The Watts 957-OSY-GXG-FS 2 1/2 is a 2-1/2" lead-free reduced pressure zone (RPZ) backflow preventer with Grooved connections, approved for high health hazard protection. It features a silicone seat. Rated to 175 psi and 33°F to 140°F. This model is certified lead-free for potable-water installations.
This 2 1/2" lead free stainless steel reduced pressure zone assembly backflow preventer help stop the reverse flow of liquids due to backpressure or backsiphonage, where potential health hazard exists. It has OSY groove by groove gate valves that show if the valve is open or closed and prevent stem corrosion. The easy maintenance assembly consists of positive seated torsion spring check modules, bottom mounted differential pressure relief valve, FM/UL outside stem and yoke resilient seated gate valves and top mounted test cocks. The temperature range is 33 to 140 degrees F (0.5 to 60 degrees C). The maximum working pressure is 175 psi (12.1 bar). 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
- 304 (Schedule 40) stainless steel housing and sleeve
- UL and FM outside stem and yoke resilient seated 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: 2-1/2"
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Inlet Size: 2-1/2"
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Outlet Size: 2-1/2"
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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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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: 957-OSY-GXG-FS 2 1/2
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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: 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
