The Watts 957-NRS-S-SS 4 is a 4" reduced pressure zone (RPZ) backflow preventer, approved for high health hazard protection. It features a stainless body and a rubber seat. Rated to 175 psi and 33°F to 140°F.
This 4" reduced pressure zone assembly backflow preventer helps prevent the reverse flow of fire protection substances and water of non-potable quality from being pumped or siphoned into potable water supply due to backsiphonage and or backpressure in accordance with national plumbing codes and water authority requirements. This extremely compact and lighter than a traditional designed assembly is approved for horizontal installation as long as the backflow assembly is installed in accordance with the direction of the flow arrow. It is ideal for protection in continuous pressure piping applications and at cross-connections identified as health hazards and from other contaminants found at the service line entrance. This assembly consists of a stainless steel body with quick access sleeve, stainless steel wye strainer, torsion spring check valves, resilient seated gate valves with non-rising stem, test cocks and corrosive resistant stainless steel bottom mounted pressure relief valve.
Features
- 304 (Schedule 40) stainless steel housing and sleeve furnished with a stainless steel strainer
- Non-rising stem, resilient seated gate valves
- Quick access sleeve
- Replaceable check disc rubber
- Bottom mounted cast stainless steel relief valve
- Compact design allows small enclosures to be used
- Patented torsion spring check modules for ease of serviceability
- Groove couplings for ease of installation and pipe alignment
- The maximum working pressure is 175 psi (12.06 bar)
- Includes: Test Cocks
- Includes: Strainer
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.
- Can this be installed on potable water?
- No. This model is not certified lead-free, so it may not be installed in potable water systems in states enforcing the NSF/ANSI 372 weighted-average lead rule. Use it on non-potable service — fire lines, irrigation or industrial water — or order the LF (lead-free) version of this model for drinking-water use.
- 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.
- How does this have to be installed?
- It is approved for horizontal installation only, with the flow arrow on the body pointing in the direction of flow.
- 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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Body Material: Stainless
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Seat / Seal Material: Rubber
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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-S-SS 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: No
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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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Approved Orientation: Horizontal
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Flood Sensor (SentryPlus Alert): No
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Strainer Included: Yes
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Air Gap Fitting Included: No
