957-NRS-GXG 4

This 4 IN lead free stainless steel reduced pressure zone assembly backflow preventer has NRS groove by groove gate valves that work well in limited headroom situations. Ideally suited for referenced cross-connections identified as health hazard continuous pressure applications, it prevents the backflow of contaminated water into the potable water supply and protects against backsiphonage and backpressure. The easy maintenance assembly consists of positive seated torsion spring check modules, bottom mounted differential pressure relief valve, non-rising stem resilient seated gate valves and top mounted test cocks. The temperature range is 33 to 140 degrees F (0.5 to 60 degrees C). The maximum working pressure is 175 psi (12.1 bar).