International comfort products R9MSB0601716A Installation instructions

Printed in U.S.A. 440 04 6000 00 8/05/13
SERVICE AND TECHNICAL
SUPPORT MANUAL
Single Stage, PSC Blower Motor
35” Tall, High Efficiency Condensing Gas Furnace
R9MSB
Save this manual for future reference.
Safety Labeling and Signal Words
DANGER, WARNING, CAUTION, and NOTE
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.
DANGER −Immediate hazards which will result in
severe personal 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 enhanced installation, reliability, or
operation.
!WARNING
Signal Words in Manuals
The signal word CAUTION is used throughout
this manual in the following manner:
!CAUTION
Signal Words on Product Labeling
Signal words are used in combination with
colors and/or pictures or product labels.
The signal word WARNING is used throughout
this manual in the following manner:
Safety−alert symbol
When you see this symbol on the unit and in
instructions or manuals, be alert to the
potential for personal injury.
TABLE OF CONTENTS
START-UP, ADJUSTMENT, AND SAFETY CHECK 3.....
GENERAL 3........................................
PRIME CONDENSATE TRAP WITH WATER 3..........
PURGE GAS LINES 3...............................
ADJUSTMENTS 3..................................
CHECK INLET GAS PRESSURE 4....................
ADJUST MANIFOLD PRESSURE 4...................
ADJUST TEMPERATURE RISE 6.....................
ADJUST BLOWER OFF DELAY) 6....................
BLOWER OFF DELAY JUMPER POSITIONS 6.........
ADJUST COOLING AIRFLOW 6......................
ADJUST THERMOSTAT HEAT ANTICIPATOR 6........
CHECK SAFETY CONTROLS 6......................
CHECKLIST 7......................................
ALTITUDE DERATE MULTIPLIER . 7..................
GAS RATE) 8......................................
ORIFICE SIZE AND MANIFOLD PRESSURE 10.........
SERVICE AND MAINTENANCE PROCEDURES 11......
PRESSURE SWITCHES 12...........................
CLEANING HEAT EXCHANGERS 18...................
SEQUENCE OF OPERATION 22......................
PARTS REPLACEMENT INFORMATION GUIDE 26......
MODELS
R9MSB0601716A
R9MSB0801716A
R9MSB1002122A
R9MSB1202422A
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 .

440 04 6000 00
Specifications are subject to change without notice.
2
SAFETY CONSIDERATIONS
Improper installation, adjustment, alteration, service,
maintenance, or use can cause explosion, fire, electrical shock,
or other conditions which may cause death, personal injury, or
property damage. Consult a qualified installer, service agency,
or your distributor or branch for information or assistance. The
qualified installer or agency must use factory−authorized kits or
accessories when modifying this product. Refer to the individual
instructions packaged with the kits or accessories when
installing.
Follow all safety codes. Wear safety glasses, protective clothing,
and work gloves. Use quenching cloth for brazing operations.
Have fire extinguisher available. Read these instructions
thoroughly and follow all warnings or cautions included in
literature and attached to the unit. Consult local building codes,
the current editions of the National Fuel Gas Code (NFCG)
NFPA 54/ANSI Z223.1, and the National Electrical Code (NEC)
NFPA 70.
In Canada refer to the current editions of the National standards
of Canada CAN/CSA−B149.1 and .2 Natural Gas and Propane
Installation Codes, and Canadian Electrical Code CSA C22.1.
Recognize safety information. This is the safety−alert symbol
. When you see this symbol on the unit and in instructions or
manuals, be alert to the potential for personal injury.
Understand these signal words; DANGER, WARNING, and
CAUTION. These words are used with the safety−alert symbol.
DANGER identifies the most serious hazards which will result in
severe personal injury or death. WARNING signifies hazards
which could result in personal injury or death. CAUTION is used
to identify unsafe practices which may result in minor personal
injury or product and property damage. NOTE is used to
highlight suggestions which will result in enhanced installation,
reliability, or operation.
!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.
!WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could cause personal
injury or death.
Before performing service or maintenance operations
on unit, always turn off main power switch to unit and
install lockout tag. Unit may have more than one power
switch.
!WARNING
CARBON MONOXIDE POISONING AND FIRE
HAZARD
Failure to follow safety warnings could result in personal
injury, death, and/or property damage.
This furnace is not designed for use in mobile homes,
trailers or recreational vehicles.
!CAUTION
CUT HAZARD
Failure to follow this caution may result in damage
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.

440 04 6000 00 3
Specifications subject to change without notice.
START−UP, ADJUSTMENT, AND SAFETY
CHECK
General
1. Furnace must have a 115-v power supply properly
connected and grounded.
NOTE: Proper polarity must be maintained for 115-v wiring.
Control status indicator light flashes rapidly and furnace
does not operate if polarity is incorrect or if the furnace is not
grounded.
2. Thermostat wire connections at terminals R, W, G,
and Y must be made at 24-v terminal block on
furnace control.
3. Natural gas service pressure must not exceed 0.5
psig (14- in. w.c., 1125 Pa), but must be no less than
0.16 psig (4.5-in. w.c., 350 Pa).
4. Blower door must be in place to complete 115-v elec-
trical circuit and supply power to the furnace
components.
UNIT OPERATION HAZARD
Failure to follow this caution may result in intermittent
unit operation or performance satisfaction.
These furnaces are equipped with a manual reset limit
switch in burner assembly. This switch opens and
shuts off power to the gas valve if an overheat
condition (flame rollout) occurs in the burner
assembly/enclosure. Correct inadequate
combustion−air supply, improper gas pressure setting,
improper burner or gas orifice positioning, or improper
venting condition before resetting switch. DO NOT
jumper this switch.
CAUTION
!
Before operating furnace, check flame rollout manual reset
switch for continuity. If necessary, press button to reset
switch.
EAC-1 (115vac) terminal is energized whenever blower
operates. HUM (24vac) terminal is only energized when the
low pressure switch (LPS) is closed on a call for heat.
Prime Condensate Trap with Water
CARBON MONOXIDE POISONING HAZARD
Failure to follow these warnings could result in personal
injury or death.
Failure to use a properly configured trap or NOT
water-priming trap before operating furnace may allow
positive pressure vent gases to enter the structure
through drain tube. Vent gases contain carbon
monoxide which is tasteless and odorless.
!WARNING
1. Remove upper and middle collector box drain plugs
opposite of the condensate trap. (See Figure 10.)
2. Connect field-supplied 5/8-in. (16 mm) ID tube with at-
tached funnel (see Figure 10) to upper collector box
drain connection.
3. Pour one quart (liter) of water into funnel/tube. Water
should run through collector box, overfill condensate
trap, and flow into open field drain.
4. Remove funnel; replace collector box drain plug.
5. Connect field-supplied 5/8-in. (16 mm) ID tube to
middle collector box drain port.
6. Pour one quart (liter) of water into funnel/tube. Water
should run through collector box, overfill condensate
trap, and flow into open field drain.
7. Remove funnel and tube from collector box and
replace collector box drain plug.
Purge Gas Lines
If not previously done, purge the lines after all connections
have been made and check for leaks.
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
Adjustments
FIRE HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
DO NOT bottom out gas valve regulator adjusting
screw. This can result in unregulated manifold
pressure and result in excess overfire and heat
exchanger failures.
!WARNING
FURNACE DAMAGE HAZARD
Failure to follow this caution may result in reduced
furnace life.
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 heat exchangers,
causing failures. (See Figure 1.)
CAUTION
!
BURNER
ORIFICE
A93059
Figure 1 −Orifice Hole
For proper operation and long term reliability the furnace
input rate must be within +/−2 percent of input rate on
furnace rating plate, or as adjusted for altitude.

