CONDENSING, 90+% AFUE GAS FURNACE

OWNER’S MANUAL
NOTE: Read the entire instruction manual before starting the .
installation.
Our products are designed, tested and built in accordance with DOE
! WARNING
standardized procedures; however, actual operating results and FIRE OR EXPLOSION HAZARD
efficiencies may vary based on manufacturing and supplier tolerances, Failure to follow safety warnings exactly could result in personal
equipment configuration, operating conditions and installation practices. injury, death, or property damage.
NOTE: To the Installer: This manual must be left with the equipment Do not store or use gasoline or other flammable vapors and liquids in
user. the vicinity of this or any other appliance.
USER: Please read all instructions in the manual and retain all WHAT TO DO IF YOU SMELL GAS
manuals for future reference - Do not try to light any appliance.
- Do not touch any electrical switch; do not use any phone in your
building.
- Leave the building immediately.
- Immediately call your gas supplier from a neighbor’s phone.
Follow the gas supplier’s instructions.
- If you cannot reach your gas supplier, call the fire department.
Installation and service must be performed by a qualified installer,
service agency or the gas supplier.

! WARNING
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury and/or
death.
A11263
Carbon Monoxide (CO) is a colorless, odorless, and tasteless poisonous
Representative drawing, some models may vary in appearance. gas that can be fatal when inhaled. Follow all installation, maintenance,
and service instructions. See additional information below regarding
the installation of a CO Alarm.

Most states in the USA and jurisdictions in Canada have laws that
require the use of Carbon Monoxide (CO) alarms with fuel burning
products. Examples of fuel burning products are furnaces, boilers, space
heaters, generators, water heaters, stoves/ranges, clothes dryers,
fireplaces, incinerators, automobiles, and other internal combustion
engines. Even if there are no laws in your jurisdiction requiring a CO
Alarm, it’s highly recommended that whenever any fuel burning product
is used in or around the home or business that the dwelling be equipped
with a CO Alarm(s). The Consumer Product Safety Commission
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 .
recommends the use of CO Alarm(s). The CO Alarm(s) must be
installed, operated, and maintained according to the CO Alarm
manufacturer’s instructions. For more information about Carbon
A200104 Monoxide, local laws, or to purchase a CO Alarm online, please visit the
following website. https://www.kidde.com.
CONDENSING, 90+% AFUE GAS FURNACE: OWNER’S MANUAL

! WARNING ! WARNING
ELECTRICAL OPERATION HAZARD ELECTRICAL SHOCK, FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury, death, or Failure to follow safety warnings exactly could result in dangerous
property damage. operation, serious injury, death, or property damage.
Do not use this furnace if any part has been under water. A Improper servicing could result in dangerous operation, serious injury,
flood-damaged furnace is extremely dangerous. Attempts to use the death or property damage.
furnace can result in fire or explosion. A qualified service agency - Before servicing, disconnect all electrical power to furnace.
should be contacted to inspect the furnace and to replace all gas - When servicing controls, label all wires prior to disconnecting.
controls, control system parts, and electrical parts that have been wet, Reconnect wires correctly.
or the entire furnace if deemed necessary. - Verify proper operation after servicing.
TABLE OF CONTENTS
FURNACE COMPONENTS
TABLE OF CONTENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
(Furnace shown in upflow position; may be used in downflow or
WELCOME TO TODAY’S GENERATION OF COMFORT . . . . . 2
horizontal orientation or applications.)
FURNACE COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
BEFORE STARTING YOUR FURNACE . . . . . . . . . . . . . . . . . . . . 4
STARTING YOUR FURNACE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
STEPS FOR STARTING YOUR FURNACE . . . . . . . . . . . . . . . . . . 4
SHUTTING DOWN YOUR FURNACE . . . . . . . . . . . . . . . . . . . . . . 6
MINIMUM & MAXIMUM TEMPERATURE SETTING FOR YOUR
FURNACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
PERFORMANCE ROUTINE MAINTNENANCE . . . . . . . . . . . . . . 7
FILTERING OUT TROUBLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
COMBUSTION AIR AND VENT SYSTEM . . . . . . . . . . . . . . . . . . 9
WINTERIZATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
A CHECK-UP CHECKLIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
BEFORE YOU REQUEST A “SERVICE CALL” . . . . . . . . . . . . . 10
For insufficient airflow: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
If furnace fails to operate: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
MAINTENANCE CHECKLIST . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

