WD Catalog 2018

920 / 1003

Chapter 8 – Troubleshooting & Service Procedures
8-20 - -
0
100
200 300
400
500
HIGH
TEMPERATURE
LOW
TEMPERATURE
150
120
90
60
30
0
10
20
30
Thermostatic Switch Malfunction
LOW SIDE NORMAL HIGH SIDE NORMAL
Tip: The low side gauge needle may fluctuate in a
very narrow range compared to a normal range.
The compressor clutch may be cycling on and off
more frequently than it should.
The low side gauge needle may fluctuate in an
above normal range as the clutch cycles. This
may be an indication that the thermostat is set
too high (someone may have attempted to adjust
the factory setting). A new thermostat may have
been installed incorrectly (capillary tube not in-
serted between the evaporator fins in the proper
position).
Cause: The thermostatic switch is not functioning prop-
erly or at all.
Repair Procedure:
Replace the thermostatic switch. When you re-
move the old thermostat, replace it with one of
the same type. (They operate in a factory preset
temperature range.) Take care in removing and
handling the thermostat and thin capillary tube
attached to it. Don’t kink or break the tube.
Position the new thermostat capillary tube at or
close to the same location and seating depth be-
tween the evaporator coil fins as the old one.
Connect the electrical leads.
Figure 8-14
Gauge reading, thermostatic
switch malfunction.