AquaMatic K520-109 1/2-Inch Retaining Ring & Nut Assembly with EPDM Seals (Pair)

Complete your commercial water manifold setups with the lightweight, corrosion-proof security of the Genuine AquaMatic K520-109 Retaining Ring & Nut Assembly Pair (SKU: 1070238). Manufactured by AqMatic (formerly Pentair), this complete plastic installation hardware set is engineered specifically to mount end piping adapters seamlessly to 1/2-Inch K520 Series Composite Body Diaphragm Valves.

Constructed from the same glass-filled thermoplastic as the valve bodies, this assembly eliminates the risk of external galvanic corrosion, making it the perfect choice for high-purity water systems, water softeners, filtration skids, and everyday industrial water processing lines.

🛠️ Core Application & Compatibility

Essential Installation Component: This assembly is required to connect and seal raw end adapters—such as the K520-PC (Solvent Weld) or K520-P (NPT Threaded) pairs—directly to the valve body ports. By utilizing this matching plastic pair, you complete a true union-style configuration that allows for simple in-line servicing and effortless valve isolation.

Key Features & Benefits

• Corrosion-Proof Plastic Design: Molded from heavy-duty, glass-filled composite materials to withstand harsh, damp environments, salt-brine splash back, and general chemical exposure without rusting.

• Premium EPDM Face Seals: Equipped with high-resilience EPDM (Ethylene Propylene Diene Monomer) O-rings to deliver long-term, drip-tight sealing performance in standard clean-water applications.

• Effortless Valve Servicing: Establishes a convenient union joint configuration. Loosening the plastic nuts allows technicians to lift the valve body straight out of the piping manifold for quick bench maintenance without cutting the pipe network.

• Sold as a Complete Matching Pair: Every package includes two plastic nuts, two snap rings, and two EPDM face seals—giving you everything required to fully outfit both the inlet and outlet ports of a single 1/2" K520 valve.

Comprehensive Kit Parts List

The K520-109 Pack is supplied as a complete dual-port installation set. Each kit contains:

• 2 x Plastic Union Nuts (Item No. 20): High-torque composite threaded rings that pull the end adapters perfectly flush against the valve body faces.

• 2 x Retaining Snap Rings: Splined split-rings that lock into the adapter grooves to distribute locking pressure evenly.

• 2 x EPDM Face O-Rings: High-performance, clean-water grade gaskets that sit between the adapter and the valve body recess to ensure an absolute hydraulic seal.

Technical Specifications

Professional Installation Advice

When assembling your valve manifold, slide the plastic union nut onto the pipe or end adapter before executing your final piping connection (solvent weld or threaded). Position the plastic retaining snap ring into the adapter groove, place the EPDM face O-ring into the valve body recess, and thread the nut onto the valve body by hand.

Hand-tighten firmly to ensure the face seals seat perfectly square. Avoid using harsh metal pipe wrenches on the composite nuts to prevent cracking. For internal valve repairs down the line, remember to use the specialized AquaMatic 520-Z Assembly Tool to protect your internal thermoplastic threads during teardown.