Carrier 58MXA, 58MTA, 58MCA, 58MVP User Manual

WELCOME TO A NEW GENERATION
OF COMFORT

Congratulations! In light of rising energy costs, the 58MXA,
58MCA, 58MTA, and WeatherMaker Infinity, Multipoise, Gas­Fired Condensing Furnaces are 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 2 heat exchangers to
“squeeze” out the maximum amount of heat from the fuel con­sumed. In fact, your new furnace is so efficient, over 90%* of the
heat generated during combustion is captured and delivered inside
your home. That is more that a 33%* increase in heating effi­ciency over conventional furnaces.

These are among the most energy-efficient furnaces you can buy to­day. They also are among the safest and most dependable. We are
proud of the technological advances incorporated into the design of
these furnaces. With only minimal care, your new furnace will deliver
many years of money-saving home comfort and enjoyment. Spend
just a few minutes with this manual to learn the operation of your new
furnace and the small amount of maintenance it takes to help keep it
operating at peak efficiency year after year.

*The output capacity and any representations of efficiency for this furnace are based on standard
Department of Energy test procedures.

INSTALLATION DATA

®

®

• • • • •• • • • •

• • • • •

need art

ICIENCY

GH EFF

A HI

TR

UL

GAS FURNANCE

MODELS 58MXA (SHOWN) AND
58MCA FIXED-CAPACITY FURNACES

1

Date Installed

Dealer Name

Address

City

State Zip

Telephone

FURNACE

Product No.

Model No.

Serial No.

SPLIT-SYSTEM

OUTDOOR UNIT:

Product No.

Model No.

Serial No.

INDOOR COIL:

Product No.

Model No.

Serial No.

2

MODEL 58MVP
VARIABLE-CAPACITY
AND MODEL 58MTA
TWO-STAGE FURNACES

2

FURNACE COMPONENTS

1

Combustion-air intake connection to ensure contami­nant-free air (right or left side).

2

Burner sight glass for viewing burner flame.

3

Burner assembly (inside). Operates with energy-saving
pilot, inshot burners, and hot surface igniter for safe,
dependable heating.

4

Redundant gas valve. Safe, efficient. Features 1 gas con­trol with 2 internal shutoff valves.

5

Vent outlet. Uses PVC pipe to carry vent gases from the
furnaces combustion system (right or left side).

6

Inducer motor. Pulls hot flue gases through the heat ex­changers, maintaining negative pressure for added safety.

7

Blower access panel safety interlock switch.

8

Air filter and retainer.

9

Condensate drain connection. Collects moisture con­densed from burned gases for disposal into home drain
system.

11
16

10

2

17

3

1

4

12

18

5

5

14

6

9

need art

15

13
7

19

8

10

Heavy-duty blower. Circulates air across the heat ex­changers to transfer heat into the home.

11

Secondary condensing heat exchanger (inside). Wrings
out more heat through condensation. Constructed with
Polypropylene-laminated steel to ensure durability.

12

Primary serpentine heat exchanger (inside). Stretches fuel
dollars with the S-shaped heat-flow design. Solid con­struction of corrosion-resistant aluminized steel means re­liability.

13

Control center.

14

3-amp fuse provides electrical and component protection.

15

Light emitting diode (LED) on control center. Code lights
are for diagnosing furnace operation and service require­ments.

16

Pressure switch(es) ensure adequate flow of flue products
through furnace and out vent system.

17

Rollout switch (manual reset) to prevent overtemperature.

18

Junction box for 115-v electrical power supply. (May be
on right or left side)

19

Transformer (24v) behind control center provides low­voltage power to furnace control center and thermostat.

20

Limit switch (manual reset) on 58MVP only.

MODELS 58MXA, 58MCA, AND 58MTA
FURNACES (UPFLOW POSITION)

2

12

1

5

11

16

9
8

3

17

3

4

18

6

5

15

14
13

7
19

10

20

MODEL 58MVP
FURNACE (UPFLOW POSITION)

3

4

IMPORTANT FACTS

Your gas furnace uses air from outside the home for combus­tion and venting. It is not to be installed using in-house air.
Therefore, both pipes must terminate outside the structure
and must not be obstructed in any way.

