Climatemaster - Code 2 / High Pressure Fault - Cooling

Article ID: 268
Last updated: 08 Feb, 2023

Climatemaster Geothermal: TT/TS

Re: Code 2 / High Pressure Fault - Cooling

Code 2 = High Pressure Fault

► There may be (2) Water Pressure Switches wired in series with the refrigerant High Pressure Switch.

► When the high pressure switch opens due to high refrigerant pressures the compressor relay is de-energized immediately since the high pressure switch is in series with the compressor contactor coil.

Qty Possible Causes:
Refrigerant Over-Charge
Bad Expansion Valve
3 Low Water Pressure
1 Low Water Flow
Bad Pressure Switch


1. Check Water Pressure

  • With the unit off, check the inlet and outlet water pressure (psig).
    • Both pressures should be the same and both should be positive pressure (at least 5psig).

2. Check Loop Pump(s)

  • Set the thermostat to call for cooling.
  • If the heat pump is in lockout, reset by removing 24VAC power to the control board.
    • Unit goes into High Pressure lockout immediately or as soon as the compressor tries to start = Open Hi Pressure Switch or Open Water Pressure Switch 
  • Once the compressor starts, check amperage on each loop pump.
    • Each pump should pull around .7 or .8 amps.
      • Excess amperage = Pump Locked-Up
      • No Amperage = No Power to Pump or Bad Pump
  • Re-check the inlet and outlet water pressures.
    • Both pressures should be positive.
    • Record pressure drop.
  • Check and Record the inlet water temperature.
  • Determine GPM/Ton based on flow chart.
    • Ideal Flow = 3GPM/Ton

3. Check Refrigerant Pressure

  • Hook-up refrigerant gauges to the pressure ports on the unit.
    • Blue ⇔ Low Pressure port (typically on the middle line of the reversing valve)
    • Red ⇔ High Pressure port (on the discharge line of the compressor)
  • Place an insulated temperature probe on the liquid line between the heat exchanger and expansion valve.
  • Ensure that the heat pump is running at full capacity.
  • Allow the unit to run for at least 5 minutes.
  • Record pressures and temperature as the system operates.
  • Record Sub-Cooling
    • Sub-Cooling = Saturation Temp (from the high-pressure gauge) - Liquid Line Temp
  • Check and Record water temperature rise.
    • Water Temperature Rise = Outlet Water Temperature - Inlet Water Temperature
  • Refer to Performance Chart for normal operating conditions.
    • High Suction Pressure + High Discharge Pressure + Low Sub-Cooling + High Water Temp Rise = Low Water Flow
    • Normal Suction Pressure + High Discharge Pressure + High Sub-Cooling + Normal Water Temp Rise = Refrigerant Over-Charge
    • Low Suction Pressure + High Discharge Pressure + High Sub-Cooling + Low Water Temp Rise = Bad Expansion Valve

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Article ID: 268
Last updated: 08 Feb, 2023
Revision: 18
Views: 4581
Comments: 0