Defrost System - KitchenAid Job Aid 4322312 Technical Education

Defrost System

Automatic defrost after every eight hours of compressor run time is accomplished by utilizing a defrost
timer thermostat in the control box, a defrost bi-metal thermostat attached to the outlet of the evapotator
and a radiant electric heater suspended beneath the evaporator. (Fig. 4)
The bi-metal thermostat is attached to the outlet side of the evaorator coil tubing (Fig. 7) and opens at
48°F to terminate the defrost heating. About 33 minutes from the start of the defrost cycle, the timer
restores operation to the compressor circuit. (Fig. 5) The bi-metal thermostat contacts close at 13°F,
enabling the defrost heater to operate during the next defrost cycle.
The defrost heater is suspended on the right side and across the bottom of the evaporator. The defrost
heater also provides warming to the defrost drain area to keep it clear during the defrost cycle.(Fig.6)
Fig.4
Defrost Timer
Evaporator
Retaining
Clip
Fig.5
Retaining
Clip
Defrost Heater
Bi-Metal
Thermostat
Fig.6
Fig.7
5