BoilerFaultCodesYour boiler's internal computer has suffered a critical failure 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 control box failure: check/replace the control box.
What causes this fault?
This fault occurs when the boiler's internal electronic brain suffers a hardware failure, preventing it from processing instructions or managing the gas burner. The most common cause is the natural degradation of electrical components on the circuit board over time, often triggered by a small power surge or excessive heat within the casing. Because the safety checks can no longer be guaranteed, the boiler shuts down instantly to prevent any risk.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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