Common Heat Pump Problems & Solutions
- Heat pump doesn’t run at all
- Heat pump runs but doesn’t heat or cool
- Heat pump cools but doesn’t heat
- Heat pump heats but doesn’t cool
- Heat pump fan doesn’t run
- Heat pump doesn’t defrost automatically; ice buildup on coils
- Auxillary light on indoor thermostat lit constantly
Heat pump doesn’t run at all
| Possible cause | Procedure |
|---|---|
| No power to unit | Replace fuse or reset circuit breaker; restore power at unit disconnect switch |
| Compressor pump overloaded | Wait 30 minutes, then press reset button once. If heat pump doesn’t start, call for service |
| Wiring loose or faulty | Check for loose or damaged connections in the electrical control box |
| Compressor contactor faulty | Call for service |
| Capacitor faulty | Discharge and test capacitors, replace if necessary |
Heat pump runs but doesn’t heat or cool
| Possible cause | Procedure |
|---|---|
| Outdoor coils dirty | Clean coils |
| Fan dirty or faulty | Lubricate fan motor; have motor serviced |
| Refrigerant leaking | Call for service |
Heat pump cools but doesn’t heat
| Possible cause | Procedure |
|---|---|
| Indoor thermostat set to ‘Cool’ | Set thermostat to ‘Heat’ |
| Reversing valve stuck or faulty | Set thermostat to ‘Cool,’ wait 30 minutes, then reset to ‘Heat.’ If pump still doesn’t heat, call for service |
Heat pump heats but doesn’t cool
| Possible cause | Procedure |
|---|---|
| Indoor thermostat set to ‘Heat’ | Set thermostat to ‘Cool’ |
| Refrigerant low | Call for service |
| Reversing valve stuck or faulty | Set thermostat to ‘Heat,’ wait 30 minutes, then reset to ‘Cool.’ If pump still doesn’t cool, call for service |
Heat pump fan doesn’t run
| Possible cause | Procedure |
|---|---|
| Wiring loose or faulty | Check for loose or damaged connections in the electrical control box |
| Fan motor burned out | Call for service |
| Capacitor faulty | Discharge and test capacitor, replace if necessary |
| Obstruction in fan blades | Access blades, remove obstruction |
Heat pump doesn’t defrost automatically; ice buildup on coils
| Possible cause | Procedure |
|---|---|
| Indoor thermostat set to ‘Heat’ | Set thermostat to ‘Automatic Heat’ |
| Airflow sensor blocked | Clear airflow sensor tube |
| Coil fins flattened | Clean and straighten coil fins |
| Reversing valve stuck or faulty, or defrost system faulty | Set thermostat to ‘Cool,’ wait 30 minutes, then reset to ‘Heat.’ If ice not thawed, call for service |
Auxillary light on indoor thermostat lit constantly
| Possible cause | Procedure |
|---|---|
| Reversing valve stuck or faulty | Set thermostat to ‘Cool,’ wait 30 minutes, then reset to ‘Heat.’ If pump still doesn’t heat, call for service |
| Outdoor temperature sensor faulty | Test sensor, replace if necessary |
