why do my air condition coils freeze up?

your coils icing up can be a syptom of from various causes. The simplest cause is lack of airflow i.e dirty return air filter or not getting rid of enough air. A second cause is possible low Freon charge. Most sytems run on R-22 and when there is not enough refrigerant it causes the coil to ice up I could go into detail about it but the need does not exist. If you have gauges check to see that the refrigerant pressure on the blue gauge called the low side is above 58 PSi which is close to 32 degrees. A third problem could be wrong sized metering device but if the system has worked well previously then that would not be the case unless the metering device is stuck in s position to starve or flood the coil.
Hope this helps.

JC_edu88
April 2007