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WATTS LF 957 - 4" - Reduced Pressure Zone Assembly RP w/ OS&Y gate valves - (0111586) - 957-OSY 4 - UPC 098268122008


Lead Free: YES

4 In Ss Reduced Pressure Zone Assembly, Osy Shutoff Valves


This 4 inch reduced pressure zone assembly is designed to prevent the reverse flow of fire protection substances and water of non-potable quality from being pumped or siphoned into the potable water supply due to backsiphonage and or backpressure in accordance with national plumbing codes and water authority requirements. This extremely compact and lighter than a traditional designed assembly is approved for horizontal installation as long as the backflow assembly is installed in accordance with the direction of the flow arrow. It is ideal for protection in continuous pressure piping applications and at cross-connections identified as health hazards and from other contaminants found at the service line entrance. This assembly consists of a stainless steel body with a quick access sleeve, torsion spring check valves, resilient seated gate valves with outside stem and yoke, test cocks, and a corrosive resistant stainless steel bottom mounted pressure relief valve.



  • Replaceable check disc rubber
  • The maximum working pressure is 175 psi (12.06 bar)
  • Patented torsion spring check modules for ease of serviceability
  • 304 (Schedule 40) stainless steel housing and sleeve
  • Groove couplings for ease of installation and pipe alignment
  • Quick access sleeve
  • UL and FM outside stem and yoke resilient seated gate valves
  • Compact design allows small enclosures to be used
  • Bottom mounted cast stainless steel relief valve


Backflow Preventer Type Reduced Pressure Zone Assembly
Body Finish Stainless Steel
Body Material Stainless Steel
Body Pattern Inline
Brand Name Watts
Buy American Act Compliant YES
Bypass No
Cap And Tether No
Disc Material Silicone
EAN 098268122008
Elbow Fitting No
Hazard Protection Level Health Hazard
Hot And Harsh Water No
Hydrant Connection No
Inlet Connection Size 4 IN
Inlet Connection Size-Metric 100 MM
Inlet Connection Type Flanged Joint
Inlet Shutoff Valve Type Outside Stem And Yoke Gate Valve
Inlet Thread Type Does Not Apply To Product
Lead Free YES
Maximum Temperature-Fahrenheit 140
Maximum Working Pressure-BAR 12.10
Maximum Working Pressure-PSI 175
Meter Type No Meter
Minimum Temperature - Celsius 0.50
Minimum Temperature-Fahrenheit 33
Outlet Connection Size 4 IN
Outlet Connection Type Flanged Joint
Outlet Shutoff Valve Type Outside Stem And Yoke Gate Valve
Outlet Thread Type Does Not Apply To Product
Part Number 0111586
Polymer Coating No
Pressure Operation Continuous
Protection Type Backpressure and Backsiphonage
Seat Material Engineered Plastic
Series 957
Strainer No
Tradename None
Type Kit



WATTS LF957 - OSY - 4" - Reduced Pressure Zone Assemblies RP - (0111586)

SKU: 0111586