The Potter Amseco VSR-S is a vane type waterflow switch for use on wet sprinkler systems that use 1" (2mm), 1-1/4" (32m), 1-1/2 (38mm) or 2 (50mm) pipe size. The unit may also be used as a sectional waterflow detector on large systems.The unit contains two single pole double throw snap action switches and an adjustable, instantly recycling pneumatic retard. The switches are actuated when a fl ow 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. Also known as -Potter / Amseco VSRS