International comfort products NAHB00101MH User manual

443 06 4003 00 8/07/13
Specifications subject to change without notice.
NAHB00101MH
INSTALLATION INSTRUCTIONS
MANUFACTURED (MOBILE) HOME KIT
Condensing Gas Furnace Conversion
CERTIFIED
NOTE: Read the entire instruction manual before starting the
installation.
SAFETY CONSIDERATION
!WARNING
FIRE, EXPLOSION, ELECTRICAL SHOCK, AND CARBON
MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury or
death.
This conversion kit shall be installed by a qualified service
agency in accordance with the manufacturer’s instructions
and all applicable codes and requirements of the authority
having jurisdiction. If the information in these instructions is
not followed exactly, a fire, explosion, or production of carbon
monoxide could result causing property damage, personal
injury, or loss of life. The qualified service agency is
responsible for the proper installation of this furnace with this
kit. The installation is not proper and complete until the
operation of the converted appliance is checked as specified
in the manufacturer’s instructions supplied with the kit.
!AVERTISSEMENT
LE FEU, L’EXPLOSION, CHOC ELECTRIQUE, ET
MONOXYDE DE CARBONE EMPOISONNER
Cette trousse de conversion doit être installée par un servie
d’entretien qualifié, selon les instructions du fabricant et selon
toutes les exigences et tous les codes pertinents de l’autorité
compétente. Assurezvous de bien suivre les instructions
dans cette notice pour réduire au minimum le risque
d’incendie, d’explosion ou la production de monoxyde de
carbone pouvant causer des dommages matériels, de
blessure ou la mort. Le service d’entretien qualifié est
responsable de l’installation de cette trousse. L’installation
n’est pas adéquate ni complète tant que le bon
fonctionnement de l’appereil converti n’a pas été vérfié selon
les instructions du fabricant fornies avec la trousse.
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. Trained service
personnel must perform all other operations. When working on
heating equipment, observe precautions in the literature, on
tags, and on labels attached to or shipped with the unit, and
other safety precautions that may apply.
Follow all safety codes. In the United States, follow all safety
codes including the current edition of the National Fuel Gas
Code (NFGC) NFPA No. 54/ANSI Z223.1. In Canada, refer to
the current edition of the National Standard of Canada, Natural
Gas and Propane Installation Codes (NSCNGPIC),
CAN/CSA−B149.1 and .2. Wear safety glasses and work
gloves. Have a fire extinguisher available during start−up,
adjustment steps, and service calls.
Recognize safety information. 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,
CAUTION and NOTE. The words DANGER, WARNING, and
CAUTION 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 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.
INTRODUCTION
!WARNING
FIRE, EXPLOSION, ELECTRICAL SHOCK AND CARBON
MONOXIDE POISONING HAZARD
Failure to follow instructions could result in 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
could result in personal injury or death. Consult your
distributor or branch for information or assistance. The
qualified installer or agency must use only factory−authorized
kits or accessories when servicing this product.
!WARNING
FIRE, EXPLOSION, ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury,
death or property damage.
Gas supply MUST be shut off before disconnecting electrical
power and proceeding with conversion.
This instruction covers the installation of kit Part No.
NAHB00101MH in the following gas furnaces for manufactured
(mobile) home applications.
This kit is only for use in single stage 40,000 through 120,000
Btuh gas input models when installed as a direct vent (2−pipe)
furnace.
NOTE: This kit is not approved for the 140,000 Btuh gas input
model furnace, any two−stage and variable speed models, any
non−direct vent (1−pipe) applications nor any furnace that does
not have a sealed combustion system with provisions for
outside air.
40,000 to 120,000 BTUH MODEL NUMBERS
BEGINNING WITH:
G9MXE F9MXE N9MXB N9MSB N9MSE R9MSB

2443 06 4003 00
Specifications subject to change without notice.
Table 1 Kit Contents
Qty. Description
1Adjustment Tool
1Drill Bit 7/64”
1Gas Valve
1Connector 1/8” NPT
1Elbow, Street Brass 1/8” NPT
1 Elbow, Street 150# 1/8” NPT
1Tee, Street Brass
1Tee Brass
1Nipple HEX Brass
7Screw HEX HD 8AB 3/4
1Pressure Switch
1Wire Tie
7Orifice 1.25mm
1Wire Assembly
1Wire Assembly
1Installation Label 322236−101
1Adhesive Pouch 337985−101
1Label, Conversion 340323−101
1Conversion Rating Plate 340306−101
1 Instructions
DESCRIPTION AND USAGE
This kit is designed for use in the furnaces listed in the
Introduction. This kit is required for furnaces that use natural
gas or propane gas. These instructions describe the
modifications required for use in a manufactured (mobile)
home. See Table 1 for kit contents.
This conversion uses a White−Rodgers 36J convertible (natural
or propane) gas valve. More parts are shipped in the kit than
will be needed to complete the conversion. When installation is
complete, the extra parts are to remain with the furnace for
future use.
This furnace must be installed in accordance with the
manufacturer’s instructions and Manufactured Home
Construction and Safety Standard, Title 24 CFR, Part 3280 or,
when such standard is not applicable, the ANSI A225.1,
Standard for Manufactured Home Installation (Manufactured
Home Sites, Communities and Set−Ups), or the Mobile Homes
Standard CAN/CSA−Z240 MH Series−09.
Ce générateur d’air chaud doit être installé conformément avec
les instructions du fabricant et la norme intitulée Manufactured
Home Construction and Safety Standard, Title 24 CFR, Part
3280 ou, lorsque cette norme ne s’applique pas, la norme ANSI
A225.1, intitulée Standard for Manufactured Home Installation
(Manufactured Home Sites, Communities and Set−Ups), ou la
norme CAN/CSA−Z240 MH Série 09 de I’ACNOR, intitulée
Maisons mobiles.
This furnace must be installed as a direct−vent/2−pipe
(combustion air and flue) system. In a direct−vent system, all
air for combustion is taken directly from the outside
atmosphere, and all flue products (exhaust) are discharged to
the outside atmosphere. See furnace and factory accessory
concentric vent instructions for proper installation.
NOTE: The factory accessory concentric vent when used for
sidewall termination MUST NOT project more than 3−in. (76
mm) beyond the surface of the wall. See the appropriate
section for installation modification.
SECTION I: Initial Kit Installation
SECTION II: Conversion from Natural Gas to Propane
SECTION III: Conversion from Propane to Natural Gas
SECTION I: INITIAL KIT INSTALLATION
Procedure 1 — General
A downflow furnace application is where furnace blower is
located above combustion and controls section of furnace, and
conditioned air is discharged downwards.
Attach adhesive pouch containing literature packet and gas
conversion parts to outside of main furnace door or accessible
side of furnace for use at a later date. (See Figure 1)
!WARNING
PERSONAL INJURY AND UNIT DAMAGE HAZARD
Failure to follow this warning could result in personal injury or
unit damage.
When installing the air conditioning coil casing or when
servicing air conditioning, caution must be taken to ensure
furnace will not fall forward.
!CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in damage to the unit.
To prevent damage during transportation of the home, coil
casing must be secured to the floor, furnace and coil casing
must be fastened together, and furnace must be secured to
wall of the structure. When a coil casing is not used, an
accessory floor base is required. (See furnace rating plate or
clearance label for special accessory floor base part
number.) Secure floor base to structure and attach furnace to
floor base.
RECOMMENDED METHODS OF SECURING
FOR TYPICAL INSTALLATION (See Figure 1)
All mounting hardware is field−supplied.
1. Secure coil casing to floor.
a. Secure coil casing to floor of structure using 5/16−in.
(8 mm) lag screws (one each side) through lower
inside flanges of coil casing.
b. Alternate method: Attach right angle mounting
brackets or pipe strap (bent 90 degrees) to coil
casing using No.10 self tapping screws. Attach other
end of brackets/strap to floor of structure using
5/16−in. (8 mm) lag screws. If coil is present in
casing, be careful not to damage condensate pan
with tip of screw or remove coil from casing.
2. Fasten furnace to coil casing. Be careful not to damage it
with tip of screw.
a. Secure furnace to coil casing using two (2) No.10 self
tapping screws (one on each side of burner
enclosure) through cell panel flange, lower furnace
casing plate, and coil casing top flange.
b. Alternate method: Attach pipe strap to both furnace
casing and coil casing (one each side).
3. Secure furnace to structure.
a. Attach pipe strap to top of furnace casing using
No.10 self−tapping screws. Angle strap down and
away from back of furnace, remove all slack, and
fasten to wall stud of structure using 5/16−in. (8 mm)
lag screws. Typical both sides of furnace.
b. Alternate method: Secure furnace to wall stud using
1/8−in. (7 mm) thick right−angle brackets. Attach
brackets to furnace using No.10 self tapping screws,
and to wall stud using 5/16−in. (8 mm) lag screws.

