Carrier 58MVP Troubleshooting Manual page 7

LED CODE
RED LED1 ON Furnace is operating in emergency heat.
RED LED2 ON The microprocessor has malfunctioned. To reset: Put setup switch "SW-1" in the "ON"
position and jumper thermostat terminals "R", "W/W1", and "Y/Y2" simultaneously with
the door switch pushed in and power to the unit "ON". Disconnect jumper and place
setup switch in the "OFF" position. If LED2 reappears replace main control board.
YELLOW LED3 ON
Furnace is operating in high heat.
GREEN LED4 ON Furnace is operating in low heat.
RED LED2 FLASHING
Line voltage polarity is reversed.
EACH OF THE FOLLOWING STATUS CODES IS A TWO DIGIT NUMBER WITH THE FIRST DIGIT
DETERMINED BY NUMBER OF FLASHES OF THE YELLOW LED AND THE SECOND DIGIT
DETERMINED BY NUMBER OF FLASHES OF THE GREEN LED.
11 NO FAULT IN RECENT HISTORY DISPLAY - Indicates no faults have occurred within last five cycles.
To read recent fault history put setup switch "SW-1" in the "ON" position. To clear recent fault
history, put setup switch "SW-1" in the "ON" position and jumper thermostat terminals
"R", "W/W1", and "Y/Y2" simultaneously until an "11" is flashed.
12 BLOWER CALIBRATION LOCKOUT - Indicates RPM calculated for low heat was less than 250 RPM
or greater than 1300 RPM on two successive attempts. Auto reset after three hours. Reset
power and refer to fault #44 section.
13 LIMIT SWITCH LOCKOUT - Indicates the occurrence of 10 successive limit trips during high heat
or three successive limit trips during low heat. Auto reset after three hours.
Check for: - Improper or misaligned limit and/or limit shield.
- Improper high or low heat gas input adjustment.
- Stuck high heat solenoid in gas valve.
14 IGNITION LOCKOUT - Control will auto-reset after three hours. Refer to #34.
21 INVALID MODEL SELECTION - Indicates model plug is missing or incorrect. See wiring diagram
for correct connector jumper location.
22 SETUP ERROR - Indicates setup switch "SW-1" or SW-6" is positioned improperly. The following
combinations will cause the fault.
- Thermostat call with "SW-1" "ON".
- Thermostat call with "SW-6" "ON".
-"SW-1" and "SW-6" both "ON" together.
23 INVALID BLOWER AIRFLOW SELECTION - Indicates improper "A/C" or "CF" switch setting. The 042
and 14 units can deliver 1-1/2 to 3-1/2 tons A/C and 600 to 1400 CFM for continuous fan. The
060 and 20 unit can deliver 2 to 5 tons A/C and 800 to 2000 CFM for continuous fan. If code is
flashing unit will default to closest allowable airflow.
24 SECONDARY VOLTAGE FUSE IS OPEN
Check for: - Short circuit in secondary voltage (24V) wiring.
31 HIGH PRESSURE SWITCH FAULT - Indicates high pressure switch is closed at call, or in low heat,
or fails to close after call, or opens in high heat.
Check for: - Plugged condensate drain.
- Water in vent piping, possibly sagging pipe.
- Improper pressure switch wiring or pressure switch tubing connections.
- Failed or "Out-of-Calibration" pressure switches.
32 LOW PRESSURE SWITCH FAULT - Indicates low pressure switch is closed at call, or fails to close
after call, or opens during operation.
Check for: - Plugged condensate drain.
- Water in vent piping, possibly sagging pipe.
- Improper pressure switch wiring or pressure switch tubing connections.
- Failed or "Out-of-Calibration" pressure switches.
33 LIMIT OR FLAME ROLL-OUT SWITCH IS OPEN - Indicates the limit, rollout switch or auxiliary limit
switch is open or the unit is operating in high heat only mode due to two successive low heat
limit trips. Check for: - Improper or misaligned limit and/or limit shield.
- Improper low heat gas input adjustment.
- Stuck high heat solenoid in gas valve.
SERVICE
STATUS
7
A99243a