Low
S.06 on Vaillant ecoTEC Pro 28

Your boiler is simply cooling itself down after providing heating and will return to normal operation shortly.

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

Heating mode: Fan overrun. The fan overrun for heating mode is activated.

Shared across the range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This occurs when the boiler has finished heating your home and needs to blow its internal fan for a short period to remove any remaining heat from the heat exchanger. It is a safety feature that protects the internal components from overheating after the burner has turned off. Your boiler has not actually failed; it is simply performing a standard cooling cycle before it can start again.

This status is more frequently seen during winter when the heating is working hard and the boiler is reaching higher internal temperatures.

DIY fix possible

Wait for a few minutes as this is a normal part of the boiler's operation cycleCheck that your thermostat is set to the desired temperatureEnsure your radiator valves are open to allow heat to dissipate

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