5x High

Boiler Fault Code 5x

Also written as 5X — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code 5x appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's central computer has encountered an internal error and can no longer control the heating or hot water safely. (As reported on Vokera Linea HE)

Pick your boiler brand for the 5x fix

Vokera 5x 3 models

Source

Information for the 5x 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 27 April 2026