Boiler Fault Code No flash

Also written as NOFLASH — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026

Fault code No 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 undergoing a standard restart process because the reset button was held down, and it will return to normal operation shortly. (As reported on Worcester Bosch Greenstar 42CDi)