Pentair FNS Plus Tank Lid Assembly 48 sf | 170021

Pentair SKU: 170021
Pentair FNS Plus Tank Lid Assembly 48 sf | 170021 - Pool Filter Parts - img - 1
Pentair FNS Plus Tank Lid Assembly 48 sf | 170021 - Pool Filter Parts - img - 2
Pentair FNS Plus Tank Lid Assembly 48 sf | 170021 - Pool Filter Parts - img - 1
Pentair FNS Plus Tank Lid Assembly 48 sf | 170021 - Pool Filter Parts - img - 2
FNS Plus 48 D.E. Filter Not sure it fits? See this part on the interactive diagram FNS Plus 48 D.E. Filter

Pentair FNS Plus Tank Lid Assembly 48 sf | 170021

Pentair SKU: 170021
  • In stock, ready to ship
  • Inventory on the way
$349.94
Instant Savings: $80.05
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Questions about returns? View our return policy.
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Pentair 170021 Tank Lid Assembly – for FNS Plus 48 sq ft D.E. Filter

This Pentair 170021 is a replacement tank lid assembly designed for use with the FNS Plus 48 sq ft vertical D.E. filter system. It restores the sealing interface and structural integrity of the filter tank assembly.

Key Features

  • Direct replacement lid designed for the 48 sq ft filter tank size.
  • Durable construction to maintain proper filtration pressure and seal performance.
  • OEM part fit ensures compatibility and avoids having to replace the entire filter tank.

Technical Specifications

  • Part Number: 170021
  • Application: Lid for vertical D.E. filter tank, 48 sq ft size.
  • Use Case: Replacement when the original lid is cracked, warped or fails to seal properly.

Installation & Compatibility Notes

Shut off the pool pump and relieve pressure in the filter tank. Remove the old lid assembly and inspect tank rim and seal surfaces for damage. Install the new 170021 lid, ensure the O-ring or gasket is properly seated, and clamp or bolt the lid according to manufacturer specification. After installation, restore flow and monitor for correct pressure behavior and absence of bypass or leaks.

Maintenance Tips

  • Inspect the lid annually for signs of cracking, warping or damage around the rim.
  • If the filter pressure drops off or the lid hangs open/moves under pressure, a replacement lid is often the solution.
  • Stock this lid as part of your service inventory to quickly address common filter tank issues without replacing the entire unit.

Why Choose This Lid Assembly?

For pool service professionals and retail storefronts, stocking the Pentair 170021 lid assembly provides a cost-effective way to restore filter system integrity. It enables longer equipment life and avoids full tank replacement while delivering correct fit and performance.

Questions about returns? View our return policy.

Hours Of Operation:

Monday - Friday: 7:00 am to 5:00 pm Phoenix Time

Saturday: 8:00 am to 2:00 pm

Sunday: Closed

  • We do not ship on Saturday or Sunday.
  • Orders totaling more than $300 will require signature confirmation upon delivery.
  • We process and prepare orders for shipment within 1 business day. Please note that many other pool supply retailers require 3–5 days of handling time before shipping.
  • Orders placed after 1:00 pm Phoenix Time may not be eligible for same-day shipment.
  • Expedited shipping options are available at checkout.

Return Policy:

  • Products that are received damaged will receive a refund in store credit.
  • Most products are eligible for return within 30 days of receipt, except where noted below.
  • To initiate a return, please complete an RMA form prior to sending your item back.
  • Original shipping costs are non-refundable and will be deducted from the return credit.
  • Items returned missing accessories or original packaging, or that are not in the same condition as received, may be subject to a restocking fee of up to 100% depending on the condition of the item upon return.
  • Some returns will be charged an automatic 15% restocking fee.
  • We are unable to issue refunds for items that have been damaged or rendered inoperable due to installer error.
  • Please complete the return form to receive your RMA number and return shipping label.
  • Chemical products are not eligible for return under any circumstances.
  • The Pentair Colorsync 618031 is not eligible for return.
  • Pool cleaners are not eligible for return.
  • Opened seals and o-rings are not eligible for return.
  • Capacitors are not eligible for return.
  • Plastic popup tools are not eligible for return.
  • Automation components and circuit boards are not eligible for return.
  • If a light is returned due to a reported malfunction and is found to be fully operational upon testing, return shipping costs and a restocking fee will be deducted from the refund.
  • Orders refused at the time of delivery will be subject to the original shipping costs being deducted from the refund.
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