A secure filter tank connection is essential for safe pool operation and consistent filtration performance. The Swimables FNS, Clean & Clear, Quad DE Style Spring Barrel Nut Assembly (SW-26-531) is a direct-replacement component designed to restore proper clamping tension on Pentair-style pool filters that use a spring-loaded clamp system.

On filters such as Pentair FNS Plus, Clean & Clear, and Quad DE, the spring barrel nut assembly plays a critical role in maintaining even pressure around the filter clamp band. This spring-loaded design allows the clamp to flex slightly under pressure, helping the tank halves remain aligned while maintaining a reliable seal during normal filtration and backwashing cycles.

Over time, the original spring barrel nut assembly can weaken, corrode, seize, or lose its ability to hold proper tension. When this happens, the filter may no longer seal correctly, increasing the risk of leaks, pressure loss, or unsafe operating conditions. Replacing the assembly with the Swimables SW-26-531 restores the clamp system to proper working order and helps ensure the filter operates exactly as designed.

The Role of the Spring Barrel Nut in Filter Safety

Unlike standard rigid fasteners, the spring barrel nut assembly is engineered to manage pressure changes inside the filter tank. As internal pressure rises and falls during operation, the spring helps maintain consistent clamping force without overstressing the clamp band or filter housing.

This controlled tension is especially important on high-pressure DE and cartridge filters. Without a properly functioning spring assembly, the clamp may loosen unevenly or be overtightened during service, both of which can compromise the tank seal.

The SW-26-531 spring barrel nut assembly restores this balance, allowing the clamp system to do its job safely and predictably.

Why Spring Assemblies Fail Over Time

Spring barrel nut assemblies are exposed to constant stress. Each startup cycle, pressure change, and service event places load on the spring and threads. Combined with pool chemicals, moisture, and outdoor exposure, these components naturally degrade.

Common failure modes include springs that lose tension, threads that corrode or strip, and nuts that seize in place. In some cases, technicians overtighten the assembly to compensate for worn parts, which can further damage the clamp system or filter housing.

Replacing the entire assembly instead of individual components ensures proper operation and reduces the risk of clamp failure.

Designed for Pentair-Style Clamp Systems

The Swimables SW-26-531 is manufactured to Pentair-style specifications, matching the dimensions, thread profile, and spring characteristics used on several common Pentair filter models.

This assembly is commonly used on filters that rely on a single clamp band with a spring-loaded tightening mechanism, making it a versatile replacement for both residential and light commercial pool systems.

Because it is a direct replacement, installation does not require modifications, special tools, or custom adjustments beyond standard filter service procedures.

When to Replace a Spring Barrel Nut Assembly

Replacing the spring barrel nut assembly should be considered any time the clamp system no longer holds tension reliably. Warning signs include difficulty achieving proper clamp tightness, visible corrosion, uneven clamp seating, or leaks around the filter tank seam after startup.

In some cases, the filter may appear sealed at first but lose pressure as the system warms up or reaches operating flow. This can indicate a fatigued spring that no longer maintains consistent tension.

Installing a new Swimables SW-26-531 restores proper clamping force and helps prevent more serious filter issues.

Built for Pool Equipment Environments

The SW-26-531 is constructed using durable, corrosion-resistant materials designed to withstand the harsh conditions found in pool equipment pads. Exposure to chlorinated water, salt systems, heat, and UV light is expected, and this assembly is built accordingly.

The spring is engineered to maintain consistent performance under repeated compression cycles, while the barrel nut threads are designed for smooth operation during installation and service.

This durability makes the assembly suitable for both routine maintenance and long-term repairs.

Installation Overview

Replacing the spring barrel nut assembly should always be done with the system powered off and pressure fully relieved. Once the clamp band is loosened and removed, the old assembly can be replaced with the SW-26-531.

After reassembly, the clamp should be tightened evenly according to manufacturer guidelines. The spring should compress as designed, indicating proper tension. Over-tightening should be avoided, as the spring is intended to manage pressure changes automatically.

Proper installation helps ensure safe startup and long-term filter reliability.

Why Proper Clamp Hardware Matters

• Maintains even pressure around the filter tank seam

• Helps prevent leaks and seal failure

• Supports safe operating pressure

• Reduces stress on filter housings and clamp bands

• Essential for safe filter reassembly after service

Small hardware components like this play an outsized role in overall filter safety.

Product Specifications

Buy with Confidence from Benchmark Pool Supply

When you purchase the Swimables Spring Barrel Nut Assembly (SW-26-531) from Benchmark Pool Supply, you’re buying from a real pool supply company that understands filtration systems and service requirements.

We stock trusted replacement parts used by professionals and homeowners alike, verify compatibility, and stand behind the products we sell. Our goal is to help keep your pool equipment safe, sealed, and operating as designed.