© 20
10
Viking Preferred Service
63
Service Diagnostics and Procedures
Freezer Thermistor
The freezer uses the same thermistor as does
the fresh food section however, the freezer
thermistor controls the cycle of the compressor.
As the temperature in the compartment changes,
the resistance in this device changes. These
changes are measured by the low voltage board,
and controls the operation of the compressor,
condenser, and freezer evaporator fan.
Refer to the
thermistor chart on page 38.
To access the freezer thermistor:
1. Remove drawers and shelves.
2. Remove screws securing the thermistor.
3. Pull thermistor into freezer cabinet, disconnect
wiring, repair/replace thermistor.
4. Reverse procedure to reinstall.
Defrost Heater
The unit use a heater to help remove ice build
up during the defrost cycle. When the defrost
terminator closes, voltage is supplied to the heater
via the control board. With the main power switch
OFF, the defrost Heater can be tested by removing
the orange wire off of terminal E6 on the HV board.
Using an ohm meter, check the brown wire and
Neutral and you should read approximately 30
Ω
.
During the defrost cycle Line voltage passes
through the Defrost Terminator the into terminal
E5 (orange wire). With the defrost heater relay
activated, the voltage exits the HV board from
Terminal E6 (orange) to the heating element.
If voltage is present at E5 but not at E6, then the
Defrost relay is open. If there is 0 volts
At E5, then the terminator is open.
Another method to test can be achieved by testing
at the 15-wire Molex plug on the right side of the
Control Housing. Refer to page 82 pin locations.
WARNING
To avoid risk of electrical shock, personal injury, or death, disconnect electrical power to unit using power
switch before servicing. Wires removed during disassembly must be replaced on proper terminals to insure
correct earth ground and polarization. After servicing, reconnect power using power switch.
Freezer Thermistor
Defrost Heater
Freezer Themistor