Evaporator Freeze Over?
 

On the way back up to Phoenix from Tucson I noticed my A/C airflow seemed restricted and the temp from the center vent was 57 F. After turning the unit off for a while, a lot of water drained off and things were OK again. Am I correct in deducing that my evaporator froze over? If yes, I have a control knob on the thermal switch on the evaporator. It was set low enough for air from the center vent to come out near freezing. I now have it set so that lowest air temp from center vent is 44 F. (at 90 F ambient, very humid) Is there a rule of thumb for lowest vent temp you can go and still avoid freeze over?

Thanks.

PS This is an Old Air Unit.

I would seem that you are on the right track. You may also know that a freon overcharge can cause this also. The thermal switch setting sounds best to me right now.

At least your getting a bump...