WELCOME TO TODAY’S GENERATION OF

COMFORT
Congratulations! In light of rising energy costs, a 90+% AFUE
Condensing Gas Furnace from Carrier Corporation is among the
soundest investments today’s homeowner can make.
Your new furnace is truly a triumph of technology in home heating. A
revolutionary design employs two heat exchangers to “squeeze” out the
maximum amount of heat from the fuel consumed. In fact, your new A170154
furnace is so efficient, over 90%1 of the heat generated during Representative drawing, some models may vary in appearance.
combustion is captured and delivered inside your home. Fig. 1 – Furnace Components
This furnace is among the safest, most dependable, energy-efficient
furnaces you can buy today. We are proud of the technological advances SAFETY CONSIDERATIONS
incorporated into the design of this furnace. With only minimal care, Installing and servicing of heating equipment can be hazardous due to
your new furnace will deliver many years of money-saving home gas and electrical components. Only trained and qualified personnel
comfort and enjoyment. Spend just a few minutes with this manual to should install, repair, or service heating equipment.
learn the operation of your new furnace and the small amount of Untrained personnel can perform basic maintenance functions such as
maintenance it takes to help keep it operating at peak efficiency year cleaning and replacing air filters. All other operations must be performed
after year. by trained service personnel. Observe safety precautions in this manual,
on tags, and on labels attached to the furnace and other safety
precautions that may apply.
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. 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
hazards which could result in personal injury or death. CAUTION is
1. The output capacity and any representations of efficiency for this furnace are based used to identify unsafe practices which may result in minor personal
on standard U.S. Department of Energy test procedures.

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
2
CONDENSING, 90+% AFUE GAS FURNACE: OWNER’S MANUAL

injury or product and property damage. NOTE is used to highlight

suggestions which will result in enhanced installation, reliability, or
operation.
To minimize the possibility of serious personal injury, fire, damage to
your furnace, or improper operation, carefully follow these safety rules
which apply to both direct-vent and non-direct vent applications:
• Your new gas furnace may have been installed in one of two ways, as
a direct-vent (2-pipe-Fig. 2) application or as a non-direct vent
(1-pipe-Fig. 3) application.
• In a direct-vent (2-pipe) application, your furnace uses air from
outside the home for combustion and vents flue gas to the outdoors.
This type of application will have two pipes running from the furnace
to the outdoors. In some cases, the inlet air pipe may be located in an
area that has access to outdoor air, such as an attic. In all cases, the
outlet vent pipe must be routed to the outdoors (see Fig. 2). In this
application, the vent and air-intake pipes must terminate outside the
structure and must not be obstructed in any way. Do not block or
obstruct air openings on furnace or spaces around furnace. A11254
• In a non-direct vent (1-pipe) application, your furnace uses air from Representative drawing, some models may vary in appearance.
adjacent to the furnace for combustion and vents flue gas to the Fig. 2 – Exterior Vent Pipes
outdoors. This type of application will have only one pipe running
from the furnace to the outdoors (see Fig. 3). The other pipe will
terminate in the same space as the furnace and is the source of
combustion air for your furnace. Therefore, the furnace must not be
enclosed in an airtight room or be sealed behind solid doors. It must
have adequate airflow for efficient combustion and safe ventilation.
Do not obstruct the combustion-air pipe in any way. The vent pipe
must terminate outside the structure and must not be obstructed in any
way. Do not block or obstruct air openings or space around furnace.

! WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow warnings could result in personal injury, death, or
property damage. A11255
Representative drawing, some models may vary in appearance.
Keep insulation clear of furnace and maintain clearances shown on unit
Fig. 3 – Interior Combustion - Air Pipe
clearance label.
Do not keep combustible materials, gasoline, and other flammable
liquids or vapors around your furnace. ! WARNING
FIRE OR EXPLOSION HAZARD
! WARNING Failure to follow this warning could result in personal injury, death, or
property damage.
CARBON MONOXIDE POISONING HAZARD Do not keep combustible materials, gasoline, and other flammable
Failure to follow instructions could result in severe personal injury or liquids or vapors around your furnace.
death due to carbon monoxide poisoning, if combustion products
• Keep the area around your furnace clear and free of combustible
infiltrate into the building.
materials, gasoline, and other flammable liquids and vapors.
Check that all openings in the outside wall around the vent (and air
intake) pipe(s) are sealed to prevent infiltration of combustion products
into the building.
Check that furnace vent (and air intake) terminal(s) are not obstructed
in any way during all seasons.

A92182
Fig. 4 – NO combustible materials near furnace
• Do not cover the furnace, store trash or debris near it, or in any way
block the flow of fresh air to the unit.

