BoilerFaultCodes 9F855 High
Boiler Fault Code 9F855
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 9F855 appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has stopped working because it cannot light the burner, which most often happens when your oil tank is empty or there is an issue with the oil supply. (As reported on Worcester Bosch Greenstar Heatslave II)
Pick your boiler brand for the 9F855 fix
Source
Information for the 9F855 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