Why Is the Air Conditioner Freezing Up?
There are numerous issues that can cause an air conditioner to freeze up, even during the hottest months of the year. Strong airflow is needed to prevent the temperature of the condenser coil from dropping below freezing, but various problems can adversely affect airflow and temperature. These issues include dirty filters, blocked or poorly sized ducts, build-up of dirt and debris, and faulty blowers. Problems with the fan may also lead to weak airflow that is not sufficient to stop freezing. Low levels of refrigerant, which can be caused by leaks or other factors, may also cause freezing; when refrigerant levels are too low, pressure in the evaporator coil falls, causing a temperature drop and eventual freezing. Finally, when nighttime temperatures are lower than 60 degrees, the system may freeze and fail to thaw back out during the day.