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 through 40 sizes 2" thru 8". 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.