The ECL pumps are electronically controlled circulating pumps to be installed into the heating and air-conditioning systems with automatic control of rotational speed and motor power. A wide setting range of hydraulic parameters allows optimum pump accomodation to the needs of a heated system with minimum consumption of electric energy. An analogue method of control ensures insensitiveness to electromagnetic interferences. All the pumps with frequency converters have an excellent property allowing saving in energy with the best possible efficiency. The pumps have built-in protection against overload, short circuit, overvoltage and excessive high temperature. The pump can operate as an independent control unit. It is computer-controlled. Flow max to 130 m3/h, pressure max. to 24 m. Temperature of medium from -15° to 140°C.