The Watts 774DCDA-LF-LM 4 is a 4" lead-free double check detector assembly (DCDA) with Flanged connections, approved for low health hazard protection. It features a stainless body. Rated to 175 psi and 33°F to 110°F. This model is certified lead-free for potable-water installations.
This 4" double check detector backflow preventer assembly prevents the backflow of fire protection system substances from being pumped or siphoned into the potable water supply. It consists of a compact construction and short lay length, ideal for retrofit installations. It features a lightweight stainless steel body, thermoplastic and stainless steel check valves, and low head loss. It can be installed in a horizontal or vertical flow-up position. It is designed for installation on applications identified by local authorities as non-health hazard, such as on fire protection systems. The maximum working pressure is 175 psi (12.06 bar).
Features
- Stainless steel for corrosion resistance
- Designed for minimum head loss
- 150 pound ANSI/AWWA CL D flanged
- Less shutoffs
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.
- 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. Most water authorities require it to be tested and certified by a licensed backflow tester at installation and annually thereafter.
- Does this ship with inlet and outlet shutoff valves?
- No. This is the "less valves" (LF) configuration — the assembly ships without inlet and outlet shutoffs. Most jurisdictions require approved shutoffs on both sides, so order them separately or choose a QT, NRS, OSY or BFG variant of this model.
- 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?
- 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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Connection: Flanged
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Body Material: Stainless
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Max Pressure (psi): 175
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Application: Fire Protection
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Backflow Protection: Backpressure
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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: 774DCDA-LF-LM 4
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Temperature: 33°F to 110°F
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Certifications: CSA-B64, UL, FM
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Lead-Free: Yes
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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: No
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Fire Protection Listing: UL Classified;FM Approved
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Field Testable: Yes
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Shutoff Valves: None
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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
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Bypass Meter: None
