WATTS F391008 3/4" LF909-QT-FS LEAD FREE REDUCED PRESSURE BACKFLOW

Watts LF909-QT-FS 3/4" RPZ Backflow Preventer Valve [F391008].

Product Overview:

The Watts LF909-QT-S-FS 3/4" Reduced Pressure Zone Assembly is engineered to prevent backflow caused by both backsiphonage and backpressure conditions. It includes two check valves and a differential pressure relief valve positioned between them. When both checks fail, the relief valve discharges to atmosphere using Watts’ patented air-in/water-out technology, minimizing contamination risk.

Standard features include:

• Compact, space-efficient body with full-port quarter-turn shutoff valves

• Integrated stainless steel relief valve with sensor for flood monitoring

• Replaceable check valve seats and no special tools required for maintenance

• Certified for both vertical (flow-up) and horizontal installations

• Lead-free compliance (≤0.25% lead content)

Product Specifications:

• Model: LF909-QT-S-FS

• Size: 3/4"

• Connection Type: NPT Female Threaded

• Max Working Pressure: 175 psi (12.1 bar)

• Temperature Range: 33°F – 140°F continuous, 180°F intermittent

• Material Construction: Lead-Free Cast Copper Silicon Alloy

• Certifications: ASSE 1013, AWWA C511, CSA B64.4, NSF, IAPMO, SBCCI

• Flow Rate Capacity: Up to 18 GPM at 10 psi pressure drop

• Includes: Quarter-turn shutoff valves, integrated bronze strainer, sensor-equipped relief valve

Installation Tips:

• Install in a high-visibility location to easily spot discharge and enable regular testing

• Avoid pit or vault installations; always maintain an air gap below the relief valve port

• Use a properly sized strainer upstream (avoid for emergency lines like fire sprinklers)

• Ensure test cocks are accessible and never install the valve in concealed locations

• Allow gradual filling to avoid damaging internal O-rings during startup

• For outdoor use in cold climates, install in an insulated WattsBox® enclosure

• Always have the unit tested by a certified backflow tester after installation

FAQs:

Q: Can this be installed vertically?
Yes. The LF909 3/4" is approved for both horizontal and vertical (flow-up) installation.

Q: Is the flood sensor active out of the box?
Not by default. A sensor connection kit is required for BMS or cellular alert integration.

Q: Is maintenance difficult?
Not at all. Seats are replaceable and accessible with no special tools required.

Q: How often should it be tested?
Annually at minimum—or more frequently as required by local codes or usage.

Technical Downloads:

• Watts LF909-QT-FS RPZ: Specification Submittal

Ready to Order?

Get the dependable, code-compliant protection your system needs. Order the Watts LF909 3/4" RPZ Backflow Preventer today and ensure safe, uninterrupted water supply across your facilities.

Shop now at MasterBuilderMercantile.com – Your source for Watts RPZ valves, backflow preventers, and commercial plumbing essentials.