Split system air conditioners are used to cool, dehumidify and also heat rooms. The consist of an inner and outer unit.

In the inner unit there is a heat exchanger with fan working as an evaporator in the refrigeration circuit during cooling operation. During heating operation it works as a condenser. The outer unit contains a compressor, another heat exchanger, expansion element (e.g. capillary tube) and an element enabling the change-over from cooling to heating operation. In cooling operation the evaporating refrigerant in the heat exchanger of the inner unit withdraws heat from the room air. In the outer unit the heat in the heat exchanger is discharged to the ambient air by condensing the refrigerant. During heating operation the heat transport is reversed.

ET 630 includes a dividing wall onto whose front and rear panel a modern split system air conditioner has been mounted. To better demonstrate its operation, an additional two pressure displays are available for the refrigerant. The operating mode, fan stage of the inner unit (fan operation) and desired room temperature are selected via a remote control. During automatic operation the actual room temperature is recorded and an operating mode automatically selected to achieve the specified room temperature.

In addition the following functions are set at the remote control: Timer for the regular switching on and off, single remaining operating time in hours (sleep mode; suitable for energy-saving operation) and horizontal position of the lamella at the air outlet for air distribution (swing mode; fixed or movable).