BoilerFaultCodes 9C:0 High
Boiler Fault Code 9C:0
Also written as 9C0 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 9C:0 appears across 1 boiler brand and 5 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has stopped working because its internal control computer has lost its configuration settings or is unable to communicate with its safety sensors. (As reported on Viessmann Vitodens 200)
Pick your boiler brand for the 9C:0 fix
Source
Information for the 9C:0 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 27 April 2026