The Pentair 170020 tank lid assembly is a replacement upper housing component designed for the FNS Plus 36 square foot pool and spa D.E. filter system. This lid forms the top half of the filter tank and creates the sealed chamber required for pressurized filtration. Its durable molded construction allows the filter to maintain proper pressure while providing access to internal filtration grids for service and maintenance.

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Key Features

• Replacement tank lid assembly designed specifically for Pentair FNS Plus 36 square foot D.E. filter systems.
• Forms the upper half of the filter housing and clamps securely to the tank bottom assembly.
• Creates a sealed chamber that maintains the pressure required for effective filtration.
• Durable molded construction designed to withstand pool chemicals, water pressure, and outdoor conditions.
• Typically includes the air relief valve assembly used to vent trapped air during operation.
• Direct replacement part for Pentair FNS Plus 36 sq ft D.E. filter model FNSP36.

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Product Overview

The Pentair 170020 tank lid assembly serves as the upper housing for the FNS Plus 36 square foot vertical-grid D.E. filter. Installed on top of the filter tank, the lid works with the tank clamp and O-ring to create a pressure-tight chamber required for effective filtration.

Inside the filter, the D.E. grid assembly captures debris and fine particles from circulating pool water. The lid assembly also provides the access point used when performing maintenance such as cleaning or replacing the filter grids. Built from durable plastic and designed for a precise OEM fit, this lid assembly restores proper sealing and structural integrity when the original tank lid becomes cracked, warped, or damaged.