The Watts LF909-DOSY-FS 4 is a 4" lead-free reduced pressure zone (RPZ) backflow preventer, approved for high health hazard protection. It features a cast iron body. Rated to 175 psi. This model is certified lead-free for potable-water installations.
This 4 inch lead free reduced pressure zone backflow preventer assembly prevents the reverse flow of polluted water from entering into the potable water supply due to backsiphonage and or backpressure. It is ideal for protection in continuous pressure piping applications and at cross-connections identified as health hazards. This assembly consists of an epoxy coated cast iron body, domestic outside stem and yoke resilient seated gate valves, captured spring check valves, replaceable seats, top mounted test cocks, and a field reversible pressure differential relief valve. The coating on this backflow assembly uses ArmorTek®, a patented 3-part advanced epoxy coating system designed to limit both microbial induced (MIC) and exposed metal substrate corrosion. This backflow assembly contains a flood sensor with SentryPlus Alert® technology to detect excessive water discharges from the relief valve. When paired with an add on connection kit, the sensor is activated to relay alerts for potential flooding events. Connection kit options include BMS, cellular communication, and the Sensor Control Monitor which enables integration with BAS via RS-485 Modbus or the Nexa® platform through Wi-Fi.
Features
- Features a flood sensor with SentryPlus Alert technology to detect continuous discharge from the relief valve
- Add-on sensor connection kit to extend flood monitoring on compatible assemblies
- Integrates with the Sensor Control Monitor to deliver maintenance alerts to BAS via RS-485 Modbus or the Nexa platform by Wi-Fi connectivity
- Utilizes advanced ArmorTek coating technology to resist corrosion of internals
- Cast iron body construction with patented 3-part advanced epoxy coating system designed to limit both microbial induced (MIC) and exposed metal substrate corrosion
- Unique patented air-in and water-out design provides high capacity relief valve discharge performance during emergency conditions
- Domestic outside stem and yoke gate valves
- Includes: Test Cocks
- Includes: Flood Sensor
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.
- 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.
- 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. This model includes the SentryPlus Alert flood sensor, which signals a relief-valve discharge before it becomes a flood.
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: Cast Iron
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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: LF909-DOSY-FS 4
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Certifications: ASSE-1013, CSA-B64, UL, FM, USC, IAPMO
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Lead-Free: Yes
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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: OSY Gate
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Flood Sensor (SentryPlus Alert): Yes
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Strainer Included: No
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Air Gap Fitting Included: No
