Riello NXHM fault H0

Communication fault between main board PCB B and main control board of hydraulic...

Heat pump

What it means

Communication failure between main board PCB B and main control board of hydraulic module, as listed in the inverter fault table.

Likely causes

  1. Wire doesn't connect between main control board PCB B and main control board of hydraulic module
  2. Communication wire sequence is not right

Where to start

  1. Check wire connection between main control board PCB B and hydraulic module main control board
  2. Check communication wire sequence

The full answer, free

  • The manual page for this fault (page 66), 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