Pentair O-Ring 2-137 Buna N | FNS Plus & Clean & Clear Plus Filters | 192320

The Pentair O-Ring 2-137 Buna N (192320) is the OEM replacement upper bulkhead O-ring for Pentair FNS Plus D.E. filters and Clean & Clear Plus cartridge filters.

IMPORTANT: DATE OF MANUFACTURE AFFECTS FITMENT
This O-ring fits FNS Plus filters manufactured before October 2004 and Clean & Clear Plus filters manufactured after November 1998. Check your filter's date-of-manufacture label before ordering — fitment is not universal across all production dates.

IMPORTANT: LUBRICATION REQUIRED — SOLD SEPARATELY
Always lubricate this O-ring with a silicone-based lubricant before installation. We carry the Pentair R172351 Lifeguard Silicone Lubricant — the OEM-matched product for Pentair equipment.

This Buna N (nitrile rubber) O-ring seals the upper bulkhead fitting on your filter tank. A failed or degraded bulkhead O-ring allows water to bypass the sealed connection, resulting in external leaks at the bulkhead port. Replacing it at the first sign of weeping or during routine filter service prevents water loss and maintains system pressure.

Specifications

Fits Into

Compatibility is based on Pentair parts documentation and available OEM records. This is not an exhaustive list. For certainty, verify the part number in your equipment's manual or on the original part itself before ordering.

Poolaroo Pro Tip

When servicing the bulkhead O-ring, inspect the bulkhead fitting and port seat for any nicks, scoring, or calcium deposits before installing the new O-ring — even a minor surface irregularity can cause a fresh O-ring to leak. Clean the seat thoroughly, then apply a thin, even coat of Pentair R172351 Lifeguard Silicone Lubricant to the O-ring before seating it. Never use petroleum-based lubricants — they degrade Buna N rubber and will cause premature failure.