Vaillant · ecoTEC plus Boilers
The flow and return temperature sensors have been physically installed on the same pipe or on incorrect pipes, leading to incorrect temperature readings.
Click steps to track your progress.
Press the reset button on the boiler display up to three times to try and clear the fault.
Contact customer service. This fault specifically indicates that the flow and return temperature sensors are physically installed incorrectly on the pipework.
A qualified technician will be required to re-install the sensors in their correct positions.