BoilerFaultCodes F81 High
Boiler Fault Code F81
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code F81 appears across 1 boiler brand and 6 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is struggling to heat up water for your taps because the internal pump or sensor that manages hot water is not working correctly. (As reported on Glow-worm Ultracom 24cx 30cx)
Pick your boiler brand for the F81 fix
Source
Information for the F81 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