To minimize the possibility of serious personal injury, fire,
furnace damage, or improper operation;

these safety rules:

• Keep the area around your furnace free of combustible
materials, gasoline, and other flammable liquids and vapors.

• Do not cover the furnace, store trash or debris near it, or
in any way block the flow of fresh air to the unit.

• A furnace installed in an attic or other insulated space
must be kept free and clear of insulating material. Examine
the furnace area when installing the furnace or adding more
insulation. Some materials may be combustible.

NOTE:

Do not use this furnace if any part has been under
water. Immediately call a qualified service technician to
inspect the furnace and to replace any part of the control
system and any gas control which has been under water.

carefully follow

This furnace contains SAFETY DEVICES which must be
MANUALLY RESET. If the furnace is left unattended for
an extended period of time, have it checked periodically for
proper operation. This precaution will prevent problems
associated with no heat, such as frozen water pipes, etc. See
“Before You Request a Service Call’’ section in this manual.

SAFETY CONSIDERATIONS

Installing and servicing heating equipment can be hazard­ous due to gas and electrical components. Only trained and
qualified personnel should install, repair, or service heating
equipment.

Untrained personnel can perform basic maintenance func­tions such as cleaning and replacing air filters. All other
operations must be performed by trained service person­nel. 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 sym-

!

bol . When you see this symbol on the furnace and in
instructions or manuals, be alert to the potential for personal
injury.

Understand the signal words—DANGER, WARNING, and
CAUTION. These words are used with the safety-alert sym­bol. DANGER identifies the most serious hazards which

will result in severe personal injury or death. WARNING

signifies hazards which
death. CAUTION is used to identify unsafe practices which

would result in minor personal injury or product and prop-

erty damage. NOTE is used to highlight suggestions which

5

will result in enhanced installation, reliability or operation.

could result in personal injury or

STARTING YOUR FURNACE

Instead of a continuously burning pilot flame which wastes
valuable energy, your furnace uses an automatic, hot surface
ignition system to light the burners each time the thermostat
starts your furnace.

Follow these important safeguards:

NOTE:

The qualified installer or agency must use only
factory-authorized replacement parts, kits, and accessories
when modifying this product.

• Never attempt to manually light the burners with a match
or other source of flame.

• Read and follow the operating instructions on the furnace,
especially the item that reads as follows:

Wait 5 minutes to clear out any gas. Then smell for gas,
including near the floor. If you smell gas,
in the safety information above on this furnace label. If you
don’t smell gas, go to the next step.

• If a suspected malfunction occurs with your gas control
system, such as the burners do not light when they should,

6

refer to the shutdown procedures on the furnace, or in the
“Shutting Down Your Furnace” section and call your dealer
as soon as possible.

4

STOP! Follow “B’’

7

•

!

WARNING

If overheating occurs or the gas valve fails to shut
off the gas supply, turn off the manual gas valve to
the furnace BEFORE turning off the electrical sup­ply. (See Fig. 9.) Failure to follow this warning
could result in a fire or explosion, and personal in­jury or death.

CHECK AIR FILTER: Before attempting to start your

furnace, be sure the furnace filter is clean and in place. See
“Performing Routine Maintenance” section in this manual.

Then proceed as follows:

STEPS FOR STARTING YOUR
FURNACE

1. Set your room thermostat to the lowest temperature set­ting. (See Fig. 8.)

2. Close the external manual gas valve. (See Fig. 9.)

1

M

O

O

F

F

F

F

3

P

2

C

ON

OR

OFF

ON

12

5. The gas valve will have EITHER a control knob or con­trol switch to turn off and on. Turn the control knob or
switch on the gas valve to the OFF position and wait
5 minutes. (See Fig. 12 or 13.)

