YH2F - Code 2 or 3 - High Pressure - Cooling

York Heat Pump: YH2F

Re: High Pressure - Code 2 or Code 3 (Cooling)

CODE 2 = High Pressure Switch Fault  (Not in Lockout)

CODE 3 = High Pressure Lockout (Multiple High Pressure Switch Faults)

CHECKOUT:

1. Check Refrigerant Pressures

• Pull the service disconnect.
• Hook-up refrigerant gauges to the pressure ports on the unit.
  • Blue ⇔ True Suction (Not Suction Line)
  • Red ⇔ Liquid Line Pressure Port
• Start the unit.
  • Re-Insert the service disconnect.
  • Reset the lockout (if necessary) by removing and re-inserting the low voltage plug from the defrost board.
  • Bypass the Anti-Short-Cycle Delay by momentarily jumping the "Test" pins.
  • Allow the unit to run for 5-10 minutes.
  • Monitor pressures as the system operates.

• High Pressure + Outdoor Fan Not Operating → Step 2. Check Outdoor Fan Motor
• High Pressure + Outdoor Fan Operating → Step 3. Check Sub-Cooling
• Normal Pressure + Code 2 or 3 Again = Suspect a Bad High Pressure Switch

2. Check Outdoor Fan Motor

• This heat pump may have either a 1) standard PSC motor & capacitor or 2) an ECM motor w/ detached controller.
• PSC Motor
  • One leg of 230V power (RED) comes directly off of the contactor.
  • The other leg of power (BLACK) breaks through the relay of the defrost board.
• When the compressor contactor is energized, check for 230V between the RED wire at T2 of the contactor and the Black wire leaving the defrost board.
  • No Power = Bad Defrost Board 
  • Power + No Fan Operation = Bad Capacitor, Bad Fan Motor or Motor Over-Heated
• ​​​​​​​​​​​​​​ECM Motor
  • 230V power (RED) and (BLACK) feed the motor module continuous from L1 & T2 of the contactor.
  • 24V power (Blue) and (Black) from the compressor contactor coil provides a run command to the motor module. 
    • ​​​​​​​Black leaves the contactor coil and breaks through the relay of the defrost board.
  • ​​​​​​​Confirm that the motor module is receiving High and Low Voltage.
    • ​​​​​​​Voltage Preset + No Motor Operation = Bad Module/Motor

3. Check Suction Pressure & Sub-Cooling

• Sub-Cooling
• Check the Liquid Line Temperature near the outdoor unit.
• Record "Saturation Temperature" from the discharge pressure gauge.
  • Sub-Cooling = Saturation Temp - Liquid Line Temp
    • Normal Sub-Cooling = 3 - 12 deg. (Sight-Glass Clear)
• Low Suction Pressure + High Discharge Pressure + High Sub-Cooling (Clear Sight Glass) = Bad Indoor Expansion Valve
• High to Normal Suction + High Discharge Pressure + High Sub-Cooling (Clear Sight Glass) = Excessive Refrigerant Charge
• High to Normal Suction + High Discharge Pressure + Normal Sub-Cooling (Clear Sight Glass) = Dirty Outdoor Coil