I moved the thermostat up to 72 from 70. So far the frost is not re-occuring but it has been hotter. The idiot that installed the furnace has it crammed inside a tiny closet. My brother had to remove all the molding and the door so that it could be installed. No thought at all had been put into servicing the unit. The vent pipe would have to be removed and all the foil tape around the a-coil just to get to the a-coil.
Pisses me off everytime I look at his phone number on the plenum. Hah very funny. Gonna get another $5k out of an old woman. This unit was installed without my knowledge before I retired.