In solar systems, the temperature in the storage tank can vary considerably,
depending on the solar radiation, and can reach very high temperatures
over long periods. In summer, and if there is little water usage, the hot water
at the storage tank outlet can actually reach temperatures around 200º F.
At these temperatures, the hot water cannot be used directly because of
the danger of scalding.

Function
The thermostatic mixing valve is used in systems for scald protection in
the production of domestic hot water.
It is designed to maintain the set temperature of the mixed water supplied
to the user when there are variations in the temperature and pressure
conditions of the incoming hot and cold water or in the water’s flow rate.
This particular series of mixing valves can function continuously at the high
temperatures of the incoming hot water from the solar storage tank.