Pentair 1.5" FNS Plus Drain Cap Plug

The Pentair 1.5" FNS Plus Drain Cap Plug (part number 190030 or 190023 depending on the configuration, and often cross-referenced with part number 271016) is a specialized external plumbing component designed specifically for Pentair FNS Plus, Clean & Clear Plus, and Quad D.E. pool and spa filtration systems. Injection-molded from a heavy-walled, high-impact, and UV-stabilized polymer composite, this threaded cap features a 1.5-inch Female National Pipe Thread (FNPT) configuration designed to spin tightly onto the lower drain spigot at the absolute base of the composite filter tank chassis. Its primary operational and structural role is to serve as the main closure for the tank's lower drainage port, establishing an absolute airtight and watertight pressure boundary capable of safely containing continuous hydraulic operating flow rates and internal system pressures up to 50 PSI without weeping or leaking. When unscrewed during routine maintenance or seasonal winterization, it allows pool owners and service technicians to smoothly evacuate water and accumulated debris from the bottom of the pressure vessel. Engineered to endure harsh outdoor weathering, relentless solar exposure, and prolonged contact with concentrated pool sanitizers like chlorine, bromine, and acid washes, this durable cap prevents catastrophic pressure loss. Due to its compact, thick-walled, and hollow plastic architecture, this individual drain cap plug carries a nominal product and shipping weight of approximately 0.15 to 0.20 pounds (about 2.4 to 3.2 ounces).