Defrost Operation; Adaptive Defrost; Pre-Chill; Defrost Heater Operation - GE GYE18JBL Technical Service Manual

Adaptive Defrost

Adaptive Defrost is a defrost system that adjusts
to a refrigerator's surrounding environment and
household usage. Unlike conventional defrost
systems that use electromechanical timers with a
fixed defrost cycle time, Adaptive Defrost utilizes
electronic controls to determine when the defrost
cycle is necessary. In order to accomplish the
optimum defrost cycle time, the main control
board monitors the following refrigerator
operations:
• Length of time the refrigerator doors were
open since the last defrost cycle
• Length of time the compressor has run since
the last defrost cycle
• Amount of time the defrost heaters were on in
the last defrost cycle
If the doors are not opened, the compressor will
run up to 96 hours between defrosts.
Defrost is divided into 4 separate cycles. Those
operations are:

• Pre-Chill

• Defrost Heater Operation

• Dwell

• Post Dwell

Pre-Chill
After accumulating the required amount of time
between defrost cycles, the unit will keep running
until the freezer temperature reaches -15°F or 45
minutes of run time has occurred. Once pre-
chill max time has passed or pre-chill minimum
temperature is achieved, defrost will begin.
Defrost Heater Operation
Once defrost is initiated, all fans are off,
compressor is off, and the heater is on, until
evaporator thermistor temperature reaches 55°F
or until the heater on time reaches 40 minutes
(whichever happens first).

Defrost Operation

Dwell
After defrost has completed, the defrost heater
will be off for 10 minutes before the compressor
starts. This time allows residual moisture from
defrost to drop off the evaporator and exit through
the defrost drain.
Post Dwell
Post-dwell is the final cycle of defrost. After dwell
is completed, the compressor and condenser
fan will start but the evaporator fan will remain
off. The evaporator fan will start once the post-
dwell minimum evaporator temperature of -10°F
is met or the max time of 10 minutes is achieved
(whichever occurs first). Once the evaporator fan
starts, the refrigerator returns to normal operation
and restarts the adaptive defrost time.

Abnormal Defrost

Abnormal defrost is a defrost cycle that lasts for
20 or more minutes. Should an abnormal defrost
occur, the next defrost will begin after 10 hours of
compressor run-time.
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