BoilerFaultCodes 312 High
Boiler Fault Code 312
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 312 appears across 1 boiler brand and 2 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 tracks the water flow or temperature, meaning it cannot safely start your heating or hot water. (As reported on Worcester Bosch Greenstar 12i System)
Pick your boiler brand for the 312 fix
Source
Information for the 312 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