Boiler Fault Code Pilot will not light (3)

Also written as PILOTWILLNOTLIGHT3 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026

Fault code Pilot will not light (3) appears across 1 boiler brand and 2 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 ignite because internal debris is blocking the tiny gas supply line responsible for starting the flame. (As reported on Chaffoteaux Flexiflame 140)