How much does it cost to fix boiler error code Flash Flash On?

Typical repair cost for the boiler Flash Flash On fault is £150-300 including labour.

Flash Flash On High

Boiler Fault Code Flash Flash On

Also written as FLASHFLASHON — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 31 August 2026

Fault code Flash Flash On appears across 3 boiler brands and 5 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 safely vent the exhaust gases, so it has locked itself to prevent unsafe operation. (As reported on Potterton Promax 15/2 HE Plus)

Pick your boiler brand for the Flash Flash On fix

Baxi Flash Flash On 2 models Main Flash Flash On 1 model Potterton Flash Flash On 2 models

Source

Information for the Flash Flash On 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