Low
S.22 on Vaillant ecoTEC Pro

Your boiler is briefly preparing itself to provide hot water and this status code is a normal part of its operation.

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

DHW mode: Pump pre-run. The pump prerun for domestic hot water 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 status code appears when the boiler detects a demand for hot water and is preparing the system to deliver it. It occurs because the internal pump needs to run for a few seconds to circulate water through the heat exchanger before the burner ignites. It is a sign that the boiler is functioning exactly as intended and is not an indication of a breakdown.

DIY fix possible

No action is required as this is a normal status message.Wait a few moments for the boiler to finish its pre-run cycle.Check if your hot water taps are working as intended.

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