Low Information
S.27 on Vaillant ecoTEC Pro / ecoTEC Plus

Your boiler is briefly running the pump after heating your water to cool down the internal components and prevent them from overheating.

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 overrun

What causes this fault?

This occurs when the boiler has finished heating your hot water and needs to move the remaining heat away from the internal heat exchanger. It is a standard safety feature where the pump continues to run for a short period to protect the internal components from heat stress. This is part of the boiler's normal cooling cycle and does not indicate a breakdown.

DIY fix possible

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

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Related fault codes

S.20View →S.28View →

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