Zurn Wilkins RK4-350ASTCK2 Backflow Preventer #2 Check Assembly Repair Kit (3509ST-300B)

Zurn Wilkins RK4-350ASTCK2 Backflow Preventer #2 Check Assembly Repair Kit.

Product Overview

The Zurn Wilkins RK4-350ASTCK2 #2 Check Assembly Repair Kit is a genuine OEM replacement kit designed to keep your Zurn Wilkins backflow preventers operating at peak performance. This kit services the #2 check valve in select 3" and 4" 375AST and 350AST series assemblies, restoring proper functionality and ensuring continued compliance with backflow prevention standards.

Built with durable materials to resist wear and corrosion, the RK4-350ASTCK2 provides a cost-effective solution for maintaining your assemblies without the need for complete replacement. Trusted by contractors, facility managers, and service technicians, this kit helps extend the lifespan of your backflow preventers while ensuring safe, reliable operation.

Features & Benefits

• Genuine OEM Kit – Guaranteed compatibility with Zurn Wilkins backflow preventers.

• Restores System Protection – Replaces worn #2 check assembly components to maintain effective backflow prevention.

• Durable Construction – Built from corrosion-resistant materials for long service life.

• Cost-Effective Maintenance – Keeps your assemblies in service without full replacement.

• Wide Compatibility – Fits both 3" and 4" Zurn Wilkins 375AST and 350AST models.

Specifications

• Kit Model: RK4-350ASTCK2

• Application: #2 check assembly repair

• Part Included: #2 Check (3509-300B)

• Compatible Zurn Wilkins Models:

  • 3" Valves: 3-375AST, 3-375ASTOSY, 3-350AST, 3-350ASTOSY

  • 4" Valves: 4-375AST, 4-375ASTOSY, 4-350AST, 4-350ASTOSY

Installation Tips

• Shut off the water supply and relieve system pressure before servicing.

• Remove the existing #2 check assembly and replace with the new kit component.

• Use proper tools and follow manufacturer guidelines for correct installation.

• Test the backflow assembly after installation to verify compliance with local codes.

• Professional servicing is recommended to ensure proper certification.

FAQs

Q: What does this repair kit include?
A: The kit includes the replacement #2 check assembly (part 3509-300B).

Q: Which models are compatible with this kit?
A: It fits Zurn Wilkins 375AST and 350AST series assemblies in 3" and 4" sizes, including OS&Y valve variations.

Q: Why replace the #2 check assembly?
A: Over time, check assemblies wear and lose sealing ability. Replacing them restores protection against backflow and maintains compliance.

Q: Do I need professional installation?
A: While basic tools can be used, professional testing and certification are required after repair to meet code.