de·frost (d-frôst, -frst)v. de·frost·ed, de·frost·ing, de·frosts v.tr.
1. To remove ice or frost from: defrosted the windshield
2. To cause to thaw.v.intr.
1. To become free of ice or frost: a freezer that defrosts automatically.
2. To become thawed.
The evaporator is automatically defrosted by an electric resistance heater. This occurs every six hours of compressor running time. The heater is located in the fin area on the underside of the evaporator. A timer activates the switch which turns on the defroster.