4440 04 6000 00
Specifications subject to change without notice.
The gas input rate on rating plate is for installations at
altitudes up to 2000 ft. (609.6M).
NOTICE
The NATURAL GAS manifold pressure adjustments in Table
4 compensate for BOTH altitude AND gas heating value. DO
NOT apply an additional de−rate factor to the pressures
shown in Table 4. The values in this Table and NOT
referenced to sea level; they are AS−MEASURED AT
ALTITUDE.
The heating content of natural gas at altitude may already
provide for a reduction in capacity or altitude. Refer to Table
4. No adjustments to the furnace may be necessary at
altitude for certain gas heating values.
Refer to the instructions provided in the factory-specified
LP/Propane conversion kit for instructions for setting gas
manifold pressures for LP/Propane applications.
In the USA, 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 refer to Table 2. The natural gas manifold
pressures in Table 4 adjust for BOTH altitude and natural
gas heating value.
In Canada, the input rating must be reduced by 5 percent for
altitudes of 2000 ft. to 4500 ft. (610 to 1372 M) above sea
level. The natural gas manifold pressures in Table 4 adjust
for BOTH altitude and natural gas heating value.
NOTE: For Canadian altitudes of 2000 to 4500 ft. (610 to
1372 M), use USA altitudes of 2001 to 3000 ft. (611 to 914
M) in Table 4.
To adjust manifold pressure to obtain the proper input rate,
first, determine if the furnace has the correct orifice installed.
At higher altitudes or different gas heat contents, it may be
necessary to change the factory orifice to a different orifice.
Tables have been provided in the furnace installation
instructions to match the required orifice to the manifold
pressure to the heat content and specific gravity of the gas.
To do this:
1. Obtain average yearly gas heat value (at installed
altitude) from local gas supplier.
2. Obtain average yearly gas specific gravity from local
gas supplier.
3. Find installation altitude range for your installation in
the manifold pressure tables in Table 4.
4. Find closest natural gas heat value and specific grav-
ity in Table 4. Follow heat value and specific gravity
lines to point of intersection to find orifice size and
low-and high-heat manifold pressure settings for
proper operation.
5. Check and verify burner orifice size in furnace.
NEVER ASSUME ORIFICE SIZE. ALWAYS CHECK
AND VERIFY.
NOTICE
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.
6. Replace orifice with correct size, if required by Table
4. Use only factory−supplied orifices. See EXAMPLE
1.
EXAMPLE 1:
0 - 2000 ft. (0 - 609.6M) altitude
Heating value = 1050 Btu/cu ft.
Specific gravity = 0.62
Therefore: Orifice No. 44
(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.)
Manifold pressure: 3.4-in. w.c. (847 Pa).
NOTE: To convert gas manifold Table pressures to Pascals,
multiply the in.w.c. value by 249.1 Pa/in. w.c. (1 in. w.c. =
249.1 Pa).
Check Inlet Gas Pressure
The inlet gas pressure must be checked with the furnace
operating in maximum heat. This is necessary to make sure
the inlet gas pressure does not fall below the minimum
pressure of 4.5 in. w.c.
1. Make sure the gas supply is turned off to the furnace
and at the electric switch on the gas valve.
2. Remove the 1/8 in. NPT plug from the inlet pressure
tap on the gas valve.
3. Connect a manometer to the inlet pressure tap on gas
valve.
4. Turn on furnace power supply.
5. Turn gas supply manual shutoff valve to ON position.
6. Turn furnace gas valve switch to ON position.
7. Jumper R and W thermostat connections at the
furnace control board.
8. When main burners ignite, confirm inlet gas pressure
is between 4.5 in. w.c. (1125 Pa) and 13.6 in. w.c.
(3388 Pa).
9. Remove jumper across thermostat connections to
terminate call for heat. Wait until the blower off delay
is completed.
10. Turn furnace gas valve electric switch to OFF
position.
11. Turn gas supply manual shutoff valve to OFF
position.
12. Turn off furnace power supply.
13. Remove manometer from the inlet pressure tap of the
gas valve.
FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Re−install manifold pressure tap plug in gas valve to
prevent gas leak.
!WARNING
14. Apply pipe dope sparingly to end of inlet gas pipe
plug and re−install in the gas valve.
Adjust Manifold Pressure
1. Adjust manifold pressure to obtain proper gas input
rate. (See Figure 3.)
a. Turn gas valve ON/OFF switch to OFF.
b. Remove manifold pressure tap plug from gas valve.
c. Connect a water column manometer or similar
device to manifold pressure tap.
d. Turn gas valve ON/OFF switch to ON.
e. Manually close blower door switch.
f. Jumper R and W thermostat connections on control
to start furnace. (See Figure 2.)
g. Remove regulator adjustment cap from gas valve
pressure regulator (See Figure 3.) and turn adjusting
screw (3/16 or smaller flat−tipped screwdriver)
counterclockwise (out) to decrease input rate or
clockwise (in) to increase input rate.

