Low
D.84 on Vaillant Atmomax

Your boiler is simply reminding you that a routine service is due soon based on the number of operating hours it has completed.

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

Maintenance indicator – number of hours until the next maintenance

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 your records to see when the boiler was last servicedBook a routine service with a Gas Safe registered engineerMonitor the boiler for normal operation until the engineer arrives

Find a Gas Safe engineer
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