Mains On (Green) light flash Low

Boiler Fault Code Mains On (Green) light flash

Also written as MAINSONGREENLIGHTFLASH — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code Mains On (Green) light flash appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is correctly receiving electrical power and is currently in standby mode, which is the normal operational state. (As reported on Potterton Performa SL HE 9 2)

Pick your boiler brand for the Mains On (Green) light flash fix

Potterton Mains On (Green) light flash 1 model

Source

Information for the Mains On (Green) light 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 27 April 2026