BoilerFaultCodesThis is a prompt or status message indicating that the boiler requires professional maintenance or has reached a specific service interval that needs an engineer's attention.
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: Telephone a heating engineer
What causes this fault?
This message is triggered by an internal timer or a specific number of burner operating hours set by a previous engineer. It physically indicates that the boiler has reached its scheduled maintenance interval and requires a safety inspection rather than being a sign of a mechanical breakdown. The status is designed to ensure the appliance continues to run efficiently and safely through preemptive servicing.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like D.98 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.