Low
S.24 on Vaillant ecoTEC exclusive System

Your boiler is currently operating normally and is in the process of heating your radiators.

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: Burner on

From this model's manual
Verified against the Vaillant Ecotec Exclusive Combi installation & service manual, page 42.
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 code appears because your boiler is functioning exactly as it should and is currently burning gas to provide central heating. It is a status indicator rather than a fault, showing that the system has successfully ignited and is actively warming up your radiators. You will see this message whenever the thermostat calls for heat and the internal components are operating correctly.

This status is most frequently seen during autumn and winter when the central heating is used daily to maintain a comfortable home temperature.

DIY fix possible

This fault may be fixable without an engineer. Check your manual first.

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