There are several factors that can lead to your heat pump freezing up during the summer cooling season or the winter heating season. You can fix some of the simple problems that lead to freezing yourself, while it will be necessary to call an HVAC expert for more technical repairs.
- It’s normal for heat pump coils to have a light coating of frost on them, but a thick ice buildup is a sign of operating problems that will prevent your system from heating and cooling properly and can lead to your heat pump freezing up. A heat pump has automatic controls that should send the unit into defrost mode to prevent ice buildup during normal operation. An HVAC technician can check to be sure those controls are operating correctly.
- Ice can build up on the coils if the airflow across them is restricted. This could be caused by clogged filters, blocked ducts or by blockage of the outdoor unit by leaves, grass or snow. Be sure your supply and return ducts are unobstructed by furniture, carpeting or closed doors; clean or replace the air filter regularly and keep your outdoor unit free of debris.
- Conditions unrelated to the mechanical integrity of your system can lead to a heat pump freezing up. Freezing rain or leaking gutters can let ice accumulate on your outdoor unit and block airflow.
- Be sure that any water that condenses in your outdoor unit is free to drain away from the equipment. Check to see that the concrete slab the unit is on hasn’t settled or shifted to cause water to accumulate inside the condensing unit.
- Other factors that could impede your heat pump’s proper operation include an insufficient refrigerant charge, faulty valve operation, a worn-out motor or fan and other electronic or mechanical problems that your technician should be able to identify and repair.