Potter Electric Signal (VSR-3) 3 inch flow switch

The Potter Electric Signal VSR-3 is a 3-inch vane-type waterflow alarm switch. Specifically, it fits 3″ (DN80) steel sprinkler pipe in Schedule 10 through 40 wet-pipe sprinkler systems. The VSR-3 belongs to Potter’s VSR family of pneumatic-retard waterflow switches.

First, a flexible vane installs through a saddle clamp into the live pipe. Then a sustained downstream flow of 10 GPM (38 LPM) or greater pushes the vane. As a result, the pneumatic retard mechanism begins timing. Therefore, momentary surges from pressure spikes do not generate false alarms.

How the Potter Electric Signal VSR-3 reports flow

The VSR-3 carries two SPDT (Form C) snap-action contacts. In addition, the retard timing is adjustable, which lets installers tune the device to local system behavior. Furthermore, the dual contact set lets one switch feed both the FACP waterflow zone and a separate central-station path. Also, the enclosure carries a NEMA 4 / IP54 rating for general indoor sprinkler-riser locations.

Verified specifications

• Pipe size: 3″ (DN80)
• Pipe compatibility: steel pipe Schedule 10 through 40
• Activation: sustained flow of 10 GPM (38 LPM) downstream
• Contacts: two SPDT (Form C) snap-action
• Electrical rating: 10 A at 125/250 VAC
• Pressure rating: 450 PSI service
• Operating temperature: 40°F to 120°F
• Enclosure: NEMA 4, IP54
• Retard: adjustable pneumatic
• Listings: UL Listed, FM Approved

Common applications

Sprinkler contractors install the VSR-3 on the 3″ main of a wet-pipe sprinkler system to signal a flowing-water event to the fire alarm control panel. For example, the VSR-3 commonly mounts at the riser, at a floor control valve, or downstream of a zone control valve. As a result, the FACP can localize the flow event by floor or by zone.

For more information, contact the Life Safety Consultants team at (888) 557-0558, or email us at: sales@lifesafetycom.com