Your boiler has detected a fault with the temperature sensor for your hot water, which means it cannot safely heat the water for your taps.

DHW sensor short circuit. Check cable/connections not damaged. Renew DHW cable/sensor assy. Part No. 5106290

What causes this fault?

This fault occurs when the electrical circuit for the hot water temperature sensor is interrupted, usually by water ingress or internal component failure. The most common reason is that the sensor's internal insulation has broken down or the connecting wires have become pinched or corroded, leading to an incorrect electrical signal. Because the boiler can no longer monitor how hot the water is, it shuts down as a safety precaution to prevent scalding.