BoilerFaultCodesYour boiler is successfully lighting, but it cannot stay lit and keeps cutting out while it is running.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: The ionisation (the flame) extinguishes during operation of the unit.
What causes this fault?
This fault occurs when the boiler successfully starts but cannot maintain a stable flame, leading the safety sensors to shut the system down. The most common reasons are a worn-out sensor that can no longer 'see' the flame or an inconsistent gas supply that causes the fire to flutter and go out. It can also be caused by a buildup of carbon on the internal components which interferes with the electrical signal required to keep the boiler running.
This fault is often seen during the first cold snap of autumn when the boiler is pushed to run for longer periods after being mostly idle throughout 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.
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A boiler cover plan would cover faults like 6L — no call-out fees, no surprises.
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Ideal Maximiser SE is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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