Boiler Fault Code Lockout lamp (red) on

Also written as LOCKOUTLAMPREDON — same fault.

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

Fault code Lockout lamp (red) on appears across 1 boiler brand 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 trying to light but cannot successfully create or detect a flame, causing it to shut down for safety. (As reported on Biasi Gaia)