Heat Pump Troubleshooting - Common Problems and Solutions

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Last updated: 
April 27, 2024

Heat Pump Troubleshooting: A Guide to Common Issues and Solutions


A heat pump is an energy-efficient solution for regulating the temperature in your home by collecting outside heat and bringing it inside during colder months and eliminating heat from inside during warmer months. According to the U.S. Department of Energy, heat pumps can reduce electricity use for heating by approximately 50% compared to electric resistance heating such as furnaces and baseboard heaters. The heat pump is part of a two-part compression refrigeration system, consisting of an indoor air handler and an outdoor unit that resembles a central air conditioner.

Common Heat Pump Issues

When a heat pump malfunctions, there are generally three common issues that homeowners may encounter. This guide will help you troubleshoot these problems and determine if professional assistance is required.

1. Heat Pump Doesn't Power On

If the heat pump fails to turn on, it could indicate an electrical problem. A tripped circuit breaker can prevent the heat pump from powering up, even if the associated circuit breakers do not appear to be tripped. Resetting the breaker may resolve the issue. Additionally, corroded or worn wires in and around the air handler and heat pump can hinder the unit's operation, sometimes due to oil, grease, or refrigerant leaks. Accidentally switched-off toggles inside the control panel or light switches on the unit's side can also prevent the heat pump from turning on.

2. Heat Pump Doesn't Heat the Whole House

Although heat pumps are efficient, they may struggle in extremely cold temperatures, particularly when reaching negative degrees. If your home feels chillier than the thermostat setting, it could be caused by a faulty thermostat, low refrigerant, leaky ducts, a dirty unit, or a faulty valve.

3. Ice Build-Up

Since the heat pump is located outside, it is exposed to heavy moisture and frigid conditions like wind, snow, and ice. These elements can hinder the defrost cycle, a built-in mechanism that thaws snow and ice off the heat pump. Ice build-up can also result from an outdoor fan problem, low refrigerant, or a blocked outdoor unit. Creating a barrier around the unit and regularly clearing off snow and ice during winter storms can help minimize ice build-up.

Tools Required for Heat Pump Troubleshooting

  • Cordless Drill or 10-in-1 or 5-in-1 Screwdriver: These tools are necessary for removing screws from the handler's and heat pump's casings to access their components for inspection. When using a cordless drill, invest in a Phillips screwdriver 1/4 inch bit and a 5/16 bit, and consider using magnetic tips for added convenience.
  • Digital Multimeter: If you are skilled at measuring voltage, a basic digital multimeter can be used to check the voltage on the heat pump equipment.

Troubleshooting Steps

The steps for troubleshooting the handler and the heat pump are similar:

1. Check the Thermostat

Ensure the thermostat is set to the correct temperature and in heat mode. Test the thermostat's operations when the unit isn't running to see if the air handler cycles on. If the system has a low battery, replace it with a new one. If these methods don't work, the thermostat may be faulty.

2. Check the Power

Verify that the main circuit is on, and if not, flip the switch to reset it. Remove the unit's service panel using a screwdriver or cordless drill to ensure the inside switch is positioned up. Inspect for damaged wires, which can cause power issues. When replacing the panel, ensure it is secure, as a loose panel can prevent the unit from powering up.

3. Check the Outdoor Unit

Remove the panel from the outdoor unit and inspect the coils for ice build-up and the wires for damage. Avoid using sharp objects to chip ice from the coils, as this can cause serious damage and personal harm. Instead, use warm water to melt the ice and snow.

4. Check the Vents and Filter

A dirty filter or blocked vents can cause your system to short cycle or transport insufficient air throughout the house. Ensure the filter is clean and the vents are not obstructed.

Caution Notes

Heat pumps are sensitive systems with intricate parts that require skill to avoid damaging the system. Working around electricity always involves the risk of shock or an electrical fire. Always shut off the power at the breaker box and the exterior shut-off box near the unit when troubleshooting. Heat pump troubleshooting also involves exposure to refrigerant gas and other gases, which can cause allergic reactions and other side effects if exposed to for too long or inhaled.


These heat pump troubleshooting steps can help you identify and potentially resolve common issues on your own. However, if the problem persists after attempting these steps, it may be time to contact an HVAC repair professional. By following this guide and taking the necessary precautions, you can save time and money on your heat pump troubleshooting efforts.

Have you already tried these steps and successfully resolved your heat pump issues? Share your experiences and any additional tips in the comments below.


  1. U.S. Department of Energy. (n.d.). Heat Pump Systems. Retrieved from https://www.energy.gov/energysaver/heat-pump-systems
  2. Amann, J. T. (2018, January 4). Heat Pump Troubleshooting: 3 Common Problems and Solutions. Retrieved from https://www.achrnews.com/articles/136858-heat-pump-troubleshooting-3-common-problems-and-solutions
  3. Coolray. (2019, November 25). 6 Reasons Your Heat Pump Isn't Heating Properly. Retrieved from https://www.coolray.com/help-guides/heat-pumps/6-reasons-your-heat-pump-isnt-heating-properly
  4. Marr, C. (2021, February 10). How to Troubleshoot Common Heat Pump Problems. Retrieved from https://www.thisoldhouse.com/heating-cooling/21015106/how-to-troubleshoot-common-heat-pump-problems
  5. Occupational Safety and Health Administration. (n.d.). Refrigerants. Retrieved from https://www.osha.gov/refrigerants

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