How much does it cost to fix boiler error code neon 4 not lit?

Typical repair cost for the boiler neon 4 not lit fault is £120-£350 including labour.

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 27 April 2026

Fault code neon 4 not lit appears across 2 boiler brands and 9 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 or cannot confirm that a flame is present, meaning the system has shut down for safety. (As reported on Glow-worm Ultimate3)

Pick your boiler brand for the neon 4 not lit fix

Glow-worm neon 4 not lit 7 models Saunier Duval neon 4 not lit 2 models

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 27 April 2026