A LOOK AT SERVICE SAFETY
Servicing
65
Step 3: Check Run Capacitor-
Continued
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 Start 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 start capacitor from the system. Use a capacitance meter to
measure the capacitance. The capacitance value should be the
rated value minus 0% to plus 20%. If it is outside of this range,
then the start capacitor needs to be replaced.
As an alternative, check the start capacitor by measuring conti-
nuity between relay terminals 1 and 4:
a. Rx1 scale: If there is continuity, then the start 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 start capacitor is open and needs to be
replaced.
Possible reasons that a start capacitor is not working properly
include:
•
Use of incorrect start capacitor. Replace with proper start
capacitor.
•
The relay contacts are not working properly. Replace
the relay.
•
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.
