Your boiler has lost its connection to the outside temperature sensor, meaning it cannot automatically adjust your heating based on the weather.

Controls according to 0°C outside temperature: Outside temperature sensor lead break

What causes this fault?

This fault occurs when the boiler's control board loses the electrical signal from the sensor located on the outside of your home. The most common reason is a broken or corroded wire between the sensor and the boiler, often caused by exposure to the elements or accidental damage. In some cases, the internal components of the sensor itself may have failed due to age.