Riello NXHM fault BH

PED PCB failure

Heat pump

What it means

PED (Power Electronic Device) PCB has failed.

Likely causes

  1. PED PCB failure
  2. IPM module board failure

Where to start

  1. Power off for 5 minutes, then power on again and observe whether it can be recovered; if not restored, replace PED safety plate, power on again, observe whether it can be restored
  2. If still not recovered, replace the IPM module board

The full answer, free

  • How to put it right, step by step
  • The manual page for this fault (page 67), right under the answer

Safety: Isolate the heat pump and any backup heater, and give the inverter capacitors time to discharge before you open the electrics. Anything on the refrigerant circuit needs F-gas certification.

From the Riello manual for the NXHM. Check the model on the data plate before you order parts.

Other Riello NXHM fault codes