You would think with it being 90+ degrees outside that it would be impossible for an air conditioner unit to freeze but in fact it’s VERY possible. Here are some reasons an air conditioner can freeze:
Poor airflow with the evaporator coil
Your A/C is designed to pull the heat from your home and the Freon in your system cools it – but if this airflow exchange isn’t taking place then the refrigerant will be working overtime causing your system to freeze.
Running your A/C in cool temperatures
If you operate your air conditioner at 62 degrees or below, the pressures can drop inside your air conditioning system and this is another possible way for your system to freeze.
Low refrigerant can contribute to freezing a system
Freon will try to expand the same amount it would normally but the more expansion Freon does, the cooler everything gets.
A low amount of Freon in your system can freeze everything up due to a low amount of pressure.
If it looks like your air conditioner is frozen over, the most important thing to do is shut it down at the thermostat to minimize further damage. Turn the fan switch to “Fan Only” to blow warm air over the coils and make melting happen more quickly. If the ice extends beyond the drip pan, it’s important that water is captured to prevent additional damage.
Additional Reasons for Poor Airflow
Be sure to check your air filter. A clogged air filter reduces airflow to the coils and can contribute to your system freezing.
Another potential reason for poor airflow is a dirty or poorly working blower fan. The motor may be defective or the blower drive belt may be broken.