Abstract: A vacuum furnace with a gas manifold branching into a plurality of secondary gas manifolds, the secondary gas manifolds each including a valve that is contained in each secondary gas manifold; a hot gas plenum including an inner and an outer shell with the outer shell attached at one side to the secondary gas manifold; a series of gas restrictor walls between the inner and outer shells of the hot gas manifold that serves the purpose of dividing the plenum into a plurality of non-circumferential sectors so that the load in the plenum may be cooled from the top, bottom, left, or right side or any combination thereof.