The NTI Boiler 64980459 Air Vent is a 1/2-inch MIP NPT air-venting component designed to remove trapped air from hydronic heating systems. It works by automatically releasing accumulated air from the boiler or piping while helping maintain proper water circulation and system efficiency. This air vent is commonly used with compatible NTI boilers and hydronic HVAC heating equipment. Its... https://www.partshnc.com/nti-boiler-64980459-air-vent-taco-1-2-mip-npt