443 06 4003 00 3
Specifications subject to change without notice.
Figure 1 Securing Furnace to Structure
RETURN AIR PLENUM
(WHEN USED)
WALL STUDS
AT TAC H
ADHESIVE
POUCH TO
DOOR
OR SIDE
FURNACE
COIL
CASING
SECURE FURNACE TO STRUCTURE
PIPE STRAP-REMOVE SLACK
(TYPICAL BOTH SIDES)
OR
1/8-IN. (7 MM) THICK ANGLE
MOUNTING
BRACKET (TYPICAL BOTH SIDES)
FASTEN FURNACE TO CASING
SCREWS THROUGH
CASING FLANGES
OR
PIPE STRAP FASTENED TO
FURNACE AND COIL CASING SIDES
(TYPICAL BOTH SIDES)
1-IN. (25 MM) MAXIMUM
SECURE COIL CASING TO FLOOR
LAG SCREWS THROUGH COIL CASING
FLANGE (TYPICAL BOTH SIDE)
OR
ANGLE BRACKET OR PIPE STRAP
NOTE: USE 5/16-IN. (8 MM) LAG SCREWS WHEN
SECURING TO STRUCTURE WALLS AND FLOOR.
USE NO. 10 SELF-TAPPING SCREWS WHEN FASTENING
TO SHEET METAL.
A11492
WHEN COIL CASING IS NOT INSTALLED (NOT SHOWN)
1. Accessory floor base MUST be used. Review floor base
Installation Instructions before installation.
2. Secure accessory floor base to structure using 5/16−in.
(8 mm) lag screws.
3. Fasten furnace to accessory floor base using No.10 self
tapping screws through tabs on both sides of base (two
each side).
Procedure 2 — Replace Gas Valve
!CAUTION
UNIT OPERATION HAZARD
Failure to follow this caution may result in unit damage or
improper operation.
Label all wires prior to disconnection when servicing controls.
!PRUDENCE
D’EQUIPEMENT D’OPERATION
Toute erreur de câblage peut être une source de danger et
de panne.
Lors des opérations d’entretien des commandes, étiqueter
tous les fils avant de les déconnecter.
!WARNING
FIRE, EXPLOSION, ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury,
death or property damage.
Gas supply MUST be shut off before disconnecting electrical
power and proceeding with conversion.

4443 06 4003 00
Specifications subject to change without notice.
!WARNING
ELECTRICAL SHOCK, FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury,
death or property damage.
Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF position and
install a lockout tag. There may be more than one disconnect
switch. Lock out and tag switch with a suitable warning label.
Verify proper operation after servicing.
Figure 2 Furnace Support for Servicing Air
Conditioner
FURNACE
FIELD-SUPPLIED
SUPPORTS
(1 X 4 (25 X 102 mm)
OR 2 X 4 (51 X 102 mm)
3 PLACES)
A99007
Figure 3 Manifold Assembly
Orifice
Connect Green/Yellow
ground wire here
Manifold
Gas Valve
Gas valve must be installed on
manifold with minimum engagement of
6 threads. Cross threading is not
acceptable.
Indicated surfaces
to be 90 ˚+ or -2˚
C
L
Gas valve is parallel to manifold
within + or - 3˚
A11407
Figure 4 Convertible Gas Valve
ON/OFF SWITCH
INLET
PRESSURE TAP
REGULATOR PLUNGER
LP/NAT
CONVERTIBLE CAP
GAS PRESSURE
REGULATOR
MANIFOLD
PRESSURE TAP
LP
NAT
A11510
1. Set room thermostat to lowest setting or OFF.
2. Disconnect power at external disconnect, fuse or circuit
breaker.
3. Turn off gas at external shut−off or gas meter.
4. Remove outer doors and set aside.
5. Turn electric switch on gas valve to OFF.
6. Disconnect the gas pipe from gas valve and remove pipe
from the furnace casing.
7. Disconnect the connector harness from gas valve
Disconnect wires from Hot Surface Igniter (HSI) and
Flame Sensor. (See Figure 9)
8. Support the manifold and remove the four (4) screws that
secure the manifold assembly to the burner box and set
aside.
9. Note the location of the green/yellow wire ground wire for
re−assembly later. (See Figure 3)
10. Remove production gas valve from manifold assembly
and discard valve.
NOTE: Production gas valve has a slotted cap on regulator
adjustment cap. The convertible valve has cap marked NAT
and LP.
11. Install new convertible gas valve to manifold. (See
Figure 4)
NOTE: Use a back−up wrench on the gas valve to prevent the
valve from rotating on the manifold or damaging the mounting
to the burner box.
NOTE: Use propane−gas−resistant pipe dope to prevent gas
leaks. DO NOT use Teflon tape.
INSTALL MANIFOLD−Natural Gas Only
NOTE: Install manifold if conversion is for use with natural gas.
For propane applications, manifold will be installed after Low
Gas Pressure Switch is installed.
1. Refer to Figure 3 and Figure 9.
2. Align the orifices in the manifold assembly with the
support rings on the end of the burner.
3. Insert the orifices in the support rings of the burners.
Manifold mounting tabs should fit flush against the burner
box.
NOTE: If manifold does not fit flush against the burner box, the
burners are not fully seated forward. Remove the manifold and
check burner positioning in the burner box assembly.
4. Attach the green/yellow wire and ground terminal to one
of the manifold mounting screws. (See Figure 3)
5. Install the remaining manifold mounting screws.
6. Connect the wires to the flame sensor and hot surface
igniter.

443 06 4003 00 5
Specifications subject to change without notice.
7. Connect the connector harness to gas valve.
NOTE: Use only propane−resistant pipe dope. Do not use
Teflon tape.
8. Insert the gas pipe through the grommet in the casing.
Apply a thin layer of pipe dope to the threads of the pipe
and thread the pipe into the gas valve.
NOTE: Use a back−up wrench on the gas valve to prevent the
valve from rotating on the manifold or damaging the mounting
to the burner box.
9. With a back−up wrench on the inlet boss of the gas
valve, finish tightening the gas pipe to the gas valve.
10. Check for leaks after the gas pipe is installed.
NOTE: If you are converting furnace for use with propane,
attach kit labels and extra parts bag as described in Procedure
3 then proceed to Section II.
Procedure 3 — Label and Extra Parts Bag Attachment
NOTE: See Figure 6, Figure 7 and Figure 8 for label location.
1. Attach Conversion Responsibility Label (340323−101)
inside of main furnace door. (See Figure 7) Date, name,
and address of organization making this conversion are
required. (See Figure 5)
2. Attach Conversion Rating Plate Label (338299−101)
inside of lower left−hand side of controls compartment
(downflow) as shown in Figure 6.
3. Attach Manufactured (Mobile) Home Installation Label
(322236−101) inside of main furnace door. (See
Figure 7)
4. Attach adhesive pouch (337985−101) containing gas
orifices and Installation Instructions to front of main
furnace door or accessible furnace side. (See Figure 1
or Figure 8)
5. Proceed to Section II or III for gas type modification and
Input rate adjustment.
Figure 5 Conversion Responsibility Label
Figure 6 Conversion Rating Plate Label Location
FURNACE CONVERSION
RATING PLATE
REPRESENTATIVE DRAWING ONLY, SOME MODELS MAY VARY.
Figure 7 Installation & Responsibility Label Locations
RESPONSIBILITY LABEL
MANUFACTURED (MOBILE)
HOME INSTALLATION LABEL
INSIDE OF DOORS
REPRESENTATIVE DRAWING ONLY, SOME MODELS MAY VARY.

