Safety first. If you can see ice on the copper line or the indoor coil, turn cooling off now. Running a frozen system can damage the compressor, the most expensive part in it.
Thaw it safely
- Set the thermostat to Off for cooling. If the blower works, running the fan only speeds up thawing.
- Put towels under the air handler. Melting ice is a lot of water, and the drain can overflow.
- Replace the filter while you wait.
- Give it several hours. Don't chip at the ice: the aluminum fins bend easily.
- Once it's fully thawed, run cooling and watch. If ice comes back within an hour or two, it isn't just the filter. Turn it off and call.
Why coils freeze
Airflow
A clogged filter, a blocked return, too many closed vents, a dirty coil, or a weak blower motor. The coil doesn't get enough warm air across it, drops below freezing, and the moisture on it turns to ice.
Low refrigerant
A leak lowers the pressure, and with it the coil temperature. The fix is finding and repairing the leak, then charging to the manufacturer's specification.
Running cooling on cool nights
On the few genuinely cool South Florida nights, running cooling hard with a low set point can ice a coil, especially one with marginal airflow.
Why it matters
A frozen coil isn't only an inconvenience. Liquid refrigerant can reach the compressor, which is designed to pump vapor, and that's how a simple airflow problem turns into a very expensive repair. Turn it off early.
AC Repair across Miami-Dade, Broward and Palm Beach. Written price before any work.