BoilerFaultCodes S.41 Medium
Boiler Fault Code S.41
Also written as S41 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code S.41 appears across 2 boiler brands and 33 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has too much water in the system, causing the pressure to rise to a level that is higher than recommended for safe operation. (As reported on Vaillant ecoTEC Pro / ecoTEC Plus)
Pick your boiler brand for the S.41 fix
Source
Information for the S.41 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