Pentair 3.75" Air Release Valve Vent Stem with O-Ring

The Pentair 3.75" Air Release Valve Vent Stem with O-Ring (part number 24206-0103S) is a precision-engineered manual venting hardware component designed exclusively for the top-mounted air relief configurations of various compact Pentair and Sta-Rite pool and spa filtration systems. This model-specific, threaded plastic plunger assembly is utilized within the air bleed networks of Sta-Rite Posi-Clear, PXC series above-ground cartridge filters, System 2 PLM modular media systems, and System 2 PLDE series modular Diatomaceous Earth (D.E.) filters (such as model PLDE48). Injection-molded from a high-impact, UV-stabilized engineering polymer composite, this 3.75-inch long core stem features an ergonomic finger-turn grip at its crown and houses a matching premium-grade elastomeric O-ring along its threaded shaft.

Its primary operational role is to act as the direct manual release mechanism situated at the highest pressure point of the filter tank lid assembly. By partially backing the stem out of its housing, the integrated internal air channel breaks its seal, allowing pool technicians and owners to safely bleed off pocketed air pockets that naturally accumulate inside the tank dome during filtration or pump start-up cycles. Once a steady stream of water escapes, tightening the stem down enables the compressed rubber O-ring to form an absolute watertight and airtight seal, which eliminates internal pressure-lock, ensures a completely flooded hydraulic state, and allows the pressure vessel to safely maintain regular operating parameters up to 50 PSI without weeping or leaking under intense pump vibrations. Built to endure harsh equipment pad environments, this resilient stem resists outdoor UV degradation, extreme seasonal thermal shifts, and continuous contact with highly concentrated sanitizers like chlorine, bromine, and winterizing acid flushes. Due to its ultra-compact, lightweight plastic profile and minimal material mass, this individual vent stem and O-ring assembly carries a net product and shipping weight of approximately 0.05 to 0.15 pounds (about 0.80 to 2.40 ounces).