The controller shows the incoming and outgoing water temperatures, the heat output in kW and the energy in kWh. When water is consumed or the temperature has started to rise, the controller constantly searches for the operating point corresponding to the maximum output of the heat exchanger, controlling the filling of the air cylinder moving the valve or the operation of the electric drive. If no water is consumed and the outlet water temperature drops, the air cylinder is regularly emptied or the valve is opened electrically to prevent clogging. In addition, the operation of the controller requires the installation of a water meter with a pulse counter (10 l / imp).