BoilerFaultCodes Er 09 High
Boiler Fault Code Er 09
Also written as ER09 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Er 09 appears across 2 boiler brands and 4 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 issue with the sensor that monitors the temperature of the exhaust fumes, meaning the system has shut down as a safety precaution. (As reported on Biasi Advance Plus)
Pick your boiler brand for the Er 09 fix
Source
Information for the Er 09 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