The Watts 757N-OSY 4 is a 4" lead-free 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 model is certified lead-free for potable-water installations.
This 4 inch lead free double check valve backflow preventer assembly is designed to prevent the reverse flow of contaminated water of non-potable quality from being pumped or siphoned into the potable contaminated water supply due to backsiphonage and or backpressure in accordance with national plumbing codes and contaminated 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 N pattern installation in accordance with the direction of the flow arrow on the assembly. It consists of a stainless steel body, tri-link check valves, outside stem and yoke resilient seated gate valves, and test cocks.
Features
- Stainless steel housing and sleeve
- Tri-link check valves are removable and serviceable without the use of any special tools
- Outside stem and yoke resilient seated gate valves
- Bronze body nickel plated test cocks
- 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.
- 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 outside screw and yoke (OS&Y) gate valves on the inlet and outlet. OS&Y gates give the visible open/shut indication that fire-line and many water-authority specs require.
- 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?
- This assembly is approved for horizontal N-pattern installation, with the shutoff valves in line with the body. USC approval is orientation-specific, so it must be installed in that position.
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: 757N-OSY 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: 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: OSY Gate
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Approved Orientation: N-Pattern
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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
