Climatemaster - Code 3 / Loss of Charge

Climatemaster Geothermal: Heating / Cooling

Re: Code 3 / Loss of Charge

Code 3 = Low Pressure Fault

The low pressure switch must be open and remain open for 30 continuous seconds during an “on” cycle to be recognized as a low pressure fault.

If the low pressure switch is open for 30 seconds prior to compressor power up it will be considered a low pressure (loss of charge) fault.

• The low pressure switch input is bypassed/ignored for the initial 60 seconds of a compressor run cycle.

CHECKOUT:

1. Check Standing Pressure

• With the unit off, hook-up refrigerant gauges to the pressure ports in the unit.
  • Blue ⇔ Low Pressure (Suction line connection behind reversing valve)
  • Red ⇔ High Pressure (Discharge line off compressor)
    • Low Standing Pressures = Loss of Charge
      • Be suspicious of a crack in the discharge line elbow leaving the compressor.

2. Check Operation

• Set the thermostat to call for cooling.
• If the heat pump is in lockout, reset by removing 24VAC power to the control board.
  • Good Pressure + Unit goes into Low Pressure lockout before the compressor tries to start = Bad Pressure Switch or Loose/Broken Terminal
    • Tug on the wires going into the spade terminals on the pressure switch (common to have bad/loose factory crimps)

3. Check Operating Pressures

• Once the compressor starts, monitor system pressures.
  • Suction pressure goes very low or into a vacuum in first 60 sec = Bad Expansion Valve