BoilerFaultCodes 9C High
Boiler Fault Code 9C
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 9C appears across 2 boiler brands and 8 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler's main control board has lost communication with its internal memory chip, meaning it cannot process the settings needed to run safely. (As reported on Ideal Maximiser SE)
Pick your boiler brand for the 9C fix
Source
Information for the 9C 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