BoilerFaultCodes Red lockout indicator bulb 29 High
Boiler Fault Code Red lockout indicator bulb 29
Also written as REDLOCKOUTINDICATORBULB29 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Red lockout indicator bulb 29 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 has failed to light the flame three times, so it has purposefully shut itself off for your safety. (As reported on Chaffoteaux Serelia 24 MFFI)
Pick your boiler brand for the Red lockout indicator bulb 29 fix
Source
Information for the Red lockout indicator bulb 29 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