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
3
CONDENSING, 90+% AFUE GAS FURNACE: OWNER’S MANUAL

STARTING YOUR FURNACE

! CAUTION
UNIT OPERATION HAZARD ! WARNING
Failure to follow this caution may result in intermittent unit operation. FIRE AND EXPLOSION HAZARD
For proper and safe operation the furnace needs air for combustion and Failure to follow this warning could result in personal injury, death or
ventilation. Do not block or obstruct air openings on the furnace, air property damage.
opening to the area in which the furnace is installed, and the space Should the gas supply fail to shut off or if overheating occurs, turn off
around the furnace the manual gas valve to the furnace BEFORE turning off the electrical
supply and install lockout tag.
In addition to the safety rules above, make sure that the following In
addition to the safety rules above, make sure that the following Instead of a continuously burning pilot flame which wastes valuable
combustion-air requirements are met for non-direct vent applications: energy, your furnace uses an automatic, hot surface ignition system to
• Combustion air must be clean and uncontaminated with chlorine or light the burners each time the thermostat signals the furnace to start.
fluorine. These compounds are present in many products around the Follow these important safeguards:
home, such as: water softener salts, laundry bleaches, detergents,
• Never attempt to manually light the burners with a match or other
adhesives, paints, varnishes, paint strippers, waxes, and plastics.
source of flame.
• Make sure the combustion air for your furnace does not contain any of
these compounds. During remodeling be sure the combustion air is
fresh and uncontaminated. If these compounds are burned in your
furnace, the heat exchangers may deteriorate.
• A furnace installed in an attic or other insulated space must be kept
free and clear of insulating material. Examine the furnace area when
the furnace is installed or when insulation is added. Some insulation
materials may be combustible.
• Should the gas supply fail to shut off or if overheating occurs, shut off
the gas valve to the furnace before shutting off electrical supply.
This furnace contains SAFETY DEVICES which must be MANUALLY A92319
RESET. If the furnace is left unattended for an extended period of time, Fig. 6 – Do Not Light Burner with Match
have it checked periodically for proper operation. This precaution will • Read and follow the operating instructions on inside of main furnace
prevent problems associated with no heat, such as frozen water pipes, door, especially the item that reads as follows:
etc. See “Before You Request a Service Call” section in this manual. “Wait 5 minutes to clear out any gas. Then smell for gas, including
near the floor. If you smell gas, STOP! Follow “B” in the safety
BEFORE STARTING YOUR FURNACE information on furnace label. If you don’t smell gas, go to the next
Examine the furnace installation to determine that: step.”
1. All flue gas carrying areas external to the furnace (i.e. chimney, • If a suspected malfunction occurs with your gas control system, such
vent connector) are clear and free of obstructions. as the burners do not light when they should, refer to the shutdown
2. The vent connector is in place, slopes upward and is physically procedures on inside of main furnace door, or in the “Shutting Down
sound without holes or gaps. Your Furnace” section and call your dealer as soon as possible.
• CHECK AIR FILTER: Before attempting to start your furnace, be
3. The return-air duct connection(s) is physically sound, is sealed to
sure the furnace filter is clean and in place. See “Performing Routine
the furnace casing, and terminates outside the space containing the
Maintenance” section in this manual. Do not run the furnace without a
furnace.
filter in place. Then proceed as follows:
4. The physical support of the furnace is sound without sagging
cracks, gaps, etc. around the base. STEPS FOR STARTING YOUR FURNACE
5. There are no obvious signs of deterioration of the furnace. 1. Set your room thermostat to the lowest temperature setting and set
6. The burner flames are in good adjustment (see Fig. 5) (by the “MODE” to “OFF” (see Fig. 7).
comparison with pictorial sketches or drawings of the main burner
flame).

Burner Flame

Burner

Manifold
A11461
Fig. 5 – Burner Flame Adjustment A09564
Fig. 7 – Lowest Temperature Setting
2. Close the external manual gas valve (see Fig. 8).

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
4
CONDENSING, 90+% AFUE GAS FURNACE: OWNER’S MANUAL

CL TWO-STAGE GAS CONTROL

SINGLE-STAGE GAS CONTROL

O
SE
GAS CONTROL SWITCH
SHOWN IN “OFF” POSITION

MODULATING GAS CONTROL

CONSULT
MANUAL
BEFORE
ADJUSTING
GAS
PRESSURE

NAT.

OFF
GAS

ON
A06188
Fig. 8 – Close Valve GAS CONTROL SWITCH
SHOWN IN “OFF” POSITION
3. Turn OFF electrical supply to the furnace (see Fig. 9).
A11292
Fig. 11 – Control Switch to OFF
6. After waiting five minutes, turn control switch on the gas control to
the ON position. Turn the control switch to ON (see Fig. 12).

