Viking VCSB360 Service Notebook page 30

PROBLEM
Compressor will not start No power at ON / OFF switch
and
Compressor runs, but no
refrigeration or insuf-
ficient refrigeration.
DIAGNOSTIC CHART
POSSIBLE CAUSE
No power at the compressor
No power at the outlet
Thermostat:
a. Turned off
b. Points not closing
Relay or overload
Loose connections
Run capacitor
Motor windings open,
shorted or grounded
Timer
Compressor stuck
Moisture restriction
Heavy frost around evaporator
TEST PROCEDURE - ACTION
Plug in electrical outlet or turn on breaker.
Press power switch to ON.
Check with test lamp or volt meter.
Should supply 110-120 volts AC, 60 HZ.
Turn knob clockwise
Place jumper between terminals. If comp-
ressor starts, thermostat is defective and
should be replaced.
Using starting cord, check compressor
Directly. If compressor starts, check relay
And overload individually with ohmmeter
Replace one found defective. If compressor
doesn't start, replace compressor.
Check circuit from power source to comp-
ressor using wiring diagram as guide.
Check capacitor, replace if defective.
Check windings with ohmmeter. See wiring
diagram for resistance values. Replace
Compressor if motor is defective.
Timer may be in defrost cycle. Turn
clockwise past 2 o'clock.
Wired wrong.
Check timer and replace if defective.
Try starting with starter cord. If compressor
won't start, change compressor.
Heat frosted area. If frost line moves farther
along coil after heating, restriction was prob
ably caused by moisture freeze up. Discharge
unit, sweep the system and recharge.
30
-