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Backwater Valves S-640 / 641

Backwater Valves S-640 / 641

Vendor: Legend Valve

Valve Type(s):
Thermoplastic Valves

Valve Category:

Thermoplastic Valves

Valve Subcategory

Solvent Ends

LEGEND MODELS S-640/S-641 backwater valves are constructed of ASTM D1784 virgin resins that will not rust, corrode or pit. They are designed for use in residential and commercial applications to prevent backflow in drainage systems. The stepped construction promotes efficient flow and helps prevent clogging. The access cap facilitates ease of clean-out or repair.

  • Stepped body design promotes efficient flow
  • Access cap allows ease of clean-out or repair
  • Flapper and cap O-ring create a positive seal against sewer gasses
  • Manufactured in an ISO 9002 accredited facility
  • Manufactured using 100% virgin resin
  • Designed for DWV installations operating at pressure less than 50 psi
  • pressures will exceed 50 psi

• UPC/IAPMO and IPC Listed: File number 4790
• Manufactured in compliance with ASME A112.14.1-2003
• End connections comply with ASTM D2665

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Backwater Valves S-640/641 Specifications and Dimensions

Material Specification
No. Part Material Specification
1 Body PVC ASTM D1784
2 Flapper PVC ASTM D1784
3 Flapper o-ring Neoprene rubber Commercial grade
4 Access cap PVC ASTM D1784
5 Access cap o-ring Neoprene rubber Commercial grade
Size A B
1-1/2" 4.19 3.88
2" 4.50 3.88
3" 7.37 6.00
4" 10.75 6.75
6" 15.13 10.13
   WARNING: Cancer and
   Reproductive Harm -