Zurn 4-375ASTDA Lead-Free Backflow Preventer - Stainless Steel Reduced Pressure Principle Detector Assembly

The Zurn Wilkins 4-375ASTDA is a 4" lead-free reduced pressure detector assembly (RPDA) with Flanged connections, approved for high health hazard protection. It features a stainless body. Rated to 175 psi and up to 140°F. This model is certified lead-free for potable-water installations.

The Wilkins 375ASTDA Reduced Pressure Detector Assembly with stainless steel body provides high hazard protection and is ideal for fire protection applications, with a metered by-pass to detect leaks and unauthorized water use.

Features

• Short lay-length for small space installation
• Improved flow characteristics, allowing for installation in lower-pressure systems
• Available as 375ASTR for backflow replacements/retrofit
• Corrosion resistant
• Lead-free law compliant

Common Questions

What hazard level is this RPDA 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 1047.

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. 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 non-rising stem (NRS) resilient-seated gate valves on the inlet and outlet.

Is this suitable for a fire sprinkler line?

Yes. Detector assemblies are built for fire sprinkler service: the metered bypass registers the low flows that reveal a leak or an unauthorized tap on the fire line. This model is UL Classified and C-UL Classified and FM Approved. The bypass meter reads in GPM.

How does this have to be installed?

It is approved for horizontal installation only, with the flow arrow on the body pointing in the direction of flow.

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.

Specifications

• Type: Backflow Preventer - Stainless Steel Reduced Pressure Principle Detector Assembly
• Size: 4"
• Connection: Flanged
• Body Material: Stainless
• Max Pressure (psi): 175
• Application: Fire Protection
• Backflow Protection: Both
• MPN: 4-375ASTDA
• Temperature: up to 140°F
• Certifications: ASSE-1047, AWWA-C550, AWWA-C606, CSA-B64.4, C-UL, UL, FM, USC, NSF-61, NSF-372
• Lead-Free: Yes
• Assembly Type: RPDA
• Hazard Protection Level: High Health Hazard
• ASSE Standard: ASSE 1047
• USC FCCCHR Approved: Yes
• Fire Protection Listing: UL Classified;C-UL Classified;FM Approved
• Field Testable: Yes
• Shutoff Valves: NRS Gate
• Approved Orientation: Horizontal
• Bypass Meter: GPM