Pentair 9/16" x 1 3/16" x 1/8" FNS and INS Large Inner Diameter Washer

The Pentair Large Inner Diameter Washer (part number 192115 or 192115Z) is a specialized mechanical sealing and spacing fastener engineered exclusively for the internal structural tie-rod assemblies of Pentair pool and spa filtration systems. This hardware component is standard across Pentair's premium high-capacity Diatomaceous Earth (D.E.) and cartridge filter lines, including the FNS Plus series (FNS24, FNS36, FNS48, FNS60), the legacy INS series, and Clean & Clear Plus filtration vessels.

Stamped from high-grade, corrosion-resistant stainless steel, this washer features precise structural dimensions measuring 9/16-inch ($0.5625"$) inner diameter, 1-3/16-inch ($1.1875"$) outer diameter, and a heavy-duty 1/8-inch ($0.125"$) thickness. Its primary operational role is to distribute the intense mechanical clamping forces generated when the central grid manifold brass nuts are torqued down onto the internal vertical tie-rod backbone. By expanding the load-bearing footprint across the plastic top manifold surface, it prevents structural crushing, cracking, or material deformation of the internal manifold under pressure.

This stable, high-tension interface ensures that the entire internal grid core remains perfectly compressed and aligned, allowing the filter to safely handle high fluid distribution velocities and sustain continuous internal system operating pressures up to 50 PSI without media bypass or structural unseating. Engineered to remain permanently submerged at the highest pressure point of the tank core, its rugged stainless steel composition completely resists rusting, pitting, material fatigue, and corrosive breakdown from continuous exposure to high-strength pool sanitizers like chlorine, bromine, and winterizing acid washes. Due to its dense but compact metal profile, this individual structural washer carries a nominal product and shipping weight of approximately 0.03 to 0.06 pounds (about 0.48 to 0.96 ounces).