How and Where To Install A Thermostatic Mixing Valve (TMV)

Understanding thermostatic mixing valves (TMVs) and their installation is a critical aspect of any commercial washroom installation. Equally, purchasing the correct size and type will help to comply with the necessary regulations.

Faced with the legislation and red tape involved with any commercial environment, you’re sure to run into items, phrases and requirements that you’ve never even heard of before. Enter the washroom and you’ll continue to be faced with a litany of Building Regulations and environmental health concerns that make the whole ordeal seem pretty daunting. 

However, while you’re navigating your grab rails and figuring out whether you need to comply with Document M of the Building Regulations, it’s worth getting to grips with thermostatic mixing valves, as these are used throughout all commercial washroom settings.

What is a thermostatic mixing valve?

A thermostatic mixer valve, also known as a TMV3 valve, is a small device that combines the hot and cold water feeds into a single warm water feed. The TMV3 plays a critical role in protecting your users against scalding themselves and also conserves your hot water supply significantly.

How To Install A Thermostatic Mixing Valve

For best practice, a thermostatic mixing valve should be fitted to each tap or shower outlet in your washroom. It is worth noting that the regulations governing the installation of a TMV in a domestic setting differ from those in a commercial washroom environment. A commercial toilet or shower room requires a minimum of a TMV3 valve and not a TMV2. The Commercial Washrooms sales team will be able to help guide you on what is needed; however, further clarification can be found in one of our earlier blogs: What is a TMV and how does it work?

TMV valves should be installed in the pipework just before the tap or shower outlet to avoid long runs of pipe where the water temperature can excessively cool. We suggest leaving adequate space beneath the washbasin and taking your TMV3, then fitting both the hot and cold feeds to it. Your valve will have an outlet left, which is where the resulting warm water is to be fed and installed to your hot tap. 

In some instances, people have installed a single thermostatic mixer valve, such as the 15mm Intamix TMV3 thermostatic mixing valve, on the hot feed supplying a whole row of washbasins. However, this is poor practice, and if the TMV3 fails or gets blocked, then the whole row of washbasins will be out of action. We recommend using one TMV for each hot tap or shower. 

Thermostatic mixing valves and showers

Thermostatic mixing valves used in showers are the same as those used to regulate the temperature of tap water. Installing a TMV3 for a shower requires a professional and is fundamental to the health and safety of your users. Of course, at peak times in places like gyms or leisure centres, the demand for hot water is excessive. In certain circumstances, this can result in your hot water being completely drained. However, with the required use of a thermostatic mixer valve, the hot feed to your shower has already been blended with cold mains water. This warm water feed now pulls less hot water for the shower, helping to protect your reserves while simultaneously preventing scalding. 

If you require additional assistance in understanding TMV3 valves or would like to discuss our design and installation services for Commercial Washrooms, please contact one of our team members on 01202 650900.