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Chapter 4
Step 1: Before Continuing with
Troubleshooting...
WARNING!
All electric power should be disconnected and
you should have already made sure that the compressor does
not have a ground fault (see “Checking for a Ground Fault”
on pages 47-48).
You should have also checked the windings
for continuity and proper resistance (see “Checking for Conti-
nuity and Proper Resistance” on pages 48-49), made sure the
system is getting proper voltage, and that the control, thermo-
stat, and contactor are working properly.
NOTE: The compressor housing MUST be at 130°F or less for
the following checks. This temperature can be read by Tempstik
or is that temperature which will allow the hand to remain in
contact with the compressor housing without discomfort.
Step 2: Check Internal Thermal
Protector
Check for continuity across the thermal protector. If there is no
continuity, then the internal thermal protector may be tripped.
Wait for it to cool off and close. This may take more than an
hour. Check continuity again. If there is replace the compressor.
Step 3: Check Run Capacitor
CAUTION:
Using a 20,000 ohm resistor, discharge the
capacitor before removing it from the system to avoid damage
to measuring devices and risk of electric shock.
Disconnect
the run capacitor from the system. Use a capacitance meter to
check capacitor. Capacitance should be ±10% of the marked
capacitor value.
As an alternative, check the run capacitor by measuring conti-
nuity across the capacitor terminals:
a. Rx1 scale: If there is continuity, then the run capacitor is
shorted and needs to be replaced.
b. Rx100,000 scale: If there is no needle deflection on an
analog meter or if a digital meter indicates infinite resis-
tance, then the run capacitor is open and needs to be
replaced.
Possible reasons that a run capacitor is not working properly
include:
•
Use of incorrect run capacitor. Replace with proper run
capacitor.
•
Line voltage is too high (greater than 110% of rated
voltage).
