To troubleshoot common heat pump problems, check the thermostat settings, inspect the air filters, ensure proper airflow, and verify the outdoor unit’s operation.
Heat pumps provide efficient heating and cooling, but like any HVAC system, they can develop issues. Knowing how to troubleshoot common problems can save you money on service calls and keep your home comfortable year-round.
Heat Pump Not Turning On
When your heat pump won’t start, check these potential causes:
Thermostat Issues
Verify your thermostat is set to “heat” mode with the correct temperature setting. For smart thermostats, ensure it’s compatible with heat pumps. Some older models may need replacement. If recently installed, wiring could be incorrect.
Power Problems
Check your circuit breaker panel for tripped breakers. Heat pumps require significant power and may trip breakers during extreme weather. Reset any tripped breakers. If the breaker trips repeatedly, call an HVAC technician.
Failed Starter Capacitor
A clicking sound without the unit starting often indicates a bad starter capacitor. This component provides the initial jolt to start the motors. Replacement requires a professional. Consider quality replacement parts for long-term reliability.
Heat Pump Blowing Cold Air
Several issues can cause your heat pump to blow cold air when heating:
Reversing Valve Failure
The reversing valve switches between heating and cooling modes. If stuck, the pump may blow cold air in heating mode. This requires professional repair.
Low Refrigerant
Insufficient refrigerant prevents proper heat transfer. Signs include reduced heating capacity and ice buildup. Refrigerant leaks require professional repair to locate and fix the leak before recharging.
Dirty Coils
Outdoor coils covered in dirt or debris can’t absorb heat efficiently. Clean coils annually with a garden hose (power off). For persistent issues, consider professional coil cleaning.
Heat Pump Running Constantly
A heat pump that never shuts off may indicate:
Extreme Weather
Heat pumps work harder in very cold temperatures. Below freezing, supplemental heat may be needed. This is normal operation.
Dirty Air Filter
A clogged filter restricts airflow, forcing the system to run longer. Replace filters every 1-3 months. High-efficiency pleated filters work best.
Undersized Unit
An improperly sized heat pump can’t keep up with demand. Have a professional evaluate if your unit is correctly sized for your home.
Ice Buildup on Outdoor Unit
Some ice is normal in winter, but excessive buildup indicates problems:
Defrost Cycle Failure
Heat pumps periodically reverse to melt ice. If this cycle fails, ice accumulates. Check that the defrost control is functioning properly.
Low Refrigerant
Insufficient refrigerant causes coils to get too cold, leading to ice. Have a technician check refrigerant levels.
Blocked Airflow
Ensure at least 2 feet of clearance around the outdoor unit. Remove snow, leaves, or debris blocking airflow.
Strange Noises
Unusual sounds often indicate mechanical issues:
| Sound | Possible Cause |
|---|---|
| Grinding | Failing motor bearings |
| Squealing | Worn blower belt |
| Rattling | Loose parts or debris in unit |
| Hissing | Refrigerant leak |
According to Energy.gov, regular maintenance can prevent many common heat pump issues. The Air-Conditioning, Heating, and Refrigeration Institute recommends annual professional maintenance.
Reduced Heating/Cooling Capacity
If your heat pump isn’t maintaining temperature:
Duct Leaks
Leaky ducts can lose 20-30% of conditioned air. Have ducts inspected and sealed if needed.
Register Issues
Ensure all supply registers are open and unobstructed by furniture or drapes.
Aging System
Heat pumps typically last 10-15 years. Older units lose efficiency and may need replacement.
When to Call a Professional
While some issues are DIY-friendly, these require professional service:
- Refrigerant leaks
- Electrical problems
- Compressor issues
- Reversing valve failure
- Persistent ice buildup
Regular maintenance is the best way to prevent heat pump problems. Schedule annual tune-ups to keep your system running efficiently.
