A thermostatic valve, which includes a main body portion, a cavity formed as part of a main body portion, and an inner wall integrally formed with the main body portion adjacent the cavity. A circumferential flange is integrally formed with the inner wall, such that the circumferential flange surrounds a valve cavity. A valve member is attached to the inner wall disposed in the valve cavity, and a flow aperture is formed as part of the inner wall. Fluid flows through the flow aperture into the valve cavity, and when the pressure in the valve cavity is above a predetermined value, the valve member contacts the inner wall, preventing fluid from flowing through the flow aperture.