BoilerFaultCodes Flame not detected. High
Boiler Fault Code Flame not detected.
Also written as FLAMENOTDETECTED — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Flame not detected. appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is unable to light the burner, meaning it cannot produce heat or hot water because it does not detect a flame. (As reported on Worcester Bosch Greenstar 25CDi)
Pick your boiler brand for the Flame not detected. fix
Source
Information for the Flame not detected. 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 7 July 2026