Component Testing
©2007 Viking Preferred Service
31
Component Description
Test
Procedures
Evaporator
Inner volume of evaporator allows
liquid refrigerant discharged from
capillary to expand into refrigerant
gas.
Expansion cools evaporator tube
and fin temperature to approximately
-20°F transferring heat from freezer
section to refrigerant.
Passing through suction line to
compressor, the refrigerant picks up
superheat (a relationship between
pressure and temperature that
assures complete vaporization of
liquid refrigerant) as the result of
capillary tube soldered to suction
line.
Refrigerant gas is pulled through
suction line by compressor,
completing refrigeration cycle.
Test for leaks in evaporator with electronic leak detector
or with soap solution. Compressor oil is circulated with
refrigerant; check for oil when checking for leaks.
For minute leaks
1. Separate evaporator from rest of refrigeration system
and pressurize evaporator up to a maximum of 140 PSI
with a refrigerant and dry nitrogen combination.
2. Recheck for leaks.
WARNING
To avoid severe personal injury or death from
sudden eruptions of high pressure gases, observe
the following:
• Protect against a sudden eruption if high pressures
are required for leak checking.
• Do not use high pressure compressed gases in
refrigeration systems without a reliable pressure
regulator and pressure relief valve in the lines.
Thermistor
Temperature sensing device
Check resistance across leads.
Temperature Resistance
77°F 10,000
ohms
36°F 29,500
ohms
0°F 86,300
ohms
Electric
damper
control
Damper control balances the air
delivery between refrigerator and
freezer compartments providing
temperature control for refrigerator.
Electrical voltage activates damper
control and door closes restricting
flow of air from freezer compartment
to refrigerator compartment.
Check resistance across terminals.
If no resistance across terminals replace damper control.
