Neon 1 lit (No) High

Boiler Fault Code Neon 1 lit (No)

Also written as NEON1LITNO — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code Neon 1 lit (No) appears across 2 boiler brands and 4 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has lost electrical power, which is usually caused by an issue with the mains supply or a blown internal fuse. (As reported on Glow-worm Ultimate3)

Pick your boiler brand for the Neon 1 lit (No) fix

Glow-worm Neon 1 lit (No) 2 models Saunier Duval Neon 1 lit (No) 2 models

Source

Information for the Neon 1 lit (No) 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