440 04 6000 00 5
Specifications subject to change without notice.
NOTICE
DO NOT set low−heat manifold pressure less than 2.8−in.
w.c. (697 Pa) or more than 3.8−in. w.c. (947 Pa) for natural
gas. If required manifold pressure is outside this range,
change main burner orifices.
h. When correct input is obtained, replace cap that
conceals gas valve regulator adjustment screws.
Main burner flame should be clear blue, almost
transparent (See Figure 12.)
i. Remove jumper R to W.
j. Reinstall manifold pressure tap plug from gas valve.
2. Verify natural gas input rate by clocking meter.
NOTE: Contact your HVAC distributor or gas supplier for
metric gas meter Tables, if required.
a. Turn off all other gas appliances and pilots served by
the meter.
b. Jumper R to W.
c. Run furnace for 3 minutes.
d. Measure time (in sec) for gas meter to complete 1
revolution and note reading. The 2 or 5 cubic feet dial
provides a more accurate measurement of gas flow.
e. Refer to Table 3 for cubic ft. of gas per hr.
f. Multiply gas rate cu ft./hr by heating value (Btuh/cu
ft.) to obtain input. If clocked rate does not match
required input from Step 1, increase manifold
pressure to increase input or decrease manifold
pressure to decrease input. Repeat steps b through
e until correct input is achieved. Re−install regulator
seal cap on gas valve.
g. If clocked rate does not match required input from
Step 1, increase manifold pressure to increase
input or decrease manifold pressure to decrease
input. Repeat steps b through e of Step 1 until
correct heat input is achieved. Re--install regulator
seal cap on gas valve.
3. Restore furnace to normal operating condition.
a. Turn gas valve ON/OFF switch to OFF.
b. Remove water column manometer or similar
device from manifold pressure tap.
c. Replace manifold pressure tap plug to gas valve.
d. Turn gas valve ON/OFF switch to ON.
e. Check for gas leaks and verify furnace operation
FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Reinstall manifold pressure tap plug in gas valve to
prevent gas leak.
!WARNING
BLW
NUETRAL
STATUS CODE LED
SEC-2 SEC-1
EAC-2 L2
FUSE 3-AMP
0.5 AMP@24VAC
HUM
TEST/TWIN
G Com W Y R
24V
120 180
90 150
BLOWER OFF-DELAY
COOL HEAT
SPARE-1 SPARE-2 PR-1
L1
PL2 1
24-V THERMOSTAT
TERMINALS
3-AMP FUSE
LED OPERATION &
DIAGNOSTIC LIGHT
115-VAC(L2)NEUTRAL
CONNECTIONS
COOL
HEAT
SPARE-1
SPARE-2
BLOWER SPEED
SELECTION TERMINALS
EAC-1 TERMINAL
(115-VAC 1.0 AMP MAX.)
115 VAC (L1) LINE
VOLTAGE CONNECTION
PL2-HOT SURFACE
IGNITER & INDUCER
MOTOR CONNECTOR
PL1-LOW VOLTAGE MAIN
HARNESS CONNECTOR
TRANSFORMER 24-VAC
CONNECTIONS
HUMIDIFIER TERMINAL
(24-VAC 0.5 AMP MAX.)
TWINNING AND/OR
COMPONENT TEST
TERMINAL
BLOWER OFF-DELAY
J2
J2 JUMPER
PLT
PL1
SPARE-3
SPARE-3
1
A11619
Figure 2 −Example of Single Stage Furnace Control

6440 04 6000 00
Specifications subject to change without notice.
Adjust Temperature Rise
NOTE: Blower door must be installed when taking
temperature rise reading. Leaving blower door off will result
in incorrect temperature measurements, due to possible
changes in duct static pressure and airflow.
FURNACE DAMAGE HAZARD
Failure to follow this caution may result in:
SOverheating the heat exchangers or
condensing flue gases in heat exchanger
areas not designed for condensate.
SShortened furnace life.
SComponent damage.
Temperature rise must be within limits specified on
furnace rating plate. Recommended operation is at
midpoint of rise range or slightly above.
CAUTION
!
Jumper R to W to check gas-heat temperature rise. Do not
exceed temperature rise ranges specified on unit rating
plate.
This furnace must operate within the temperature rise
ranges specified on the furnace rating plate. Determine the
air temperature as follows:
1. Place duct thermometers in return and supply ducts
as close to furnace as possible. Be sure
thermometers do not “see” heat exchangers so that
radiant heat does not affect thermometer readings.
This is particularly important with straight−run ducts.
2. When thermometer readings stabilize, subtract
return−air temperature from supply−air temperature to
determine temperature rise.
If the temperature rise is outside this range, check the
following:
1. Gas input rate.
2. Derate for altitude if applicable.
3. Return and supply ducts for excessive restrictions
causing static pressures greater than 0.50−in. w.c.
(125 Pa)
4. Adjust temperature rise by adjusting blower speed.
SIncrease blower speed to reduce temperature rise.
SDecrease blower speed to increase temperature
rise.
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal
injury or death.
Disconnect 115vac electrical power before changing
speed tap.
!WARNING
(Read following caution before changing taps).
UNIT DAMAGE HAZARD
To avoid operating outside the rise range and avoid
component damage:
Refer to the Air Delivery Tables to determine which
airflows and settings are allowed for proper heating
airflow. DO NOT use the highlighted settings for
Heating airflow. The highlighted settings are to be used
for Cooling and Continuous Fan ONLY.
CAUTION
!
Change the blower speed taps as required to maintain
proper temperature rise for Heating and Cooling as
described above. To change blower motor speed selections
for heating mode, remove blower motor lead from control
HEAT terminal(s). (See Figure 2) Select desired blower
motor speed lead(s) from the other motor leads and relocate
it/them to HEAT (heating blower tap) terminal(s). Reconnect
original lead on SPARE terminal.
Adjust Blower Off Delay (Heat Mode)
If desired, the main blower off time delay period may be
lengthened or shortened when operating in the heating
mode to provide greater comfort. For position and location
of jumpers on control center. (See Figure 2 and Figure 16)
The blower off-delay has four adjustable settings from 90
sec to 180 sec. (See Table 1) To change the blower off
delay setting, move the jumper from one set of pins on the
control to the pins used for the desired blower off delay.
Factory blower off-delay setting is 120 sec.
Table 1 – Blower Off Delay Jumper Positions
PINS 1 AND 2 2 AND 3 3 AND 4 4 AND 5
Time (in sec.) 90 120 150 180
Adjust Cooling Airflow
The cooling airflow can be set from the remaining blower
speed taps. Refer to the Air Delivery Tables in these
instructions.
FURNACE OVERHEATING HAZARD
Failure to follow this caution may result in reduced
furnace life.
Recheck temperature rise. It must be within limits
specified on the rating plate. Recommended operation
is at the mid--point of rise range or slightly above.
CAUTION
!
Adjust Thermostat Heat Anticipator
Mechanical thermostat: Set thermostat heat anticipator to
match the amp. draw of the electrical components in the
R-W circuit. Accurate amp. draw readings can be obtained
at the wires normally connected to thermostat sub-base
terminals, R and W. The thermostat anticipator should NOT
be in the circuit while measuring current.
1. Remove thermostat from sub-base or from wall.
2. Connect an amp. meter across the R and W
sub-base terminals or R and W wires at wall.
3. Record amp. draw across terminals when furnace is
in low heat and after blower starts.
4. Set heat anticipator on thermostat per thermostat
instructions and install on sub-base or wall.
5. Install blower access door.
Electronic thermostat: Set cycle rate for 3 cycles per hr.
Check Safety Controls
The flame sensor, gas valve, and pressure switch were all
checked in the Start−up procedure section as part of normal
operation.
1. Check Main Limit Switch
This control shuts off combustion system and
energizes air−circulating blower motor, if furnace
overheats. By using this method to check the temper-
ature limit control, it can be established that the limit is
functioning properly and that the limit will operate if
there is a restricted return−air supply or motor failure.
If the limit control does not function during this test,
the cause must be determined and corrected.
a. Run furnace for at least 5 minutes.
b. Gradually block off return air with a piece of
cardboard or sheet metal until the limit trips.
c. Unblock return air to permit normal circulation.

