BoilerFaultCodesYour boiler thinks it can still see a flame inside even though it has been told to turn off, which is a safety conflict that prevents it from starting up again.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flame detected even though appliance is switched off
What causes this fault?
This fault occurs when the boiler's control system detects an electrical signal from the flame sensor at a time when the gas should be completely shut off. The most common reason is a contaminated or damaged sensor sending a false signal, or a gas valve that is failing to close fully and allowing a tiny amount of fuel to continue burning.
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 F7 — no call-out fees, no surprises.
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