The Watts 757-DNRS 4 is a 4" double check valve assembly, approved for low health hazard protection. It features a stainless body and a silicone seat. Rated to 175 psi and 33°F to 140°F.
This 4 inch stainless steel double check valve backflow preventer assembly is designed to prevent the reverse flow of objectionable but not toxic water from being pumped or siphoned into the potable water supply due to backsiphonage and or backpressure in accordance with national plumbing codes and water authority requirements. It is ideal for protection at cross-connections identified as non-health hazards and from other contaminants found at the service line entrance. This compact modular design with a single access sleeve for easy maintenance is approved for horizontal or vertical installation in accordance with the direction of the flow arrow on the assembly. It consists of a stainless steel body, tri-link check valves, non-rising stem domestic resilient seated gate valves, and test cocks.
Features
- Stainless steel housing and sleeve
- Domestic non-rising stem gate valves
- Ball valve type test cocks
- No special tools required for servicing
- Includes: Test Cocks
Common Questions
- What hazard level is this Double Check approved for?
- It is rated for low health hazard (non-toxic, "pollutant") cross-connections only. Where the substance downstream could be a health hazard, codes require a reduced pressure zone (RPZ) assembly instead. The assembly is listed to ASSE 1015.
- 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 either horizontal or vertical installation, with the flow arrow on the body pointing in the direction of flow.
Specifications
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Type: Double Check
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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: 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: 757-DNRS 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: Double Check
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Hazard Protection Level: Low Health Hazard
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ASSE Standard: ASSE 1015
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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 & Vertical
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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
