FHP - Flashing Code 2

Florida Heat Pump: EM015

Re: Error Code 2 / Fault Code 2

Code 2 = Low Pressure Switch Fault

Possible Causes (From Most to Least Likely):

1. Low Refrigerant Charge
2. Bad Expansion Valve
3. Low Water Flow (Heating)
4. Low Airflow (Cooling)
5. Bad Pressure Switch

CHECKOUT

1. Check Refrigerant Pressures
   1. Hook-up refrigerant gauges to the system.
   2. 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
2. 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
3. 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)