Your boiler has lost the connection to its outdoor temperature sensor and is assuming a fixed temperature of 0°C to keep your heating running safely.

Regulates as if the outside temperature was 0 °C

What causes this fault?

This fault occurs when the boiler's internal computer is unable to process the data it receives from its electronic sensors. The most common reason is a component failure on the main circuit board, which prevents the system from accurately measuring how the boiler is burning gas.