Boiler Fault Code E9 210

Also written as E9210 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026

Fault code E9 210 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 shut down because it detected that the exhaust gases are getting too hot, which is a safety mechanism to prevent damage to the internal components. (As reported on Worcester Bosch 30i Junior)