BoilerFaultCodes Control failed High
Boiler Fault Code Control failed
Also written as CONTROLFAILED — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Control failed 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's internal computer brain has developed a critical error and is now unable to control the heating or hot water system safely. (As reported on Potterton Envoy 30)
Pick your boiler brand for the Control failed fix
Source
Information for the Control failed 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