Drain Pan Fan; Defrost System; Adaptive Defrost - GE ZIC36ON Series Technical Service Manual

Drain Pan Fan

The Monogram BMNF has an auxiliary evaporation
fan located under the unit. The purpose of this fan
is to improve the evaporation rate of drain water
should extreme conditions occur.
Should this fan malfunction, there is no
replacement procedure. The absence of this fan
will not affect drain water evaporation under
normal conditions. A stainless steel hot gas loop
routed through the drain pan will provide ample
evaporation.
To remove the fan
1. Remove toe kick (2 screws).
2. Slide out and remove drain pan.
3. Disconnect harness from fan motor.
4. Remove fan by unscrewing 2 screws
accessible from within the pan housing.

DEFROST SYSTEM

Adaptive Defrost

Adaptive Defrost can be described as a defrost
system that adapts 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 an intelligent,
electronic control to determine when the defrost
cycle is necessary. In order to accomplish the
correct 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
Adaptive Defrost is divided into 5 separate cycles.
Those operations are:
• Cooling Operation
• Pre-Chill Operation
• Defrost Heater Operation
• Dwell Period
• Post Dwell
(See Pub. #31-9062 for more information on
Adaptive Defrost.)
Adaptive Defrost (Cooling Operation)
During the cooling operation, the main control
board monitors door opening (fresh food door and
freezer drawer) and compressor run times. The
board counts the time the doors are open. It
reduces the length between defrosts by 300
seconds (multiplication factor) for each second
that each door is open (if both doors are open, it
reduces it by twice the amount). The multiplication
factor reduces compressor run time. If the doors
are not opened, the compressor will run up to 60
hours between defrosts. If the doors are opened
frequently and/or for long periods of time, the
compressor run time between defrosts will be
reduced to as little as 8 hours.
Adaptive Defrost (Pre-Chill Operation)
PRE-CHILL MODE
F
F˚ / C˚
R
E
25˚ / -4˚
E
Z
20˚ / -7˚
E
R
15˚ / -9˚
A
10˚ / -12˚
I
R
5˚ / -15˚
T
E
0˚ / -18˚
M
08:00 09:00
10:00
P
-5˚ / -21˚
E
R
-10˚ / -23˚
A
T
U
-15˚ / -26˚
R
E
-20˚ / -29˚
S
When the main control board determines that
defrost is necessary, it will force the refrigerator
into a continuous cool mode (pre-chill). During pre-
chill, the freezer temperature may be driven below
the set point. However, the fresh food temperature
will be regulated by the evaporator fan running at
low speed. Pre-chill will last for 15 minutes. These
models do not have a defrost holdoff.
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12:00 14:00 15:00 16:00 17:00
11:00 13:00 18:00
Pre-Chill Defrost