Remeha E40 Fault Code

What causes the Remeha E40 fault?

This fault occurs when the boiler's internal computer loses communication with the sensor that monitors water levels. The most common reason is that the sensor's internal electrical components have failed or the wiring connecting it to the main control board has become loose or damaged. Because the boiler cannot verify that it has enough water to operate safely without this sensor, it shuts down to prevent overheating.