A ball float vent valve includes a valve body having an inlet port, an outlet port and an axial passageway there-between. The passageway may be defined by a cylindrical inlet chamber, a cylindrical outlet chamber and a tapered seat connecting the inlet chamber and outlet chamber. The outlet chamber may include an annular retaining groove proximate the outlet port. A spherical float may be positioned in the outlet chamber. The float may be dimensioned to seal the passageway when seated on the tapered seat. A retainer positioned in the retaining groove may include an outer crescent region having a plurality of apertures, a center region dimensioned to retain the float in the outlet chamber, and a linking region connecting the outer region to the center region.