6443 06 4003 00
Specifications subject to change without notice.
Figure 8 Label Locations
IMPORT
ANT
THIS B
AG
WITH
IN
STRUC
TION
S
E
NCLOS
ED M
UST
BE A
T
TACH
ED T
O
FURN
ACE
ADHESIVE POUCH
REPRESENTATIVE DRAWING ONLY, SOME MODELS MAY VARY.
SECTION II: CONVERSION FROM NATURAL
GAS TO PROPANE
BURNER REMOVAL
1. Slide one−piece burner assembly out of slots on sides of
burner box.
2. Remove the flame sensor from the burner assembly.
3. Remove the natural gas orifices from the manifold and
discard.
Figure 9 Burner Assembly
FLAME SENSOR
(BELOW BURNER)
FLAME ROLL-OUT
SWITCH
FLAME ROLL-OUT
SWITCH
IGNITER
IGNITER
A11226
ORIFICE SELECTION/DERATE
!WARNING
FIRE AND FURNACE DAMAGE HAZARD
Failure to follow this warning could result in personal injury,
death, property damage and/or unit damage.
DO NOT redrill orifices. Improper drilling (burrs, out−of−round
holes, etc.) can cause excessive burner noise and
misdirection of burner flames. This can result in flame
impingement of burners and heat exchangers causing
failures.
Figure 10 Burner Orifice
BURNER
ORIFICE BURNER
ORIFICE
A96249
Refer to conversion kit rating plate 338298−101 to determine
main burner orifice size. (See Figure 12)
Furnace gas input rate on furnace rating plate is for installations
at altitudes up to 2000 ft. (610 M).
In the U.S.A., the input rating for altitudes above 2000 ft. (610
M) must be reduced by 2 percent for each 1000 ft. (305 M)
above sea level.
In Canada,the input rating must be derated by 5 percent for
altitudes of 2000 ft. to 4500 ft. (610 M to 1372 M) above sea
level.
The Conversion Kit Rating Plate accounts for high altitude
derate.
INSTALL ORIFICES
1. Install main burner orifices. Do not use Teflon tape.
Finger−tighten orifices at least one full turn to prevent
cross−threading, then tighten with wrench.
2. There are enough orifices in each kit for largest furnace.
Discard extra orifices.
NOTE: DO NOT reinstall the manifold at this time.
INSTALL MIXER SCREWS
NOTE: There is a set of mixer screws. Use the parts in the bag
marked “REQUIRED FOR THE CONVERSION OF
CONDENSING GAS FURNACES TO PROPANE GAS”
1. See Figure 11 to verify you have the correct set of mixer
screws.
2. Locate the dimple on each burner venturi tube.
3. If you cannot locate the dimple, refer to Figure 13 for
location of the mixer screw.
4. Drill a 7/64−in (2.8 mm) hole (supplied in kit) in each
dimple.
5. Install a mixer screw in each drilled hole drilling as
straight as possible (i.e. in the center of the gas flow
stream as well as perpendicular to the gas flow stream).
6. The screw head should be flush with the top of the
burner venturi.
Figure 11 Gas Conversion Kit
A11294

443 06 4003 00 7
Specifications subject to change without notice.
Figure 12 Conversion Kit Rating Plate
Figure 13 Mixer Screw Location
1.9”
(48.76 mm)
1.8”
(46.96 mm)
Drill out with
7/64” drill bit
A11460
Figure 14 Igniter Position −Back View
2-1/2-in.
(64.4)
1-1/4-in.
(31.8)
A11405
Figure 15 Igniter Position −Side View
A12392
2−in.
(2.5 mm
3/8 −in.
3/16−in.
, +0.8 -1.5)
(50 mm)
(9.6 mm)
(4.6 mm)
3/32−in., +1/32 -3/64-in.
Figure 16 Convertible Gas Valve
ON/OFF SWITCH
INLET
PRESSURE TAP
REGULATOR PLUNGER
LP/NAT
CONVERTIBLE CAP
GAS PRESSURE
REGULATOR
MANIFOLD
PRESSURE TAP
NAT
LP
BURNER ENCLOSURE
PRESSURE REFERENCE
TAP
A11508

8443 06 4003 00
Specifications subject to change without notice.
REINSTALL BURNER ASSEMBLY
To reinstall burner assembly:
1. Attach flame sensor to burner assembly.
2. Insert one−piece burner in slot on sides of burner box
and slide burner back in place.
3. Verify igniter to burner alignment. (See Figure 14 and
Figure 15)
CONVERT GAS VALVE
!WARNING
FIRE, EXPLOSION, ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury,
death or property damage.
Gas supply and electrical power MUST be shut off to the
furnace before proceeding with conversion.
!WARNING
ELECTRICAL SHOCK, FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury,
death or property damage.
Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF position and
install a lockout tag. There may be more than one disconnect
switch. Lock out and tag switch with a suitable warning label.
Verify proper operation after servicing.
1. Refer to Figure 16.
2. Be sure gas and electrical supplies to furnace are OFF.
3. Orient gas valve LP/NAT cap for propane gas. The LP
arrow should point toward gas valve.
INSTALL LOW GAS PRESSURE SWITCH
NOTE: Install the Low Gas Pressure Switch (LGPS) before
installing the manifold on the burner assembly.
There are two ways to mount the Low Gas Pressure Switch.
All 14 3/16−in Casings or Vent Passed Between Inducer
Assembly and Burner Assembly
If the vent pipe passes between the inducer and burner
assembly, or the furnace is a 14−3/16−in. wide casing, install
the switch as follows: (See Figure 17)
1. Remove the 1/8−in. NPT pipe plug from the gas valve
inlet pressure tap.
NOTE: Use pipe dope approved for use with Propane Gas.
NOTE: Tighten all fittings and the Low Gas Pressure Switch
with a small wrench. Do not over−tighten, check for gas leaks
after gas supply has been turned on.
!WARNING
FIRE AND EXPLOSION HAZARD
Failure to follow this warning could result in personal injury
and/or death.
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.
!AVERTISSEMENT
RISQUE D’EXPLOSION ET D’INCENDIE
Le fait de ne pas suivre cet avertissement pourrait entraîner
des dommages corporels et / ou la mort.
Ne jamais examiner pour les fuites de gaz avec une flamme
vive. Utilisez plutôt un savon fait specifiquement pour la
détection des fuites de gaz pour verifier tous les connections.
Un incendie ou une explosion peut entrainer des dommages
matériels, des blessures ou la mort.
2. Apply pipe dope sparingly to the male threads of the
1/8−in. black iron street elbow. Install the street elbow
into the gas valve inlet pressure tap. Point the open end
of the street elbow toward you.
3. Apply pipe dope sparingly to the male threads of the
1/8−in. brass street tee. Install the male end of the street
tee as shown in Figure 17. One opening on the street
tee should face you. The other opening should be
parallel with the inlet of the gas valve.
4. Apply pipe dope sparingly to the male threads of the
1/8−in. brass hex nipple. Install the hex nipple into the
open end of the brass street tee. See Figure 17. The
hex nipple should be parallel with the boss on the gas
valve.
5. Install the open end of the brass street elbow on the end
of the hex nipple. Tighten the street elbow so the male
threads of the elbow point away from you.
6. Apply pipe dope sparingly to the male threads of the
1/8−in. brass street elbow. Install the Low Gas Pressure
Switch on the male threads of the street elbow. Tighten
switch at hex fitting at base of switch. Do not use switch
body to tighten switch. Do not over−tighten switch.
7. The remaining opening on the brass street tee is the new
gas valve inlet pressure tap. Install manometer fitting to
the open end of the brass street tee. Or if installation is to
be completed later, apply pipe dope to inlet pressure
plug from gas valve and install in open end of brass
street tee.
8. Check all fittings for leaks after gas supply has been
turned on.
Casings Wider Than 14−3/16−in/Vent Does Not Pass
Between Inducer and Burner Assembly
If the vent pipe does not pass between the inducer and burner
assembly, or the furnace is wider than a 14−3/16−in. wide
casing, install the switch as follows: (See Figure 18)
1. Remove the 1/8−in. NPT pipe plug from the gas valve
inlet pressure tap.
NOTE: Use pipe dope approved for use with Propane Gas.
NOTE: Tighten all fittings and the Low Gas Pressure Switch
with a small wrench. Do not over-tighten, check for gas leaks
after gas supply has been turned on.
2. Apply pipe dope sparingly to the male threads of the
1/8-in. brass street elbow. Install the street elbow into the
gas valve inlet pressure tap. One end of the opening of
the street elbow should be parallel with the inlet boss on
the gas valve. The other opening should be pointing
toward you..
3. Apply pipe dope sparingly to the male threads of the
1/8-in. long brass nipple. Install the nipple into the open
end of the brass street elbow.
4. Install the open end of the brass street elbow on the end
of the brass nipple. Tighten the street elbow so the male
threads of the elbow point away from you.
5. Apply pipe dope sparingly to the male threads of the
1/8-in. brass street elbow. Install the Low Gas Pressure
Switch on the male threads of the street elbow finger

