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

Typical repair cost for the boiler Lights On Flash On fault is £90-160 including labour.

Lights On Flash On High

Boiler Fault Code Lights On Flash On

Also written as LIGHTSONFLASHON — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code Lights On Flash On appears across 2 boiler brands and 6 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has detected a problem with its internal temperature sensor, meaning it cannot accurately tell how hot the water is and has shut down as a safety precaution. (As reported on Baxi Solo 3)

Pick your boiler brand for the Lights On Flash On fix

Baxi Lights On Flash On 3 models Potterton Lights On Flash On 3 models

Source

Information for the Lights On 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 27 April 2026