My Heat Pump Has Ice On It, What Should I Do?

Posted: Dec 07, 2011

The recent cold weather has caught many Arizona homeowners off guard and we have received many calls about ice or frost on heat pumps. While some noticeable frost on the outside coils of your heat pump is normal, a unit covered in ice may be cause for greater concern.

Should I Be Worried?
The important thing to remember is that frost and ice can sometimes form on the coils of your heat pump. This is normal. Heat pumps have a defrost mode that will kick in to keep the coils thawed and allow the Freon to continue to transfer heat.

How Does Defrost Mode Work?
All heat pumps have a built-in defrost mode. In order to melt the ice from the coils, the heat pump will turn off the indoor fan (that blows heat through your vents), the outdoor fan will be stopped, and the heat pump will activate its cooling mode. In this way, the refrigerant becomes warm and melts the ice off the coils.

Once the heat pump melts the ice from the coils, or a set time has elapsed, it will reactivate its normal heating mode. From start to finish, the defrost process can take anywhere from 2-10 minutes depending on the heat pump.

But My Unit Isn’t Defrosting…
If the defrost mode on your heat pump is not activating, you may notice a buildup of ice on the rest of your unit as well. Ice buildup on the top of the unit and inside of the coil for any extended period of time may be a symptom of a larger problem that should be corrected as quickly as possible.

Before calling a cooling and heating professional, you may check for the following problems that can prevent the heat pump from properly defrosting.
  • Coil blocked by leaves or debris
  • Improper drainage – ice melt cannot drain off
  • Roof gutter dripping water onto top of heat pump
  • Clogged air intake filter – prevents proper airflow
Make sure your heat pump is elevated off the ground and standing water does not collect around it. Keep leaves and other debris away from the heat pump. You can remove the ice from the top of your heat pump by first turning the unit off and then using a garden hose.

If your heat pump remains iced up or ices up again, there could be a variety of problems, such as faulty defrost control, thermostat or sensor, bad defrost relay or low refrigerant charge, to name a few. You should contact a licensed HVAC technician to make the necessary heating repairs.

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