Monogram ZIS42 - Fill Tube Heater Operation; Water Valve Servicing

MONOGRAM REFRIGERATORS
DEFROST SYSTEM
Frost that has collected on the evaporator
is automatically defrosted by an electrical
heater. After 10 hours of accumulated
compressor operation time, the defrost
control
opens the circuit to the compressor
and closes the circuit to the defrost
heater, drain trough heater (and on later
models), the fill tube heater for 35
minutes. The defrost heater (rated 350
watts) and the drain trough heater (rated
40 watts) remain energized until the
temperature of the evaporator
rises to
450 F (approximately 10 minutes). The
defrost thermostat then opens the circuit
to the heaters. During the remaining time
allotted for the defrost interval, water is
permitted to drain from the evaporator into
the drain trough
below the evaporator. At
the end of the 35-minute defrost interval,
the defrost control opens the contacts for
the
defrost circuit and closes the contacts
to the compressor
circuit.
After the compressor resumes operation, the
defrost thermostat will be cooled by the
evaporator.
When the evaporator
temperature drops to
250 F, the thermostat
contacts will close in preparation for the
next
defrost cycle.
Defrost Control
The defrost control is located at the front
of the unit compartment, behind the top
panel.
The control is mounted to a sound
baffle which is attached to the front of
the
slide-out-chassis. For access to the
defrost control, the top panel must be
removed.
To remove the defrost control, remove two
screws holding the control to the baffle,
rotate the control out and disconnect the
harness connector.
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ZIS MODELS
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