Heat Pump Frozen Outside

When this becomes an emergency

• The outdoor coil is buried under solid ice rather than a thin white frost.
• Ice has grown up over the fan grille or filled the space under the unit.
• Indoor air has gone lukewarm and the backup heat is carrying the load.
• You hear the fan blade slapping ice each time it starts.

What a pro does

Some frost's part of the job. In heating mode the outdoor coil runs below freezing and pulls moisture out of the air, and the unit periodically reverses itself to melt it off. When that defrost stops working, ice compounds. A tech confirms whether defrost is being called at all, checks the coil sensor and the board that reads it, verifies the reversing valve actually shifts, and measures charge, since a low system frosts unevenly and gives itself away by the pattern. Airflow gets checked too, because leaves, drifted snow, or a fan motor turning slowly will ice a coil that is otherwise healthy. Placement counts around here. A unit sitting where snow blows off a roofline or where wind off the bay packs drift against one face will fight defrost all winter, and raising it or shielding it does more good than any part swap. Never chip at the coil with a tool. Bent fins don't come back.

Frequently asked questions

Heat Pump Frozen Outside?

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