York Package Heat Pump: BHX

Re: No Heat

When a customer reports "No Heat' with a heat pump, that generally indicates a problem with the indoor blower or electric heaters.

► There may be a problem with the heat pump itself, but the auxiliary heaters should cycle on to keep the temperature within 1 degree of the Heat Setpoint.

CHECKOUT:

1. Check Operation

• Make sure the thermostat is set correctly and calling for Heat.
• 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

• Turn off power to the unit.
  • If present, use the service disconnect(s).
  • Be aware that some package heat pumps have up to 3 power supplies!
• Remove access panel.
• Look for any signs of burnt wires or controls.
• Check resistance across each fuse.
  • No Resistance = Blown Fuse
• Turn power back on to the unit.
• 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 "W" and "C" on the low voltage wiring.
  • No Power = No call for Aux Heat from the thermostat or Mis-Wiring
  • Power Present + Blower Running →  Step 5. Check Heaters

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

5. Check Heaters

• Amperage
  • With a call for "W" (or W1 and W2) use an Amp Probe to check amperage of each heater.
    • No amperage ⇒ Cycle high voltage power to the unit the re-check heaters. (Even though there is no indication light, the heater board has a 3-Limit Trip Lockout = No Heaters + Fan Runs Continuous until power is cycled)
      • Heaters Start Working → Step 6. Check Airflow
      • Heaters Still Not Working ⇒ Check Relays
• Check Relays
  • With 24VAC on W1 & W2, check for 22VDC across the coil of each heat relay.
    • No Voltage = Bad Heater Board or Bad Limit
    • Voltage but No Amperage = Bad Heat Relay or Bad Heater ⇒ Check High Voltage to each heater. 
      • High Voltage + No Amperage = Bad Heater
      • No High Voltage = Bad Relay

6. Check Airflow

• Check air filter & indoor coil
• Check airflow settings