TWO-STAGE GAS CONTROL

SINGLE-STAGE GAS CONTROL

GAS CONTROL SWITCH

SHOWN IN “ON” POSITION

MODULATING GAS CONTROL

A92185
Fig. 9 – Turn Off Electrical Supply
4. Remove the main furnace door (see Fig. 10). CONSULT
MANUAL
BEFORE
ADJUSTING
GAS
PRESSURE

NAT.
GAS
OFF

ON

GAS CONTROL SWITCH

SHOWN IN “ON” POSITION

A11291
Fig. 12 – Control Switch to ON
7. Replace main furnace door (see Fig. 13).

A11256
Representative drawing, some models may vary in appearance.
Fig. 10 – Remove Main Furnace Door (Upflow Configuration)
5. Turn the control switch on the gas control to the OFF position and
wait five minutes (see Fig. 11). Then smell for gas, including near
the floor. If you smell gas, STOP! Follow “B” on furnace label. If
you don’t smell gas, go to next step. A11257
Representative drawing, some models may vary in appearance.
Fig. 13 – Furnace Door Replaced (Upflow Configuration)
8. Turn ON the electrical supply to the furnace and wait one minute
(see Fig. 14).

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
5
CONDENSING, 90+% AFUE GAS FURNACE: OWNER’S MANUAL

blower will switch to the next higher speed. There are at least three
speeds to choose from. If the blower is running on its highest speed, a
request to change will direct the blower to return to its lowest speed.

SHUTTING DOWN YOUR FURNACE

Should you need to shut down your furnace for service or maintenance,
you will need to turn the furnace off. The following procedures must be
followed:
1. Set your room thermostat to the lowest temperature setting and set
the “MODE” to “OFF” (see Fig. 16).

A92359
Fig. 14 – Turn on Electrical Supply
9. Open the external manual gas valve (see Fig. 15).

OP
EN

A09564
Fig. 16 – Lowest Temperature Setting
A06189
2. Close the external manual gas valve (see Fig. 17).
Fig. 15 – Open Valve
10. Set the room thermostat “MODE” to “HEAT” and adjust the set
point to a temperature slightly above the room temperature. This CL

O
will automatically signal the furnace to start.

SE
11. When the furnace receives the start signal, the combustion air draft
inducer is started. When the pressure switch senses that there is
sufficient combustion air, the hot surface igniter is energized.
After the hot surface igniter is heated for about 20 seconds, the gas
valve permits gas to flow to the main burners. After ignition and a
time delay of up to 60 seconds, the furnace blower will start.
Variable-capacity furnaces start at low speed until the control
makes the necessary adjustments to operate the blower at either the
low- or high-heat speed.
NOTE: If the main burners fail to ignite after four attempts, the furnace
A06188
control system will lock out. If lockout occurs, main burners fail to light, Fig. 17 – Close the External Manual Valve
or blower does not come on, shut down the furnace and call your dealer
3. Turn off electrical supply to the furnace (see Fig. 18).
for service.
12. Set your thermostat to the temperature that satisfies your comfort
requirements.
SUGGESTION: Setting the thermostat back a few degrees—and
compensating for the difference with warmer clothing—can make a big
difference in your fuel consumption on extremely cold days. The few
degrees at the top of your thermostat “comfort level” are the most costly
degrees to obtain.
When the room temperature drops below the temperature selected on the
thermostat, the furnace will switch on automatically. When the room
temperature reaches the setting selected on the thermostat, the furnace
will be automatically switched off.
Continuous Fan Operation -Some thermostats have a “FAN” switch
with two selections: AUTO and ON. When the thermostat is set on A92185
AUTO, the furnace blower cycles on and off, controlled by the Fig. 18 – Turn Off Electrical Supply
thermostat. In ON position, the furnace blower runs continuously. 4. Remove main furnace door (see Fig. 10).
Continuous fan keeps the temperature level in your home more evenly 5. Turn control switch on the gas control to “OFF” position (see
balanced. It also continuously filters the indoor air. Fig. 11).
On all but the base series furnace, the blower speed can be increased or 6. Replace main furnace door (see Fig. 13).
decreased if desired due to change of seasons, large gatherings in your 7. If the furnace is being shut down because of a malfunction, call
home, etc. Simply change your FAN from ON to OFF for 1 to 3 seconds your dealer as soon as possible.
(or AUTO depending on your thermostat), and then return to ON. The

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
6
CONDENSING, 90+% AFUE GAS FURNACE: OWNER’S MANUAL

! CAUTION ! CAUTION
UNIT AND PROPERTY DAMAGE HAZARD UNIT PERFORMANCE HAZARD
Failure to follow this caution may result in unit component or property Failure to follow this caution may result in unit component damage.
damage. Never operate your furnace without a filter in place. Doing so may
Furnace is not to be installed, operated, and then turned off and left damage the furnace blower motor. An accumulation of dust and lint on
turned off in an unoccupied structure during winter. See internal parts of your furnace can cause a loss of efficiency.
“Winterization” procedures in this manual.

