Pentair FNS Plus Top Manifold

You should inspect your manifold if you notice D.E. powder returning to your pool, reduced water flow, or if the manifold shows visible cracks or warping. If the internal grid assembly is no longer sitting securely, the manifold is likely compromised and needs replacement to maintain filtration efficiency.

This part is specifically designed as a direct replacement for the Pentair FNS Plus D.E. filter line. While it fits most FNS Plus models, always verify your specific filter model number against the part number 59023700 to ensure a perfect match.

Yes, replacing the top manifold is a manageable DIY task for most pool owners. It involves opening the filter tank, removing the grid assembly, and swapping out the old manifold, but ensure you have a fresh tank O-ring on hand to reseal the unit properly once reassembled.

This product is the manifold housing itself. It does not typically include the hardware or the filter grids, so you should retain your existing grid hardware or purchase new fasteners if your current ones are corroded.

Using a genuine Pentair part ensures the precise tolerances required for the manifold to seat correctly against the filter grids. This prevents D.E. bypass, which can lead to cloudy water and inefficient filtration that generic alternatives may not reliably solve.