“I have a solar system preheating my water heater so the water heater sometimes puts out scalding hot water on very sunny days. I installed the mixing valve to prevent this very hot water from reaching the shower and other hot water faucets. It does work reasonably well most of the time, but when you first turn on the faucets you get cool water which quickly turns too hot and then tapers off. It isn't clear to me why this happens. My guess is that the valve does not react quickly enough to changes in the hot water reaching the valve. This Resideo valve replaced a brand new, equivalent Honeywell valve that didn't adjust the temperature at all.”
