Neon 4 lit (No) High

Boiler Fault Code Neon 4 lit (No)

Also written as NEON4LITNO — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code Neon 4 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 is failing to light the gas flame or cannot detect that the flame has started, so it has shut down for safety. (As reported on Glow-worm Ultimate3)

Pick your boiler brand for the Neon 4 lit (No) fix

Glow-worm Neon 4 lit (No) 2 models Saunier Duval Neon 4 lit (No) 2 models

Source

Information for the Neon 4 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