BoilerFaultCodes n5 High
Boiler Fault Code n5
Also written as N5 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code n5 appears across 2 boiler brands and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler's internal computer has lost communication with the main control board, which means it cannot safely manage your heating or hot water. (As reported on Protherm 100EC)
Pick your boiler brand for the n5 fix
Source
Information for the n5 fault code is sourced from the official service / installation manual for each model that displays it. Read more about how we source fault codes →
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026