An air vent (AKA air separator) is a device that removes air from the fluid in a pump system. Air separators are typically used in commercial and residential hydronic heating and cooling systems to increase heat transfer and comfort. Air water separators may vary by maximum working pressure, material of construction, maximum temperature, dimensions, inlet size and other considerations. Brands include Bell & Gossett, Armstrong International, and others. For more on pump parts, see our compression seals, pump gaskets, and pump heads.