BoilerFaultCodesYour boiler has detected that the external cover is not sealed correctly, which is a safety feature designed to prevent combustion gases from escaping.
Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now — this fault can be dangerous if ignored.
Technical description: Replace outer casing panel (13)
What causes this fault?
This fault occurs when the boiler's internal safety sensors detect that the main front cover isn't making an airtight seal with the chassis. It is usually triggered if the casing has been knocked, the securing clips have loosened, or if the rubber seals have perished and flattened over time. The boiler stops immediately because a perfect seal is required to ensure harmful exhaust gases are safely carried away through the flue.
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 A3 — no call-out fees, no surprises.
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