BoilerFaultCodes S.88 Low
Boiler Fault Code S.88
Also written as S88 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code S.88 appears across 1 boiler brand and 18 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is currently running an automatic air removal process to clear bubbles from the system and does not require a repair. (As reported on Vaillant ecoTEC Pro)
Pick your boiler brand for the S.88 fix
Source
Information for the S.88 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