BoilerFaultCodesTechnical description
eBUS undervoltage: Short-circuit on eBUS input, eBUS overload or two power supplies with different polarities on the eBUS
What causes this fault?
This fault occurs when the electrical communication line between your boiler and its thermostat becomes overloaded or suffers a short circuit. It is often caused by damaged wiring, an incompatible external controller, or a component failure on the main circuit board that prevents the system from sending clear signals. Essentially, the boiler can no longer 'talk' to its controls, so it shuts down as a safety precaution.
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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