6. After waiting 5 minutes, turn the control knob or switch
on the gas valve to the ON position. (See Fig. 14 or 15.)

F

O

F

®

C

L

O

S

E

910

3. Turn OFF electrical supply to the furnace. (See Fig. 10.)

4. Remove control access door. (See Fig. 11.)

13

8

1

M

O

O

F

F

F

F

3

P

2

C

ON

OR

OFF

ON

14

ON

11

15

5

7. Replace control access door. (See Fig. 16.)

16

O

P

E

N

17 18

8. Turn ON the electrical supply to the furnace and wait 1
minute. (See Fig. 17.)

9. Open the external manual gas valve. (See Fig. 18.)

10. Set the room thermostat to a temperature slightly
above the room temperature. This will automatically
signal the furnace to start.

11. When the furnace receives the start signal, the hot surface
ignitor at the main burners is automatically heated for 15
to 20 sec. When the microprocessor control verifies that
there is sufficient heat to ignite, the gas valve permits gas
to flow to the main burners. After ignition and a time delay
of about 35 sec, the furnace blower will start. Variable­capacity furnaces start at low speed until the control
makes the necessary adjustments to operate the blower at
either the low- or high-fire speed.

NOTE:

If the burners fail to ignite after 4 attempts, the fur­nace control system will lock out. If lockout occurs, main
burners fail to light, or blower does not come on, shut down
the furnace and call your dealer 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 “com-
fort 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 degree
selected on the thermostat, the furnace will be switched off
automatically.

Some thermostats have a “FAN’’ mode with 2 selections:
AUTO and ON. When set on AUTO, the furnace blower
cycles on and off, controlled by the thermostat. In the ON

mode, the furnace blower runs continuously. This keeps the
temperature level in your home more evenly balanced. It also
continuously filters the indoor air.

SHUTTING DOWN YOUR FURNACE

Should you ever 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. (See Fig. 19.)

2. Close the external manual gas valve (See Fig. 9.)

3. Turn off electrical supply to the furnace. (See Fig. 20.)

®

19

4. Remove main furnace door. (See Fig. 11.)

5. Turn the control knob or switch on the gas valve to the
OFF position. (See Fig. 21 or 22.)

6. Replace the control access door. (See Fig. 16.)

7. If the furnace is being shut down because of a malfunc­tion, call your dealer as soon as possible.

!

CAUTION

Furnace is not to be installed, operated, and then
turned off and left turned off in an unoccupied
structure during winter. (See winterizing proce­dures in maintenance section).

PERFORMING ROUTINE
MAINTENANCE

With proper maintenance and care, your furnace will operate
economically and dependably. Instructions for basic mainte­nance are found on this and the following pages. However,
before beginning maintenance, follow these safety precautions:

20

6

1

M

O

O

F

F

F

F

3

P

2

C

ON

OR

OFF

ON

21

!

WARNING

Turn off electrical power supply to your furnace
before removing the access doors to service or
perform maintenance. A failure to follow this
warning could result in personal injury or death.

F

O

F

22

!

CAUTION

Although special care has been taken to minimize
sharp edges, be extremely careful when handling
parts or reaching into the furnace.

1. Turn off electrical supply to furnace. (See Fig. 20)

2. Remove door/access panel

• AIR FILTERS(S) LOCATED IN BLOWER COMPART­MENT
a. Remove main furnace door. (See Fig. 23)
b. Remove blower access panel. (See Fig. 24)

NOTE: It will be necessary to remove 2 screws

• AIR FILTER LOCATED IN FILTER CABINET
a. Remove filter cabinet door (See Fig. 36 and 37)

NOTE: It will be necessary to remove 1 thumbscrew

3. Remove air filter from furnace.

• AIR FILTER LOCATED IN BLOWER COMPARTMENT

BOTTOM:
a. Slide filter retainer sideways until it is free of latch. (See
Fig. 25)
b. Slide air filter out of furnace. (See Fig. 26)

