BoilerFaultCodes Fan Overrun Low
Boiler Fault Code Fan Overrun
Also written as FANOVERRUN — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Fan Overrun appears across 1 boiler brand 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 is continuing to run its internal fan after the heating or hot water has switched off to safely clear out any leftover gases, which is a normal design feature. (As reported on Potterton Envoy 30)
Pick your boiler brand for the Fan Overrun fix
Source
Information for the Fan Overrun 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