957NRPDA-DOSY-CFM 4

This 4 inch N pattern reduced pressure detector backflow preventer assembly is designed to prevent the reverse flow of fire protection substances and water of non-potable quality from being pumped or siphoned into the potable water supply due to backsiphonage and or backpressure in accordance with national plumbing codes and water authority requirements. Extremely compact and lighter than traditional designs it is approved for horizontal N pattern installation. It is ideal for protection at cross-connections identified as health hazards such as on fire sprinkler systems and from other contaminants found at the service line entrance. This assembly consists of a stainless steel body with a quick access sleeve, torsion spring check valves, domestic outside stem and yoke resilient seated gate valves, test cocks, corrosive resistant bottom mounted pressure relief valve, and a cubic foot per minute meter to detect underground leaks and unauthorized water use.