23
RS4100004 Rev. 0
Checking Overload Protectors
Overload protectors protect compressor from current
and temperature overloads by removing power from
compressor before it is damaged.
To check overload protector:
1. Disconnect power to unit.
2. Discharge capacitor by shorting capacitor terminals
through a 10,000 ohm resistor.
3. Remove overload lead from compressor terminal.
4. Use ohmmeter to test continuity between overload
terminals. If open, replace overload.
Checking Compressor Windings
Resistance Test
1. Disconnect power to unit.
2. Discharge capacitor by shorting capacitor terminals
through a 10,000 ohm resistor.
3. Remove leads from compressor terminals.
4. Set ohmmeter to lowest scale.
5. Attach ohmmeter to compressor terminals C and S.
Note reading.
6. Attach ohmmeter to compressor terminals C and M.
Note reading.
If either compressor winding reads open (infinite or very
high resistance) or dead short (0 ohms), replace
compressor.
NOTE: Motor windings typically have very little
resistance. When checking windings for shorts,
ensure ohmmeter is set on lowest scale. Good
windings may indicate as little as 2 ohms of
resistance.
Ground Test
1. Disconnect power to unit.
2. Discharge capacitor by shorting capacitor terminals
through a 10,000 ohm resistor.
3. Remove leads from compressor terminals.
4. Set ohmmeter to highest scale.
5. Attach one lead of ohmmeter to body of compressor.
Ensure connection point is clean, and makes good
contact with compressor.
6. Attach remaining lead on ohmmeter to C, then S,
then M terminals on compressor.
If ohmmeter indicates continuity between compressor
case and any terminal, replace compressor.
Testing Procedures
!
WARNING
To avoid risk of electrical shock, personal injury, or death, disconnect electrical power source to unit and
discharge capacitor through a 10,000 ohm resistor before attempting to service, unless test procedures require
power to be connected. Ensure all ground wires are connected before certifying unit as repaired and/or
operational.
