BoilerFaultCodes C6 / 215 High
Boiler Fault Code C6 / 215
Also written as C6215 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code C6 / 215 appears across 1 boiler brand and 3 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 that the internal exhaust fan is spinning faster than it safely should, causing it to automatically shut down to prevent damage. (As reported on Worcester Bosch Greenstar i)
Pick your boiler brand for the C6 / 215 fix
Source
Information for the C6 / 215 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