MINIMUM & MAXIMUM TEMPERATURE ! CAUTION

SETTING FOR YOUR FURNACE
PERSONAL INJURY HAZARD
This furnace is designed for minimum continuous return-air temperature
of 60°F (16°C) or intermittent operation down to 55°F (13°C) such as Failure to follow this caution may result in personal injury.
when used with a night setback thermostat. Return-air temperature must Use care when cutting support rods in filters to protect against flying
not exceed 80°F (27°C). Failure to follow these return-air temperature pieces and sharp rod ends. Wear safety glasses, gloves, and appropriate
limits may affect reliability of heat exchangers, motors, and controls. protective clothing.

PERFORMANCE ROUTINE MAINTNENANCE A dirty filter will cause excessive stress on the furnace, heat exchanger,
NOTE: The qualified installer or agency must use only and blower motor, and can cause it to overheat and automatically shut
factory-authorized replacement parts, kits, and accessories when down. The furnace filter should be checked every four weeks and be
modifying this product. cleaned or replaced if necessary.
Installing and servicing of heating equipment can be hazardous due to If installed with factory-specified disposable media filter, check or
gas and electrical components. replace filter before each heating and cooling season. Replace disposable
Only trained and qualified personnel should install, repair, or service media filter at least once a year.
heating equipment. Untrained personnel can perform basic maintenance If your furnace filter needs replacing, be sure to use the same size and
functions such as cleaning and replacing air filters. type of filter that was originally specified.
All other operations must be performed by trained service personnel. The air filter for the furnace may be located an external filter cabinet
Observe safety precautions in this manual, on tags, and on labels attached to the side or bottom of the furnace casing. If the air filter has
attached to the furnace and other safety precautions that may apply. been installed in another location, contact your dealer for instructions.
With proper maintenance and care, your furnace will operate To inspect, clean and/or replace the air filter(s), follow these steps:
economically and dependably. Instructions for basic maintenance are 1. Turn off electrical supply to the furnace (see Fig. 19).
found on this and the following pages. However, before beginning 2. Remove air filter from the filter cabinet.
maintenance, follow these safety precautions: a. Remove filter cabinet door (see Fig. 20 and Fig. 21).
NOTE: It maybe necessary to remove one thumbscrew.
! WARNING b. Slide air filter out of furnace. Keep dirty side up (if dirty) to
avoid spilling dirt (see Fig. 22 and Fig. 23).
ELECTRICAL SHOCK HAZARD 3. Inspect the filter. If torn replace it.
Failure to follow this warning could result in personal injury or death. NOTE: If a washable filter was supplied with the furnace and has been
Turn off electrical power supply to your furnace and install lockout tag replaced by:
before removing the access doors to service or perform maintenance. • Disposable media filter-Do not clean. If dirty, replace only with media
filter having the same part number and size. Install with airflow
direction arrow pointing towards blower.
! CAUTION • Electronic Air Cleaner (EAC), refer to the EAC Owner’s Manual for
maintenance information.
CUT HAZARD
4. If washable filter, wash filter (if dirty) in a sink, bathtub, or outside
Failure to follow this caution may result in personal injury.
with a garden hose. Always use cold tap water. A mild liquid
Although special care has been taken to minimize sharp edges, be detergent may be used if necessary. Spray water through filter in the
extremely careful when handling parts or reaching into the furnace. opposite direction of airflow. Allow filter to dry.
Wear safety glasses, gloves, and appropriate protective clothing.
5. Reinstall clean air filter.
6. Turn on electrical supply to the furnace.
FILTERING OUT TROUBLE
If your furnace air filter needs to be replaced, be sure to use a
NOTE: The manufacturer has specified filters which will enable your
factory-authorized filter of the same size that was originally specified.
furnace to provide lasting comfort and efficiency throughout its life.
Use the filter tables and compare your furnace size with the proper filter
Contact your dealer to help you choose filters for your furnace that both
size.
collect dirt before it enters your furnace, as well as provide a low
resistance to circulating air. Avoid filters that report high cleaning
efficiencies, but do not allow air to pass easily through them.

