Common Heat Pump Problems & Troubleshooting

Common Heat Pump Problems & Solutions

  1. Heat pump doesn’t run at all
  2. Heat pump runs but doesn’t heat or cool
  3. Heat pump cools but doesn’t heat
  4. Heat pump heats but doesn’t cool
  5. Heat pump fan doesn’t run
  6. Heat pump doesn’t defrost automatically; ice buildup on coils
  7. Auxillary light on indoor thermostat lit constantly

Heat pump doesn’t run at all

Possible causeProcedure
No power to unitReplace fuse or reset circuit breaker; restore power at unit disconnect switch
Compressor pump overloadedWait 30 minutes, then press reset button once. If heat pump doesn’t start, call for service
Wiring loose or faultyCheck for loose or damaged connections in the electrical control box
Compressor contactor faultyCall for service
Capacitor faultyDischarge and test capacitors, replace if necessary
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Heat pump runs but doesn’t heat or cool

Possible causeProcedure
Outdoor coils dirtyClean coils
Fan dirty or faultyLubricate fan motor; have motor serviced
Refrigerant leakingCall for service
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Heat pump cools but doesn’t heat

Possible causeProcedure
Indoor thermostat set to ‘Cool’Set thermostat to ‘Heat’
Reversing valve stuck or faultySet thermostat to ‘Cool,’ wait 30 minutes, then reset to ‘Heat.’ If pump still doesn’t heat, call for service
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Heat pump heats but doesn’t cool

Possible causeProcedure
Indoor thermostat set to ‘Heat’Set thermostat to ‘Cool’
Refrigerant lowCall for service
Reversing valve stuck or faultySet thermostat to ‘Heat,’ wait 30 minutes, then reset to ‘Cool.’ If pump still doesn’t cool, call for service
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Heat pump fan doesn’t run

Possible causeProcedure
Wiring loose or faultyCheck for loose or damaged connections in the electrical control box
Fan motor burned out Call for service
Capacitor faultyDischarge and test capacitor, replace if necessary
Obstruction in fan bladesAccess blades, remove obstruction
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Heat pump doesn’t defrost automatically; ice buildup on coils

Possible causeProcedure
Indoor thermostat set to ‘Heat’Set thermostat to ‘Automatic Heat’
Airflow sensor blockedClear airflow sensor tube
Coil fins flattenedClean and straighten coil fins
Reversing valve stuck or faulty, or defrost system faultySet thermostat to ‘Cool,’ wait 30 minutes, then reset to ‘Heat.’ If ice not thawed, call for service
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Auxillary light on indoor thermostat lit constantly

Possible causeProcedure
Reversing valve stuck or faultySet thermostat to ‘Cool,’ wait 30 minutes, then reset to ‘Heat.’ If pump still doesn’t heat, call for service
Outdoor temperature sensor faultyTest sensor, replace if necessary
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