[bbergie1]

The coil on the unit is freezing up every few weeks. I can manually put the unit in defrost and defrost the coil but then it freezes up after a few weeks again. I had a tech out and they said the control board was bad but they have replaced it twice and it still doesn't work. What else could cause the coil to freeze up?

[denman]

First things that come to mind are the defrost heater and the defrost thermostat

There should be a way to force it into a defrost cycle, check your manual
Then with the coils opened up make sure the heater comes on
Note the freezer must be at freezing for this to work so remove the covers then let the unit run for an hour or so before doing this.