This 1/2 inch bronze combination dial set fill valve and backflow preventer is for use in commercial and residential hydronic heating systems to provide make-up water to the boiler, and prevent backflow when supply pressure falls below system pressure. It consists of a bronze model 9D backflow preventer and a bronze model BD1156F feed water pressure regulator in one pre-assembled unit. The high capacity fill valve provides quick system filling and purging. It is designed for use in the boiler feed lines of hydronic heating systems. This valve includes both 1/2 inch union solder and 1/2 inch union female NPT inlet connection tailpieces, and a 1/2 NPT union threaded outlet connection. The maximum pressure is 100 psi (6.9 bar).
