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

Typical repair cost for the boiler Flash On Flash fault is £300-500 including labour.

Flash On Flash High

Boiler Fault Code Flash On Flash

Also written as FLASHONFLASH — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 31 August 2026

Fault code Flash On Flash 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's electronic control centre has developed a internal fault and is unable to safely manage the heating process, meaning the unit will not start. (As reported on Potterton Promax Heat Only)

Pick your boiler brand for the Flash On Flash fix

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

Source

Information for the Flash On 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 31 August 2026