BoilerFaultCodesYour boiler is struggling to light its internal flame correctly, which might cause it to shut down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Maximum ignition time
What causes this fault?
This fault occurs when the boiler's internal computer tries to light the gas burner but cannot confirm a stable flame within the set safety time limit. It is usually caused by a worn ignition lead failing to create a spark or a layer of carbon buildup on the sensors preventing the boiler from 'seeing' the flame it has created.
This issue often surfaces during the first cold snap of autumn when the boiler is pushed to run at maximum power after being relatively idle over the summer.
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.65 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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