440 04 6000 00 7
Specifications subject to change without notice.
d. Burners will re−light when furnace cools down.
2. Check Pressure Switch(es)
This control proves operation of the draft inducer
blower.
a. Turn off 115−v power to furnace.
b. Disconnect inducer motor lead wires from wire
harness.
c. Turn on 115−v power to furnace.
d. Set thermostat to “call for heat” and wait 1 minute.
When low pressure switch is functioning properly, hot
surface igniter should NOT glow and control
diagnostic light flashes a status code 31. If hot
surface igniter glows when inducer motor is
disconnected, shut down furnace immediately.
e. Determine reason low pressure switch did not
function properly and correct condition.
f. Turn off 115−v power to furnace.
g. Reconnect inducer motor wires, replace door, and
turn on 115−v power.
h. Blower will run for 90 sec before beginning the call
for heat again.
i. Furnace should ignite normally.
Checklist
1. Put away tools and instruments. Clean up debris.
2. Verify that the jumper is removed from the TEST/
TWIN terminal. Verify that there is nothing plugged in-
to the PLT connector.
NOTE: If there is a jumper connector plugged into PLT,
remove it and discard. (See Figure 2)
3. Verify that the Blower/Heat Off Delay jumpers are set
as desired. (See Figure 2 and Figure 16)
4. Verify that the blower (lower door in upflow position)
and control (“Main” or upper door in upflow position)
doors are properly installed.
5. Verify that the Status LED glows. If not, check that the
power supply is energized and that the blower door is
secure. See Figure 5 to interpret diagnostic codes.
6. Cycle test furnace with room thermostat to be sure
that it operates properly with the room thermostat.
Check all modes including Heat, Cool and Fan.
7. Check operation of accessories per manufacturer’s
instructions.
8. Review Owner’s Manual with owner.
9. Attach literature packet to furnace.
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.
ON/OFF Switch
Regulator Seal Cap
Regulator Adjustment
Regulator Seal Cap under Cap
1/2”NPT Outlet
1/8”NPT Manifold
Pressure Tap
1/8”NPT Inlet
Pressure Tap
1/2”NPT Inlet
SINGLE-STAGE
A11153
Figure 3 −Gas Valve
R Y W G
10 TURNS
THERMOSTAT SUBBASE
TERMINALS WITH
THERMOSTAT REMOVED
(ANITICIPATOR, CLOCK, ETC.,
MUST BE OUT OF CIRCUIT.)
HOOK-AROUND
AMMETER
EXAMPLE: 5.0 AMPS ON AMMETER
10 TURNS AROUND JAWS
= 0.5 AMPS FOR THERMOSTAT
ANTICIPATOR SETTING
FROM UNIT 24-V
CONTROL TERMINALS
A96316
Figure 4 −Amp. Draw Check with Ammeter

8440 04 6000 00
Specifications subject to change without notice.
Table 3 – 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

440 04 6000 00 9
Specifications subject to change without notice.
338309-201 Rev. E
A11602
Figure 5 −Service Label Information

10 440 04 6000 00
Specifications subject to change without notice.
Table 4 – 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

440 04 6000 00 11
Specifications subject to change without notice.
Table 4 −Orifice Size and Manifold Pressure (in. w.c.) for Gas Input Rate (Cont.)
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
A11253B
SERVICE AND MAINTENANCE
PROCEDURES
FIRE, INJURY OR DEATH HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
The ability to properly perform maintenance on this
equipment requires certain knowledge, mechanical
skills, tools, and equipment. If you do not possess
these, do not attempt to perform any service and
maintenance on this equipment other than those
procedures recommended in the Owner’s Manual.
!WARNING
ENVIRONMENTAL HAZARD
Failure to follow this caution may result in
environmental pollution.
Remove and recycle all components or materials (i.e.
oil, refrigerant, control board, etc.) before unit final
disposal.
CAUTION
!
ELECTRICAL SHOCK, FIRE OR EXPLOSION
HAZARD
Failure to follow this warning could result in personal
injury or 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.
!WARNING
ELECTRICAL OPERATION HAZARD
Failure to follow this caution may result in improper
furnace operation or failure of furnace.
Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and
dangerous operation.
CAUTION
!
General
These instructions are written as if the furnace is installed in
an upflow application. An upflow furnace application is
where the blower is located below the combustion and
controls section of the furnace, and conditioned air is
discharged upward. Since this furnace can be installed in
any of the 4 positions shown in Figure 6, you must revise
your orientation to component location accordingly.

12 440 04 6000 00
Specifications subject to change without notice.
Electrical Controls and Wiring
Pressure Switches
Each pressure switch is labeled with the reference location
(noted as “COLLECTOR BOX−LPS” or “HOUSING−HPS”
ON THE SWITCH). The nominal break point of each switch
is shown on the label below the reference location in inches
of water column, “W.C.” The maximum and minimum break
point of the switch is +/−0.05 inches of water column from
the nominal break point of the switch. The maximum make
point of the switch is 0.10 inches of water above the
maximum break point of the switch
Example: Nominal break point on pressure switch is
0.68−in. W.C. The minimum break point of the switch is
0.63−in. W.C. The maximum break point of the switch is
0.73−in. W.C. The maximum make point of the switch is
0.83−in. W.C.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
There may be more than one electrical supply to the
furnace. Check accessories and cooling unit for
additional electrical supplies that must be shut off
during furnace servicing. Lock out and tag switch with
a suitable warning label.
!WARNING
The electrical ground and polarity for 115−v wiring must be
properly maintained. Refer to Figure 7 for field wiring
information and to Figure 16 for furnace wiring information.
NOTE: If the polarity is not correct, the STATUS LED on the
control will flash rapidly and prevent the furnace from
heating. The control system also requires an earth ground
for proper operation of the control and flame−sensing
electrode.
The 24−v circuit contains an automotive−type, 3−amp. fuse
located on the control. (See Figure 2.) Any shorts of the
24−v wiring during installation, service, or maintenance will
cause this fuse to blow. If fuse replacement is required, use
ONLY a 3−amp. fuse. The control LED will display status
code 24 when fuse needs to be replaced.
Troubleshooting
Refer to the service label. (See Figure 5—Service Label.)
The Troubleshooting Guide (See Figure 15) can be a useful
tool in isolating furnace operation problems. Beginning with
the word “Start,” answer each question and follow the
appropriate arrow to the next item.
The Guide will help to identify the problem or failed
component. After replacing any component, verify correct
operation sequence.
Proper instrumentation is required to service electrical
controls. The control in this furnace is equipped with a
Status Code LED (Light−Emitting Diode) to aid in
installation, servicing, and troubleshooting. Status codes
can be viewed at the indicator in blower door. The amber
furnace control LED is either ON continuously, rapid
flashing, or a code composed of 2 digits. The first digit is the
number of short flashes, the second digit is the number of
long flashes.
For an explanation of status codes, refer to service label
located on control door or Figure 5, and the troubleshooting
guide which can be obtained from your distributor.
Retrieving Stored Fault Codes
NOTE: Fault codes cannot be retrieved if a thermostat
signal (24-v on W, Y, G, etc.) is present, or if any delays
such as blower off-delays are active.
The stored status codes will NOT be erased from the control
memory when 115- or 24-v power is interrupted. See the
Service Label (Figure 5) for more information. The most
recent fault code may be retrieved as follows:
1. Leave 115-v power connected to furnace.
2. Observe the status LED through the blower door (the
lower door on upflow applications) indicator. Refer to
the Service Label (Figure 5) to interpret the LED.
3. Remove the Main/Control door (the upper door on
upflow installations).
4. BRIEFLY (2−3 seconds) disconnect and reconnect
ONE of the main limit wires.
5. The LED will flash the last stored fault code. Refer to
the Service Label (Figure 5) to interpret the LED.
6. A component test sequence will follow.
7. Reinstall the Main/Control door.
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
Figure 6 −Multipoise Orientations

