Your boiler's internal computer is having trouble measuring its own temperature, which prevents it from operating safely.

Failure regarding to control panel reference temperature.

What causes this fault?

This fault occurs when the boiler's main control board loses the ability to calibrate itself against its own internal reference temperature. It is usually caused by a physical failure of the electronic components on the circuit board or a communication error within the control panel assembly. Because the boiler can no longer verify it is reading temperatures accurately, it shuts down as a safety precaution.