My heat pump has frozen: what now?

Seeing frost or ice on your heat pump in a Scottish winter can be alarming, but a certain amount is completely normal. Here is how to tell normal frosting from a fault that needs an engineer.

Normal frosting and defrost cycles

In cold, damp weather a light layer of frost forms on the outdoor unit, and the heat pump runs a defrost cycle to clear it automatically. You may hear a brief whoosh and see steam, which is normal.

When ice is a problem

If the unit is encased in thick ice, iced up for long periods, or the defrost cycle never seems to clear it, something is wrong, often low refrigerant, a stuck fan or a drainage issue.

What to do

Never chip ice off with tools, as you can damage the coil. Turn the system to standby if ice is heavy and call an engineer. We diagnose the cause and get it running properly again.