Specification Sheet

ManualsBrandsWatts ManualsBackflow Preventers4" 757 Double Check Valve Assembly (OSY)

757OSY

(Vertical)

ES-757/757N

Job Name

–––––––––––––––––––––––––––––––––––––––––––

Contractor

––––––––––––––––––––––––––––––––––––––––––––

Job Location

–––––––––––––––––––––––––––––––––––––––––

Approval

–––––––––––––––––––––––––––––––––––––––––––––

Engineer

–––––––––––––––––––––––––––––––––––––––––––––

Contractor’s P.O. No.

––––––––––––––––––––––––––––––––––

Approval

–––––––––––––––––––––––––––––––––––––––––––––

Representative

––––––––––––––––––––––––––––––––––––––––

Series 757, 757N

Double Check Valve Assemblies

Sizes: 2

⁄2" – 10"

Series 757, 757N Double Check Valve Assemblies are used to

prevent backflow of non-health hazard pollutants that are objec-

tionable but not toxic, from entering the potable water supply

system. Series 757, 757N may be installed under continuous

pressure service and may be subjected to backpressure and

backsiphonage. Series 757, 757N consists of two independently

operating check valves, two shutoff valves, and four test cocks.

Features

• Extremely compact design

• 70% Lighter than traditional designs

• 304 (Schedule 40) Stainless steel housing & sleeve

• Groove fittings allow integral pipeline adjustment

• Patented tri-link check provides lowest pressure loss

• Unmatched ease of serviceability

• Available with grooved butterfly valve shutoffs

• Available for horizontal, vertical or N pattern installations

• Replaceable check disc rubber

• Sizes 2

⁄2", 3" and 4" available with quarter-turn ball valve

shutoffs

Specifications

The Double Check Valve Assembly shall consist of two inde-

pendent tri-link check modules within a single housing, sleeve

access port, four test cocks and two drip tight shut-off valves.

Tri-link checks shall be removable and serviceable, without the

use of special tools. The housing shall be constructed of 304

Schedule 40 stainless steel pipe with groove end connections.

Tri-link checks shall have reversible elastomer discs and in opera-

tion shall produce drip tight closure against reverse flow caused

by backpressure or backsiphonage. Assembly shall be a Watts

Series 757, 757N.

757OSY

757NBFG

* The wetted surface of this product contacted by consumable water

contains less than 0.25% of lead by weight.

LEAD FREE

Watts product specifications in U.S. customary units and metric are approximate and are provided for reference only. For precise measurements,

please contact Watts Technical Service. Watts reserves the right to change or modify product design, construction, specifications, or materials with-

out prior notice and without incurring any obligation to make such changes and modifications on Watts products previously or subsequently sold.

The information contained herein is not intended to replace the full

product installation and safety information available or the experi-

ence of a trained product installer. You are required to thoroughly

read all installation instructions and product safety information

before beginning the installation of this product.

NOTICE

Summary of content (4 pages)

PAGE 1
ES-757/757N Job Name –––––––––––––––––––––––––––––––––––––––––––– Contractor ––––––––––––––––––––––––––––––––––––––––––––– Job Location –––––––––––––––––––––––––––––––––––––––––– Approval –––––––––––––––––––––––––––––––––––––––––––––– Engineer –––––––––––––––––––––––––––––––––––––––––––––– Contractor’s P.O. No.
PAGE 2
Available Models Materials Suffix: Housing & Sleeve: 304 (Schedule 40) Stainless Steel NRS – non-rising stem resilient seated gate valves Elastomers: EPDM, Silicone and Buna-N OSY – UL/FM outside stem and yoke, resilient seated gate valves Tri-link Checks: Noryl®, Stainless Steel BFG – UL/FM grooved gear operated butterfly valves with tamper switch Check Discs: Reversible Silicone or EPDM Test Cocks: Lead Free* Bronze Body Pins & Fasteners: 300 Series Stainless Steel QT – 21⁄2", 3" and 4" quar
PAGE 3
Dimensions — Weight continued J C D I A P H G P1 757QT SIZE DIMENSIONS A C D G H WEIGHT I J P P1 QT QTN in. in. mm in. mm in. mm in. mm in. mm in. mm in. mm in. mm in. mm lbs. kgs. lbs. kgs.
PAGE 4
Capacity Flow capacity chart identifies valve performance based upon rated water velocity up to 25fps • Service Flow is typically determined by a rated velocity of 7.5fps based upon schedule 40 pipe. • Rated Flow identifies maximum continuous duty performance determined by AWWA. • UL Flow Rate is 150% of Rated Flow and is not recommended for continuous duty. • AWWA Manual M22 [Appendix C] recommends that the maximum water velocity in services be not more than 10fps.