Watts 0590716 Air Vent Lower ports typically require different

Lower ports typically require different diameters

Built with high-grade copper windings and professional-grade encapsulation

Precise Thermal Protection: Calibrated to open at exactly 135°F (57°C) to protect sensitive heater components and prevent hazardous operating conditions

To maintain a proper airtight seal

20" WC rating on your existing switch to ensure proper pressure differential matching

Watts 0590716 Air Vent Lower ports typically require differentThe Watts 0590716 (Series FV 4M1) is a heavy duty 1 4 inch automatic air vent designed for high performance hydronic heating systems. As the direct replacement for the discontinued 590715, this valve is engineered to purge entrapped air from hot or cold water distribution systems automatically. Built with a rugged brass body and cover, it features a high temperature resistant polyethylene float and a durable silicone rubber seal, making it fully