<p>A mixing valve for use in a faucet includes a sleeve which may be formed of plastic and a stem positioned within the sleeve and reciprocal and rotatable relative thereto. The sleeve has hot and cold water inlet ports and at least one outlet port. The stem has inlet and outlet openings such that movement of the stem is effective to control the volume and temperature of water discharged from the sleeve. The stem has an air passage connecting its opposite ends. There is a generally cylindrical seal enclosing the sleeve adjacent its inlet ports and effective to form a seal between the exterior of the sleeve, the exterior of the stem within the sleeve and the interior of the housing enclosing the stem and sleeve. The valve includes means for preventing water hammer.</p>
