Thermostatic mixing valves and systems

Thermostatic mixing valves and systems for mixing fluids of dissimilar temperature are disclosed. A thermostatic mixing valve in accordance with an illustrative embodiment of the present invention can include an elongated valve body defining a cold fluid inlet, a hot fluid inlet, a mix fluid outlet and a mixing chamber, a fluid flow regulator for adjusting the flow of cold and hot fluid injected into the mixing chamber, and temperature selection means for adjusting the temperature of fluid contained within the mixing chamber. The valve body may have a vertical, in-line configuration wherein the hot fluid inlet, mixing chamber, and mix fluid outlet are substantially axially aligned along a vertical longitudinal axis of the valve body, allowing hot fluid to pass substantially vertically through the valve body towards the mix fluid outlet. The thermostatic mixing valve can be provided as part of a water heater system to permit the water heater to operate at elevated temperatures, thereby increasing the capacity of hot water available to the system.