BoilerFaultCodesTechnical description
Communication error with internal control unit
What causes this fault?
This fault occurs when the boiler's main control board loses its electronic connection with the internal sensors or ignition components. The most common reason is a loose or damaged wiring harness, or a physical failure within the Printed Circuit Board itself that prevents it from sending commands.
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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