856STDCDA-DOSY-CFM 4

This 4 inch MasterSeries (R) double check detector backflow preventer assembly prevents the backflow of pollutants due to backsiphonage and or backpressure that are objectionable but not toxic, from entering into the potable water supply. This assembly consists of ductile iron fused epoxy coated body construction, two in-line independent check valves, replaceable stainless steel check seats, domestic outside stem and yoke shutoff valves, a cubic foot per minute metered bypass, and ball valve test cocks. It is ideal for protection of non-health hazard cross-connections or for containment at the service line entrance. It is used primarily on fire sprinkler and standpipe systems requiring detection of unauthorized water use.