How much does it cost to fix boiler error code S.37?

Typical repair cost for the boiler S.37 fault is £150-350 including labour.

S.37 Medium

Boiler Fault Code S.37

Also written as S37 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code S.37 appears across 2 boiler brands 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 temporarily pausing because the fan speed is not within the required range for a safe startup. (As reported on Vaillant ecoMAX 613)

Pick your boiler brand for the S.37 fix

Heatline S.37 8 models Vaillant S.37 10 models

Source

Information for the S.37 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