Tips for Installing a Thermostatic Mixing Valve

The home thermostatic mixing valve is an important part of any sink, shower or bath mixer. The thermostatic valve is a helpful device because it shuts off the hot water supply if the cold water supply is stopped or interrupted. Without this device a person who is using a mixer may be scalded by the hot water. This valve not only shuts off the hot water supply, but it provides a pre-mixed supply of cold/hot water. This pre-mixed water is safely warm and may not scald or burn the skin. The valve is usually housed in a box built in the bathroom wall, so it can be easily accessed to make some adjustments.


To access the valve, just open the cover plate on top of the box. The water in the hot water boiler should be constantly maintained at about 140 degrees F. to kill any harmful bacteria (such as Legionella which causes Legionnaire's disease).This temperature is extremely high and dangerous for human beings, therefore a thermostatic valve is the right solution, as it mixes the hot water with cold water to prevent scalding. Many building authorities now require the installation of a thermostatic valve in homes and apartments. In order to install a thermo valve, follow these tips.

Follow the Local Authority Codes

Before you install a thermo valve, you have to find out the local authority codes. Building codes are regulations that must be followed when you are building a home, renovating or installing some plumbing. These regulations will govern the methods and specifications used in the installation. They will touch anything related to building including the plumbing fittings used in a project.

Shut off the Main Supply

Prior to installing the thermostatic valve, ensure that the water supply from the main pipe is shut off. Open the faucets and leave the pipes and drains to dry. When you are doing any plumbing installation, you do not want to cause any water breaks or leaks from the pipe joints that you are working on. Water will gush out or leak from loose points if you do not close the main water supply.

Solder the Joints

It is good practice to solder the joints on the thermostatic valve prior to connecting it. This will prevent any damage to the rubber gaskets. Make sure the solder is kept away from portable water, otherwise it should be safe. If the solder is unsafe, then it may contaminate the drinking water.

Testing Water

Turn the hot water on. Using a thermometer, test its temperature. Wait for the water to get to the faucet prior to measuring the temperature.

Types of Thermo Valves

Before installing the thermostatic valve, you should know that there are generally 2 types of valves that you can install. These valves are certified and approved by the building authorities.

The TMV-2 valve is a thermostatic valve that is made for domestic purposes. However, they can also be used in other premises.

The TMV-3 valve is a high performance thermostatic valve that is made to provide maximum safety. These valves are suitable for hospitals, or homes where there are mentally disturbed or disabled people.