Abstract: In one example, a proportioning valve, comprises a valve body, a first fitting coupled to the valve body, a second fitting coupled to the valve body, and a third fitting coupled to the valve body, where the second fitting and the third fitting each extend in parallel to the first fitting. In one example, an inner bore of the valve body is substantially cylindrical. In one example, the first fitting is an outlet fitting, the second fitting is a first inlet fitting, and the third fitting is a second inlet fitting. In another example, the first fitting is an inlet fitting, the second fitting is a first outlet fitting, and the third fitting is a second outlet fitting. In one example, the valve body includes a flow diverter positioned within the valve body.