Carrier 58MTA User's Information Manual page 12

FAULT
CODE FAULT CODE DESCRIPTION
13 or 33 Limit Switch Lockout
Ignition Lockout or
14 or 34
Ignition Proving Fault
24 Furnace Fuse Open
31, 32, 43 Pressure Switch Fault
12, 21, 22,
Any Other Fault Code
23 or 45
No Fault
Furnace Fails to Operate and No
Code
Fault is Signaled
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
FAULT
CODE FAULT CODE DESCRIPTION
12 Blower Calibration Lockout
13 or 33 Limit Switch Lockout
Ignition Lockout or
14 or 34
Ignition Proving Fault
24 Furnace Fuse Open
31, 32, or 43 Pressure Switch Fault
42 Inducer Outside Valid Speed Range
44 Blower Calibration Fault
21, 22, 23, Any Other Fault Code or Either of the Red
or 41 Lights On Continuously
No Fault
Furnace Fails to Operate and No
Code
Fault is Signaled
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.
MODEL 58MTA DIAGNOSTIC CHART
(See Fig. 3.)
CHECKLIST
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 for blown fuse and possible short in 24-v wiring.
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.
Call dealer for service.
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.)
CHECKLIST
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 for blown fuse and possible short in 24-v wiring.
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 call-
ing 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.
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