440 04 6000 00 13
Specifications subject to change without notice.
115-V FIELD-
SUPPLIED
DISCONNECT
AUXILIARY
J-BOX
24-V
TERMINAL
BLOCK
THREE-WIRE
HEATING-ONLY
FIVE WIRE
NOTE 1
NOTE 2
FIELD-SUPPLIED
DISCONNECT
CONDENSING
UNIT
TWO
WIRE
FURNACE
C
O
N
T
R
O
L
R
G
COM
WCR GY
GND
GND
FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-V WIRING
208/230- OR
460-V
THREE
PHASE
208/230-V
SINGLE
PHASE
BLOWER DOOR SWITCH
WHT
BLK
WHT
BLK
NOTES: Connect Y-terminal in furnace as shown for proper blower operation.
Some thermostats require a "C" terminal connection as shown.
If any of the original wire, as supplied, must be replaced, use
same type or equivalent wire.
W
Y
GND
THERMOSTAT
TERMINALS
1.
2.
3.
A11387
Figure 7 −Typical Single−Stage Wiring Diagram
Component Self-Test
NOTE: The furnace control component test allows all
components to run for a short time; except the gas valve
and humidifier terminal HUM are not energized. The EAC-1
terminal is energized when the blower is energized. This
feature helps diagnose a system problem in case of a
component failure. The component test feature will not
operate if any thermostat signal is present at the control and
not until all time delays are completed.
To Begin Component Self-Test:
1. Remove blower access door.
2. Disconnect the thermostat R lead from furnace
control.
3. Manually close blower door switch.
Caution must be taken when manually closing this switch for
service purposes.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury, or death.
Blower door switch opens 115−v power to furnace
control. No component operation can occur unless
switch is closed. Exercise caution to avoid electrical
shock from exposed electrical components when
manually closing this switch for service purposes.
!WARNING
4. For approximately 2 sec, short (jumper) the COM-24v
terminal on control to the TEST/TWIN 3/16—in. (5
mm) quick-connect terminal on control until the LED
goes off. Remove jumper from terminals. (See
Figure 2.)
NOTE: If TEST/TWIN and COM-24v terminals are
jumpered longer than 2 sec, LED will flash rapidly and
ignore component test request.
Component test sequence is as follows:
a. LED will display previous status code 4 times.
b. Inducer motor starts and continues to run until Step
f of component test sequence.
c. After 7 sec the hot surface igniter is energized for
15 sec., then off.
d. Blower motor operates on HEAT speed for 10 sec.
e. Blower motor operates on COOL speed for 10 sec.
f. Inducer motor stops.
5. Reconnect R lead to furnace control, remove tape
from blower door switch, and re-install blower door.
6. Verify furnace shut down by lowering thermostat
setting below room temperature.
7. Verify that furnace restarts by raising thermostat
setting above room temperature.
Checklist
1. Put away tools and instruments. Clean up debris.
2. Verify that the jumper is removed from the TEST/
TWIN terminal. Verify that there is nothing plugged
into the PLT connector. (Note: If there is a jumper
connector plugged into PLT, remove it and discard.)
(See Figure 2.)
3. Verify that the Blower/Heat Off Delay jumpers are set
as desired. (See Figure 2.)
4. Verify that the blower and control (“Main”) doors are
properly installed.
5. Verify that the Status LED glows. If not, check that the
power supply is energized and that the blower door is
secure. (See Figure 5.)
6. Cycle test furnace with room thermostat to be sure
that it operates properly with the room thermostat.
Check all modes including Heat, Cool and Fan.
7. Check operation of accessories per manufacturer’s
instructions.
8. Review Owner’s Manual with owner.
9. Attach entire literature packet to furnace.

14 440 04 6000 00
Specifications subject to change without notice.
Care and Maintenance
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
Never store flammable or combustible materials on,
near, or in contact with the furnace, such as:
1. Spray or aerosol cans, rags, brooms, dust
mops, vacuum cleaners, or other cleaning
tools.
2. Soap powders, bleaches, waxes or other
cleaning compounds, plastic or plastic
containers, gasoline, kerosene, cigarette lighter
fluid, dry cleaning fluids, or other volatile fluids.
3. Paint thinners and other painting compounds,
paper bags, or other paper products. Exposure
to these materials could lead to corrosion of the
heat exchangers.
!WARNING
For continuing high performance and to minimize possible
furnace failure, periodic maintenance must be performed on
this furnace. Consult your local dealer about proper
frequency of maintenance and the availability of a
maintenance contract.
ELECTRICAL SHOCK AND FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Turn off the gas and electrical supplies to the furnace
and install lockout tag before performing any
maintenance or service. Follow the operating
instructions on the label attached to the furnace.
!WARNING
CARBON MONOXIDE POISONING AND FIRE
HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
Never operate furnace without a filter or filtration
device installed. Never operate a furnace with filter or
filtration device access doors removed.
!WARNING
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
!
The minimum maintenance on this furnace is as follows:
1. Check and clean air filter each month or more
frequently if required. Replace if torn.
2. Check blower motor and wheel for cleanliness each
heating and cooling season. Clean as necessary.
3. Check electrical connections for tightness and
controls for proper operation each heating season.
Service as necessary.
4. Inspect burner compartment before each heating
season for rust, corrosion, soot or excessive dust. If
necessary, have furnace and burner serviced by a
qualified service agency.
5. Inspect the vent pipe/vent system before each
heating season for water leakage, sagging pipes or
broken fittings. Have vent pipes/vent system serviced
by a qualified service agency.
6. Inspect any accessories attached to the furnace such
as a humidifier or electronic air cleaner. Perform any
service or maintenance to the accessories as
recommended in the accessory instructions.
Cleaning and/or Replacing Air Filter
The air filter type may vary depending on the application or
orientation. The filter is external to the furnace casing. There
are no provisions for an internal filter with this furnace. See
“Filter Arrangement” under the “Installation” section of this
manual.
CARBON MONOXIDE POISONING AND FIRE
HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
Never operate furnace without a filter or filtration
device installed. Never operate a furnace with filter or
filtration device access doors removed.
!WARNING
NOTE: If the filter has an airflow direction arrow, the arrow
must point toward the blower.
To clean or replace filters, proceed as follows:
ELECTRICAL SHOCK, FIRE OR EXPLOSION
HAZARD
Failure to follow this warning could result in personal
injury or 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.
!WARNING
1. Turn off electrical supply to furnace.
2. Remove filter cabinet door.
3. Slide filter out of cabinet.
4. If equipped with permanent, washable filter, clean
filter by spraying cold tap water through filter in
opposite direction of airflow. Rinse filter and let dry.
Oiling or coating of the filter is not recommended.
5. If equipped with factory specified disposable media
filter, replace only with a factory specified media filter
of the same size.
6. Slide filter into cabinet.
7. Replace filter cabinet door.
8. Turn on electrical supply to furnace.

