52
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.
Step 2: Disconnect Fan Motor or Any
Other Devices
If there is a fan motor or any other auxiliary device, open the
circuit for the fan motor or any other device.
Step 3: Check External Thermal
Protector
Check for continuity across the thermal protector. If there is no
continuity, then the thermal protector may be tripped. Wait at
least 5 minutes, then check continuity again. If there is still no
continuity, replace the thermal protector.
Step 4: Check Current Relay
Keep the relay upright. Check the relay by measuring continuity
between:
a. Relay terminals 1 (or L) and S. If there is continuity,
then the contacts are closed when they should be open.
Replace the current relay.
b. Relay terminals 1 (or L) and M. If there is no continuity,
replace the current relay.
Step 5: Replace Current Relay
If all above tests prove satisfactory, there is no capillary restric-
tion, and the unit still fails to operate properly, replace the relay.
The new relay will eliminate any electrical problems which can-
not be determined with above tests.
Step 6: Continue Troubleshooting
If the new relay does not correct the problem, check for ade-
quate compressor pumping as outlined in the procedure on
page 83.