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

Typical repair cost for the boiler Lights: Flash On Flash fault is £250-400 including labour.

Lights: Flash On Flash High

Boiler Fault Code Lights: Flash On Flash

Also written as LIGHTSFLASHONFLASH — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code Lights: Flash On Flash appears across 2 boiler brands and 7 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's internal computer has developed an electronic fault and is no longer able to communicate with the rest of the system to turn on your heating. (As reported on Potterton Promax Heat Only)

Pick your boiler brand for the Lights: Flash On Flash fix

Baxi Lights: Flash On Flash 3 models Potterton Lights: Flash On Flash 4 models

Source

Information for the Lights: 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 7 July 2026