BoilerFaultCodesYour boiler has detected a flame when there shouldn't be one, which has caused it to shut down for safety purposes.
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 - Monitoring electrode reports an incorrect flame
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 has started. The most common reason is a faulty sensing electrode sending a false signal, but it can also be caused by a leaking gas valve or moisture on the control board electronics.
This fault can be more common during periods of high humidity or heavy rain, as moisture entering the flue or building up inside the casing can interfere with the sensitive electrical signals.
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?
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