Device to control the functioning of a heat exchanger, said device comprising: - a current and/or tension electric generator, associable to the heat exchanger; - at least an emission element, disposed in an emission point or zone, connected to the electric generator and associable to the heat exchanger, configured to generate a medium- or high-frequency electromagnetic field by means of the electric current and/or tension generated by said electric generator; - at least a detection element, disposed in a detection point or zone, distanced from the emission element and not in physical contact with it, and in such a manner that between the emission element and the detection element there is a zone of the heat exchanger, the detection element being configured to detect a value of the electromagnetic field received in the detection point, with respect to the value generated by the electric or electromagnetic field in the emission point; - a detector, connected to the detection element to determine functioning conditions of the heat exchanger as a function of the electromagnetic field detected in the detection point or zone, the device further comprising a frequency generator configured to determine at least a frequency with which the electric generator operates, wherein the frequency generator is configured to generate a frequency from about 100 kHz to 1 GHz, more preferably from 1 MHz to 500 MHz, even more preferably from 10 MHz to 50 MHz, characterised in that the device further comprises an encoded modulator configured to create a real and proper signature on a signal generated by said electric generator until the signal is recognized uniquely and unequivocally even in the presence of disturbances of any type, and an encoded de-modulator associated to the detection element configured to recognize the electromagnetic field generated by said emission element. - a current and/or tension electric generator, associable to the heat exchanger; - at least an emission element, disposed in an emission point or zone, connected to the electric generator and associable to the heat exchanger, configured to generate a medium- or high-frequency electromagnetic field by means of the electric current and/or tension generated by said electric generator; - at least a detection element, disposed in a detection point or zone, distanced from the emission element and not in physical contact with it, and in such a manner that between the emission element and the detection element there is a zone of the heat exchanger, the detection element being configured to detect a value of the electromagnetic field received in the detection point, with respect to the value generated by the electric or electromagnetic field in the emission point; - a detector, connected to the detection element to determine functioning conditions of the heat exchanger as a function of the electromagnetic field detected in the detection point or zone, the device further comprising a frequency generator configured to determine at least a frequency with which the electric generator operates, wherein the frequency generator is configured to generate a frequency from about 100 kHz to 1 GHz, more preferably from 1 MHz to 500 MHz, even more preferably from 10 MHz to 50 MHz, characterised in that the device further comprises an encoded modulator configured to create a real and proper signature on a signal generated by said electric generator until the signal is recognized uniquely and unequivocally even in the presence of disturbances of any type, and an encoded de-modulator associated to the detection element configured to recognize the electromagnetic field generated by said emission element.