443 06 4003 00 9
Specifications subject to change without notice.
tight. Tighten switch at hex fitting at base of switch. Do
not use switch body to tighten switch. Do not over-tighten
switch.
6. The remaining opening on the brass street tee is the new
gas valve inlet pressure tap. Install manometer fitting to
the open end of the brass street tee. Or if installation is to
be completed later, apply pipe dope to inlet pressure
plug from gas valve and install in open end of brass
street tee.
7. Check all fittings for leaks after gas supply has been
turned on.
Figure 17 Low Gas Pressure Switch −All Widths
(Must be used on the 14−3/16−in.)
L13F012
Brass Street Tee
Brass Hex Nipple
Brass Street 90
Low Gas Pressure Switch
Black Iron Street 90 Pointing
Inlet Pressure Tap with Plug
Re−install pipe plug
after removal
Figure 18
LGPS for casing wider than 14−3/16 in
and vent does not pass between
inducer and burner assembly
A11533
Brass Street 90
Brass Nipple
For larger casing when Vent Pipe does not pass across Casing. All Sizes switch
contacts must point tward the Cell Panel. Black Iron Street 90 can be used at Valve Inlet
instead of Brass Street 90.
Low Gas Pressure
Switch
Inlet Pressure Tap with Plug
Brass Street Tee
INSTALL LOW GAS PRESSURE SWITCH
WIRES
1. Locate the orange wire in the kit with an insulated
straight female spade terminal and an insulated straight
male terminal on the other end.
2. Connect the female terminal to a terminal on the Low
Gas Pressure Switch.
3. Locate the orange wire in kit with an insulated straight
female spade terminal and an insulated female flag
terminal on the other end.
4. Connect both straight female terminals of the orange
wires to the terminals on the Low Gas Pressure Switch.
INSTALL MANIFOLD
1. Refer to Figure 3 and Figure 9.
2. Align the orifices in the manifold assembly with the
support rings on the end of the burner.
3. Insert the orifices in the support rings of the burners.
Manifold mounting tabs should fit flush against the burner
box.
NOTE: If manifold does not fit flush against the burner box, the
burners are not fully seated forward. Remove the manifold and
check burner positioning in the burner box assembly.
4. Attach the green/yellow wire and ground terminal to one
of the manifold mounting screws. (See Figure 3)
5. Install the remaining manifold mounting screws.
6. Connect the wires to the flame sensor and hot surface
igniter.
7. Connect the wires to gas valve.
NOTE: Use only propane−resistant pipe dope. Do not use
Teflon tape.
8. Insert the gas pipe through the grommet in the casing.
Apply a thin layer of pipe dope to the threads of the pipe
and thread the pipe into the gas valve.
NOTE: Use a back−up wrench on the gas valve to prevent the
valve from rotating on the manifold or damaging the mounting
to the burner box.
9. With a back−up wrench on the inlet boss of the gas
valve, finish tightening the gas pipe to the gas valve.
MODIFY PRESSURE SWITCH WIRING
!CAUTION
UNIT OPERATION HAZARD
Failure to follow this caution may result in unit damage or
improper operation.
Label all wires prior to disconnection when servicing controls.
!PRUDENCE
D’EQUIPEMENT D’OPERATION
Toute erreur de câblage peut être une source de danger et
de panne.
Lors des opérations d’entretien des commandes, étiqueter
tous les fils avant de les déconnecter.
1. Disconnect orange wire from Low Heat Pressure Switch
LPS on inducer housing.
2. Connect the orange wire from the Low Heat Pressure
Switch to the orange wire with the insulated male spade
terminal. (See Figure 19)
3. Connect the orange wire from the Low Gas Pressure
Switch to the terminal on the Low Heat Pressure Switch.
4. Route orange wires along wire harness. If possible,
secure with wire tie provided in kit.
Figure 19 Pressure Switch Wiring
ORN
A11534

10 443 06 4003 00
Specifications subject to change without notice.
Figure 20 Single−Stage Furnace Control
ÏÏÏÏ
ÏÏÏÏ
ÏÏÏÏ
ÏÏÏÏ
TWINNING AND/OR
COMPONENT TEST
TERMINAL
P1 ïLOW VOLTAGE MAIN
HARNESS CONNECTOR
TRANSFORMER 24VAC
CONNECTIONS
EAC TERMINAL
(115 VAC 1.0 AMP MAX.)
COOL
SPARE2
SPARE1
COM/BLUE
115 ïVAC (L2) NEUTRAL
CONNECTIONS
24ïV THERMOSTAT
TERMINALS
HUMIDIFIER TERMINAL
(24ïVAC 0.5 AMP MAX)
3ïAMP FUSE
LED OPERATION &
DIAGNOSTIC LIGHT
24VAC/RED
BLOWER SPEED
SELECTION TERMINALS
BLï1XFMR
Y1 DHUM
HEAT OFFïDELAY
120 180
90 150
Ï
ÏÏ
ÏÏ
ÏÏ
ÏÏ
ÏÏ
ÏÏ
ÏÏ
NEUTRAL ïL2
115 VAC (L1)
CONNECTIONS
L1 IND
P2ïHOT SURFACE IGNITOR (HSI) &
INDUCER MOTOR (IND) CONNECTOR
HEAT
FAN
HUM
24VAC
EAC
1 AMP
HSI
P2
COM
HEAT
COOL
FAN
SPARE 1
24V MTR TAPS
SPARE 2
REPRESENTATIVE DRAWING ONLY, SOME MODELS MAY VARY.
CHECK INLET GAS PRESSURE
!CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in unit damage.
DO NOT operate furnace more than one minute to check
inlet gas pressure, as conversion is not complete at this time.
NOTE: This kit is to be used only when inlet gas pressure is
between 12.0−in. w.c. and 13.6−in. w.c.
NOTE: Verify LP arrow on LP/NAT cap is pointed toward gas
valve.
1. Verify manometer is connected to inlet pressure tap on
gas valve. (See Figure 16)
2. Turn on furnace power supply.
3. Turn gas supply manual shutoff valve to ON position.
!WARNING
FIRE, EXPLOSION, ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury,
death or property damage.
Gas supply MUST be shut off before disconnecting electrical
power before proceeding with conversion.
!WARNING
ELECTRICAL SHOCK, FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury,
death or property damage.
Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF position and
install a lockout tag. There may be more than one disconnect
switch. Lock out and tag switch with a suitable warning label.
Verify proper operation after servicing.
4. Turn furnace gas valve switch to ON position.
5. Jumper R−W thermostat connections on control.
6. When main burners ignite, confirm inlet gas pressure is
between 11.0−in. w.c. and 13.6−in. w.c.
7. Remove jumper across R−W thermostat connections to
terminate call for heat.
8. Turn furnace gas valve switch to OFF position.
CHECK FURNACE AND MAKE
ADJUSTMENTS
1. Be sure main gas and electric supplies to furnace are off.
2. Remove 1/8−in. (3 mm) pipe plug from manifold pressure
tap on downstream side of gas valve.
3. Attach manometer to manifold pressure tap on gas
valve. (See Figure 16)
4. Turn gas supply manual shutoff valve to ON position.
5. Turn furnace gas valve switch to ON position.
!WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury
and/or death.
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.
!AVERTISSEMENT
RISQUE D’EXPLOSION ET D’INCENDIE
Le fait de ne pas suivre cet avertissement pourrait entraîner
des dommages corporels et / ou la mort.
Ne jamais examiner pour les fuites de gaz avec une flamme
vive. Utilisez plutôt un savon fait specifiquement pour la
détection des fuites de gaz pour verifier tous les connections.
Un incendie ou une explosion peut entrainer des dommages
matériels, des blessures ou la mort.
6. Check all threaded pipe connections for gas leaks.
7. Turn on furnace power supply.
GAS INPUT RATE INFORMATION
The gas input rate for propane is the same as for natural gas.
See furnace rating plate for input rate. (See Figure 12) The
input rate for propane is determined by manifold pressure and
orifice size.
The gas valve must be set for Low Heat first and then set for
High Heat on two−stage and variable−speed furnaces. Furnace
gas input rate on rating plate is for installations at altitudes up to
2000 ft. (610 M).
In the U.S.A.; the input rating for altitudes above 2000 ft.
(610M) must be reduced by 2 percent for each 1000 ft. (305 M)
above sea level.
In Canada; the input rating must be derated by 5 percent for
altitudes of 2000 ft. (610 M) to 4500 ft. (1372 M) above sea
level.
The Conversion Kit Rating Plate accounts for high altitude
derate.
SET GAS INPUT RATE
1. Jumper R and W thermostat connections to call for heat.
(See Figure 20)
2. Check manifold orifices for gas leaks when main burners
ignite.
3. Adjust manifold pressure to obtain input rate. (See
Figure 12)
4. When main burners have ignited, confirm proper
manifold pressure is between 9.5−in. w.c. and 11.0−in.
w.c.. (See Figure 12)
5. If manifold pressure needs to be adjusted, use gas valve
adjustment key, factory−supplied in this kit or adhesive
pouch. (See Figure 21)

