BoilerFaultCodesYour boiler's internal computer has forgotten its settings or has developed a technical communication error, meaning it cannot safely control the heating process.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Printed circuit board (PCB) unconfigured or fault
What causes this fault?
This fault occurs when the boiler's central control board loses its identity or suffers a data communication failure, preventing it from managing the gas valve and pumps. The most common reason is a hardware failure within the motherboard or a missing configuration chip, which acts like a memory card telling the boiler exactly which model it is. It can also be triggered by a sudden power surge or electrical interference that corrupts the board's stored settings.
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 L8 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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