The SpeedComfort N operates by the use of an external temperature sensitive switch. The temperature sensitive switch is mounted into a special holder with two magnets to secure the sensor to the back of your radiator. Preferably close to the warm water supply pipe.
The switch can also be mounted between the radiator plates.
The cable attached to the temperature sensitive switch should be inserted into the three-way, that is also connected to the power supply and the SpeedComfort N.