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
7
CONDENSING, 90+% AFUE GAS FURNACE: OWNER’S MANUAL

A00228
Representative drawing, some models may vary in appearance.
Fig. 23 – Removal of Filter from Bottom Blower Cabinet

A92185
Fig. 19 – Turn Off Electrical Supply

A00229
Representative drawing, some models may vary in appearance.
Fig. 24 – Replacement of Filter Cabinet Door to Side Blower
Cabinet

A00225
Representative drawing, some models may vary in appearance.
Fig. 20 – Removal of Filter Cabinet Door from Side Blower Cabinet

A00230
Representative drawing, some models may vary in appearance.
Fig. 25 – Replacement of Filter Cabinet Door to Bottom Blower
Cabinet
A00226
Representative drawing, some models may vary in appearance.
Fig. 21 – Removal of Filter Cabinet Door from Bottom Blower Table 1 – Air Filter Located in Filter Cabinet
Cabinet

FILTER CABINET
FILTER SIZE - IN (MM) FILTER TYPE
HEIGHT - IN (MM)
(1) 16 x 25 x 3/4* (406 x 635 x 19)
or
16 (406) Washable†
(1) 16 x 25 x 4-5/16
(406 x 635 x 110)
(1) 20 x 25 x 3/4* (508 x 635 x 19)
or
20 (508) Washable†
(1) 20 x 25 x 4-5/16
(508 x 635 x 110)
A00227 (1) 24 x 25 x 3/4* (610 x 635 x 19)
Representative drawing, some models may vary in appearance.
or
Fig. 22 – Removal of Filter from Side Blower Cabinet 24 (610) Washable†
(1) 24 x 25 x 4-5/16
(610 x 635 x 110)
*. Filters with a side return-air may have a different filter size. Measure the
filter to obtain the correct size.
†. Recommended to maintain air filter face velocity. See Product Data for
part number.

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
8
CONDENSING, 90+% AFUE GAS FURNACE: OWNER’S MANUAL

HOT SURFACE

COMBUSTION AIR AND VENT SYSTEM

IGNITOR

! WARNING
GAS BURNER
ASSEMBLY MANUAL RESET
LIMIT SWITCH
FLAME
SENSOR

MANUAL RESET

CARBON MONOXIDE POISONING HAZARD LIMIT SWITCH MAIN LIMIT SWITCH

(BEHIND GAS VALVE)

Failure to follow this warning could result in personal injury or death.

GAS VALVE

If holes are found or if the vent pipe is obstructed or is not connected,

toxic fumes can escape into your home. DO NOT OPERATE YOUR
FURNACE. Call your dealer for service. A11319
Fig. 26 – Gas Burner Assembly (Upflow)

! CAUTION
UNIT OPERATION HAZARD
GAS VALVE

Failure to follow this caution may result in intermittent unit operation. MAIN LIMIT SWITCH
(BEHIND GAS VALVE) MANUAL RESET

For proper and safe operation the furnace needs air for combustion and LIMIT SWITCH
FLAME

ventilation. Do not block or obstruct air openings on the furnace, air MANUAL RESET
LIMIT SWITCH
SENSOR
GAS BURNER

opening to the area in which the furnace is installed, and the space ASSEMBLY

around the furnace.

HOT SURFACE
IGNITOR
Visually inspect the combustion area and vent system before each
heating season. Make sure that all PVC pipes leading into the A11320
combustion area and vent are free from any cracks and sags. An Fig. 27 – Gas Burner Assembly (Downflow)
accumulation of dirt, soot, or rust can mean a loss of efficiency and 3. Inspect the combustion-air and vent PVC pipes for sags, holes,
improper performance. Buildups on the main burners can cause faulty cracks, water leaks, blockage or disconnections. Horizontal
firing. This “delayed ignition” is characterized by an alarmingly loud portions of vent pipe must slope downward toward the furnace.
sound. 4. If your furnace is free of the above conditions, turn on electrical and
Check the combustion-air intake adjacent to the furnace or outside your gas supplies to the furnace.
home for blockage. Also check the vent pipe on the outside of your 5. Start your furnace and observe its operation. Watch the burner
home for blockage. flames to see if they are clear blue, almost transparent (see Fig. 28).
NOTE: If your furnace makes a loud noise when the main burners are If you observe a suspected malfunction, or the burner flames are not
ignited, shut down the furnace and call your servicing dealer. clear blue, call your dealer.
Use your flashlight and follow these steps for inspecting the combustion 6. Replace main furnace door.
area and vent system of your furnace:

! WARNING
Burner Flame

Burner

CARBON MONOXIDE POISONING HAZARD

Failure to follow this warning could result in personal injury or death.
If dirt, rust, soot, or scale accumulations are found, call your dealer. Do
not operate your furnace. Manifold

A11461
1. Turn off electrical supply and gas supply to the furnace and remove Fig. 28 – Burner Flame Adjustment
the main furnace door (see Fig. 7, Fig. 8, Fig. 9, Fig. 10 and
WINTERIZATION
Fig. 11).

