BoilerFaultCodes 306 Emergency
Boiler Fault Code 306
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 306 appears across 2 boiler brands and 7 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has detected that a flame is still present even though it has tried to turn the gas supply off, which indicates a potential safety control issue. (As reported on Worcester Bosch Greenstar 1000)
Pick your boiler brand for the 306 fix
Source
Information for the 306 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 31 August 2026