Pentair FNS Plus Internal Air Bleed Assembly

The Pentair FNS Plus Internal Air Bleed Assembly (part number 59023600 or 59023600Z) is a critical internal air-scavenging component engineered exclusively for high-capacity pool and spa Diatomaceous Earth (D.E.) vertical grid filtration networks. This genuine original equipment manufacturer (OEM) part is standard hardware for the entire family of Pentair FNS Plus D.E. filters (models FNSP24, FNSP36, FNSP48, and FNSP60).

System Integration & Hardware

The air bleed assembly consists of a flexible, chemical-resistant vinyl tube, an internal support sleeve, a specialized fabric filter sock, and a retention clip. It is designed to snap directly into the designated receiving port on the underside of the Pentair FNS Plus Top Manifold (part number 59023700).

Primary Operational Role

• Continuous Air Evacuation: Positioned at the absolute highest internal point inside the pressurized tank dome, its primary role is to continuously draw in pockets of trapped atmospheric gas or pump-induced air.

• Water-Hammer Prevention: By routing these trapped gases down through the core plumbing and out before they can accumulate in the upper hull, it prevents the filter from becoming air-bound or experiencing destructive "water-hammer" pressure spikes.

• Media Retention: The integrated fine-mesh fabric filter sock at the tip of the assembly allows air and water to pass freely while blocking loose D.E. powder or debris from bypassing the filter membrane and returning to the pool.

Materials & Performance

This assembly allows the internal plumbing grid to safely manage high circulation velocities and sustain continuous system operating metrics up to 50 PSI. Fabricated from advanced, non-corrosive polymers, the entire assembly completely resists material softening, structural warping, and advanced bleaching from continuous contact with pool sanitizers like chlorine, bromine, or routine scale-removing acid flushes. Due to its lightweight, flexible profile, this individual replacement part carries a nominal product and shipping weight of approximately 0.10 to 0.15 pounds (about 1.6 to 2.4 ounces).