Neon 4 NOT lit High

Boiler Fault Code Neon 4 NOT lit

Also written as NEON4NOTLIT — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code Neon 4 NOT lit appears across 3 boiler brands and 5 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has failed to light the pilot flame or cannot verify that the burner is safely lit, resulting in no heating or hot water. (As reported on Glow-worm Space Saver 30 40 50)

Pick your boiler brand for the Neon 4 NOT lit fix

Glow-worm Neon 4 NOT lit 3 models Ikon Neon 4 NOT lit 1 model Protherm Neon 4 NOT lit 1 model

Source

Information for the Neon 4 NOT lit 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 31 August 2026