Watts® 1/2-B911S-M3 Combination Fill Valve and Backflow Preventer, 1/2", Bronze FREE SHIPPING Increased high speed steel height

Increased high speed steel height (highest in the industry) improves hole saw durability

When moisture build-up is reduced

Close shape tread provides great traction & wide shoulder design

thermal-bonded black graduations in 1/8"

non-health hazard outlets where backpressure may occur

Watts® 1/2-B911S-M3 Combination Fill Valve and Backflow Preventer, 1/2", Bronze FREE SHIPPING Increased high speed steel heightUse 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 Watts Model 9D backflow preventer and a bronze Watts Model 1156F feed water pressure regulator in one pre assembled unit. High capacity fill valve that provides quick system filling and purging. It is designed for use in the boiler feed lines of hydronic