Low Information
S.15 on Vaillant ecoTEC Pro / ecoTEC Plus

Your boiler is briefly keeping the internal pump and fan running to clear away excess heat after you have finished using hot water.

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.

Technical description

DHW mode pump and fan overrun

What causes this fault?

This occurs because the internal components of the boiler have become very hot while heating your water. The boiler is simply running the pump and fan for a short period to circulate water and air, which safely carries away that residual heat and protects the internal parts from damage. This is a normal part of the boiler's operation and not a sign of a mechanical failure.

DIY fix possible

This fault may be fixable without an engineer. Check your manual first.

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Related fault codes

S.07View →S.14View →

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