BoilerFaultCodesYour boiler has sensed a flame when there shouldn't be one, so it has shut down as a safety precaution.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Safety switch-off: Flame simulation
What causes this fault?
This fault occurs when the boiler's internal sensors detect a flame after the burner should have switched off, or even before it tries to ignite. The most common reason is a faulty flame sensing electrode sending a false signal, or a gas valve that is leaking slightly and allowing fuel through when it shouldn't.
This fault is more common during periods of high humidity or heavy rain, as moisture entering the casing can interfere with the sensitive electrical signals sent to the control board.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like F.27 — 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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