Defrost Cycle
An automatic cycle in frost-free freezers and heat pumps that periodically melts ice off the evaporator coil.
Definition
The defrost cycle is an automatic mode that periodically warms the evaporator coil to clear accumulated frost. In a frost-free refrigerator/freezer, the defrost cycle runs once every 6-12 hours of compressor runtime; a small heater turns on for 20-40 minutes to melt ice off the coil, with the meltwater draining to the drip pan over the compressor where it evaporates. In a heat pump, the defrost cycle reverses the refrigerant flow briefly during heating to melt ice off the outdoor coil. Defrost cycle failures (defrost heater, thermostat, or controller) are among the most common refrigerator repairs.
Where this term appears
Defrost Cycle comes up in product spec sheets, service reports, and troubleshooting documentation across most major appliance brands. If you encountered it in a manual or a service description and want context for how it fits into the larger picture, the related articles in the sidebar drill into the practical details. The glossary as a whole is intended as a quick lookup reference; for a deep dive on any specific topic, jump to the related buying guide or troubleshooting article.