• Function

The thermostatic mixing valve is used in systems that produce domestic hot water. It is designed to maintain the preset temperature of the mixed water delivered to the user outlet, when there are variations in the temperature and pressure of the hot and cold water at the inlet, or in the drawn-off flow rate. These devices are also available with fittings complete with strainers and check valves on the hot and cold water inlets.

• Operating principle

The regulating element in the thermostatic mixing valve consists of a temperature sensor fully immersed in the mixed water outlet pipe which, by expanding and contracting, continuously ensures correct proportioning of hot and cold water at the inlet. The water proportions are regulated by a piston that slides inside a special cylinder placed between the hot and cold water passage channels. Even if the pressure drops due to hot or cold water drawn-off by other users or temperature variations at the inlet, the mixing valve automatically adjusts the water flow rate until the set temperature is achieved.

• Check valves

In systems with thermostatic mixing valves, check valves must be installed to prevent undesired backflow.