Watts® 1/2-B911S-M3 Combination Fill Valve and Backflow Preventer, 1/2", Bronze FREE SHIPPING thermal-bonded black graduations in 1/8"

thermal-bonded black graduations in 1/8"

Close shape tread provides great traction & wide shoulder design

Addition of rubber enhances performance to last longer

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

Replacing your thermocouple may reduce pilot outage & lighting problems

Watts® 1/2-B911S-M3 Combination Fill Valve and Backflow Preventer, 1/2", Bronze FREE SHIPPING thermal-bonded black graduations in 1/8"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 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