BoilerFaultCodes Fan runs Low
Boiler Fault Code Fan runs
Also written as FANRUNS — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Fan runs 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's fan is running continuously to keep the internal temperature steady, which is a normal part of the system's operation process. (As reported on Worcester Bosch Greenstar 25Si)
Pick your boiler brand for the Fan runs fix
Source
Information for the Fan runs 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