BoilerFaultCodesYour boiler's main internal computer has developed a serious communication fault and can no longer control the heating process safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Internal boiler control failure
What causes this fault?
This fault occurs when the boiler's central control board suffers an internal electronic failure, meaning it can no longer send or receive signals from the sensors and gas valve. It is typically caused by aged electrical components on the circuit board wearing out or developing a short circuit over time. In some cases, a loose or damaged wiring connection between the board and the main internal components can also trigger this communication breakdown.
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 A09-12 — no call-out fees, no surprises.
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