b65 High

Boiler Fault Code b65

Also written as B65 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code b65 appears across 2 boiler brands and 4 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's fan is not spinning fast enough to clear the pipes, which prevents the system from safely lighting the gas to provide heating or hot water. (As reported on Vokera Pinnacle)

Pick your boiler brand for the b65 fix

Johnson Starley b65 3 models Vokera b65 1 model

Source

Information for the b65 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