The Model VSR-C is a vane type waterflow switch for use on wet sprinkler systems. It is UL Listed for use on Type K, L, and M copper pipe, sizes 2" thru 4" (50mm, 100mm). The VSR-C may also be used as a sectional waterflow detector on large systems. The VSR-C contains two single pole, double throw, snap action switches and an adjustable, instantly recycling pneumatic retard. The switches are actuated when a flow of 10 GPM (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.