Boiler Fault Code Activate

Also written as ACTIVATE — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026

Fault code Activate appears across 1 boiler brand and 1 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 ignite and cannot establish a flame, likely because it is not properly recognising its internal control settings or requires a part replacement. (As reported on Halstead Ace)