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.
| Qty |
Possible Causes: |
| 3 |
Loose/Broken Pressure Switch Terminal |
| 2 |
Low Refrigerant Charge |
|
Bad Expansion Valve |
|
Bad Pressure Switch |
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