BoilerFaultCodesYour boiler's internal computer brain has experienced a malfunction and can no longer communicate with the heating system.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: internal failure - electronic
What causes this fault?
This fault occurs when the boiler's central control board suffers a hardware failure, meaning it can no longer process instructions or monitor safety sensors. The most common reason is an electrical short-circuit or component degradation on the circuit board that prevents it from 'thinking' correctly. Because the control board is the brain of the appliance, it shuts down completely for safety when it detects this internal error.
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 401 — no call-out fees, no surprises.
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