BoilerFaultCodesYour boiler's internal computer brain has developed a communication fault and can no longer process instructions 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 control unit error
What causes this fault?
This fault occurs when the boiler's internal circuit board suffers a critical hardware failure or loses the ability to talk to other electronic components. It is often caused by an electrical surge, moisture ingress, or simply the natural degradation of the solder joints and microchips over time. Because the brain of the boiler can no longer guarantee safe operation, it shuts down the system entirely.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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