Wuflex's automatic switch-off system, including signal lamps for pump filter units, enables the efficiency of the filter process to be increased and operating costs to be reduced at the same time with little effort and investment. An acid-proof pressure monitor made of PVDF/FKM continuously monitors the pressure in the filter and controls the operation of the pump. The pump stops automatically when the previously set maximum filter pressure is reached. Hot or even dry running is thus avoided. According to the manufacturer, the costs for maintenance and time-consuming repairs are significantly reduced. By changing the maximum filter pressure, the degree of contamination of the filter can be flexibly adapted to the application and the quality of the filter process can be improved. With the help of the signal lamps, the operator can record the current operating status continuously and easily. The monitoring effort is minimized and premature filter changes are prevented. The well-protected and compact automatic shut-off system is simple to design and can be used regardless of the pump type. Instead of a manometer, the pressure switch can be easily screwed into existing filter units and retrofitted. The automatic switch-off with optical status display controls the operation of the pump via the measured pressure in the filter unit. If this rises above the previously set maximum due to contamination or other faults, an electrical contact automatically switches off the pump and the "red" signal lamp lights up. The actual ACTUAL condition of the filter is continuously monitored and the pump operation is controlled accordingly.