The air vent valve includes a vent valve body and a valve adapter that sealingly mate together. A vent outlet of the vent valve body and a fluid inlet of the valve adapter are connected through interior flow chambers of the vent valve body and valve adapter. A spherical ball float is constrained for longitudinal movement within a tubular collar in the interior chamber of the vent valve body, and a planar valve seat member with a central flow aperture is disposed within the vent valve body between the tubular collar and the outflow passage of the vent valve body.