443 06 4003 00 11
Specifications subject to change without notice.
6. Remove cap that conceals adjustment screw for gas
valve regulator. (See Figure 23)
7. Turn adjusting screw using supplied ADJUSTING KEY
either counterclockwise (out) to decrease input rate or
clockwise (in) to increase rate. (See Figure 21)
8. Replace cap and check rate. Cap MUST be in place to
actuate regulator.
9. Repeat Steps 5 through 8 until correct input rate is
obtained.
Figure 21 Manifold Pressure Adjustment Key
ON/OFF SWITCH
INLET
PRESSURE TAP
REGULATOR PLUNGER
ADJUSTING KEY
GAS PRESSURE
REGULATOR
MANIFOLD
PRESSURE TAP
BURNER REFERENCE
PRESSURE TAP
A11509
NOTE: Gas valve LP/NAT cap MUST be in place with LP
arrow pointing toward gas valve when checking input rate.
When correct input is obtained, main burner flame should be
clear blue, almost transparent (See Figure 22). Be sure cap is
in place when finished.
Figure 22 Burner Flame
Burner Flame
Burner
Manifold
A11461
When correct input is obtained, make sure cap that conceals
gas valve regulator adjustment screw is oriented properly for
propane (LP) gas. The LP arrow should be pointing toward gas
valve. (See Figure 21)
10. Remove jumper across R and W thermostat connections
to terminate call for heat.
11. Turn furnace gas valve control knob or switch to OFF
position.
12. Turn gas supply manual shutoff valve to OFF position.
13. Turn off furnace power supply.
14. Remove manometer and replace manifold pressure tab
plug. (See Figure 21)
15. Turn furnace gas valve switch to ON position.
16. Turn on furnace power supply.
17. Set room thermostat to call for heat.
!WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury
and/or death.
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.
!AVERTISSEMENT
RISQUE D’EXPLOSION ET D’INCENDIE
Le fait de ne pas suivre cet avertissement pourrait entraîner
des dommages corporels et / ou la mort.
Ne jamais examiner pour les fuites de gaz avec une flamme
vive. Utilisez plutôt un savon fait specifiquement pour la
détection des fuites de gaz pour verifier tous les connections.
Un incendie ou une explosion peut entrainer des dommages
matériels, des blessures ou la mort.
18. Check pressure tap plug for gas leaks when main
burners ignite.
19. Check for correct burner flame.
20. Observe unit operation through two complete heating
cycles.
21. See Sequence of Operation in furnace Installation,
Start−Up, and Operating Instructions.
22. Set room thermostat to desired temperature.
23. After making the required manifold pressure
adjustments, check and adjust the furnace temperature
rise per the furnace installation instructions.
CHECK LOW GAS PRESSURE SWITCH
The newly installed low gas pressure switch is a safety device
used to guard against adverse burner operating characteristics
that can result from low gas supply pressure. Switch opens at
not less than 6.5 in. w.c. and closes at not greater than 10.2 in.
w.c.
This switch also prevents operation when the propane tank
level is low which can result in gas with a high concentration of
impurities, additives, and residues that have settled to the
bottom of the tank. Operation under these conditions can
cause harm to the heat exchanger system. This normally open
switch closes when gas is supplied to gas valve under normal
operating pressure.
The closed switch completes control circuit. Should an
interruption or reduction in gas supply occur, the gas pressure
at switch drops below low gas pressure switch setting, and
switch opens. Any interruption in control circuit (in which low
gas pressure switch is wired) quickly closes gas valve and
stops gas flow to burners. When normal gas pressure is
restored, the system must be electrically reset to re−establish
normal heating operation.
Before leaving installation, observe unit operation through two
complete heating cycles. During this time, turn gas supply to
gas valve off just long enough to completely extinguish burner
flame, then instantly restore full gas supply. To ensure proper
low gas pressure switch operation, observe that there is no gas
supply to burners until after hot surface igniter begins glowing.
LABEL APPLICATION
1. Fill in Conversion Responsibility Label (337991−101)
previously applied to inside of main furnace door by
installer. Date, name, and address of organization

