BoilerFaultCodesYour boiler is still detecting a flame even though it has been told to turn off, which is a safety conflict that prevents it from running.
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 internal sensor continues to detect a flame signal after the heating cycle has finished. It is usually caused by a carbon-coated ionisation electrode providing a false reading, or a gas valve that isn't sealing completely, allowing a tiny amount of gas to keep burning. Because the boiler believes a flame is present when it shouldn't be, it enters a safety lockout to prevent overheating.
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 F7 — no call-out fees, no surprises.
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Worcester Bosch Greenstar 25i (ZWB 7-25) 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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