S.98 Low

Boiler Fault Code S.98

Also written as S98 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code S.98 appears across 4 boiler brands and 78 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is temporarily pausing to check its temperature sensors before heating your home, which may cause a delay in getting hot water or heating. (As reported on Glow-worm Flexicom 18sx)

Pick your boiler brand for the S.98 fix

British Gas S.98 1 model Glow-worm S.98 31 models Heatline S.98 7 models Vaillant S.98 39 models

Source

Information for the S.98 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 31 August 2026