From the Blog · College Grove, TN
Heat Pump Frozen in Winter: What to Do
Light frost on the outdoor coil in cold, damp weather is normal, and your heat pump should melt it in a defrost cycle every so often, with a puff of steam and a whoosh. A unit encased in thick ice that never clears is not normal: switch the thermostat to emergency heat so the house stays warm, and call for service. Do not chip ice off the unit; you can damage the coil and refrigerant lines.
Normal frost versus a real freeze-up
During defrost you may see steam, hear the fan stop while the unit hums, and feel cooler air briefly indoors while auxiliary heat covers. That cycle should end with a mostly clear coil. A freeze-up looks different: ice building over the top and sides, ice that survives all day, and a system that runs constantly while the house cools. Causes include a failed defrost board or sensor, low refrigerant, a dead outdoor fan, or airflow blocked by leaves and debris, a common find on large College Grove lots.
What to do, step by step
Switch to emergency heat at the thermostat so your family stays warm. Check that nothing blocks the unit: clear snow, leaves and debris from around it with the power in mind, no tools against the coil. Note whether the outdoor fan spins when the unit runs. Then call for heat pump repair and tell us what you saw; it speeds the diagnosis.
Preventing the next freeze-up
Keep the area around the outdoor unit clear, keep filters changed so indoor airflow stays strong, and have the defrost controls tested at the fall tune-up. Our maintenance visits include exactly that check before the cold weather that exposes it.