BoilerFaultCodes 22.D High
Boiler Fault Code 22.D
Also written as 22D — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 22.D appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler's computer has detected a potential communication error or a generic system check failure, meaning it has safely switched itself off to prevent a fault from worsening. (As reported on Vaillant Thermocompact)
Pick your boiler brand for the 22.D fix
Source
Information for the 22.D 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