The invention relates to a device for the optical display of information regarding the actual operating state of a liquid system and/or for setting parameters for a set operating state of the liquid system, comprising a housing (12) arranged in the area of the operation of the liquid system, a display unit (14), accommodated by the housing (12), for optical display of the information in electronic form, and actuating device (16), accommodated by the housing (12), for setting at least one parameter and a, in particular electronic, control unit (18; 44) for processing and/or conditioning of data and/or signals referring to the actual or set operating state of the liquid system, and their use.