DIAGNOSIS Heavy icing in normal temps signals a problem with the defrost cycle, a dirty filter restricting airflow, or low refrigerant causing the coils to get too cold.
FIX Turn the unit off and let the ice melt completely (do not chip it off). Once thawed, clean the rear air filter thoroughly. A clogged filter reduces airflow, causing the cold coils to freeze the moisture instead of condensing it.
IF THAT DIDN'T WORK After a full thaw and with a clean filter, run it again. If it ices up within an hour, the defrost thermostat or control board may be faulty, failing to cycle the compressor off to melt the frost. This is a component-level repair.
HEADS UP Running the unit while the coils are iced will damage the compressor. If you see ice, stop it immediately. Persistent icing is a serious symptom—if cleaning the filter doesn’t solve it, contact support as continued operation can kill the unit.