Riello NXHM fault codes

43 codes from the Riello manual for the NXHM heat pump. Pick one for what it means, the likely causes and where to start.

CodeWhat it means
BHPED PCB failure
C7Transducer module temperature too high protection
E0Water flow fault (after 3 times E8)
E1Phase loss or neutral wire and live wire connected reversely (three phase unit only)
E2Communication fault between controller and hydraulic module
E3Final outlet water temp. sensor (T1) fault
E4Water tank temp. sensor (T5) fault
E5Condenser outlet refrigerant temperature sensor (T3) error
E6Ambient temperature sensor (T4) error
E7Buffer tank up temp. sensor (Tbt1) fault
E8Water flow failure
E9Suction temperature sensor (th) error
EADischarge temperature sensor (tp) error
EBSolar temp. sensor (tsolar) fault
ECBuffer tank low temp. sensor (Tbt2) fault
EDInlet water temp. sensor (Tw_in) malfunction
EEHydraulic module EEprom failure
F1Low DC generatrix voltage protection
H0Communication fault between main board PCB B and main control board of hydraulic...
H1Communication error between inverter module PCB A and main control board PCB B
H2Refrigerant liquid temp. sensor (T2) fault
H3Refrigerant gas temp. sensor (T2B) fault
H5Room temp. sensor (ta) fault
H6The DC fan failure
H7Voltage protection
H9Outlet water for zone 2 temp. sensor (Tw2) fault
HAOutlet water temp. sensor (Tw_out) fault
HECommunication error between main board and thermostat transfer board
HFSuction temperature sensor (th) error (EEprom related)
L0Module protection (P6 group)
L1DC generatrix low voltage protection (P6 group)
L2DC generatrix high voltage protection (P6 group)
L4MCE malfunction (P6 group)
L5Zero speed protection (P6 group)
L8Speed difference >15Hz protection between the front and the back clock (P6 group)
L9Speed difference >15Hz protection between the real and the setting speed (P6 group)
P0Low pressure switch protection
P3Compressor overcurrent protection
P4High discharge temperature protection
P5Inlet water temp. sensor (Tw_in) malfunction
PBAnti-freeze mode
PDHigh temperature protection of refrigerant outlet temp of condenser
PPTw_out - Tw_in unusual protection