Technical description
Controller ABM03B error – controller has an internal error
What causes this fault?
This fault occurs when the boiler's central control board suffers a hardware failure, meaning it can no longer send or receive instructions to vital components like the pump or gas valve. The most common reason is that the delicate electrical circuits on the main PCB have burnt out or degraded, often due to age or an unexpected electrical surge.
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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