Your boiler has detected an issue with the sensor that monitors water returning from your radiators, which may stop it from heating efficiently or starting up.

Automatictestprogramme:Returntemperaturesensor,heatingdemandsblocked.

What causes this fault?

This fault occurs when the boiler’s control board receives a signal from the return pipe sensor that is outside of its expected range. The most common reason is that the internal components of the sensor have failed, or the electrical connection between the sensor and the main control board has become loose or damaged.