BoilerFaultCodesTechnical description
Internal control box failure: check/replace the control box.
What causes this fault?
This fault occurs when the boiler's internal computer brain suffers a hardware failure, preventing it from processing information or sending commands to other parts. The most common reason is electrical degradation of the circuit board over time, though it can also be triggered by loose connections or a short circuit in the internal wiring harness.
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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