1 Jul 2021

The Potter PS40-EX Supervisory Pressure Actuated Switch is designed primarily to detect an increase and/or decrease from normal system pressure in automatic fire sprinkler systems located in hazardous locations.

Typical applications are Dry pipe systems, pre-action air/nitrogen supervision, pressure tanks, air supplies, and water supplies. The PS40-EX switch is factory set for 40 PSI (2,8 BAR) normal system pressure. The switch marked with the word LOW is set to operate at a pressure decrease of 10 PSI (7 BAR) at 30 PSI (2,1 BAR). The switch marked with the word HIGH is set to operate at a pressure increase of 10 PSI (7 BAR) at 50 PSI (3,5 BAR).

detection in automatic sprinklers

The Potter PS10-EX Pressure Actuated Switch is designed for the detection of a water flow condition in automatic fire sprinkler systems located in hazardous locations.

Typical applications are Wet pipe systems with alarm check valves, dry pipe, preaction, or deluge valves. The PS10-EX is also suitable to provide a low-pressure supervisory signal; adjustable between 4 and 20 psi (0,27 and 1,3 BAR).

Unique Features

  • Independent switch adjustment allows for the adjustment of one switch without affecting the other
  • Pressure adjustments are accessible without removing the explosion-proof cover

Codes and Approvals

  • UL, cUL, FM, CSFM, NYMEA, CENELEC, ATEX
  • Class I Division 1 & 2 Groups B, C, D. Class II Division 1 & 2 Groups E, F, G. Class III Division 1 & 2
  • NEMA 4 Weatherproof enclosure
  • Complies with all applicable service requirements of NFPA 13, 72

Engineering Specifications

Waterflow Alarm Pressure Switch For Use In Hazardous Locations: UL Listed/FM Approved Waterflow alarm pressure switch shall be furnished and installed at each sprinkler system connection to the dry pipe alarm port where indicated on the drawings, and as required by NFPA Standards. Waterflow pressure switch shall be capable of operation in system pressures up to 250 PSI and shall operate on increasing pressure at the alarm port to 6 PSI. Switch configuration shall consist of two sets of single pole double throw (S.P.D.T.).

The switch shall employ independent pressure elements for each switch

Form C synchronized sets of contacts rated at 15A, 125 VAC, and 2A, 24 VDC.  The switch shall employ independent pressure elements for each switch. Switch enclosure shall be suitable for use in Class I Division 1 & 2 Groups B, C, D, Class II Division 1 & 2 Groups E, F, G, Class III Division 1 & 2, and the cover shall be held captive by tamper-resistant screws or supervised for removal by a cover tamper switch.

Pressure connection to the system shall be via 1/2 inch male NPT. All in-line valves shall be electrically supervised for their fully open position. The water flow alarm pressure switch shall be Model PS10-EX manufactured by Potter Electric Signal Company.

Installation Tips

  • Use Teflon tape, do not use pipe dope because it could block the pressure chamber
  • Install with the threaded connection pointing down towards the floor

Tech Tips

  • If there is a shut-off valve installed in line with the PS10-EX, the valve shall be monitored to comply with requirements in IBC, IRC 2009, 903.4 and NFPA 72, 2010 23.8.5.10.4