12 443 06 4003 00
Specifications subject to change without notice.
making this conversion are required. Specify that unit is
now converted for use with natural gas.
2. Place ALL unused parts, adjusting key, and these
Installation Instructions in adhesive pouch attached to
outside of main furnace door or accessible side of
furnace.
3. Reinstall main furnace door.
CHECKOUT
1. Observe unit operation through two complete heating
cycles.
2. See Sequence of Operation in furnace Installation,
Start−Up, and Operating Instructions.
3. Set room thermostat to desired temperature.
SECTION III: CONVERSION FROM
PROPANE TO NATURAL GAS
INSTALLATION
1. Set room thermostat to lowest setting or “OFF”.
2. Disconnect power at external disconnect, fuse or circuit
breaker.
3. Turn off gas at external shut−off or gas meter.
4. Remove outer doors and set aside.
5. Turn electric switch on gas valve to OFF.
MANIFOLD/ORIFICE/BURNER REMOVAL
!CAUTION
UNIT OPERATION HAZARD
Failure to follow this caution may result in unit damage or
improper operation.
Label all wires prior to disconnection when servicing controls.
!PRUDENCE
D’EQUIPEMENT D’OPERATION
Toute erreur de câblage peut être une source de danger et
de panne.
Lors des opérations d’entretien des commandes, étiqueter
tous les fils avant de les déconnecter.
NOTE: Use a back−up wrench on the gas valve to prevent the
valve from rotating on the manifold or damaging the mounting
to the burner box.
1. Disconnect the gas pipe from gas valve and remove pipe
from the furnace casing.
2. Disconnect the connector harness from gas valve.
3. Disconnect wires from Hot Surface Igniter (HSI) and
Flame Sensor. (See Figure 9)
4. Remove the orange wires connected to the Low Gas
Pressure Switch.
5. Support the manifold and remove the four (4) screws that
secure the manifold assembly to the burner box and set
aside. (See Figure 3)
6. Note the location of the green/yellow wire ground wire for
re−assembly later.
7. Slide one−piece burner assembly out of slots on sides of
burner box.
8. Remove the flame sensor from the burner assembly.
9. Remove the orifices from the manifold and discard.
ORIFICE SELECTION/DERATE
GAS INPUT RATE INFORMATION
The gas input rate for natural is the same as for propane gas.
See furnace rating plate for input rate. (See Figure 12) The
input rate for propane is determined by manifold pressure and
orifice size.
Furnace gas input rate on rating plate is for installations at
altitudes up to 2000 ft. (610 M).
In the U.S.A., the input rating for altitudes above 2000 ft.
(610M) must be reduced by 2 percent for each 1000 ft. (305 M)
above sea level.
In Canada, the input rating must be derated by 5 percent for
altitudes of 2000 ft. (610 M) to 4500 ft. (1372 M) above sea
level.
Furnace input rate must be within +/−2 percent of input on
furnace rating plate adjusted for altitude.
1. Determine natural gas orifice size and manifold pressure
for correct input.
a. Obtain average yearly heat value (at installed
altitude) from local gas supplier.
b. Obtain average yearly specific gravity from local gas
supplier.
c. Find installation altitude in Table 3.
NOTE: For Canada altitudes of 2000 to 4500 ft., (610 to 1372
M) use USA. altitudes of 2001 to 3000 ft. (610 to 914 M) in
Table 3.
d. Find closest natural gas heat value and specific
gravity on Table 3.
e. Follow heat value and specific gravity lines to point of
intersection to find orifice size and manifold pressure
settings for proper operation.
2. Check and verify burner orifice size in furnace. NEVER
ASSUME ORIFICE SIZE; ALWAYS CHECK AND
VERIFY.
NOTE: If orifice hole appears damaged or it is suspected to
have been redrilled, check orifice hole with a numbered drill bit
of correct size. Never redrill an orifice. A burr−free and squarely
aligned orifice hole is essential for proper flame characteristics.
EXAMPLE: 0 −2000 ft. (0 −609.6M) altitude
Heating value = 1050 Btu/cu ft.
Specific gravity = 0.62
Therefore: Orifice No. 44
Manifold pressure: 3.4−in. w.c.
* Furnace is shipped with No. 44 orifices. In this example,
all main burner orifices are the correct size and do not need
to be changed to obtain proper input rate.
INSTALL ORIFICES
1. Locate natural gas orifices in loose parts bag attached to
furnace casing. Verify orifices selected are correct
orifices for natural gas.
2. Install main burner orifices. Do not use Teflon tape.
Finger−tighten orifices at least one full turn to prevent
cross−threading, then tighten with wrench. (See
Figure 3)
3. There are enough orifices in each kit for largest furnace.
Discard extra orifices.
NOTE: DO NOT reinstall the manifold at this time.
REMOVE MIXER SCREWS
1. Locate the mixer screw on each burner venturi tube.
2. Remove each screw and discard.
3. It is not necessary to plug or seal the screw hole in the
burner venturi.
REINSTALL BURNER ASSEMBLY
To reinstall burner assembly:
1. Attach flame sensor to burner assembly.

443 06 4003 00 13
Specifications subject to change without notice.
2. Insert one−piece burner in slot on sides of burner box
and slide burner back in place.
3. Reattach HSI wires to HSI.
4. Verify igniter to burner alignment. See Figure 14 and
Figure 15)
CONVERT GAS VALVE
!WARNING
FIRE, EXPLOSION, ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury,
death or property damage.
Gas supply MUST be shut off before disconnecting electrical
power before proceeding with conversion.
!WARNING
ELECTRICAL SHOCK, FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury,
death or property damage.
Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF position and
install a lockout tag. There may be more than one disconnect
switch. Lock out and tag switch with a suitable warning label.
Verify proper operation after servicing.
1. Refer to Figure 23.
2. Be sure gas and electrical supplies to furnace are off.
3. Orient gas valve LP/NAT cap for natural gas. The NAT
arrow should point toward gas valve.
Figure 23 Convertible Gas Valve
ON/OFF SWITCH
INLET
PRESSURE TAP
REGULATOR PLUNGER
LP/NAT
CONVERTIBLE CAP
GAS PRESSURE
REGULATOR
MANIFOLD
PRESSURE TAP
LP
NAT
A11510
REMOVE LOW GAS PRESSURE SWITCH
!CAUTION
UNIT OPERATION HAZARD
Failure to follow this caution may result in unit damage or
improper operation.
Label all wires prior to disconnection when servicing controls.
!PRUDENCE
D’EQUIPEMENT D’OPERATION
Toute erreur de câblage peut être une source de danger et
de panne.
Lors des opérations d’entretien des commandes, étiqueter
tous les fils avant de les déconnecter.
1. Remove the orange wire from the terminal on the Low
Pressure Switch.
2. Connect the orange wire from the wiring harness to the
terminal on the Low Pressure Switch.
3. Discard loose orange wire.
4. Remove the 1/8−in. NPT pipe plug from the tee fitting on
the Low Gas Pressure Switch.
5. Remove the Low Gas Pressure Switch from fittings on
gas valve and discard.
6. Remove remaining fittings from gas valve and discard.
7. Install manometer fitting to the open end of the brass
street tee. Or if installation is to be completed later, apply
pipe dope to inlet pressure plug from gas valve and
install in open end of brass street tee.
!WARNING
FIRE AND EXPLOSION HAZARD
Failure to follow this warning could result in personal injury
and/or death.
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.
!AVERTISSEMENT
RISQUE D’EXPLOSION ET D’INCENDIE
Le fait de ne pas suivre cet avertissement pourrait entraîner
des dommages corporels et / ou la mort.
Ne jamais examiner pour les fuites de gaz avec une flamme
vive. Utilisez plutôt un savon fait specifiquement pour la
détection des fuites de gaz pour verifier tous les connections.
Un incendie ou une explosion peut entrainer des dommages
matériels, des blessures ou la mort.
8. Check all fittings for leaks after gas supply has been
turned on.
Figure 24 Pressure Switch Wiring
ORN
A11534
INSTALL MANIFOLD
1. Refer to Figure 3 and Figure 9.
2. Align the orifices in the manifold assembly with the
support rings on the end of the burner.
3. Insert the orifices in the support rings of the burners.
Manifold mounting tabs should fit flush against the burner
box.
NOTE: If manifold does not fit flush against the burner box, the
burners are not fully seated forward. Remove the manifold and
check burner positioning in the burner box assembly.
4. Attach the green/yellow wire and ground terminal to one
of the manifold mounting screws. (See Figure 3)
5. Install the remaining manifold mounting screws.
6. Connect the wires to both rollout switches.
7. Connect the wires to the flame sensor and hot surface
igniter.
8. Connect the connector harness to gas valve.

