Heat Pump Troubleshooting Tips – DOs and DON’Ts

Posted in: Heating

If your home has a heat pump system that provides both heating and cooling, it may seem like there are twice as many possible causes when something goes wrong.  So, how do you begin heat pump troubleshooting? Are there issues you can fix yourself? America’s Best Mechanical & Electrical would like to share these troubleshooting tips!

In some cases, there are issues you can prevent and problems you can solve on your own when you are aware of the heat pump troubleshooting steps. Here is a list of the most common problems we see with heat pumps, possible causes and what to do next.


During the cold winter months, your heat pump’s outside unit will sometimes be covered with a coating of frost on the sides, or even light ice. This is perfectly normal. Every so often, the unit will go into defrost mode to remove that frost.

However, if the top of the unit has a heavy coat of ice, the coils are encased in ice, or the entire unit is covered with a thick sheet of snow and ice, this indicates a problem. All that ice prevents the transfer of heat between the refrigerant and the outside air, and impedes the operation of the heat pump. If you don’t take care of it soon, you could damage the unit beyond repair. Ice in the coils can damage the sensitive fins, the fan blades, and eventually lead to compressor failure.




The unit is not defrosting. Under normal conditions, your heat pump periodically switches to air conditioning mode for a few minutes, which heats up the outdoor coils enough to melt any frost and light ice that has accumulated. If the unit is not defrosting, ice can build up in a hurry. Defrost issues can be caused by faulty relays, controls, or sensors. There could also be a problem with the reverse valve that switches the unit from heat to air conditioning mode.


Outdoor fan problem. The fan motor may be failing or completely dead. Or the fan itself could be damaged, which impedes the release of heat from the unit and causes ice to accumulate.


Low refrigerant. If your heat pump system has a slow leak of refrigerant, eventually the charge becomes so low that the system is not producing enough heat to melt the frost. If this is the case, you will probably also have issues with the unit reaching set temperature.


Outdoor unit is blocked. If piles of snow have accumulated around the outdoor unit, the impeded air flow can cause more icing.


Water is leaking onto the unit. Water constantly dripping on the unit from leaky gutters can gradually form a layer of ice on top.




Those fan coils are very delicate and can easily be damaged. Instead, use water from a hose to melt the ice.

1) Remove and debris or snow that may be blocking the unit.

2) Check for leaking gutters that may be dripping water onto the unit, and repair them.

3) Call America’s Best Mechanical & Electrical to troubleshoot your system professionally.


For more information and other tips and tricks, visit our Facebook page. If you need service now or need additional information not found on our website, please contact us online to schedule a return phone call, or give us a call directly at 888-456-2525.

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