The Model VSG is a flexible vane type of waterflow switch for use in wet pipe water mist systems where a low flow for alarm is required. It is designed for installation in sections of 2 to 4 inch (50mm to 100mm) stainless steel or brass pipe with wall thickness indicated inthe product datasheet (see "Nominal OD and Wall Thickness").

The unit may also be used as a sectional waterflow detector on large systems.

The unit contains an output relay and an adjustable electronic retard. The relay is actuated when a flow of 3 gallons per minute (11,4 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.

Unique Features:

  • The only Listed waterflow switch for Water Mist systems
  • Operates at 3 GPM
  • Electronic Retard operates on 120 VAC or 24 VDC
  • Rated for 450 PSI

Codes & Approvals:

  • NFPA 750 - Standard on Water Mist Fire Protection Systems
  • NFPA 72, National Fire Alarm Code
  • NFPA 13, Standard for the Installation of Sprinkler Systems

Engineering Specifications:

Low Flow Waterflow Alarm Vane Switch With Electronic Retard: UL, ULC Listed CSFM Approved waterflow alarm switches shall be furnished and installed at each sprinkler system connection to the wet pipe main where indicated on the drawings, and as required by NFPA Standards. Waterflow switches shall be capable of operation in system pressures up to 450 PSI, maximum surges of up to 18 FPS and alarm activation at 3 GPM. Switch configuration shall consist of two sets of single pole double throw (S.P.D.T.) Form C synchronized sets of contacts rated at 2A, 125 VAC and 2A, 30 VDC. Switch enclosure shall meet NEMA 4 rating and shall be equipped with an electronic, instantly recycling, adjustable retard with a 0-90 second switch selectable range. Power for the operation of the switch shall be 120 VAC or 24 VDC as required. Enclosure cover shall be held captive by tamper resistant screws or supervised for removal by a cover tamper switch. Flow switch saddles shall be corrosion resistant by means of a factory installed non-corrosive insert. Waterflow alarm vane switch shall be Model VSG manufactured by Potter Electric Signal Company.

  • Can be powered by the auxiliary 24 VDC power of most fire panels
  • Can be powered by 120 VAC if 24 VDC is not available
  • Can be used in place of a standard flowswitch if a lower flow is expected

Installation Tips:

  • Installs just like a standard Potter VSR series flowswitch

Tech Tips:

  • Since it has an electronic retard, it will not operate without power. The power to the device should be supervised using an End Of  Line Relay as indicated in Fig 2 on page 2 of the installation instructions

Additional Information:

Click here to view more info about the VSG

For additional questions, contact customer service:, or tech support:

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