Iced-Up AC Lines or Coil in Gresham

How to thaw it safely

1. Turn the cooling Off at the thermostat.
2. Keep the fan set to On. Moving air melts the ice much faster.
3. Put towels under the furnace or air handler, since a lot of water comes off as it thaws.
4. Give it several hours. Do not chip at the ice, because the coil fins and tubes are thin.

Why the coil freezes

• Clogged filter. The most common reason. Low airflow lets the coil drop below freezing.
• Low refrigerant. A leak lowers pressure in the coil, and that makes it colder.
• Blower trouble. A weak blower motor or a dirty blower wheel moves too little air.
• Closed vents. Shutting too many registers starves the system of airflow.
• Running on cool nights. Some systems freeze when the AC runs while it is in the 50s outside, which happens a lot here after the sun goes down.

Heat pumps freeze differently

A heat pump building frost on the outdoor coil in winter is normal, and the defrost cycle clears it. Thick ice that stays, or a unit encased after freezing rain, is a separate problem. See the ice storm page for that one.

Questions about Frozen AC Coil in Gresham

Can I run the AC while it is frozen?

No. Running it frozen can send liquid refrigerant back to the compressor and damage it. Let it thaw first.

If I change the filter, will it stop freezing?

If the filter was the cause, yes. If it freezes again with a clean filter, call a contractor to check the refrigerant and blower.

How long does a coil take to thaw?

Often three to six hours with the fan running. A thick block of ice can take longer.