Low
D.97 on Vaillant Atmomax

Your boiler has entered a specialist programming mode used by engineers to perform advanced system checks or adjustments.

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

Activation of the second diagnostic level

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

Press the 'i' button briefly to clear the diagnostic display.If the boiler is unresponsive, turn the power switch off, wait 30 seconds, and turn it back on.Avoid pressing and holding both the 'i' and '+' buttons together, as this manual combination activates this mode.

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