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

Typical repair cost for the boiler Lights: On Off On fault is £100-280 including labour.

Lights: On Off On High

Boiler Fault Code Lights: On Off On

Also written as LIGHTSONOFFON — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code Lights: On Off On appears across 1 boiler brand and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has tried to light several times but failed, so it has locked itself out for safety. (As reported on Baxi Solo 2)

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

Baxi Lights: On Off On 2 models

Source

Information for the Lights: On Off 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 7 July 2026