1/2" Bronze Combination Fill Valve and Backflow Preventer, Threaded

Watts 386463 – 1/2" Bronze Combination Boiler Fill Valve and Backflow Preventer

The Watts 386463 is a factory-assembled combination unit featuring two proven components: the Model 1156F feed water pressure regulator and the Model 9D dual-check backflow preventer. Together, they provide automatic boiler system filling and reliable backflow protection in hydronic heating applications.

Integrated Design for Simplified Installation

This unit is engineered to maintain system pressure and prevent contamination of the potable water supply. Its compact, pre-assembled configuration minimizes installation time and leak points while meeting residential and light commercial job site requirements.

Key Features

• Bronze Body Construction – Corrosion-resistant materials ensure long service life in closed-loop heating systems.
• Model 1156F Pressure Regulator – Automatically feeds water to the system and maintains factory-set 15 psi (adjustable) operating pressure.
• Model 9D Backflow Preventer – Protects potable water from backpressure and backsiphonage.
• Threaded Connections – 1/2" union NPT inlet x 1/2" NPT outlet for straightforward integration into system piping.
• Compact Profile – Ideal for installation in confined mechanical spaces without sacrificing accessibility.

Technical Specifications

• Size: 1/2 inch nominal
• Max Working Pressure: 100 psi
• Pressure Regulator Setting: 15 psi (field adjustable)
• Inlet Connection: 1/2" union NPT
• Outlet Connection: 1/2" female NPT
• Orientation: Can be installed vertically or horizontally

Installation Notes

Though the Watts 386463 is designed to simplify system filling and safety compliance, installation should be performed by a licensed contractor to ensure proper setup and adherence to local plumbing codes. Pressure settings may require adjustment depending on the specific system’s design pressure.

For the Trade Professional

Trusted on job sites for decades, Watts combination valves are known for dependable performance and easy serviceability. The 386463’s integrated design reduces component sourcing, simplifies inspection points, and speeds up installation time—all without compromising reliability or safety.

Optimize Your Hydronic System

When consistent pressure regulation and backflow prevention are essential, the Watts 386463 delivers proven results. Built with contractor needs in mind, it’s a dependable choice for both new installs and system upgrades.