The Watts 0590712, also designated as the HAV-1/8, is a heavy-duty automatic air vent designed for high-performance air management in hydronic heating systems and low-pressure steam applications. Built with a robust 2-piece chromed brass body, this 1/8" NPT straight-pattern vent maintains system efficiency by continuously purging trapped air from radiators, baseboards, and convectors. The core of the unit utilizes advanced hygroscopic technology, featuring specialized moisture-retaining cellulose fiber discs. These discs shrink when dry to allow air to vent freely and expand upon contact with water to provide a reliable, positive shut-off that prevents system leaks. A built-in stainless steel ball check valve allows for seamless maintenance, enabling technicians to replace the hygroscopic cartridge without draining the system or requiring a full shutdown. Rated for a maximum pressure of 125 psi and temperatures up to 240°F, the HAV-1/8 ensures air-free operation and optimal heat transfer in demanding commercial and residential piping high points. Key Benefits: Dual Operation Mode: Features a heat-resistant ABS handwheel for easy switching between automatic air venting and manual air release. System Protection: Integrated stainless steel check valve prevents water loss during internal cartridge servicing, maintaining system pressure and integrity. Corrosion Resistance: The chrome-plated brass body and copper thermostat assembly provide superior durability against harsh hydronic environments. Universal Compatibility: Standard 1/8 inch NPT connection allows for a direct drop-in replacement for older Hoffman 500 or generic manual air bleeders. Common Questions: How do I set the valve to automatic mode? To engage the automatic venting function, ensure the black handwheel is turned fully clockwise to the closed position. In this state, the internal hygroscopic discs regulate air discharge based on moisture levels. Can this be used on steam radiators? Yes, the 0590712 is rated for low-pressure steam systems up to 10 psi, as well as standard hot water hydronic loops. Does the system need to be drained for repair? No. Because of the positive shut-off ball check, the disc cartridge can be removed and replaced under full system pressure without leakage. Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.