• AIR FILTER(S) LOACTED IN BLOWER COMPART­MENT SIDE:
a. Remove filter retainer from latch. (See Fig. 27.)
b. Gently remove air filter and carefully turn the dirty side up
(if dirty) to avoid spilling dirt from the filter. (see Fig. 28)

• AIR FILTER LOCATED IN FILTER CABINET:
a. Slide air filter out of furnace. Keep dirty side up (if dirty)
to avoid spilling dirt. (See Fig. 38 and 39)

4. Inspect the filter. If torn, replace it.

NOTE: If washable filter that was shipped with the furnace has

been replaced by:
a) Factory specified 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.
b) Electronic air cleaner (EAC) – Refer to EAC Owner’s
Manual for maintenance information.

FILTERING OUT TROUBLE

A dirty air filter will cause a loss of airflow in your duct
system. When excessive loss of airflow occurs, the furnace
may cycle on its safety controls. If this condition is left unat­tended, the furnace will eventually lock out. It is recom­mended that the furnace air filter be checked every 3 or 4
weeks and cleaned if necessary.

If installed with factory specified disposable media filter,
check or replace filter before each heating and cooling sea­son. Replace disposable media filter at least once a year.

!

CAUTION

Never operate your furnace without a filter in place.
Doing so may damage the furnace blower motor.
An accumulation of dust and lint on internal parts
of your furnace can cause a loss of efficiency.

The air filter is normally located in the blower compartment.
(See Fig. 3 or 4) or in the factory-supplied filter cabinet
attached to the side or bottom of the blower cabinet. If air
filter has been installed in another location, contact your deal­er for instructions. To inspect, clean, and/or replace the air
filter(s), follow these steps:

23 24

25 26

7

27 28

5. Wash filter (if dirty) in sink, bathtub, or outside with a garden
hose. Always use cold tap water. A mild liquid detergent may
be used if necessary. Spray water through filter in the oppo­site direction of airflow. Allow filter to dry.

6. Reinstall clean air filter

7. Reinstall filter retainer (for blower compartment locations
only)

8. Replace blower access panel and main furnace door (see Fig.
29 and 30) or filter cabinet door (Fig. 40 and 41)

9. Turn on electrical supply to furnace.

!

CAUTION

Use care when cutting support rods in filters to
protect against flying pieces and sharp rod ends.
Wear safety glasses, gloves, and appropriate pro­tective clothing. Failure to follow this caution
could result in personal injury.

COMBUSTION AREA AND VENT
SYSTEM

Visually inspect the combustion are and vent system before
each heating season. Make sure that all PVC pipes leading
into the combustion area and vent are free from any cracks
and sags. Check the combustion-air intake adjacent to the fur­nace for blockage. Also check vent pipe on the outside of
your home for blockage.

When dirt, soot, scale, or rust is allowed to build up, your
furnace can suffer a loss of efficiency and perform improper­ly. Accumulations on the main burners can result in firing out
of normal sequence. This delayed ignition creates an alarm­ingly loud sound.

29 30

UPFLOW FURNACE AIR FILTER TABLE

AIR FILTER LOCATED IN BLOWER COMPARTMENT

FURNACE

CASING

WIDTH (IN.)

17-1/2 (1) 16 x 25 x 1* (1) 16 x 25 x 1* Cleanable

21 (1) 16 x 25 x 1 (1) 20 x 25 x 1* Cleanable

24-1/2 (1 or 2) 16 x 25 x 1 (1) 24 x 25 x 1* Cleanable

AIR FILTER LOCATED IN FILTER CABINET

FILTER

CABINET

HEIGHT (IN)

16 (1) 16 x 25 x 1*

20 (1) 20 x 25 x 1*

24 (1) 24 x 25 x 1*

* Factory-provided with the furnace. Filters may be field modified by cutting

filter material and support rods (3) in filters. Alternate sizes and additional
filters may be ordered from your dealer.

