Low
S.05 on Vaillant ecoTEC plus aquaPLUS

Your boiler is simply cooling itself down after a period of heating, which is a normal part of its operation.

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

Fan and water pump over run (heating operation)

From this model's manual
Verified against the Vaillant Ecotec Plus Aquaplus installation & service manual, page 38.
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

Wait for a few minutes as this status code usually clears automatically once the boiler has cooled.Ensure your radiator valves are open to allow heat to dissipate.Check that your room thermostat is not set significantly higher than the current room temperature.

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