BoilerFaultCodes Neon L3 High
Boiler Fault Code Neon L3
Also written as NEONL3 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Neon L3 appears across 2 boiler brands and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is struggling to clear exhaust fumes because it cannot confirm that the internal fan is moving air properly, preventing it from lighting safely. (As reported on Halstead Hero)
Pick your boiler brand for the Neon L3 fix
Source
Information for the Neon L3 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