Contactor Won't Energize - No Fault Codes

CHECKOUT:

1. Check Power

• Check for 230VAC at contactor inlet.
  • No Power --> Check for Electrical Short-to-Ground & Check Breaker.
• Check for 24VAC across R & C on low voltage terminal strip.
  • No Power --> Check the Low Voltage Mini-Breaker on transformer.
    • Tripped --> Check for a Low Voltage Short
      • Be especially cautious of low voltage wires pinched by control door.
• Check Green status light on CXM (tan) board.
  • Green light Off = No Power or Bad CXM Board
  • Green light On Steady = Normal Operation
  • Green light Flashing = Fault Present --> Short TEST pins to display current fault code.

2. Check Unit Status

• Set the thermostat to call for heat or cool operation.
• Check for 24VAC between "Y" and "C" on the Green control board.
  • No Power = No Call from the Thermostat --> Check Thermostat
• Check for 24VAC between "Y" and "C" on the CXM (Tan) control board.
  • No Power --> Check wiring between control boards
  • Power = Unit should start within 5 minutes.
    • Check the control board for active Diagnostics.
      • LED Flashing = Control in Lockout due to active diagnostic --> Short TEST pins to show diagnostic code.

3. Check Contactor

• Check for 24VAC across the coil of the contactor.
  • No Power = Bad CXM Board
  • Power Present but Not Pulled-In = Bad Contactor