440 04 6000 00 15
Specifications subject to change without notice.
Blower Motor and Wheel Maintenance
To ensure long life, economy, and high efficiency, clean
accumulated dirt and grease from blower wheel and motor
annually.
The inducer and blower motors are pre−lubricated and
require no additional lubrication. These motors can be
identified by the absence of oil ports on each end of the
motor.
The following items should be performed by a qualified
service technician. Clean blower motor and wheel as
follows:
1. Turn off electrical supply to furnace.
2. Remove blower door.
3. All factory wires can be left connected, but field
thermostat and accessory wiring may need to be
disconnected depending on their length and routing.
4. If the vent and combustion air pipe passes through
the blower compartment, it will be necessary to
remove the pipes from the blower compartment.
Disconnect the vent and combustion air pipe by:
a. Loosen the clamps on the vent couplings and
combustion air pipe external to the furnace.
b. Separate the pipes from the couplings and move
them aside.
c. Loosen the clamps on the vent couplings and
combustion air pipe located on the blower shelf.
d. Separate the pipes from the blower compartment
and set aside.
e. Remove the couplings from the pipe adapters and
set aside.
f. After servicing the blower, reverse steps a through
e.
g. Tighten all clamps 15 lb −in.
See Figure 13 for steps 5 through 14.
5. Remove screws securing blower assembly to blower
shelf and slide blower assembly out of furnace.
Detach ground wire and disconnect blower motor
harness plugs from blower motor.
NOTE: Blower wheel is fragile. Use care.
6. Clean blower wheel and motor by using a vacuum
with soft brush attachment. Be careful not to disturb
balance weights (clips) on blower wheel vanes. Do
not bend wheel or blades as balance will be affected.
7. If greasy residue is present on blower wheel, remove
wheel from the blower housing and wash it with an
appropriate degreaser. To remove wheel:
a. Mark blower wheel location on shaft before
disassembly to ensure proper reassembly.
b. Loosen setscrew holding blower wheel on motor
shaft.
NOTE: Mark blower mounting arms and blower housing so
each arm is positioned at the same hole location during
reassembly.
c. Mark blower wheel orientation and cutoff plate
location to ensure proper reassembly.
d. Remove screws securing cutoff plate and remove
cutoff plate from housing.
e. Remove bolts holding motor mounts to blower
housing and slide motor and mounts out of housing.
f. Remove blower wheel from housing.
g. Clean wheel per instructions on degreaser cleaner.
Do not get degreaser in motor.
8. Reassemble motor and blower wheel by reversing
items 7b through 7f. Ensure wheel is positioned for
proper rotation.
9. Torque motor mounting bolts to 40 +/−10 lb−in. when
reassembling.
10. Torque blower wheel set screw to 160 +/−20 lb−in.
when reassembling.
11. Verify that blower wheel is centered in blower housing
and set screw contacts the flat portion of the motor
shaft. Loosen set screw on blower wheel and
reposition if necessary.
12. Spin the blower wheel by hand to verify that the wheel
does not rub on the housing.
13. Reinstall blower assembly in furnace.
14. Reinstall 2 screws securing blower assembly to
blower deck.
15. Reconnect blower leads to furnace control. Refer to
furnace wiring diagram, and connect thermostat leads
if previously disconnected.
NOTE: Be sure to attach ground wire and reconnect blower
harness plugs to blower motor.
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal
injury or death.
Blower door switch opens 115−v power to control. No
component operation can occur unless switch is closed.
Caution must be taken when manually closing this
switch for service purposes.
!WARNING
16. Downflow or horizontal furnaces with vent pipe
through furnace only:
a. Install and connect short piece of vent pipe inside
furnace to existing vent.
b. Connect vent connector to vent elbow.
17. Turn on electrical supply. Manually close blower door
switch. Use a piece of tape to hold switch closed.
Check for proper rotation and speed changes
between heating and cooling by jumpering R to G and
R to Y/Y2 on furnace control thermostat terminals. If
outdoor temperature is below 70_F (21_C), turn off
circuit breaker to outdoor unit before running furnace
in the cooling cycle. Turn outdoor circuit breaker on
after completing cooling cycle. (See Figure 2.)
NOTE: If R−W/W1 thermostat terminals are jumpered at the
time blower door switch is closed, blower will run for 90 sec
before beginning a heating cycle.
a. Perform component self−test as shown at the bottom
of the SERVICE label, located on the control door.
b. Verify blower is rotating in the correct direction
18. If furnace is operating properly, RELEASE BLOWER
DOOR SWITCH. Remove any jumpers or reconnect
any disconnected thermostat leads. Replace blower
door.
19. Turn on gas supply and cycle furnace through one
complete heating cycle. Verify the furnace
temperature rise as shown in Adjustments Section.
Adjust temperature rise as shown in Adjustments
Section.
Cleaning Burners and Flame Sensor
The following items must be performed by a qualified
service technician. If the burners develop an accumulation