FILTER SIZE (IN)

FILTER

SIZE (IN)

or (1) 16 x 25 x 4-5/16

or (1) 20 x 25 x 4-5/16

or (1) 24 x 25 x 4-5/16

FILTER

TYPESide Return Bottom Return

FILTER

TYPE

Cleanable

Disposable

Cleanable

Disposable

Cleanable

Disposable

!

CAUTION

If your furnace makes an especially loud noise
when the main burners light, shut down your fur­nace and call your dealer.

To inspect the combustion area and vent system, you will
need a flashlight. Refer to Fig. 3 or 4, and proceed as follows:

1. Turn off the gas and electrical supplies to the furnace and
remove the main furnace door. (See Fig. 9, 10, and 11.)

2. Remove burner enclosure front. (See Fig. 31 or 32.)

Inspect the gas burners and ignitor area for dirt, rust, soot, or
scale.

!

CAUTION

If dirt, rust, soot, or scale accumulations are found,
call your dealer. Do not operate your furnace.

3. Inspect the combustion-air and vent pipes for sags, holes,
cracks, or disconnections.

31 32

8

!

DANGER

If holes are found in the pipes or if any portion has
become disconnected, toxic fumes can escape
into your home. DO NOT OPERATE YOUR FUR­NACE. Call your dealer for service.

4. Reinstall burner enclosure front.

5. If your furnace is free of the above conditions, replace
main furnace door and turn on electrical and gas supplies
to the furnace. (See Fig. 16, 17, and 18.)

6. Start the furnace and observe its operation. Watch the
burner flames to see if they are clear blue, almost transpar-
ent. (See Fig. 33.) If you observe a suspect malfunction,
or the burner flames are not clear blue, call your dealer.

33

HEADING SOUTH FOR THE WINTER?

DON’T FORGET YOUR FURNACE!

!

CAUTION

If the furnace is installed in an unconditioned space
where the ambient temperatures may be 32°F or
lower, freeze protection measures must be taken.

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 or lower unless winterized. Follow these procedures
to winterize your furnace:

1. Obtain propylene glycol (RV/swimming pool antifreeze
or equivalent).

!

CAUTION

Do not use ethylene glycol (Prestone II antifreeze
coolant or equivalent). Failure of plastic compo­nents will occur.

34

2. Turn off electrical supply to the furnace. (See Fig. 20.)

3. Remove main furnace door. (See Fig. 23.)

4. Remove upper inducer housing drain connection cap.
(See Fig. 34.)

35

5. Connect field-supplied 1/2-in. ID tube to upper inducer
housing drain connection.

6. Insert field-supplied funnel into tube.

9

7. Pour 1 quart of antifreeze into funnel/tube. Antifreeze
should run through inducer housing, overfill condensate
trap, and flow into open field drain. (See Fig. 35.)

8. Remove funnel and tube from inducer housing and
replace drain connection cap and clamp.

9. Replace main furnace door. (See Fig. 30.)

39

36

37

40

41

38

A CHECK-UP CHECKLIST

Your furnace represents an important investment in your fami­ly’s comfort and your home’s value. To keep it performing
properly and as a preventative to future problems, have a trained
service specialist give your furnace a professional check-up
annually. The following checklist can be used as a guideline to
proper service:

• Inspect all flue gas passages, burners, heat exchangers, cou­pling box(es), and inducer assembly.

• Inspect all combustion-air and vent piping inside structure
and vent pipe termination outside the structure.

• Check gas pipes leading to and inside of your furnace for leaks.

10

11

• Inspect and clean the blower motor and wheel.

NOTE: 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.

• Inspect and change or clean air filters(s) if necessary.

• Inspect all supply-and return-air ducts for obstructions, air

leaks, and insulation. Remedy any problem when necessary.

• Inspect the return-air duct connections(s) at the furnace to en­sure it is physically sound, sealed to the furnace casing, and ter­minates outside the space containing the furnace.

• Inspect electrical wiring, connections, and components for
loose connections.

• Perform an operational checkout to determine whether your
furnace is working properly and if it requires adjustments.

