E09 High

Boiler Fault Code E09

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code E09 appears across 3 boiler brands and 13 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 communication problem between its electronic brain and the gas supply system, meaning it cannot safely light the flame. (As reported on Keston C36)

Pick your boiler brand for the E09 fix

Biasi E09 9 models ECA E09 1 model Keston E09 3 models

Source

Information for the E09 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