AquaMatic K521-RFN Internal Parts Kit (Plastic) | Part 1079621

The AquaMatic K521-RFN Internal Parts Kit (Manufacturer Part Number: 1079621) is a premium, factory-original plastic reconstruction kit designed for AquaMatic K521 Series 1-inch composite body diaphragm valves. This specific kit is meticulously engineered to rebuild internal configurations for Normally Open (N.O.) valve operations.

Constructed from high-grade, corrosion-resistant engineered plastic materials, the K521-RFN kit replaces worn or degraded structural components within the valve stack. It is essential for restoring positive seating, maintaining optimal flow dynamics, and preventing internal bypass or malfunctions in demanding commercial and industrial fluid systems.

Parts Included List

This comprehensive maintenance kit includes all critical structural internal items required to rebuild the core valve assembly. It consists of the following factory schematic item numbers:

• Item 2 – Disc Plate (1075845): Secures the internal sealing disc firmly to the assembly, providing rigid support.

• Item 4 – Shaft: The central structural backbone that transmits diaphragm movement to actuate the valve.

• Item 5 – Shaft Guide: Ensures smooth vertical travel and precise axial alignment of the internal stack.

• Item 10 – Lower Diaphragm Plate (1075844): Clamps the lower side of the flexible elastomer diaphragm to maintain structural shape and prevent tearing.

• Item 11 – Upper Diaphragm Plate (1075843): Secures the top profile of the diaphragm assembly for uniform pressure distribution and efficient sealing.

• Item 16 – Screw / Fastener: Engineered for a precise thread-lock fit to secure the complete internal component stack tightly together.

Note: Elastomer seal components and diaphragms are sold separately under specialized seal kits (such as the K521-RAN Buna-N or K521-RAV Viton kits) depending on your fluid compatibility needs.

Key Features & Benefits

• OEM Precision Fit: Designed exclusively for AqMatic / Pentair K521 (1") composite control valves operating in a Normally Open state.

• Corrosion-Resistant Plastic: Ideal for systems handling deionized (DI) water, harsh water softeners, chemical injection loops, acids, and caustic solutions that degrade standard metals.

• Complete Core Rebuild: Eliminates the guesswork of tracking down individual internal components by providing the full moving assembly stack in one SKU.

• Reduces System Downtime: Allows for a rapid bench or field service routine when combined with the AquaMatic 521-Z assembly tool.

Technical Specifications

Applications & Compatibility

The AquaMatic K521-RFN kit is the primary service solution for water conditioning, purification, and industrial fluid control setups utilizing Y-pattern composite valves. It is widely used in:

• Industrial water softening and commercial media filtration backwash loops.

• Pure water processing and deionization (DI) exchange plants.

• Chemical handling, plating, and harsh process water applications.

Installation Tip: To safeguard the new plastic components from scoring or stripping during installation, use the dedicated AquaMatic 521-Z Assembly Tool (Part 1075059) to lock and align the shaft guide precisely into the valve body. Ensure all threads are clean and free of debris before final tightening.