Florida Heat Pump: EM015
Re: Error Code 2 / Fault Code 2
Code 2 = Low Pressure Switch Fault
Possible Causes (From Most to Least Likely):
- Low Refrigerant Charge
- Bad Expansion Valve
- Low Water Flow (Heating)
- Low Airflow (Cooling)
- Bad Pressure Switch
CHECKOUT
- Check Refrigerant Pressures
- Hook-up refrigerant gauges to the system.
- Start unit and monitor pressures.
- Normal R-22 Pressures = 55 - 75 Suction, 200 - 275 Discharge.
- Normal R410A Pressures = 100 - 150 Suction, 275 - 400 Discharge.
- Cooling
- Check Suction Line Temperature --> Calculate Superheat
- Normal Superheat = 8 to 18 deg.
- Low Suction + Low Discharge + High Superheat = Low Refrigerant Charge or Bad Expansion Valve
- Low Suction + Low Discharge + Normal Superheat = Low Air Flow
- Heating
- Check water temperature drop at the unit
- Normal temperature drop = 6 - 12 deg.
- Low Suction + Low Discharge + High Temp Drop = Low Water Flow
- Low Suction + Low Discharge + Normal or Low Temp Drop = Low Refrigerant Charge or Bad Expansion Valve
- Check Expansion Valve
- If Low Refrigerant Pressure or Bad Expansion Valve are expected add refrigerant to system.
- Discharge Pressure Increase & Suction Stays Low or Drops = Bad Expansion Valve
- Discharge Pressure & Suction Pressure Increase = Good
- Check Pressure Switch
- If refrigerant pressures stays in a normal range but still shows Code 2:
- Check Pressure Switch
- Without removing wires, check for 2VAC on both sides of the pressure switch.
- Power on both sides = Switch Closed (Ok)
- Power on one side only = Switch Open (Bad Switch)