• Inspect all condensate drain tubes and condensate trap assem­bly for leaks. The condensate removal system should be cleaned
annually by a qualified service agency. Refer to the Service and
Maintenance Instructions for further information.

• Examine the physical support of the furnace. Support should
be sound with not cracks, sagging, gaps, etc. around the base.

• Check furnace for any obvious signs of deterioration.

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.

FOR INSUFFICIENT AIRFLOW:

• Check for dirty air filter(s).

• Check for blocked return-air or supply-air grilles throughout

your home. Ensure they are open and unobstructed.

If problem still exists, call your dealer for service.

IF FURNACE FAILS TO OPERATE:

Follow this checklist step by step, advancing to the next step

only if furnace fails to start.

• Check thermostat for proper temperature. Is thermostat set
above room temperature?

• Is thermostat set on HEAT?

• Check fuses and circuit breakers. Is electrical supply on?

• Is manual shutoff valve in gas supply pipe in open position?

(Follow start-up procedures if you open gas valve.)

NOTE: Turn off electrical supply before continuing with

checklist.

• Is control switch or knob on gas valve in ON position? (Fol­low start-up procedures if you must reset switch or knob to ON
position.)

• Check manual reset flame rollout switch located on the burner
box. (See Fig. 3 or 4.) 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 the furnace still fails to operate, call your service representa­tive.

For your convenience, record the furnace product and serial
numbers on page 2. should you ever require service, you will
have ready access to the information needed by your service
representative.

This furnace has an LED operation and fault code display to aid
the installer, service technician, or homeowner while installing
or servicing the unit. The LED code can be seen by removing
the main furnace door and viewing the LED(s) through the view
port in the blower access panel.

NOTE: Removing the blower access panel or turning off the

115-v electrical power supply will terminate LED diagnostic
code display.

To decipher the meaning of the LED code, and suggested
action, the following cross-reference can be used.

MODEL 58MCA and 58MXA DIAGNOSTIC CHART

(See Fig. 3.)

FAULT
CODE FAULT CODE DESCRIPTION CHECKLIST

13 or 33 Limit Switch Lockout

14 or 34

24 Furnace Fuse Open Check for blown fuse and possible short in 24-v wiring.

31 Pressure Switch Not Closed

12, 21, 22,
or 23

No Fault
Code
Signaled

Ignition Lockout or
Ignition Proving Fault

Any Other Fault Code Call dealer for service.

Furnace Fails to Operate and No
Fault is Signaled

NOTES:

1. Light on continuously means control has power and working properly.

2. The fault code is a 2 digit number. The first digit is determined by the number of short flashes of the light and the second digit is determined by number of long
flashes of the light.

Check for dirty air filter.
Check for blocked return-air or supply-air grilles.

Check to be sure manual shutoff valve in gas supply pipe is in the open position. (Follow
start-up procedure if you open gas line.)

NOTE: Turn off the electrical supply and remove access doors before continuing with this

checklist.
Check to be sure control switch or knob on gas valve is in ON position. (Follow start-up
procedures if you must reset switch or knob to ON position.)

Check to make sure that all PVC pipes leading into the combustion-air intake and vent/
exhaust are free from any cracks and sags. Also check the combustion-air intake adjacent to
the furnace and vent/exhaust pipe on the outside of your home for blockage.
Check for low propane gas pressure.

Check thermostat for proper temperature setting.
Check for blown fuses and circuit breakers.
Check to be sure blower access panel is properly in place.

MODEL 58MTA DIAGNOSTIC CHART

(See Fig. 3.)

FAULT
CODE FAULT CODE DESCRIPTION CHECKLIST

13 or 33 Limit Switch Lockout

14 or 34

24 Furnace Fuse Open Check for blown fuse and possible short in 24-v wiring.

31, 32, 43 Pressure Switch Fault

12, 21, 22,
23 or 45

No Fault
Code
Signaled

Ignition Lockout or
Ignition Proving Fault

Any Other Fault Code Call dealer for service.

