Replaced the Contactor - Now Compressor Won't Start
Issue: The compressor was operating before replacing the contactor, but now it just hums and won't come on.
Cause: This is generally the result of mis-wiring the high voltage going to the compressor.
Proper Wiring:
It is not uncommon for the "R" of the compressor to feed from the "C" (or Common) of the capacitor instead of coming directly from the contactor. It doesn't matter as long as it comes from the opposite side that feeds the compressor "C".
Check Voltage:
If you feel that the wiring is correct but the compressor still hums and doesn't start, check voltage at the compressor terminals (if accessible).