The Model VSR-AT is an electronic vane type waterflow switch for use on wet sprinkler systems which may be remotely tested without flowing water. It is UL Listed and FM Approved for use on steel pipe schedules 10 thru 40 sizes 2" thru 8". See ordering Information chart. The VSR-AT may also be used as a sectional waterflow detector on large systems. The VSR-AT has two sets of alarm contacts and an adjustable instantly recycling electronic retard. The alarm contacts 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 time. The VSR-AT may be remotely tested without flowing water by using the optional auto test Control model ATC-1 or ATC-4 or the use of addressable relays and monitor modules as part of a listed addressable fire alarm panel.