Heat Pump: Cooling

Re: Code 3 - High Discharge Temperature

The Yorkguard Module on this heat pump has a temperature sensor on the compressor discharge line.

If the Yorkguard senses a discharge temperature above 250 deg. the unit will enter a lockout mode and flash a code 3.

Normal Discharge Temperature = 135 - 180 deg.

CHECKOUT:

1. Use Analyzer to Check Conditions

• If the unit is equipped with a Yorkguard IV (Off-White Plastic Cover), you should hook-up directly with a YorkGuard analyzer to see the actual operating conditions.
• If the unit has a Yorkguard V (open circuit board), a Yorkguard V Interface is required to use the Yorkguard analyzer.
• If the display data is flashing - the analyzer is showing the conditions at the time of lockout. To get live data you must reset the unit by removing 24V power or using the "Speed-Up" button.

2. Check Refrigerant Pressures

• Hook-up refrigerant gauges to the pressure ports on the unit.
  • Blue --> "True Suction" Low Pressure
  • Red --> High Pressure (either refrigerant line)
• Allow the unit to run for at least 10 minutes.
• Monitor pressures and temperature as the system operates.

3. Check Sub-Cooling & Super-Heat

• Sub-Cooling
• Record "Saturation Temperature" from the discharge pressure gauge.
• Subtract the Actual liquid line temperature reading.
  • Saturation Temp - Liquid Line Temp = Sub-Cooling
  • Normal Sub-Cooling = 2 to 14 deg.
• Super-Heat
• Record "Evaporation Temperature" from the suction pressure gauge.
• Record the actual suction line temperature.
  • Suction Temperature - Evaporation Temp = Superheat
  • Normal Super-Heat = 8 to 18 deg.
    • Low Sub-Cooling + High Super-Heat + Low Suction Pressure = Low Refrigerant Charge
    • Low Sub-Cooling + High Super-Heat + High Suction Pressure = Bad Compressor Valves
    • High Sub-Cooling + High Super-Heat + Low Suction Pressure  = Under-Feeding Expansion Valve

4. Check Compressor Discharge Temperature & Sensor