Pentair 59023400 Complete Element Grid Assembly – 48 sq ft D.E. Filter Internals

Part # 59023400 — a full replacement grid assembly designed for 48 sq ft vertical grid D.E. pool filters (such as the FNS Plus 48 series). This kit includes the top manifold, bottom manifold, tie rods, seven full-sized grids, one partial grid, air-bleed assembly and all required hardware to restore the filter internals to like-new condition.

Key Features

• Designed for 48 square feet of filtration area — suited to FNS Plus 48 and similar vertical grid D.E. filters.
• Includes full grid set: seven full grids and one partial grid plus manifolds, tie rods and air-bleed components.
• Pre-assembled kit makes replacement quick and service-friendly — drop-in assembly rather than individual parts.
• Optimizes filter performance by renewing internal flow paths, reducing bypass and restoring efficient backwash operation.
• Allows reuse of existing filter tank and plumbing, providing a cost-effective upgrade versus full filter replacement.

Typical Applications

This grid assembly is ideal when your D.E. filter is showing signs of age such as elevated pressure, poor cleaning performance, torn grid media, or when the internal components are damaged but the tank body remains sound. It is suitable for residential in-ground pools using a 48 sq ft vertical D.E. filter configuration.

Installation & Compatibility Notes

Before installing, shut off the pump, relieve system pressure, and disconnect power if required. Remove the filter tank lid, drain the filter housing and extract the old grid assembly. Clean the interior of the tank, inspect for cracks or corrosion, then install the new 59023400 grid assembly ensuring proper seating of manifolds and tie rods. Re-assemble the filter, fill with water, prime the pump and verify normal operation and backwash cycles. Confirm compatibility with your tank’s 48 sq ft rating and vertical grid layout.

Why Choose This Assembly?

Selecting the 59023400 grid assembly allows you to restore your existing filter to optimal performance without the expense of tank replacement. It delivers improved flow, cleaner water, fewer short backwash cycles and extended runtime between servicing.

Maintenance Tips

• Check the pressure gauge monthly — when it rises ~8–10 psi above clean start, inspect grids for buildup or tears.
• Rinse the grids during backwash service intervals and consider full replacement when grid media is fatigued or damaged.
• Inspect tie rods and manifold seals annually for wear or corrosion and replace if needed.
• During each service, verify the air-bleed is functioning properly and that water flow from grids is even across the tank.