Pentair 1" Posi-Flo Air Relief Valve

The Pentair 1" Posi-Flo Air Relief Valve (part number 25010-0004 or 25010-0004Z) is a compact but essential air-management plumbing component designed specifically for Sta-Rite Posi-Flo, PRC, and PRD series aboveground pool and spa cartridge and D.E. filtration systems. Injection-molded from a high-impact, UV-stabilized polymer composite, this small threaded valve is engineered to seat directly into the top center port of the upper filter tank lid. Its primary operational role is to allow pool owners and service technicians to manually purge compressed air pockets that naturally accumulate at the high point of the pressurized filter shell during pump startup, ensuring a completely flooded hydraulic flow and protecting the tank from dangerous pressure surges. When twisted closed, the valve creates an absolute airtight and watertight boundary capable of safely containing continuous internal system operating pressures up to 50 PSI without leaking or weeping. Built to withstand relentless outdoor weathering, extreme solar exposure, and constant contact with highly concentrated sanitizing chemicals like chlorine and bromine, this durable part features a streamlined, ultra-lightweight profile. Because it consists of a highly compact, hollow plastic architecture measuring just a few inches in length, this individual air relief valve carries an exceptionally minimal net product and shipping weight of approximately 0.02 pounds (about 0.32 ounces).