BoilerFaultCodes Flash High
Boiler Fault Code Flash
Also written as FLASH — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Flash 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 is failing to light the flame needed to produce heat or hot water, causing it to lock itself out for safety. (As reported on Worcester Bosch CDi Classic)
Pick your boiler brand for the Flash fix
Source
Information for the Flash 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