14 443 06 4003 00
Specifications subject to change without notice.
NOTE: Use only propane−resistant pipe dope. Do not use
Teflon tape.
9. Insert the gas pipe through the grommet in the casing.
Apply a thin layer of pipe dope to the threads of the pipe
and thread the pipe into the gas valve.
NOTE: Use a back−up wrench on the gas valve to prevent the
valve from rotating on the manifold or damaging the mounting
to the burner box.
10. With a back−up wrench on the inlet boss of the gas
valve, finish tightening the gas pipe to the gas valve.
CHECK INLET GAS PRESSURE
NOTE: This kit is to be used only when inlet gas pressure is
between 4.5-in. w.c. and 13.6-in. w.c..Natural gas service
pressure must not exceed 0.5 psig (14−in. w.c.) but be no less
than 0.16 psig (4.5−in. w.c.).
NOTE: Verify NAT arrow on LP/NAT cap is pointed toward gas
valve.
1. Verify manometer is connected to inlet pressure tap on
gas valve. (See Figure 23)
2. Turn on furnace power supply.
3. Turn gas supply manual shutoff valve to ON position.
!WARNING
FIRE, EXPLOSION, ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury,
death or property damage.
Gas supply MUST be shut off before disconnecting electrical
power before proceeding with conversion.
!WARNING
ELECTRICAL SHOCK, FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury,
death or property damage.
Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF position and
install a lockout tag. There may be more than one disconnect
switch. Lock out and tag switch with a suitable warning label.
Verify proper operation after servicing.
4. Turn furnace gas valve switch to ON position.
5. Jumper R−W thermostat connections on control.
6. When main burners ignite, confirm inlet gas pressure is
between 4.5−in. w.c. and 13.6−in. w.c.
7. Remove jumper across R−W thermostat connections to
terminate call for heat.
8. Turn furnace gas valve switch to OFF position.
CHECK FURNACE AND MAKE
ADJUSTMENTS
!WARNING
FIRE AND EXPLOSION HAZARD
Failure to follow this warning could result in personal injury
and/or death.
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.
!AVERTISSEMENT
RISQUE D’EXPLOSION ET D’INCENDIE
Le fait de ne pas suivre cet avertissement pourrait entraîner
des dommages corporels et / ou la mort.
Ne jamais examiner pour les fuites de gaz avec une flamme
vive. Utilisez plutôt un savon fait specifiquement pour la
détection des fuites de gaz pour verifier tous les connections.
Un incendie ou une explosion peut entrainer des dommages
matériels, des blessures ou la mort.
1. Be sure main gas and electric supplies to furnace are off.
2. Remove 1/8−in. (3 mm) pipe plug from manifold pressure
tap on downstream side of gas valve.
3. Attach manometer to manifold pressure tap on gas
valve. (See Figure 13)
4. Turn gas supply manual shutoff valve to ON position.
5. Turn furnace gas valve switch to ON position.
6. Check all threaded pipe connections for gas leaks.
7. Turn on furnace power supply.
SET GAS INPUT RATE
1. Jumper R and W thermostat connections to call for heat.
(See Figure 20)
2. Check manifold orifices for gas leaks when main burners
ignite.
3. Adjust manifold pressure to obtain input rate. (See
Table 3)
4. When main burners have ignited, confirm proper
manifold pressure is between 3.2−in. w.c. and 3.8−in.
w.c. (See Table 3)
5. If manifold pressure needs to be adjusted, use gas valve
adjustment key, factory−supplied in this kit or adhesive
pouch. (See Figure 25)
6. Remove cap that conceals adjustment screw for gas
valve regulator. (See Figure 25)
7. Turn adjusting screw using supplied ADJUSTING KEY
either counterclockwise (out) to decrease input rate or
clockwise (in) to increase rate. (See Figure 25)
8. Replace cap and check rate. Cap MUST be in place to
actuate regulator.
9. Repeat Steps 5 through 8 until correct input rate is
obtained.
Figure 25 Manifold Pressure Adjustment Key
ON/OFF SWITCH
INLET
PRESSURE TAP
REGULATOR PLUNGER
ADJU
S
TIN
G
KEY
GAS PRESSURE
REGULATOR
MANIFOLD
PRESSURE TAP
BURNER REFERENCE
PRESSURE TAP
A11509
NOTE: Gas valve LP/NAT cap MUST be in place with NAT
arrow pointing toward gas valve when checking input rate.
When correct input is obtained, main burner flame should be
clear blue, almost transparent (See Figure 22). Be sure cap is
in place when finished.

443 06 4003 00 15
Specifications subject to change without notice.
When correct input is obtained, make sure cap that conceals
gas valve regulator adjustment screw is oriented properly for
natural (NAT) gas. The NAT arrow should be pointing toward
gas valve. (See Figure 23)
10. Remove jumper across R and W thermostat connections
to terminate call for heat.
11. Turn furnace gas valve control knob or switch to OFF
position.
12. Turn gas supply manual shutoff valve to OFF position.
13. Turn off furnace power supply.
14. Remove manometer and replace manifold pressure tab
plug. (See Figure 25)
15. Turn furnace gas−valve switch to ON position.
16. Turn on furnace power supply.
17. Set room thermostat to call for heat.
18. Check pressure tap plug for gas leaks when main
burners ignite.
19. Check for correct burner flame. (See Figure 22)
20. Observe unit operation through two complete heating
cycles.
21. See Sequence of Operation in furnace Installation,
Start−Up, and Operating Instructions.
22. Set room thermostat to desired temperature.
23. After making the required manifold pressure
adjustments, check and adjust the furnace temperature
rise per the furnace installation instructions.
24. Verify Natural Gas Input Rate By Clocking Gas Meter.
NOTE: Be sure all pressure tubing, combustion-air and vent
pipes, and burner enclosure front are in place when checking
input by clocking gas meter.
a. Calculate high-altitude adjustment (if required).
UNITED STATES
At altitudes above 2000 ft, this furnace has been approved for a
2 percent derate for each 1000 ft above sea level. See Table 2
for derate multiplier factor.
CANADA
At installation altitudes from 2000 to 4500 ft, this furnace must
be derated 5 percent by an authorized Gas Conversion Station
or Dealer.
To determine correct input rate for altitude, see example above
and use 0.95 as derate multiplier factor.
b. Turn off all other gas appliances and pilots.
c. Start furnace and let operate for 3 minutes.
d. Measure time (in sec) for gas meter test dial to
complete one revolution.
e. Refer to Table 4 for cu ft of gas per hr.
f. Multiply gas rate (cu ft/hr) X heating value (Btu/cu ft)
using natural gas heating value from local gas
utility/supplier.
g. Fill in Conversion Responsibility Label (321102-101)
located on inside of main furnace door. Date, name,
and address of organization making the conversion is
required.
h. Check for gas leaks.
Table 2 Altitude Derate Multiplier for U.S.A.
ALTITUDE PERCENT
OF
DERATE
DERATE
MULTIPLIER
FACTOR*
FT. M
0–2000 0−610 0 1.00
2001–3000 610−914 4−6 0.95
3001–4000 914−1219 6−8 0.93
4001–5000 1219−1524 8−10 0.91
5001–6000 1524−1829 10−12 0.89
6001–7000 1829−2134 12−14 0.87
7001–8000 2134−2438 14−16 0.85
8001–9000 2438−2743 16−18 0.83
9001–10,000 2743−3048 18−20 0.81
*Derate multiplier factors are based on midpoint altitude for altitude range.
!WARNING
FIRE AND EXPLOSION HAZARD
Failure to follow this warning could result in personal injury
and/or death.
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.
!AVERTISSEMENT
RISQUE D’EXPLOSION ET D’INCENDIE
Le fait de ne pas suivre cet avertissement pourrait entraîner
des dommages corporels et / ou la mort.
Ne jamais examiner pour les fuites de gaz avec une flamme
vive. Utilisez plutôt un savon fait specifiquement pour la
détection des fuites de gaz pour verifier tous les connections.
Un incendie ou une explosion peut entrainer des dommages
matériels, des blessures ou la mort.
LABEL MODIFICATION
NOTE: See Figure 6, Figure 7 and Figure 8 for label location.
1. Fill in Conversion Responsibility Label (334973−101)
previously applied to inside of main furnace door by
installer. Date, name, and address of organization
making this conversion are required. Specify that unit is
now converted for use with natural gas.
2. Place ALL unused parts, adjusting key, and these
Installation Instructions in adhesive pouch attached to
outside of main furnace door or accessible side of
furnace.
3. Reinstall main furnace door.

