The Watts 757NDCDA-BFG-LM 3 is a 3" double check detector assembly (DCDA) with Grooved connections, approved for low health hazard protection. It features a silicone seat. Rated to 175 psi and 33°F to 140°F.
This 3", N pattern, double check detector backflow preventer assembly prevents the backflow of pollutants that are objectionable but not toxic, from entering into the potable water supply. Its compact housing consists of two independently operating tri-link check valves, two UL/FM butterfly shutoff valves, and four test cocks. It features a stainless steel housing and sleeve and is 70 percent lighter than traditional designs. It is designed for non-health hazard applications and may be installed under continuous pressure service to protect against both backpressure and backsiphonage. It is used primarily on fire sprinkler lines when it is necessary to monitor unauthorized use of water. The maximum working pressure is 175 psi (12.06 bar).
Features
- Stainless steel for corrosion resistance
- Lightweight construction
- Grooved end connections
- Gear operated butterfly shutoffs with tamper switches
- Includes: Test Cocks
- Includes: Gear Operator
- Includes: Tamper Switch
Common Questions
- What hazard level is this DCDA 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 1048.
- 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. 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 grooved-end butterfly valves with gear operators on the inlet and outlet.
- Is this suitable for a fire sprinkler line?
- Yes. Detector assemblies are built for fire sprinkler service: the metered bypass registers the low flows that reveal a leak or an unauthorized tap on the fire line. This model is UL Classified and FM Approved. This is the "less meter" (LM) variant — the bypass line is supplied without the meter, which you specify separately.
- 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: 3"
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Inlet Size: 3"
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Outlet Size: 3"
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Connection: Grooved
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Seat / Seal Material: Silicone
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Max Pressure (psi): 175
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Application: Fire Protection
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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: 757NDCDA-BFG-LM 3
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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: DCDA
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Hazard Protection Level: Low Health Hazard
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ASSE Standard: ASSE 1048
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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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Shutoff Valves: Butterfly (Grooved)
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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
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Bypass Meter: None
