York Package Unit: DNQ

Re: Variable Speed Blower Not Running - Cooling

The unit is calling for either Fan or Cooling, but the indoor blower is not operating.

CHECKOUT:

1. Check Operation

• Make sure the thermostat is set correctly and calling for Fan or Cooling.
• Check to see if sufficient air flow is coming from the supply registers.
  • No Airflow →  Step 2. Check Line Voltage Power
  • Airflow →  Step 3. Check Low Voltage Power

2. Check Line Voltage Power

• At the outdoor unit, remove the filter/control access panel.
• Look for any signs of burnt wires or controls.
• Check resistance across each fuse.
  • No Resistance = Blown Fuse
• Check for 230V power across each power supply.
  • No Power = Check Breaker Panel, Bad Breaker

3. Check Low Voltage Power

• Check for 24VAC between "R" and "C" on the low voltage wiring.
  • No Power = Blown Low Voltage Fuse or Bad Transformer
• Check for 24VAC between "G" and "C" on the low voltage wiring.
  • No Power = No Call for Fan
  • Power Present + No Fan →  Step 4. Check Blower Motor
• Check for 24VAC between "Y" and "C" on the low voltage wiring.
  • No Power = No call for Cooling
  • Power Present + No Fan →  Step 4. Check Blower Motor

4. Check Blower Motor

• Check Blower Motor
  • Check for 230V across blower motor "Prp" at Pin#4 and "Blk" at Pin#5 on the ECM motor.
    • No Power = Blown Fuse
  • Check for 24VAC between "G/Pr" at Pin#15 and "C1/Br" at Pin#1.
    • Power + No Fan Operation = Bad ECM Motor