Low
S.31 on Vaillant ecoTEC plus 412

Your boiler is perfectly healthy and is simply waiting for a signal from your thermostat or timer to start heating your home.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Noheatingdemand:Summermode,eBUScontroller,waitingperiod

Shared across the ecoTEC plus range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Check your room thermostat is set to a temperature higher than the current room temperatureEnsure your heating programmer or timer is set to 'On' for the current time periodWait a few minutes for the boiler to register the request

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Related fault codes

S.30View →S.33View →

All 72 fault codes on the ecoTEC plus 412

Seeing a different code? Every code this model can display, in one place.

Connectiond.02d.10d.11F.00F.01F.10F.11F.13F.20F.23F.24F.25F.27F.28F.29F.32F.49F.61F.62F.63F.64F.65F.67F.68F.70F.71F.72F.77F.78F.83F.84F.85F.86F.87F.88F.91P.01S.0S.01S.02S.03S.04S.05S.06S.07S.08S.20S.21S.22S.23S.24S.25S.26S.27S.28S.30S.32S.34S.39S.42S.46S.53S.54S.88S.91S.96S.98S.99S.108S.109

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