If your central air conditioner keeps freezing up, you may wonder what could be causing the buildup of ice. If so, look for the following possible causes of your frozen air conditioning unit to see if there is a simple way you can fix it.
1. Thermostat Set Too Low on a Cold Night
If you wake up some mornings to find that your air conditioner has frozen up, one possible cause of the problem could be that you have the thermostat set too low. If the temperature on the thermostat is set lower than the temperature outside, this could make your AC unit freeze up.
When the air outdoors is cool, the pressure inside the compressor lowers as the refrigerant contracts. This contraction, in turn, makes the refrigerant sluggish, making it harder to pass through the compressor. The stalled refrigerant then makes the compressor colder, causing it to freeze up.
To thaw the ice, run the fan without turning on the air conditioner. Then, make sure you set the thermostat to a temperature greater than the forecasted overnight temperature to help keep the problem from happening again.
2. Air Flow Is Blocked
Another possible problem that could make your central AC unit freeze up is lack of adequate air flow. If air is not allowed to travel freely throughout the system, the cold air travels back onto the compressor and motor where it freezes the air around the components and causes ice buildup.
To check to see if blocked air flow is the problem, thaw out the air conditioner as discussed in the previous section. Then, check the vents on the outer casing of the unit to see if dirt or leaves have become lodged inside the openings. If so, use a broom or hand brush to clean out the openings.
Once you have cleaned out the vents, check the AC unit's filter for excess dirt and dust. If enough dirt and dust have accumulated on the filter, they can keep air from moving through the unit. If the filter is even partially dirty, replace it with a clean one.
If you cannot find the reason why your air conditioner keeps freezing up, you should have a professional take a look at it to see if you are low on refrigerant or have a compressor leak. Contact an AC repair services contractor to have them inspect the unit and discuss your options for making any necessary repairs.