A valve assembly includes a housing defining an aperture, a passageway,
and a branch passage. The branch passage extends from the aperture and
intersects and communicates with the passageway. The branch passage is
disposed at an angle greater than 90 degrees with respect to the
passageway. A piston is disposed at least partially within the branch
passage and is movable from a first position to a second position. The
piston allows communication between the passageway and the aperture when
the piston is in the first position, and the piston blocks communication
between the passageway and the aperture when the piston is in the second
position. An angled seal may be positioned around the piston.