BoilerFaultCodesTechnical 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 is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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