Method for manufacturing valve unit

A method of manufacturing a valve unit comprising:

• providing a plurality of injection molding dies that define a cavity corresponding in shape to the valve unit, wherein the valve unit includes a housing and a valve, wherein the housing defines a fluid flow path with an axis having an upstream direction and a downstream direction corresponding to a predetermined direction of fluid flow in the fluid flow path, wherein the valve is cantilevered and includes a valve body having a coupled end rotationally coupled to the housing and a free end, and wherein the valve body rotates about the coupled end to thereby change flow through the fluid flow path;
• simultaneously molding the housing and the valve within the cavity such that the valve body is formed with the free end extending away from the downstream direction of the axis of the fluid path;
• and
• wherein the housing includes a first recessed portion and a second recessed portion that are upstream of the valve body and that extend away from the downstream direction of the axis of the fluid flow path.