Caleffi 521359A 3/4-Inch Solar Thermostatic Mixing Valve - Scald Protection & Anti-Chill - Pressure Balanced for Solar Water Heaters & Hydronic Systems - Perfect for Residential & Commercial Solar Installations

It says "Solar" for some reason that escapes me. True, this valve could be used in a system that provides hot water from solar panels for domestic hot water use, or even for radiant home heating. But calling it 'Solar" is too limiting. In particular, I do not use it in a solar system.As I age, I imagine my immune system may be of lowering effectiveness. And one threat is the growth of Legionaire's bacteria in my hot water heater. To ensure that they do not grow well in a domestic hot water heater, it is desirable to run the heater at between 140F and 160F. But it is dangerous to supply water of that temperature to showers, basin, and sink taps. Domestic hot water heaters have thermostats that are not very precise. I have tried to set mine to a minimum temperature of 140F, and it is now set that way. But the heating does not shut off until the water temperature goes up to almost 160F. Had I set it to 120F, it can still coast up to 140F.This Caleffi mixing valve is the solution. It takes the hot water from the heater and mixes it with cold water and delivers the mixed water to the house. The delivered temperature is adjustable, and mine is set to deliver 120F water provided the flow rate is at least 1/2 gallon per minute. I had the plumber install a thermometer in the hot water supply line and the mixed water delivery line, so I can be sure it is working right, and that the water heater is correctly adjusted. A convenience, though not absolutely necessary. This valve is able to shut off the water if the cold water supply should fail. It will also do that if the hot water should fail.It works just as it should.