AquaMatic K521-111 1" Retaining Ring & Nut Assembly - Viton (Pair)

The AquaMatic K521-111 Retaining Ring & Nut Assembly is a factory-original, commercial-grade hardware kit designed to securely mount pipe end adapters to AquaMatic K521 Series 1-inch composite body diaphragm valves.

This premium Viton-equipped configuration contains a complete pair of nuts, split retaining rings, and high-performance Viton (FKM) O-rings. It provides the crucial mechanical clamping force and leak-tight face seal required to connect pipe adapters—such as the K521-PC 1" Solvent Weld Adapters (1070226)—directly to the valve body. Because it utilizes Viton elastomers, this assembly is engineered specifically for systems exposed to high temperatures, aggressive chemicals, or harsh water treatment processes that would rapidly compromise standard sealing materials.

Parts Included List

One kit contains enough hardware to complete both the inlet and outlet connections for a single 1" K521 series valve. The assembly includes:

• 2 x Heavy-Duty Union Retaining Nuts: Threaded collars that draw the pipe adapter tightly against the valve face.

• 2 x Split Retaining Rings: Interlocking rings that seat firmly into the grooves of the pipe adapters to distribute mechanical clamping pressure evenly.

• 2 x Viton (FKM) Face O-Rings: High-performance, chemical-resistant elastomeric seals that prevent fluid bypassing at the connection interface.

Key Features & Benefits

• Premium Viton Sealing: Equipped with authentic Viton (FKM) O-rings for exceptional resistance against acids, caustics, ozone, and chlorinated water loops.

• Robust Mechanical Coupling: Provides a reliable union connection, allowing the valve to be quickly disconnected from the pipework for maintenance or bench servicing without cutting the lines.

• Perfect 1" System Matching: Explicitly engineered by AqMatic / Pentair to fit the 1-inch K521 composite valve body thread and flange profiles.

• Corrosion-Resistant Components: Constructed from high-durability engineered materials designed to withstand the harsh environments of chemical feed and water purification plants.

Technical Specifications

Applications & Compatibility

The K521-111 Viton assembly is the preferred choice for industrial and heavy commercial installations where fluid compatibility demands more than standard seals. It is widely used in:

• Deionization (DI) exchange systems undergoing aggressive acid/caustic regeneration cycles.

• Chemical dosing, plating, and chemical handling distribution lines.

• High-purity process water loops and high-temperature water treatment systems.

Installation Tip: Always remember to slide the union retaining nut and the split ring onto your pipe adapter before completing any permanent solvent welding or pipe jointing. Ensure the Viton O-ring is seated flat in the face groove without twists before hand-tightening the nut onto the valve body. Do not over-torque, as the high-precision engineered threads are designed to seal efficiently under standard hand-tight union loads.