Screw semihermetic,  compressors with built-in oil separator, suction filter, cranckcase heater, oil sight glass, thermal protection, hot gas shut off valves and stepless capacity steps. Fans. Axial fans directly coupled to a three-phase electric motor with external rotor. Condenser. Two copper tube and aluminum finned coils. Evaporator. Shell and tube, with two indipendent refrigerant circuits and one water circuit. Managing system and microprocessor regulation. Electronic proportional device to decrease the sound level, with a continuous regulation of the fan speed. This device allows also the cooling functioning of the unit by external temperature till 0°C. Water circuit basic.Includes: evaporator, temperature sensor, antifreeze sensor and water drain