116B 115-60-1 127 104 10.2 13.4 27.0 (8.2) 15.0 14
1102122B 115-60-1 127 104 13.0 16.8 34.0 (10.4) 20.0 12
1352422B 115-60-1 127 104 13.0 16.8 34.0 (10.4) 20.0 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 furnace and service panel for maximum 2 percent voltage drop.
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 6 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
rapidly 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. (See
Figure 23)
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. (See Figure 23)
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 the two screws removed in
Step 1.
5. Route J−Box wires within furnace away from sharp edges,
rotating parts and hot surfaces.
Electrical Connection to J−Box
Electrical Box on Furnace Casing Side (See Figure 24)
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 posi-
tion the hole in the electrical box over the hole in the fur-
nace casing.
3. Fasten the electrical box to casing by driving two field−sup-
plied screws from inside electrical box into casing steel.
Figure 23 −Relocating J−Box
FACTORY
INSTALLED
LOCATION ALTERNATE
FIELD
LOCATION
4. Remove and save two screws holding J−Box. (See
Figure 23)
5. Pull furnace power wires out of 1/2−in. (12 mm) diameter
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 re-
moved in Step 4.
11. Secure field ground wire to J−Box green ground screw.

20 441 01 2122 01
Specifications are subject to change without notice.
Figure 24 −Field−Supplied Electrical Box on Furnace
Casing
12. Complete electrical box wiring and installation. Connect
line voltage leads as shown in Figure 24. Use best prac-
tices (NEC in U.S. for wire bushings, strain relief, etc.
13. Reinstall cover to J−Box. Do not pinch wires between cov-
er and bracket.
Power Cord Installation in Furnace J−Box
NOTE: Power cords must be able to handle the electrical
requirements listed in Table 5. Refer to power cord
manufacturer’s listings.
1. Remove cover from J−Box.
2. Route listed power cord through 7/8−in. (22 mm) diameter
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 25.
6. Reinstall cover to J−Box. Do not pinch wires between cov-
er and bracket.
BX Cable Installation in Furnace J−Box
1. Remove cover from J−Box.
2. Route BX cable into 7/8−in. (22 mm) 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 25.
6. Reinstall cover to J−Box. Do not pinch wires between cov-
er and bracket.
24−V Wiring
Make field 24−v connections at the 24−v terminal strip. (See
Figure 25 −Figure 33) Connect terminal Y/Y2 as shown in
Figure 27 −Figure 33 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.
ACCESSORIES
1. Electronic Air Cleaner (EAC)
Connect an accessory Electronic Air Cleaner (if used) us-
ing 1/4−in female quick connect terminals to the two male
1/4−in quick−connect terminals on the control board
marked EAC−1 and EAC−2. The terminals are rated for
115VAC, 1.0 amps maximum and are energized during
blower motor operation. (See Figure 26)
2. Humidifier (HUM)
Connect an accessory 24 VAC, 0.5 amp. maximum humid-
ifier (if used) to the 1/4−in male quick−connect HUM ter-
minal and COM−24V screw terminal on the control board
thermostat strip. The HUM terminal is energized when
blower is energized in heating. (See Figure 26)
NOTE: DO NOT connect furnace control HUM terminal to H
terminal on humidity sensing thermostat, or similar device. See
the humidity sensing thermostat, instructions for proper
connection.
VENTING
The furnace shall be connected to a listed factory built
chimney or vent, or a clay−tile lined masonry or concrete
chimney. Venting into an unlined masonry chimney or
concrete chimney is prohibited.
When an existing Category I furnace is removed or replaced,
the original venting system, may no longer be sized to properly
vent the attached appliances. An improperly sized Category I
venting system could cause the formation of condensate in the
furnace and vent, leakage of condensate and combustion
products, and spillage of combustion products into the living
space.