Furnace Fails to Operate and No
Fault is Signaled

NOTES:

1. Light on continuously means control has power and working properly.

2. The fault code is a 2-digit number. The first digit is determined by the number of short flashes of the light and the second digit is determined by number of long

Check for dirty air filter.
Check for blocked return-air or supply-air grilles.

Check to be sure manual shutoff valve in gas supply pipe is in the open position. (Follow
start-up procedure if you open gas line.)
NOTE: Turn off the electrical supply and remove access doors before continuing with this
checklist.
Check to be sure control switch on gas valve is in ON position. (Follow start-up
procedures if you must reset switch to ON position.)
Check for disconnected ground wire.

Check to make sure that all PVC pipes leading into the combustion-air intake and vent/
exhaust are free from any cracks and sags. Also check the combustion-air intake and vent/
exhaust pipes on the outside of your home for blockage.
Check for low propane gas pressure.

Check thermostat for proper temperature setting.
Check for blown fuses and circuit breakers.
Check to be sure blower access panel is properly in place.

MODEL 58MVP DIAGNOSTIC CHART

(See Fig. 4.)

FAULT
CODE FAULT CODE DESCRIPTION CHECKLIST

12

13 or 33

14 or 34

24 Furnace Fuse Open Check for blown fuse and possible short in 24-v wiring.

31, 32, or 4342Pressure Switch Fault

44 Blower Calibration Fault

21, 22, 23,
or 41

No Fault
Code
Signaled

NOTES:

1. Red light 1 on continuously means furnace is operating in emergency heat.

2. Red light 2 on continuously means the microprocessor board has malfunctioned.

3. Yellow light on continuously means furnace is operating in high heat.

4. Green light on continuously means furnace is operating in low heat.

5. The fault code is a 2 digit number. The first digit is determined by the number of flashes of the yellow light and the second digit is determined by number of flashes
of the green light.

Blower Calibration Lockout

Limit Switch Lockout

Ignition Lockout or
Ignition Proving Fault

Inducer Outside Valid Speed Range

Any Other Fault Code or Either of the Red
Lights On Continuously

Furnace Fails to Operate and No
Fault is Signaled

Check for dirty air filter.
Check for blocked return-air or supply-air grilles.
Turn electrical supply off, then back on. Set the thermostat to call for heat.

Check to be sure manual shutoff valve in gas supply pipe is in the open position. (Follow
start-up procedure if you open gas line.)
NOTE: Turn off the electrical supply and remove access doors before continuing with this
checklist.
Check to be sure control switch or knob on gas valve is in ON position. (Follow start-up
procedures if you must reset switch or knob to ON position.)
Check for disconnected ground wire.

Check to make sure that all PVC pipes leading into the combustion-air intake and vent/
exhaust are free from any cracks and sags. Also check the combustion-air intake adjacent to
the furnace and vent/exhaust pipe on the outside of your home for blockage.
Check for low propane gas pressure.

Check for dirty air filter(s).
Check for blocked return- or supply-air grilles.
NOTE: In zoned applications, fault 44 may flash during operation when a single zone is call­ing for heat. When other zones call for heat, or the unit cycles, the fault should clear itself.
Call for service if fault 12 develops.

Call dealer for service.

Check thermostat for proper temperature setting.
Be sure thermostat is set to HEAT.
Check for blown fuses and circuit breakers.
Check to be sure blower access panel is properly in place.

12

131415

TO OBTAIN INFORMATION ON PARTS: Consult your installing dealer or the classified section of your local telephone directory under the

“Heating Equipment’’ or “Air Conditioning Contractors & Systems’’ heading for dealer listing by brand name.

Have available the Model No., Series Letter, & Serial No. of your equipment to ensure correct replacement part.

Carrier Corporation 7310 West Morris St. Indianapolis, IN 46231

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.

Copyright 2001 Carrier Corporation Form: OM58-95 Replaces: OM58-91 Printed in the U.S.A. a 3-01 PC 101 Catalog No. 535-80002