What is a TMV and how does it work?

TMV stands for thermostatic mixer valve, a fitting that’s installed to control the temperature of the water coming from a tap or showerhead. It’s an essential piece of the pipework that protects users from being scalded. 

In all buildings, particularly large locations like hospitals and schools, it can be difficult to ensure the same temperature of the water coming from a tap at one end of the property to the other. By fitting thermostatic mixer valves, the flow of water is regulated to a safe temperature throughout the site. 

The difference between mixer taps and mixer valves

You might have heard the term mixer tap before, which refers to a single tap that offers both hot and cold water. Often, this tap will have a control where you can slide the opening between hot and cold water. However, you should not confuse a TMV with a mixer tap. 

While a mixer tap or shower will let you adjust the temperature of the water coming out of the tap, the TMV is directly responsible for the temperature of the hot water feed before it comes out the tap, regardless of whether it is a mixer or not. 

How a TMV works

A thermostatic mixer valve works by blending a mains hot and a mains cold feed into a single warm feed. In some cases, one TMV can be used to supply up to three or four outlets, though it’s important to remember that the further away from the TMV an outlet is, the temperature will begin to drop.

TMV2 or TMV3?

There are two types of thermostatic mixer valves, TMV2, and TMV3. Your common TMV2 is the kind of valve used in domestic environments, though it is sometimes used in small business settings. They work with water pressures from 0.1 - 5 bar.

TMV3 is a commercial grade mixer valves that work with pressures up to 10 bar. These are specifically designed for the commercial environment and required for hospitals schools and healthcare environments. TMV3s are needed to adhere to NHS D08 regulations. While TMV2 still meets two main British standards, it can’t be used in healthcare settings. TMV3s are more robust and powerful, essential for commercial grade wash, shower and changing rooms.

If you would like more advice on which TMV you need for your washroom, or to speak with one of the team, get in touch on 01202 650900.