BoilerFaultCodes yellow ❍ High
Boiler Fault Code yellow ❍
Also written as YELLOW — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code yellow ❍ appears across 2 boiler brands 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's computer memory has encountered a data corruption error, meaning it can no longer remember its settings or operating instructions. (As reported on Ariston Clas One)
Pick your boiler brand for the yellow ❍ fix
Source
Information for the yellow ❍ 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