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How to Defrost a Heat Pump

Many households in Maryland use heat pumps to efficiently heat and cool their living areas. They are reliable HVAC systems but can experience problems from time to time. One issue our technicians commonly see is a heat pump that freezes over during cold weather in the winter, which will cause issues if not corrected. Learn how to defrost a heat pump and what to do if you run into problems with a frozen heat pump.

Problems with a Frozen Heat Pump

It’s normal for a bit of frost to develop on a heat pump’s outdoor unit coils during the colder months. The frost you see is simply condensation from the heating process freezing to the coil. Heat pumps have a built-in defrost cycle which normally activates periodically to remove frost and ice from the coils.

Issues with the heat pump’s defrost cycle, component malfunctions, or external sources such as a gutter leak above the unit can cause heavy ice accumulation on the coils as well as the fins on the exterior of the equipment. Larger masses of ice make it difficult for the defrost cycle to remove the frozen moisture, and the heat pump may not thaw.

If the heat pump remains covered in ice and you continue to run the heat, a few issues occur. First, you’ll likely notice that the heat pump cannot generate enough heat output to keep your home comfortable. Ice can block airflow through the fins and outdoor coil, which can cause damage to the coil, refrigerant leaks, and other malfunctions. Ice can also damage outdoor fan blades within the unit.

How to Defrost a Heat Pump

Sometimes, it may take a few hours for the heat pump to completely thaw a frozen coil, so don’t be alarmed if ice doesn’t melt right away. If the heat pump defrost cycle doesn’t work properly or isn’t able to melt away the frost or ice on the unit, you’ll need to know how to defrost a heat pump manually.

  1. Shut off power to the heat pump system at the circuit breaker.
  2. Use a garden hose to spray water over the frozen heat pump components and melt ice. Do not use tools or sharp objects in attempts to chip away ice from coils, as serious damage can be caused.
  3. Look for causes of excess ice on your heat pump. Check the air filter and replace it if it is dirty. Clear away debris that has collected on the exterior of the heat pump. Fix leaky overhead gutters.
  4. At the thermostat, turn the fan “ON” to test for issues with the blower fan motor. If the fan comes on, the blower motor isn’t the problem. You can also allow the fan to run for about an hour, which helps move air through the system and thaw the coils.

What to Do If Your Heat Pump Won’t Defrost

If the above steps fail to clear away the ice on your unit, do not use your heat pump while it is frozen. Your backup heating system should automatically turn on to keep your home warm, if you have one installed. 

If your heat pump’s defrost mode doesn’t clear away ice, or the heat pump keeps icing up over and over again, there could be a component malfunction causing this problem, such as faulty temperature sensors, wiring issues, or low refrigerant levels. These issues need to be identified and repaired by a professional heat pump technician. You don’t want to have to continually repeat the steps for defrosting a heat pump.

Don’t hesitate to call a professional heating and air conditioning technician if you experience a frozen heat pump. Heating and cooling technicians are able to defrost heat pump units as well as find and repair the malfunction contributing to this problem. For heat pump repair in Maryland, call Grove Heating & Cooling today to schedule an appointment to fix the problem!

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