Low Information
S.6 on Vaillant ecoTEC

Your boiler is briefly cooling down internal components after it has stopped heating your water or radiators.

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

Fan and pump overrun

What causes this fault?

This occurs after the boiler has finished a heating cycle to safely dissipate residual heat from the internal heat exchanger. The fan and pump continue to run briefly to ensure the unit cools down gradually and prevents internal components from overheating. It is a normal safety function of the system rather than a mechanical failure.

This status is more visible during winter months when the boiler is working harder and more frequently to heat the home, leading to more frequent cooling cycles.

DIY fix possible

Wait for the code to clear automaticallyEnsure at least one radiator valve is fully open to allow water flowCheck that the boiler pressure is between 1.0 and 1.5 bar

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Related fault codes

S. 0View →S. 7View →S. 8View →

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