A LOOK AT SERVICE SAFETY
Servicing
79
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 Plug-in 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:
Check the run capacitor by measuring continuity:
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).
Step 4: Check External Thermal
Protector
Check the external thermal protector by measuring continuity
between C and L on the starting and protector package. 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:
a. GE modules: replace the entire starting and protector
package.
b. TI modules: replace the thermal protector.
