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Brass combination fill valve and backflow preventer with sweat union connection

Watts

Watts B911S-M3 Combination Fill Valve and Backflow Preventer 1/2 in 10 to 25 psi 100 psi 212°F Brass ASSE 1012

SKU CH-9GD1-QH8QM

A combination fill valve and backflow preventer with a 1/2-inch FNPT by sweat union connection, adjustable from 10 to 25 psi, rated for 100 psi and 212°F, and meeting ASSE 1012

  • TypeOther
  • Adjustable pressure control from 10 to 25 psi
  • Brass body withstands 100 psi and 212°F fluid temperature
  • ASSE 1012 certified backflow prevention protects potable water
  • 1/2 in FNPT by sweat union fits standard piping
  • California Proposition 65 chemical warning applies to this product

Watts B911S-M3 Fill Valve and Backflow Preventer

This Watts B911S-M3 unit combines a boiler feed valve with an integral backflow preventer for hydronic heating systems. It is designed for installers and facility managers who need automatic make-up water control with code-compliant cross-connection protection in a single device.

Brass body with FNPT and sweat union connections

The brass body provides corrosion resistance for closed-loop heating applications. Its dual connection type — female NPT on one side and a sweat union on the other — allows direct adaptation to threaded or copper piping without extra fittings, simplifying rough-in and future service access.

Adjustable 10 to 25 psi range with 100 psi maximum

The valve maintains system pressure within a 10 to 25 psi adjustment range while withstanding up to 100 psi supply pressure. Rated for fluid temperatures up to 212 degrees F, it meets ASSE 1012 standards for backflow prevention. Not suited for potable water lines or systems requiring pressure settings outside the stated range.

Highlights

  • Adjustable pressure control from 10 to 25 psi
  • Brass body withstands 100 psi and 212°F fluid temperature
  • ASSE 1012 certified backflow prevention protects potable water
  • 1/2 in FNPT by sweat union fits standard piping
  • California Proposition 65 chemical warning applies to this product

Specifications

BrandWATTS
TypeOther

Questions about this item

What pressure range does the ASSE 1012 valve regulate?

The valve adjusts between 10 and 25 psi and is rated for a maximum of 100 psi.

What are the connection type and overall dimensions?

It uses a 1/2 inch FNPT by sweat union connection and measures 8 1/2 inches long by 5 1/4 inches high.

How is the adjustment range set on the Watts B911S-M3?

Turn the adjustment screw clockwise to raise the outlet pressure within the 10 to 25 psi range, then tighten the lock nut to secure the setting.

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