16 440 04 6000 00
Specifications subject to change without notice.
of light dirt or dust, they may be cleaned by using the
following procedure:
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 assembly.
ELECTRICAL SHOCK AND FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Turn off the gas and electrical supplies to the furnace
and install lockout tag before performing any
maintenance or service. Follow the operating
instructions on the label attached to the furnace.
!WARNING
Refer to Figure 14.
1. Disconnect power at external disconnect, fuse or
circuit breaker.
2. Turn off gas at external shut-off or gas meter.
3. Remove control door and set aside.
4. Turn electric switch on gas valve to OFF.
5. Disconnect the gas pipe from gas valve and remove
pipe from the furnace casing.
6. Remove individual wires from terminals on gas valve.
7. Disconnect Hot Surface Igniter (HSI) wires from HSI.
8. Disconnect Flame Sensor wire from Flame Sensor.
9. Support the manifold and remove the 4 screws that
secure the manifold assembly to the burner assembly
and set aside. Note the location of the green/yellow
wire and ground terminal.
10. Inspect the orifices in the manifold assembly for
blockages or obstructions. Remove orifice and clean
or replace orifice.
11. Remove the four screws that attach the top plate of
the casing to the furnace.
12. Raise top plate up slightly and prop it up with a small
piece of wood or folded cardboard.
13. Support the burner assembly and remove the screws
that attach the burner assembly to the heat
exchanger cell panel.
14. Remove wires from both rollout switches.
15. Slide one--piece burner out of slots on sides of burner
assembly.
16. Remove the flame sensor from the burner assembly.
17. (Optional) Remove the Hot Surface Igniter (HSI) and
bracket from the burner assembly.
18. Check igniter resistance. Nominal resistance is 40 to
70 ohms at room temperature and is stable over the
life of the igniter.
19. Clean burner with a brush and a vacuum.
20. Clean the flame sensor with fine steel wool (0000
grade). Do not use sand paper or emery cloth.
To reinstall burner assembly:
1. Install the Hot Surface Igniter (HSI) and bracket in
burner assembly.
2. Install flame sensor on burner.
3. Align the edges of the one-piece burner with the slots
in the burner assembly and slide the burners forward
until they are fully seated in the burner assembly.
4. Align the orifices in the manifold assembly with the
support rings on the end of the burner.
5. Insert the orifices in the support rings of the burners.
NOTE: If manifold does not fit flush against the burner, do
not force the manifold on the burner assembly. The burners
are not fully seated forward in the burner assembly. Remove
the manifold and check burner positioning in the burner
assembly assembly before re-installing the manifold.
6. Attach the green/yellow wire and ground terminal to
one of the manifold mounting screws.
7. Install the remaining manifold mounting screws.
8. Check the igniter alignment. See Figure 8, Figure 9
and Figure 14.
9. Attach the wires to the roll-out switches.
10. Align the burner assembly with the openings in the
primary cell inlet panel and attach the burner
assembly to the cell panel.
11. Connect the wire for the flame sensor.
12. Connect the wire for the Hot Surface Igniter.
NOTE: Use propane-resistant pipe dope to prevent leaks.
Do not use Teflon tape.
13. Install the gas pipe to the gas valve.
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
14. Check for gas leaks with a commercially available
soap solution made specifically for the detection of
leaks.
15. Turn gas on at electric switch on gas valve and at
external shut-off or meter
16. Turn power on at external disconnect, fuse or circuit
breaker.
17. Run the furnace through two complete heating cycles
to check for proper operation
18. Install control door when complete.
Servicing Hot Surface Igniter
The igniter does NOT require annual inspection. Check
igniter resistance before removal. Refer to Figure 8,
Figure 9 and Figure 14.
1. Turn off gas and electrical supplies to furnace.
2. Remove control door.
3. Disconnect igniter wire connection.
4. Check igniter resistance. Igniter resistance is affected
by temperature. Only check resistance when the
igniter is at room temperature.
a. Using an ohm meter, check resistance across both
igniter leads in connector.
b. Cold reading should be between 40 ohms and 70
ohms.
5. Remove igniter assembly.
a. Using a 1/4−in. driver, remove the two screws
securing the igniter mounting bracket to the burner
assembly (See Figure 14 .)
b. Carefully withdraw the igniter and bracket assembly
through the front of the burner assembly without
striking the igniter on surrounding parts.

440 04 6000 00 17
Specifications subject to change without notice.
c. Inspect igniter for signs of damage or failure.
d. If replacement is required, remove the screw that
secures the igniter on igniter bracket and remove the
igniter.
6. To replace igniter and bracket assembly, reverse
items 5a through 5d.
7. Reconnect igniter harness to the igniter, dressing the
igniter wires to ensure there is no tension on the
igniter itself. (See Figure 14.)
8. Turn on gas and electrical supplies to furnace.
9. Verify igniter operation by initiating control board self−
test feature or by cycling thermostat.
10. Replace control door.
Flushing Collector Box and Drainage System
ELECTRICAL SHOCK AND FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Turn off the gas and electrical supplies to the furnace
and install lockout tag before performing any
maintenance or service. Follow the operating
instructions on the label attached to the furnace.
!WARNING
1. Turn off gas and electrical supplies to furnace.
2. Remove control door.
3. Disconnect pressure switch tube from pressure
switch port.
NOTE: Ensure the pressure switch tube disconnected from
the pressure switch is higher than the collector box opening
or water will flow out of tube.
4. Remove the collector box plug from the top port on
the upper corner of the collector box. (See Figure 10)
5. Attach a funnel with a flexible tube to port on the
collector box.
6. Flush inside of collector box with water until discharge
water from condensate trap is clean and runs freely.
7. Repeat steps 4 thru 6 with middle plug on upper
corner of collector box.
8. Remove the pressure switch tube from the collector
box.
NOTE: Do NOT blow into tube with tube connected to the
pressure switch.
9. Clean pressure switch port on collect box with a small
wire. Shake any water out of pressure switch tube.
10. Reconnect tube to pressure switch and pressure
switch port.
11. Remove the relief tube from the port on the collector
box and the trap.
12. Clean the relief port on collect box and the trap with a
small wire. Shake any water out of the tube.
13. Reconnect relief tube to trap and collector box ports.
Cleaning Condensate Drain and Trap
NOTE: If the condensate trap is removed, a new gasket
between the trap and collector box is required. Verify a
condensate trap gasket is included in the service kit or
obtain one from your local distributor.
1. Disconnect power at external disconnect, fuse or
circuit breaker.
2. Turn off gas at external shut-off or gas meter.
3. Remove control door and set aside.
4. Turn electric switch on gas valve to OFF.
5. Disconnect external drain from condensate drain
elbow or drain extension pipe inside the furnace and
set aside.
6. Disconnect the condensate trap relief hose from
collector box port and condensate trap.
NOTE: If condensate has a heat pad attached to the trap,
trace the wires for the pad back to the connection point and
disconnect the wires for the heat pad.
7. Remove the screw that secures the condensate trap
to the collector box, remove the trap and set aside.
8. Remove the trap gasket from the collector box if it did
not come off when the trap was removed.
9. Discard the old trap gasket.
10. Rinse condensate trap in warm water until trap is
clean.
11. Flush condensate drain lines with warm water.
Remember to check and clean the relief port on the
collector box.
12. Shake trap dry.
13. Clean port on collector box with a small wire.
To re-install Condensate Drain and Trap:
1. Remove adhesive backing from condensate trap
gasket
2. Install gasket on collector box
3. Align the condensate trap with the drain opening on
the collector box and secure the trap with the screw
4. Attach the relief hose to the relief port on the
condensate trap and collector box.
5. Secure tubing to prevent any sags or traps in the
tubing.
6. Connect condensate drain elbow or drain extension
elbow to the condensate trap
7. Connect the leads of the condensate heat pad (if
used)
8. Connect external drain piping to the condensate drain
elbow or drain extension pipe.
9. Turn gas on at electric switch on gas valve and at
external shut-off or meter
10. Turn power on at external disconnect, fuse or circuit
breaker.
11. Run the furnace through two complete heating cycles
to check for proper operation
12. Install control door when complete.
Checking Heat Pad Operation (If Applicable)
In applications where the ambient temperature around the
furnace is 32_F (0_C) or lower, freeze protection measures
are required. If this application is where heat tape has been
applied, check to ensure it will operate when low
temperatures are present.
NOTE: The Heat Pad, when used, should be wrapped
around the condensate drain trap. There is no need to use
heat tape within the furnace casing. Most heat tapes are
temperature activated, and it is not practical to verify the
actual heating of the tape. Check the following:
1. Check for signs of physical damage to heat tape such
as nicks, cuts, abrasions, gnawing by animals, etc.
2. Check for discolored heat tape insulation. If any
damage or discolored insulation is evident, replace
heat tape.
3. Check that heat tape power supply circuit is on.
Cleaning Heat Exchangers
The following items must be performed by a qualified
service technician.

