Pentair FNS Plus Tank Bottom Assembly 36 sf | 170016

Pentair 170016 Tank Bottom Assembly for FNS Plus 36 Sq Ft D.E. Filter (FNSP36)

The Pentair 170016 is an OEM replacement tank bottom assembly (lower tank half) for the Pentair/PacFab FNS Plus 36 sq ft vertical-grid D.E. filter, commonly referenced as FNSP36. This part forms the lower half of the filter tank and provides the base structure and sealing surface for the tank O-ring and clamp band.

Compatibility

• Fits: Pentair / PacFab FNS Plus 36 sq ft D.E. filter
• Common model reference: FNSP36
• Part type: Tank bottom / lower tank half assembly

Always verify your filter model and parts diagram before ordering. FNS Plus tank parts vary by filter size (24, 36, 48, and 60 sq ft).

What This Part Does

• Forms the lower half of the filter tank housing
• Provides the seating surface for the tank O-ring and clamp band connection
• Supports internal filter components and helps maintain a pressure-tight filter body

When to Replace the Tank Bottom

• Cracks, hairline fractures, or visible seepage from the lower tank shell
• Warping or damage that prevents proper sealing with the tank O-ring
• Damage at the clamp contact area from age, impact, UV exposure, or overtightening
• Persistent leaks after replacing the tank O-ring and confirming clean sealing surfaces

Installation Notes

• Turn off the pump and relieve all filter pressure before opening the filter.
• Inspect and replace the tank O-ring if it is flattened, cracked, swollen, or nicked.
• Clean all sealing surfaces thoroughly before reassembly.
• Reinstall the clamp band evenly and follow manufacturer tightening procedure (do not over-tighten).
• After restart, check for leaks once the system reaches full operating pressure.

Related Products (Aqua Pool Supply)

• Pentair 170016 Tank Bottom (Search)
• Pentair 170020 Tank Lid Assembly for FNS Plus 36 (Search)
• FNS Plus Tank O-Ring 39010200 (Search)
• FNS Plus Clamp Kit (Search)
• FNS Plus 36 Grid Assembly (Search)

Maintenance Tips

• Keep the tank O-ring clean and lightly lubricated with pool-safe silicone lubricant to reduce pinching and leaks.
• Never open the filter until the pressure gauge reads zero and air has been fully relieved.
• If the filter is in direct sun, shade can help extend the life of plastic tank components.
• Record your clean starting pressure after service so you can track when the filter needs cleaning.