Low Information
S.5 on Vaillant ecoMAX System 612

Your boiler is currently cooling itself down after a heating cycle and will resume normal operation shortly.

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 status occurs because the boiler needs to remove excess heat from the internal heat exchanger after it has finished a period of heating. The fan and pump continue to run for a few minutes to safely circulate water and air, ensuring the internal components don't experience heat stress. It is a normal safety function of the system rather than a mechanical failure.

DIY fix possible

Wait 5-10 minutes for the boiler to complete its cooling cycleEnsure your thermostat or timer is still calling for heatCheck that your radiator valves are open to allow heat to dissipate

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Related fault codes

S. 7View →S. 8View →

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