Pentair 1/8" x 2 1/8" Backwash Valve Shaft O-Ring

The Pentair 1/8" x 2-1/8" Backwash Valve Shaft O-Ring (Product #: 271101) is a factory-original OEM replacement sealing gasket engineered to provide an airtight, leak-proof hydraulic barrier within the internal piston assemblies of pool and spa push-pull slide valves. Designed specifically for Pentair and PacFab 2-inch PVC side-mount backwash valves—frequently installed on Triton® series sand filters and FNS® Plus vertical grid D.E. filtration systems—this specialized ring sits securely within the perimeter grooves of the vertical shaft piston. As the operator manually pushes or pulls the valve handle to transition between standard filtration and backwash modes, this dynamic o-ring creates a tight compression seal against the inner walls of the valve cylinder, preventing pressurized water from escaping out of the waste line or bypassing the filter media. Molded from a high-grade, chemical-resistant nitrile rubber (Buna-N) compound, the component delivers exceptional compression memory, superior structural elasticity, and long-term ozone resistance, allowing it to withstand continuous exposure to high chlorine concentrations, pool mineral scaling, and heavy mechanical friction without tearing or dry-rotting. Replacing a worn, flattened, or cracked shaft o-ring is an essential maintenance task that instantly corrects common pump room issues, such as water continuously weeping down the backwash line or suction-side air induction that causes pump cavitation and loss of prime. Built to handle continuous system operating pressures up to 50 PSI and extreme summer pump pad temperatures, this featherweight component ensures peak hydraulic performance. The physical weight of this single Pentair Backwash Valve Shaft O-Ring is approximately 0.015 pounds (roughly 0.24 ounces, with a nominal inner diameter of 2-1/8 inches, a cross-section thickness of 1/8 inch, and a packaged shipping weight of approximately 0.05 pounds), providing pool professionals and residential managers with an essential, low-cost, and highly reliable hardware solution for flawless water management.