WFD Series Waterflow Detectors System Sensor’s WFD series Waterflow detectors are housed in a rugged, NEMA-4 rated enclosure. Designed for both indoor and outdoor use, the WFD series operates across a wide temperature range, from 32°F to 120°F. To simplify installation, the WFD series uses two conduit openings — one open, one knockout type — to permit easy attachment to the local alarm system. The retard mechanism and terminal blocking enclosing dual SPDT switches are field-replaceable. System Sensor’s WFD series utilizes vane-type paddles to detect the flow of water through pipes. Models designed for commercial pipe rang­e in diameter from 2 to 8 inches and for the 1-inch NPT connections used in residential or branch line signaling. The series provides two options for the retard mechanisms that reduce the risk of false alarms. WFD products feature an adjustable mechanical retard. In addition, the WFD line of waterflow detectors includes devices for special applications. The WFD-EXP line of explosion-proof detectors is designed for use in hazardous locations that may contain volatile fumes.

Placement

For optimal performance, water flow detectors should be mounted in an area where there is adequate clearance for installation, removal and inspection. To prevent damage, water flow detectors should be installed between six and seven feet above the floor. When installing a water flow detector on horizontal pipe, the detector should always be placed on top of the pipe to avoid build up of rust or other particles from collecting and interfering with the actuation of the device. When installing a water flow detector on vertical pipes, make sure the detector is installed in an area where there is an upward flow. It is important that the detector is installed in the proper flow direction, which is indicated by an arrow on the product.

Testing, Maintenance and Service

System Sensor water flow detectors offer replaceable terminal blocks and timer delay (retard) mechanisms, so the detector can be serviced or maintained without draining the fire sprinkler system and removing the detector.

Before repairing, maintaining, or testing water flow devices, it’s important to notify the central station monitoring the water flow alarms. To prevent accidental water damage during maintenance, control valves should be closed and the system completely drained before the water flow detectors are removed or replaced. Any detector that shows evidence of water leakage should be replaced.

Water flow detectors should be tested at least quarterly to ensure proper operation. However, the AHJ may require detectors to be tested more frequently.

For a free copy of the new System Sensor Applications Guide: Fire Sprinkler Systems Monitoring, contact System Sensor at 800/736-7672 or visit www.systemsensor.com/html/applicat.html.

Specifications: WFD25
The WFD25 is a water flow detector for use with 2.5 in. pipe.
Pipe Size:		2.5 in.
Pipe Schedule:		10 through 40
Conduit Entrances:		1/2 in. conduit one open, one knockout type
UL Pressure Rating:		450 PSI
Triggering Threshold Bandwidth Flow Rate:		4-10 GPM
Maximum Surge:		18 FPS
Enclosure Rating:		UL NEMA-4
Operating Temperature Range:		32°F to 120°F (0° to 49°C)
Contact Ratings:		Two sets of SPDT (Form C); 10.0 A, 1/2 HP @ 125/250 VAC; 2.5 A @ 6/12/24 VDC
Overall Dimensions:		4.6 in. H x 4.6 in. W
Shipping Weight:		4.3 lbs.

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Tags: Fire sprinklers, Web exclusive

Posted in Commercial, Design and Installation, Fall 2008, Sprinkler Systems Monitoring

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