Low
D.70 on Vaillant Atmomax

Your boiler is currently stuck in a diagnostic test mode used to check if the internal valve is pointing toward the radiators or the hot water.

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

Set diverter valve position

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 to exit the information menuTurn the main power switch off and back on again to reset the displayWait 15 minutes for the automatic test sequence to complete

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D.71View →D.90View →

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