Service manual

20. SERVICE PROBLEMS AND POSSIBLE SOLUTIONS

COOLING MODE

Problems

Nothing Runs - Cooling Mode

IDFM Runs, No Compressor, No ODFM

IDFM Runs, ODFM Runs, No Compressor

IDFM Runs, Compressor Runs, No ODFM

5. Compressor Runs, ODFM Runs, No IDFM

6. Compressor, ODFM, IDFM Runs, Insufficient

Cooling

7. Compressor, ODFM, IDFM Runs, Unit Is Heating

While In Cool Mode

Possible Solutions

No A/C Voltage, No 12 VDC, Thermostat, Wiring, P.C. Board

Cooling Freeze Thermistor - (Insufficient Indoor Air Flow),

Thermostat, Wiring, Compressor, Contactor, P.C. Board

Insufficient Voltage To Unit, Run Capacitor, Start Device,

Overload, Wiring, Compressor

Run Capacitor, Fan Motor, P.C. Board, Wiring

Thermostat, Run Capacitor, Wiring, Fan Motor, P.C. Board

Air Flow Restriction, High Ambient Temperature, Undersized

Refrigeration System, Very Little Or No Refrigerant Charge,

Compressor

Thermostat, Wiring, P.C. Board, Reversing Valve

HEATING MODE

Problems

1. Nothing Runs - Heat Mode

IDFM Runs, No Compressor, No ODFM

IDFM Runs, ODFM Runs, No Compressor

IDFM Runs, Compressor Runs, No ODFM

Compressor Runs, ODFM Runs, No IDFM

6. Compressor Runs, ODFM Runs, IDFM Runs,

Insufficient Heating

7. Compressor, ODFM, IDFM, Unit Is Cooling While In

Heat Mode

Possible Solutions

No A/C Voltage, No 12 VDC, Thermostat, Sub-base, Wiring,

P.C. Board

Heating Freeze Thermister, Low Outdoor Ambient Conditions,

Wiring, Compressor, Contactor, P.C. Board

Insufficient Voltage To Unit, Run Capacitor, Start Device,

Overload, Wiring, Compressor

Run Capacitor, Fan Motor, Wiring, P.C. Board

Air Flow Restriction, Low Ambient Temperature, Undersized

Refrigeration System, Very Little Or No Refrigerant Charge,

Compressors

Wiring, P.C. Board, Reversing Valve