The pre-assembled, ready-to-connect blowdown unit is used for automatic control of the salt content in the circulating water of cooling and humidifier circuits. The functions of the control system include blowdown, enabling of the circulation pump and control of up to three dosing pumps (1x volume-controlled for hardness stabilizer, 2x time-controlled with monthly timer for biocide 1 and 2). Thanks to the built-in micro SD card (4 GB), data logging is possible in accordance with the 42nd BImSchV.