18 440 04 6000 00
Specifications subject to change without notice.
Primary Heat Exchangers
If the heat exchangers get an accumulation of light dirt or
dust on the inside, they may be cleaned by the following
procedure:
NOTE: If the heat exchangers get a heavy accumulation of
soot and carbon, both the primary and secondary heat
exchangers should be replaced rather than trying to clean
them thoroughly due to their intricate design. A build−up of
soot and carbon indicates that a problem exists which
needs to be corrected, such as improper adjustment of
manifold pressure, insufficient or poor quality combustion
air, improper vent termination, incorrect size or damaged
manifold orifice(s), improper gas, or a restricted heat
exchanger (primary or secondary). Action must be taken to
correct the problem.
1. Turn off gas and electrical supplies to furnace.
ELECTRICAL SHOCK, FIRE OR EXPLOSION
HAZARD
Failure to follow this warning could result in personal
injury or 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.
!WARNING
ELECTRICAL SHOCK AND FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Turn off the gas and electrical supplies to the furnace
and install lockout tag before performing any
maintenance or service. Follow the operating
instructions on the label attached to the furnace.
!WARNING
2. Remove control door.
3. Disconnect wires or connectors to flame rollout
switch, gas valve, igniter, and flame sensor.
4. Using backup wrench, disconnect gas supply pipe
from furnace gas control valve.
5. Remove two screws attaching top filler plate and
rotate upwards to gain access to screws attaching
burner assembly to cell panel.
6. Remove screws attaching burner assembly to cell
panel. (See Figure 14.)
NOTE: Burner cover, manifold, gas valve, and burner
assembly should be removed as one assembly.
7. Clean heat exchanger openings with a vacuum and a
soft brush. (See Figure 11.)
NOTE: After cleaning, inspect the heat exchangers to
ensure they are free of all foreign objects that may restrict
flow of combustion products.
8. Reverse items 6 through 1 for reassembly.
9. Refer to furnace wiring diagram and reconnect wires
to flame rollout switch, gas valve, igniter, and flame
sensor.
10. Turn on gas and electrical supplies to furnace.
11. Check furnace operation through 2 complete heat
operating cycles. Look at burners. Burner flames
should be clear blue, almost transparent. (See
Figure 12.)
12. Check for gas leaks.
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
13. Replace main furnace door.
Secondary Heat Exchangers
The condensing side (inside) of the secondary heat
exchanger CANNOT be serviced or inspected without
complete removal of the heat exchanger assembly. Detailed
information on heat exchanger removal can be obtained
from your Distributor.
WINTERIZATION
UNIT AND PROPERTY DAMAGE HAZARD
Failure to follow this caution may result in unit
component or property damage.
If the furnace is installed in an unconditioned space
where the ambient temperatures may be 32_F (0_C) or
lower, freeze protection measures must be taken to
prevent minor property or product damage.
CAUTION
!
Since the furnace uses a condensing heat exchanger, some
water will accumulate in the unit as a result of the heat
transfer process. Therefore, once it has been operated, it
cannot be turned off and left off for an extended period of
time when temperatures will reach 32_F (0_C) or lower
unless winterized. Follow these procedures to winterize your
furnace:
UNIT COMPONENT DAMAGE HAZARD
Failure to follow this caution may result in damage to the
furnace and other property damage.
Do not use ethylene glycol (automotive antifreeze
coolant or equivalent). Failure of plastic components
may occur.
CAUTION
!
1. Obtain propylene glycol (RV/swimming pool
antifreeze or equivalent).
2. Turn off gas and electrical supplies to your furnace.
3. Remove furnace control door.
4. Remove the top unused rubber plug from the port on
the collector box opposite the condensate trap. See
Figure 10.
5. Connect a field supplied 3/8−in. (9.5−mm) ID tube to
the open port on the collector box.
6. Insert a field supplied funnel into the tube.
7. Pour 1 quart of anti−freeze solution into the funnel/
tube. Antifreeze should run through the inducer
housing, overfill condensate trap and flow to an open
drain.
8. Replace the rubber plug in the port on the collector
box.
9. Remove the middle unused rubber plug from the port
on the collector box opposite the condensate trap.
See Figure 10.
10. Repeat Steps 5 through 8.

440 04 6000 00 19
Specifications subject to change without notice.
11. If a condensate pump is used, check with pump
manufacturer to verify pump is safe for use with
antifreeze used. Allow pump to start and pump anti−
freeze to open drain.
12. Replace main door.
13. When furnace is re−started, flush condensate pump
with clear water to check for proper operation before
re−starting furnace.
14. Propylene glycol need not be removed before
re−starting furnace.
2-1/2-in.
(64.4)
1-1/4-in.
(31.8)
A11405
Figure 8 −Igniter Position −Top 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 9 −Igniter Position −Side View
A11392
Figure 10 −Priming Condensate Trap
A11273
Figure 11 −Cleaning Heat Exchanger Cell
Burner Flame
Burner
Manifold
A11461
Figure 12 −Burner Flame

20 440 04 6000 00
Specifications subject to change without notice.
SET SCREW
MOTOR WHEEL HUB
MOTOR SHAFT FLAT
SCREW
MOTOR ARM
GROMMET
SCREW LOCATION
BLO HSG ASSY
BRACKET
BRACKET
ENGAGEMENT
SEE DETAIL
A
CAPACITOR
OR POWER CHOKE
(WHEN USED)
BRACKET
SCREW
(GND)
BLOWER HSG ASSY
MOTOR, BLOWER
WHEEL, BLOWER
CUTOFF, BLOWER
DETAIL A
A11584
Figure 13 −Blower Assembly