! CAUTION ! CAUTION
ELECTRICAL SHOCK HAZARD UNIT AND PROPERTY DAMAGE HAZARD
Failure to follow this warning could result in personal injury or death. Failure to follow this caution may result in unit component or property
Turn off electrical power supply to your furnace and install lockout tag damage.
before removing the access doors to service or perform maintenance. If the furnace is installed in an unconditioned space where the ambient
temperatures may be 32° F (0° C) or lower, freeze protection measures
2. Inspect the gas burners, igniter area, and remainder of furnace for must be taken to prevent minor property or product damage.
dirt, rust, soot or scale.
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:

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
9
CONDENSING, 90+% AFUE GAS FURNACE: OWNER’S MANUAL

A CHECK-UP CHECKLIST
! CAUTION Your furnace represents an important investment in your family’s
comfort and your home’s value. To keep it performing properly and to
UNIT COMPONENT DAMAGE HAZARD prevent future problems, have a trained service specialist give your
Failure to follow this caution may result in damage to the furnace and furnace a professional check-up annually. The following checklist can be
other property damage. used as a guideline to proper service:
Do not use ethylene glycol (Automotive antifreeze coolant or • Inspect all flue gas passages, burners, heat exchangers, coupling
equivalent). Failure of plastic components may occur. box(es), and inducer assembly.
• Inspect all combustion-air and vent piping inside structure and pipe
1. Obtain propylene glycol (RV/swimming pool antifreeze or terminations outside the structure.
equivalent). • Check gas pipes leading to and inside of your furnace for leaks.
2. Turn off gas and electrical supplies to your furnace. • Inspect and clean the blower motor and wheel.
NOTE: The inducer and blower motors are pre-lubricated and require
! WARNING no additional lubrication. These motors can be identified by the absence
of oil ports on each end of the motor.
ELECTRICAL SHOCK HAZARD • Inspect and change or clean air filter(s) if necessary.
Failure to follow this warning could result in personal injury or death. • Inspect all supply- and return-air ducts for obstructions, air leaks, and
Turn off electrical power supply to your furnace and install lockout tag insulation. Remedy any problem when necessary.
before removing the access doors to service or perform maintenance. • Inspect the return-air duct connection(s) at the furnace to ensure it is
physically sound, sealed to the furnace casing, and terminates outside
3. Remove furnace control compartment door. the space containing the furnace.
4. Remove one of the unused rubber plugs in the port on the collector • Inspect electrical wiring, connections, and components for loose
box opposite the condensate trap. See Fig. 29 connections.
5. Connect a field supplied 3/8-in. (9.5-mm) ID tube to the open port • Perform an operational checkout to determine whether your furnace is
on the collector box. working properly and if it requires adjustments.
6. Insert a field supplied funnel into the tube. • Inspect all condensate drain tubes and condensate trap assembly for
7. Pour 1 quart of anti-freeze solution into the funnel/tube. Antifreeze leaks. The condensate removal system should be cleaned annually by
should run through the inducer housing, overfill condensate trap a qualified service agency. Refer to the Service and Maintenance
and flow to an open drain. Instructions Guide for further information.
8. If a condensate pump is used, check with pump manufacturer to • Examine the physical support of the furnace. Support should be sound
verify pump is safe for use with antifreeze used. Allow pump to with no cracks, sagging, gaps, etc. around the base.
start and pump anti-freeze to open drain. • Check furnace for any obvious signs of deterioration.
9. Remove funnel and tube from collector box. • Ask your servicing dealer for further details about an economical
10. Replace plug in collector box. service contract that covers seasonal inspections.
11. Remove the other plug and repeat steps 4-10.
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.
FOR YOUR SAFETY READ BEFORE OPERATING

A11318
Fig. 30 – Information Booklet Location

BEFORE YOU REQUEST A “SERVICE CALL”

If your furnace is not operating or not performing properly, you may
save the expense of a service call by checking a few things yourself
before calling for service.
NOTE: Record the LED status code BEFORE removing the blower
access door or turning off 115-v power to the furnace. See the
information booklet inside the main furnace door for a service code
legend (see Fig. 30).
For insufficient airflow:
• Check for dirty air filter(s).
A11392
Fig. 29 – Winterizing Furnace • Check for blocked return-air or supply-air grilles. Be sure they are
open and unobstructed.

