Bosch M15G - P2 Fault / H5 Fault (Heating)

Heat Pump: Bosch M15G

Re: P2 Fault / H5 Fault (Heating Mode)

P2 Fault = Low Pressure Protection (Heating or Cooling)

H5 Fault = P2 Fault occurred 5 times in 100 minutes or runtime (Requires Power Reset)

CHECKOUT:

1. Check Refrigerant Pressures

• Pull the service disconnect.
• Make sure the outdoor coil is not frozen-over.
  • Frozen coil = Not Defrosting
• Hook-up refrigerant gauges to the pressure ports on the unit.
  • Blue ⇒ True Suction (Not Suction Line)
  • Red ⇒ Liquid Line Pressure Port
    • Low Standing Pressure (both sides) = Loss of Charge
    • Normal Pressures ⇒ Continue
• Start the unit.
  • Re-Insert the service disconnect.
• Allow the unit to run for 5-10 minutes.
• Monitor pressures as the system operates.
  • Normal R410a Suction Pressure = 100 - 150 psig
• Check Parameter No. 9 to confirm that the Suction Pressure Transducer is reading correctly.