850-DOSY DC 4

This 4 inch MasterSeries (R) in-line design double check valve backflow preventer assembly is designed to prevent the backflow of polluted water from entering into the potable water supply due to backsiphonage and or backpressure in accordance with national plumbing codes and water authority requirements. Its compact modular design facilitates easy maintenance for in-line repairs. It is ideal for protection in continuous pressure piping applications and at cross-connections identified as non-health hazards and for other non-toxic contaminants at the service line entrance. This assembly consists of a fused epoxy ductile iron body, domestic outside stem and yoke resilient seated gate valves, top mounted test cocks, two in-line independent positive seating check modules, captured springs, and replaceable check discs and seats.