70
Chapter 4
Step 5: Check Start Capacitor-
Continued
•
Prolonged operation on start cycle due to low voltage.
Determine if the line voltage is too low (less than 90% of
rated voltage).
•
Prolonged operation on start cycle due to incorrect
relay. Replace with correct relay.
•
Prolonged operation on start cycle due to starting load
too high. Refer to the OEM service information to use
pump down arrangement, if necessary.
•
Excessive short cycling. Short cycling can be caused by
problems with the compressor’s thermal protector or sys-
tem components such as the thermostat, control, contac-
tor, or high or low pressure cut-out. For more information
on troubleshooting the thermal protector, see Step 3. For
troubleshooting the system components, refer to the OEM
service information.
Step 6: Replace Potential 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 7: 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.