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
10
CONDENSING, 90+% AFUE GAS FURNACE: OWNER’S MANUAL

If problem still exists, call your dealer for service.

If furnace fails to operate:
Follow this checklist step by step, advancing to the next stop only if
furnace fails to start.
• Check thermostat for proper temperature. Is thermostat set above
room temperature?
• Is thermostat set to HEAT mode?
• Check fuses and circuit breakers. Is the electrical power supply switch
on?
• Is the manual shut-off valve in the gas supply pipe leading to the
furnace open?
NOTE: Turn off electrical supply before continuing with checklist.
• Is control switch on gas valve in ON position? (Follow start-up
procedures if you must reset switch to ON position.)
• Check manual reset rollout switch located on the burner box. See
Furnace Components in Fig. 1. If furnace has experienced high
temperature conditions, this switch will shut off the furnace. Reset it
by pushing the button on the switch. If it trips again, shut down the
furnace and call for service. See “Shutting Down Your Furnace”
section in this manual.
• Check for obstructions around the vent termination.
If your furnace still fails to operate, call your service representative.
For your convenience, record the furnace product and serial numbers on
back page. Should you ever require service, you will have ready access
to the information needed by your service representative.
This furnace has a light emitting diode (LED) status code display to aid
the installer, service technician, or homeowner while installing or
servicing the unit. The LED code can be seen through the view port in
the blower access panel.

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
11
CONDENSING, 90+% AFUE GAS FURNACE: OWNER’S MANUAL

NOTE TO EQUIPMENT OWNER:

For your convenience, please record the model and serial numbers of your new equipment in the spaces
provided. This information, along with the installation data and dealer contact information will be helpful
should your system require maintenance or service.
FURNACE INSTALLATION INFORMATION:
Model # _____________________________________ Date Installed ________________________________
Serial # ______________________________________ DEALERSHIP CONTACT INFORMATION:
AIR CONDITIONER OR HEAT PUMP Company Name_______________________________
Model # _____________________________________ Address______________________________________
Serial # _____________________________________ _____________________________________________
INDOOR COIL (Furnace Coil or Fan Coil) Phone Number _______________________________
Model # _____________________________________ Technician Name _____________________________
Serial # _____________________________________ _____________________________________________
_____________________________________________
NOTE TO INSTALLER:
This manual must be left with the equipment owner.

A200102

MAINTENANCE CHECKLIST
In addition to the type of routine maintenance you might be willing to perform; your furnace should be inspected regularly by a properly trained
service technician.
You should work with your dealer or service technician to assure your inspection includes the following at a minimum.
This list may not include all maintenance items, and inspection interval times may vary depending on operational conditions of the furnace.
INSPECTION INTERVAL
DESCRIPTION
Monthly Semi-Annually Annually

Furnace specific, external items:

Clean or replace air filters. X
Inspect cabinet for signs of damage. X
Inspect and clean door louvers if needed. X
Inspect electrical disconnect for proper function. Repair or replace as necessary. X
Inspect external wiring for damage. X
Inspect gas supply line and manual shut-off for leaks. X
Ensure there is no debris or clutter that could interfere with operation of furnace X

Furnace specific, internal items:

Inspect and clean blower assembly (includes blower housing, blower wheel and motor). X
Inspect gas valve and check for proper manifold gas pressure Adjust as needed. X
Inspect ignition system and safety controls. Clean and adjust as needed. X
Inspect control box, associated controls, wiring and connections. X
Check combustion blower housing for lint and debris and clean as necessary. X
Inspect burner assembly - clean as needed. X
Inspect heat exchanger - clean as needed. X
Inspect flue system-check for proper attachment to the furnace, any dislocated sections,
X
and for signs of corrosion. Replace if necessary.
Clean out condensate trap and refill with water X
Measure combustion byproducts with calibrated analyzer to ensure byproducts are within
X
acceptable range

System:
Inspect airflow system (ductwork)-check for leaks and repair as needed. X
Inspect evaporator coil, drain pan and condensate drain lines as applicable. Clean as
X
needed.

© 2022 Carrier. All rights reserved. Edition Date: 03/22 Catalog No: 90GSFRN-C-03OM
Replaces: OM9GFRC-02
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
12