Low
D.22 on Vaillant Atmomax

Your boiler is letting you know that a hot water tap is currently turned on or being requested.

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

Hot water demand

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.

DIY fix possible

Check all hot water taps in the property are fully closedEnsure any mixer showers are turned off completelyCheck for any leaking hot water pipes or dripping taps

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