The Watts 757-DOSY 4 is a 4" lead-free double check valve assembly, approved for low 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 4 inch lead free double check valve backflow preventer assembly is designed to prevent the reverse flow of water of non-potable quality from being pumped or siphoned into the potable water supply due to backpressure and or backsiphonage in accordance with national plumbing codes and water authority requirements. It is ideal under continuous pressure service and protection at cross-connections identified as non-health hazards and from other non toxic contaminants found at the service line entrance. This compact modular design with a single access sleeve for easy maintenance is approved for horizontal or vertical installation in accordance with the direction of the flow arrow on the assembly. It consists of a stainless steel housing and sleeve, tri-link check valves, domestic outside stem and yoke resilient seated gate valves, and test cocks.
Features
- Stainless steel housing and sleeve
- Domestic outside stem and yoke gate valves
- Non-health hazard application
- No special tools required for servicing
- Includes: Test Cocks
Common Questions
- What hazard level is this Double Check approved for?
- It is rated for low health hazard (non-toxic, "pollutant") cross-connections only. Where the substance downstream could be a health hazard, codes require a reduced pressure zone (RPZ) assembly instead. The assembly is listed to ASSE 1015.
- 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.
- How does this have to be installed?
- It is approved for either horizontal or vertical installation, with the flow arrow on the body pointing in the direction of flow.
Specifications
-
Type: Double Check
-
Size: 4"
-
Inlet Size: 4"
-
Outlet Size: 4"
-
Seat / Seal Material: Silicone
-
Max Pressure (psi): 175
-
Application: Domestic Water
-
Backflow Protection: Both
-
Operation: Continuous
-
Country of Origin: United States
-
Warranty: 1 Year Limited
-
MPN: 757-DOSY 4
-
Temperature: 33°F to 140°F
-
Certifications: UL, FM, USC
-
Lead-Free: Yes
-
Assembly Type: Double Check
-
Hazard Protection Level: Low Health Hazard
-
ASSE Standard: ASSE 1015
-
USC FCCCHR Approved: Yes
-
Fire Protection Listing: UL Classified;FM Approved
-
Field Testable: Yes
-
Number of Test Cocks: 4
-
Shutoff Valves: OSY Gate
-
Approved Orientation: Horizontal & Vertical
-
Flood Sensor (SentryPlus Alert): No
-
Strainer Included: No
-
Air Gap Fitting Included: No
