The mixing valve mixs in cold water to the hot water coming out to bring the temp down to where you choose. 140 water never leaves the valve, which is mounted on the exit from the hot water heater. The design is super simple, so failure is very unlikely. But it is designed to fail to full cold.
The part on the left is the mixing valve, you attach it to the output of your hot water heater. The part on the right is just a basic T junction you out on the inlet to the hot water heater so you have a source of cold water for the mixing valve.
The mixing valve mixs in cold water to the hot water coming out to bring the temp down to where you choose. 140 water never leaves the valve, which is mounted on the exit from the hot water heater. The design is super simple, so failure is very unlikely. But it is designed to fail to full cold.
I have never heard of a whole home mixing valve. That sounds like it would be a pretty complicated retrofit.
Nope, super simple. I could theoretically even do it myself. I didn’t but it is that simple. This looks a lot like the one I have. https://www.lowes.com/pd/Honeywell-Home-AMX300TLF-DirectConnect-Water-Heater-Kit/5018636545?user=shopping&feed=yes
The part on the left is the mixing valve, you attach it to the output of your hot water heater. The part on the right is just a basic T junction you out on the inlet to the hot water heater so you have a source of cold water for the mixing valve.