Troubleshooting Heat Pumps: 6 Common Problems and Solutions

Posted: June 14, 2024

Heat pumps play a vital role in maintaining comfortable indoor temperatures by cooling and heating spaces efficiently. However, like any mechanical system, heat pumps may encounter issues that can affect their performance. In this guide, we will explore six common problems that heat pumps may experience and provide practical solutions to fix a heat pump issue. By identifying and addressing these common challenges, you can ensure your heat pump operates effectively and efficiently, keeping your home comfortable year-round.

How does a heat pump work?

A heat pump operates on the principle of transferring heat from one space to another, providing both heating and cooling functions. A heat pump uses a refrigerant to transfer heat between indoor and outdoor environments. In heating mode, it extracts heat from the outdoor air (even in cold temperatures) and transfers it indoors. In cooling mode, it removes heat from the indoor air and releases it outside. The heat pump's refrigeration cycle involves four main stages compression, condensation, expansion, and evaporation. During these stages, changes in pressure and temperature absorb and release heat as it circulates between the indoor and outdoor units.

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Checkout: How Does A Heat Pump Work In Winter

Components of a heat pump system



Outdoor unit (condenser)

The outdoor unit houses the compressor, condenser coil, and fan. The compressor pressurizes the refrigerant, the condenser coil releases heat to the outside air, and the fan facilitates heat dissipation.

Indoor unit (evaporator)

The indoor unit contains an evaporator coil and a fan. In heating mode, the evaporator absorbs heat from the indoor air, and in cooling mode, it removes heat from the indoor air to be expelled outside.

Refrigerant lines

Copper or aluminum refrigerant lines connect the indoor and outdoor units, allowing the refrigerant to circulate between the two units.

Reversing valve

The reversing valve is responsible for reversing the flow of refrigerant to switch the heat pump between heating and cooling modes.

Expansion valve

The expansion valve, also known as a thermal expansion valve, regulates the flow of refrigerant into the evaporator coil, controlling the pressure and temperature of the refrigerant.

Control panel and thermostat

A control panel, often integrated with a thermostat, allows users to set the desired temperature and control the heat pump's operation.

Effective solutions for common heat pumps issues_PartsHnC

Heat pump not turning on

Possible causes

  • Power supply issues: A lack of power reaching the heat pump.
  • Thermostat problems: Incorrect settings or malfunctioning thermostat.
  • Tripped circuit breakers: Circuit breakers may have tripped, interrupting power flow to the heat pump.

Effective solutions

  • Check the power supply: Ensure the heat pump is receiving power. Verify the main electrical panel and the power connection to the heat pump.
  • Reset the circuit breaker: If heat pump stopped working, circuit breakers have tripped, reset them by switching them off and then on.
  • Verify thermostat settings: Check the thermostat settings to confirm they are correct for heating or cooling. Replace the batteries in the thermostat if needed.

Insufficient heating or cooling

Possible causes

  • Dirty filters: Accumulated dirt and debris in the filters can be a sign of heat pump not cooling
    Low refrigerant levels: Inadequate levels of refrigerant can hinder the heat pump's ability to transfer heat effectively.
  • Blocked vents: Obstructed vents can impede the proper circulation of heated or cooled air throughout the living space.
  • Faulty thermostat: A malfunctioning thermostat may not accurately control the operation of the heat pump, leading to the heat pump not heating or cooling.

Effective solutions

  • Clean or replace air filters: Regularly clean or replace the air filters to ensure unrestricted airflow through the system, promoting efficient heating and cooling.
  • Check for blocked vents: Inspect all vents and registers to ensure they are not blocked by furniture, drapes, or other obstructions that could hinder proper airflow.
  • Refill refrigerant if necessary: If low refrigerant levels are confirmed, enlist the expertise of a professional to inspect the system and replenish refrigerant as needed.
  • Verify thermostat functionality: Ensure the thermostat is functioning correctly and accurately communicating temperature settings to the heat pump.

Frequent cycling

Possible causes and solutions

  • Incorrect thermostat settings: Ensure that the thermostat is set correctly to prevent short cycling. Improper settings can cause the heat pump to cycle on and off frequently.
  • Dirty filters: Dirty filters can restrict airflow and lead to frequent cycling. Regularly cleaning or replacing filters can help maintain proper airflow and prevent this issue.

Unusual noises from heat pump

  • Loose components within the heat pump system: Carefully inspect the heat pump window unit for any loose components, such as screws, bolts, or panels. Tighten them securely to eliminate potential sources of noise. clear any accumulated debris, leaves, or foreign objects from the heat pump's internal and external parts. Ensure that the unit is free from obstructions that could cause noise during operation.

Ice buildup on the outdoor unit

Possible causes

  • Restricted airflow: Blockage or obstruction hindering proper airflow.
  • Malfunctioning defrost cycle: Issues with the heat pump's defrost cycle operation.
  • Low refrigerant: Inadequate levels of refrigerant in the system.

Effective solutions

  • Ensure proper airflow: Clear any obstructions around the outdoor unit to allow for adequate airflow.
  • Check and clean the defrost system: Inspect the defrost system to ensure it is functioning correctly. Clean any ice buildup on the outdoor unit to prevent further issues.

High energy bills

  • Perform regular heat pump maintenance to ensure efficient operation, including cleaning or replacing filters and scheduling professional inspections.
  • Consider upgrading to a more energy-efficient heat pump model if the current system is old or experiencing significant wear and tear.

Refer: How Much Does It Cost To Install A Heat Pump?

Troubleshooting heat pumps can help homeowners maintain the efficiency and performance of their heating and cooling systems. By addressing problems such as not turning on, insufficient heating or cooling, frequent cycling, unusual noises, ice buildup, and high energy bills with practical solutions, individuals can ensure their heat pumps operate effectively. Regular maintenance, proper care, and timely professional assistance with heat pump repair can go a long way in maximizing the lifespan and efficiency of heat pump systems, providing reliable comfort for your home or business.


Is it okay for a heat pump to run continuously?

It's normal for a heat pump to run continuously in extreme weather conditions to maintain desired indoor temperatures. However, if it's running continuously in milder weather, it may indicate a problem and should be checked by a professional.

How to check a heat pump?

You can check the heat pump by inspecting the air filters, ensuring proper airflow, and examining the outdoor unit for any obstructions.

How to reset a heat pump?

To reset a heat pump, locate the reset button on the outdoor unit, press it, and wait for a few minutes. If unsure, refer to the manufacturer's instructions.

Why is the heat pump fan not spinning?

The heat pump fan may not be spinning due to issues such as a faulty motor, electrical problems, or a malfunctioning fan relay.