54
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 Wired-in PTC Relay
Check the relay by measuring continuity between the pin holes
where the R and S pins on the compressor are inserted. If there
is no continuity, the relay may be open. Wait 3 minutes, then
check continuity again. If there is still no continuity, replace the
relay.
Step 4: Check External Thermal
Protector
Check the external thermal protector by measuring continuity
between the power-in terminal and the female C (common) ter-
minal pin. If there is no continuity, 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 5: Continue Troubleshooting
If all above tests prove satisfactory and unit still fails to operate
properly, check for adequate compressor pumping as outlined in
the procedure on page 83.