Abstract: A central vacuum system with several suction hoses provided with a suction nozzle which, after having vacuumed with the suction hose concerned, must be placed in a suction nozzle holder and which, before vacuuming with the suction hose concerned, must be taken out of the suction nozzle holder. The central vacuum system includes a detection system for detecting whether a suction nozzle is either or not placed in its corresponding suction nozzle holder, as well as a control unit which is connected to the detection system. The control unit controls the suction force of the central pump installation as a function of the number of suction hoses being used.