Domestic water heater thermostatic mixing valves

DF

I am sort of doing a survey. I want to know how many people in the industry routinely specify or install thermostatic mixing valves at the outlet of domestic hot water storage water heaters to ensure a steady water supply temperature. It is sort of a grey area in most codes, but is required by most domestic water heater manufacturers. Any thoughts would be appreciated.

bob young

Holby

a mixing valve is a must for any domestic storage tank. my choice is holby.

hot_rod

more and more I see tank

manufacturers including thermostatic valvesin the box with the tank.

A couple thoughts....

The use of a mixer will allow the tank to operate at higher temperature. This will extend the drawdown, and also address legionella concerns.

In Europe "hygine" or legionella cycles are being built into controllers. It allows the tank to ramp up during the nightime. The Buderus fellow at AHR showed me that function in their new boiler controls.

It also helps with "soft tissue lawsuit" concerns. If the correct valve is installed with the "fail cold" function, of course.

On the down side, the do impose a pressure drop, and they do require maintenance, especially in hard water conditions. Installing them with isolation valves is a good idea. Keep a replacement on the truck for a quick switch.

Some brands offer higher Cv valves now, also. I like the dry well and temperature gauge option on the Caleffi valves

hr