16 443 06 4003 00
Specifications subject to change without notice.
Table 3 Orifice Size and Manifold Pressure (in. w.c.) for Gas Input Rate
SAGLARUTANFOYTIVARGCIFICEPSSAG.GVA
HEATVALUE0.580.600.620.64
AT ALTITUDE Orifice Manifold Orifice Manifold Orifice Manifold Orifice Manifold
(Btu/cu ft) No. Pressure No. Pressure No. Pressure No. Pressure
900 43 3.8 42 3.2 42 3.3 42 3.4
092543 3.6 43 3.7 43 3.8 42 3.2
(0) 950 43 3.4 43 3.5 43 3.6 43 3.7
975 44 3.7 44 3.8 43 3.4 43 3.6
to 1000 44 3.5 44 3.6 44 3.8 43 3.4
1025 44 3.3 44 3.5 44 3.6 44 3.7
2000 1050 44 3.2 44 3.3 44 3.4 44 3.5
(610) 1075 45 3.7 45 3.8 44 3.3 44 3.4
1100 46 3.7 46 3.8 45 3.8 44 3.2
U.S.A. 800 42 3.4 42 3.5 42 3.6 42 3.7
2001 (611) 825 43 3.8 42 3.3 42 3.4 42 3.5
to 850 43 3.6 43 3.7 42 3.2 42 3.3
3000 (914) 875 43 3.4 43 3.5 43 3.7 43 3.8
900 44 3.7 44 3.8 43 3.5 43 3.6
Canada 925 44 3.5 44 3.6 44 3.8 43 3.4
2001 (611) 950 44 3.3 44 3.4 44 3.6 44 3.7
to 975 44 3.2 44 3.3 44 3.4 44 3.5
4500 (1372) 1000 44 3.0 44 3.1 44 3.2 44 3.3
775 42 3.3 42 3.4 42 3.5 42 3.6
3001 800 43 3.8 42 3.2 42 3.3 42 3.4
(915) 825 43 3.6 43 3.7 43 3.8 42 3.2
850 44 3.8 43 3.5 43 3.6 43 3.7
875 44 3.6 44 3.7 43 3.4 43 3.5
4000 900 44 3.4 44 3.5 44 3.7 44 3.8
(1219) 925 44 3.2 44 3.4 44 3.5 44 3.6
950 44 3.1 44 3.2 44 3.3 44 3.4
750 42 3.3 42 3.4 42 3.5 42 3.6
4001 775 43 3.7 43 3.8 42 3.3 42 3.4
(1220) 800 43 3.5 43 3.6 43 3.7 43 3.8
825 44 3.8 43 3.4 43 3.5 43 3.6
850 44 3.5 44 3.7 44 3.8 43 3.4
5000 875 44 3.3 44 3.5 44 3.6 44 3.7
(1524) 900 44 3.2 44 3.3 44 3.4 44 3.5
925 44 3.0 44 3.1 44 3.2 44 3.3
725 42 3.2 42 3.3 42 3.4 42 3.5
5001 750 43 3.7 43 3.8 42 3.2 42 3.3
(1525) 775 43 3.4 43 3.5 43 3.7 43 3.8
800 44 3.7 44 3.8 43 3.4 43 3.5
825 44 3.5 44 3.6 44 3.7 44 3.8
6000 850 44 3.3 44 3.4 44 3.5 44 3.6
(1829) 875 44 3.1 44 3.2 44 3.3 44 3.4
900 44 2.9 44 3.0 44 3.1 44 3.2
675 42 3.4 42 3.5 42 3.6 42 3.8
6001 700 42 3.2 42 3.3 42 3.4 42 3.5
(1830) 725 43 3.6 43 3.7 43 3.8 42 3.3
750 43 3.4 43 3.5 43 3.6 43 3.7
775 44 3.6 44 3.7 43 3.4 43 3.5
7000 800 44 3.4 44 3.5 44 3.6 44 3.7
(2133) 825 44 3.2 44 3.3 44 3.4 44 3.5
850 44 3.0 44 3.1 44 3.2 44 3.3
to
to
to
to
ALTITUDE
RANGE
ft (m)
U.S.A. and Canada
SINGLE-STAGE FURNACE
(TABULATED DATA BASED ON 20,000 BTUH PER BURNER, DERATED 2%/1000 FT (305M) ABOVE SEA LEVEL)
U.S.A. Only
U.S.A. Only
U.S.A. Only U.S.A. Only U.S.A. and Canada
A11253A

443 06 4003 00 17
Specifications subject to change without notice.
Table 3 Orifice Size and Manifold Pressure (in. w.c.) for Gas Input Rate −Cont.
A11253B
SAGLARUTANFOYTIVARGCIFICEPSSAG.GVA
HEATVALUE0.580.600.620.64
AT ALTITUDE Orifice Manifold Orifice Manifold Orifice Manifold Orifice Manifold
(Btu/cu ft) No. Pressure No. Pressure No. Pressure No. Pressure
ALTITUDE
RANGE
ft (m)
SINGLE-STAGE FURNACE
(TABULATED DATA BASED ON 20,000 BTUH PER BURNER, DERATED 2%/1000 FT (305M) ABOVE SEA LEVEL)
650 42 3.4 42 3.5 42 3.6 42 3.7
7001 675 43 3.8 42 3.2 42 3.3 42 3.4
(2134) 700 43 3.5 43 3.7 43 3.8 42 3.2
725 44 3.8 43 3.4 43 3.5 43 3.6
750 44 3.5 44 3.7 44 3.8 43 3.4
8000 775 44 3.3 44 3.4 44 3.5 44 3.7
(2438) 800 44 3.1 44 3.2 44 3.3 44 3.4
825 44 2.9 44 3.0 44 3.1 44 3.2
625 42 3.4 42 3.5 42 3.6 42 3.7
8001 650 43 3.8 42 3.2 42 3.3 42 3.4
(2439) 675 43 3.5 43 3.6 43 3.7 42 3.2
700 44 3.7 43 3.4 43 3.5 43 3.6
725 44 3.5 44 3.6 44 3.7 44 3.8
9000 750 44 3.3 44 3.4 44 3.5 44 3.6
(2743) 775 44 3.0 44 3.2 44 3.3 44 3.4
9001 600 42 3.3 42 3.4 42 3.6 42 3.7
(2744) 625 43 3.7 42 3.2 42 3.3 42 3.4
650 43 3.5 43 3.6 43 3.7 43 3.8
675 44 3.7 44 3.8 43 3.4 43 3.5
10000 700 44 3.4 44 3.5 44 3.7 44 3.8
(3048) 725 44 3.2 44 3.3 44 3.4 44 3.5
* Orifice numbers shown in BOLD are factory-installed.
to
to
to
U.S.A. Only U.S.A. OnlyU.S.A. Only

18 443 06 4003 00
Specifications subject to change without notice.
Table 4 Gas Rate (CU ft./hr)
SECONDS
FOR
1 REVOLUTION
SIZE OF TEST DIAL SECONDS
FOR
1 REVOLUTION
SIZE OF TEST DIAL
1 Cu Ft. 2 Cu Ft. 5 Cu Ft. 1 Cu Ft. 2 Cu Ft. 5 Cu Ft.
10 360 720 1800 50 72 144 360
11 327 655 1636 51 71 141 355
12 300 600 1500 52 69 138 346
13 277 555 1385 53 68 136 340
14 257 514 1286 54 67 133 333
15 240 480 1200 55 65 131 327
16 225 450 1125 56 64 129 321
17 212 424 1059 57 63 126 316
18 200 400 1000 58 62 124 310
19 189 379 947 59 61 122 305
20 180 360 900 60 60 120 300
21 171 343 857 62 58 116 290
22 164 327 818 64 56 112 281
23 157 313 783 66 54 109 273
24 150 300 750 68 53 106 265
25 144 288 720 70 51 103 257
26 138 277 692 72 50 100 250
27 133 267 667 74 48 97 243
28 129 257 643 76 47 95 237
29 124 248 621 78 46 92 231
30 120 240 600 80 45 90 225
31 116 232 581 82 44 88 220
32 113 225 563 84 43 86 214
33 109 218 545 86 42 84 209
34 106 212 529 88 41 82 205
35 103 206 514 90 40 80 200
36 100 200 500 92 39 78 196
37 97 195 486 94 38 76 192
38 95 189 474 96 38 75 188
39 92 185 462 98 37 74 184
40 90 180 450 100 36 72 180
41 88 176 439 102 35 71 178
42 86 172 429 104 35 69 173
43 84 167 419 106 34 68 170
44 82 164 409 108 33 67 167
45 80 160 400 110 33 65 164
46 78 157 391 112 32 64 161
47 76 153 383 116 31 62 155
48 75 150 375 120 30 60 150
49 73 147 367
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