The Watts 957-NRS-GXG 4 is a 4" lead-free reduced pressure zone (RPZ) backflow preventer with Grooved connections, approved for high health hazard protection. It features a stainless body and a silicone seat. Rated to 175 psi and 33°F to 140°F. This model is certified lead-free for potable-water installations.
This 4" lead free stainless steel reduced pressure zone assembly backflow preventer has NRS groove by groove gate valves that work well in limited headroom situations. Ideally suited for referenced cross-connections identified as health hazard continuous pressure applications, it prevents the backflow of contaminated water into the potable water supply and protects against backsiphonage and backpressure. The easy maintenance assembly consists of positive seated torsion spring check modules, bottom mounted differential pressure relief valve, non-rising stem resilient seated gate valves and top mounted test cocks. The temperature range is 33 to 140 degrees F (0.5 to 60 degrees C). The maximum working pressure is 175 psi (12.1 bar).
Features
- Light weight lead free stainless steel body for long term corrosion protection
- Short lay length for retrofits
- Groove by groove gate valves
- Patented torsion spring design
- Includes: Test Cocks
Common Questions
- What hazard level is this RPZ approved for?
- It is rated for high health hazard (toxic) cross-connections, so it may be used on either high or low hazard service. The assembly is listed to ASSE 1013.
- Is this model legal for potable water?
- Yes. It is certified lead-free to NSF/ANSI 372, which is what state plumbing codes require for any device in a drinking-water line.
- Does this assembly have to be tested every year?
- Yes. This is a field-testable assembly with 4 test cocks. Most water authorities require it to be tested and certified by a licensed backflow tester at installation and annually thereafter. It carries USC FCCCHR approval, which many jurisdictions accept as their sole approval list.
- What shutoff valves are included?
- It is supplied with non-rising stem (NRS) resilient-seated gate valves on the inlet and outlet.
- Is this listed for fire protection service?
- Yes — it is UL Classified and FM Approved, the listings normally required for a backflow device on a fire sprinkler supply.
- Does the relief valve need a drain?
- Yes. An RPZ relief valve is designed to discharge, and it can dump a large volume of water, so it must never be installed in a pit or below grade and the discharge must be piped to an adequate drain through an air gap. The air gap fitting is not included with this model and is ordered separately.
Specifications
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Type: RPZ
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Size: 4"
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Inlet Size: 4"
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Outlet Size: 4"
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Connection: Grooved
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Body Material: Stainless
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Seat / Seal Material: Silicone
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Max Pressure (psi): 175
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Application: Domestic Water
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Backflow Protection: Both
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Operation: Continuous
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Country of Origin: United States
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Warranty: 1 Year Limited
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MPN: 957-NRS-GXG 4
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Temperature: 33°F to 140°F
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Certifications: UL, FM, USC
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Lead-Free: Yes
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Assembly Type: RPZ
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Hazard Protection Level: High Health Hazard
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ASSE Standard: ASSE 1013
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USC FCCCHR Approved: Yes
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Fire Protection Listing: UL Classified;FM Approved
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Field Testable: Yes
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Number of Test Cocks: 4
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Shutoff Valves: NRS Gate
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Flood Sensor (SentryPlus Alert): No
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Strainer Included: No
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Air Gap Fitting Included: No
