The Model VSR-FE-2 is a vane-type water flow switch for use on wet sprinkler systems. It is UL Listed and FM Approved for use on steel pipe; schedules 10 through 40, sizes 2" through 8" (50mm, 200mm). The unit may also be used as a sectional waterflow detector on large systems. The unit contains an output relay and an adjustable electronic retard. The relay is actuated when a flow of 10 gallons per minute (38 LPM) or more occurs downstream of the device. The flow condition must exist for a period of time necessary to overcome the selected retard period.