BoilerFaultCodes E021 High
Boiler Fault Code E021
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code E021 appears across 1 boiler brand and 9 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has detected an internal electronic or mechanical failure with the component that controls the gas supply, meaning it cannot ignite safely for heating or hot water. (As reported on Vokera Pinnacle System)
Pick your boiler brand for the E021 fix
Source
Information for the E021 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 7 July 2026