BoilerFaultCodesYour boiler is simply reminding you that it is due for its routine annual service soon.
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.
Technical description: Maintenance indicator – number of hours until the next maintenance
What causes this fault?
This code is triggered by an internal countdown timer that tracks the boiler's operating hours or the time elapsed since its last check-up. It is not caused by a mechanical failure or a broken part, but rather a pre-set software limit reaching its end. Once this milestone is hit, the boiler displays the message to ensure safety and efficiency through professional inspection.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like D.84 — no call-out fees, no surprises.
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