Aquatec ® PSW 240 & PSW 340 Pressure Switch. Compact & High Reliability - 100% factory tested - Built-in John Guest connectors - Aquatec's PSW tank pressure sensing electrical switches are intended for inline mounting as close to the hydropneumatic product water tank as possible. Its purpose is to turn off the Booster Pump when the tank is full. Normally closed switch set for 40 PSI. The PSW, when used with a typical under-counter RO system, enables the hydraulic shut off valve to open and close very reliably and positively. The PSI trigger point can be adjusted using a 050 Allen Wrench inserted into the small chrome nut in one of the two adjacent circular surfaces on the switch. Simply turn to adjust the actual water PSI shut off point for your system. Counter clockwise will decrease the off pressure of the pump and clockwise will increase the off pressure. To make the pump turn off at a lower pressure setting turn the screw counter clockwise. Set the switch once the system has filled and shut off. Our techs love these. NSF Approved - Flow Through Design (i.e. no Dead Legs) Single Pole, Double Throw Switch. WETTED MATERIALS Polypropylene, Santoprene, EPDM SWITCH RATING: 250 VAC, 15 amp, UL listed. ELECTRICAL CONNECTION: AMP Mate-N-Lok. The PSW Series also includes a modular connector for plug-and-play integration with Aquatec’s other system components. Easy installation and simple to use. Choose either the PSW 240 1/4" or PSW 340 3/8".