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Thermostatic mixing valves

It is a device that controls and regulates mixing of hot and cold water to ensure a constant temperature and prevent scalding. Thermostatic mixing valve precisely controls and regulates the temperature when bathing, showering and washing hands. The valves are designed so that the required water temperature remains unchanged even when the inlet pressure / flow changes. Mechanical valves are not able to adapt to these changes. Today, thermostatic valves also exist in digital versions. They can be installed in bathtubs or as part of showers.

Hot and cold water entering the valve is mixed so that the resulting temperature corresponds to our desired temperature. Heat sensor inside the valve automatically mixes hot and cold water to reach the desired temperature. The mechanism then automatically compensates for any pressure / temperature changes so that the set temperature remains constant and there are no thermal fluctuations. In the event of a cold water supply failure, the valve detects the danger of hot water and switches itself off. The water also shuts off when the hot water source fails to prevent scalding. For more information on minimum and maximum temperatures, see the pictures below.

Main components

Thermostatic element
A thermally sensitive element that expands or contracts depending on the temperature of the surrounded water. When the thermostatic element detects a change in the water temperature, it instructs the piston to change the ratio of the hot or cold water supplied.


It is usually connected to a thermostatic element. The piston moves back and forth through the cold and hot water inlets, changing the temperature of the outlet water.

Return spring

As the thermostatic element expands (warms), it moves the piston and thus compresses the spring. When the thermostatic element cools down, it retracts and the spring pushes the piston back.

Temperature adjustment

Thermostatic mixing valves normally have a separate temperature setting (usually locked under the top cover). This can be adjusted so that the piston is in a different position, thus adjusting the ratio of the required hot and cold water or their mixture.

termostatické směšovací ventily

Visualization of piston position setting, and spring reaction in possible situations in heating systems

More than 3/4 of severe scalds are suffered by children under the age of 5. By limiting the temperature of the water and preventing a sudden change in its temperature, thermostatic mixing valves protect their users and are a logical prevention of serious injuries caused by scalding. Too high a temperature in the bathtub is the cause of up to 70% of all scalding in households. Young children and their skin are much more sensitive to heat changes and are therefore at greater risk. Another risk group are people with various disabilities, without the ability to perceive risks or respond to dangerous situations. Thermostatic mixing valves prevent these events. The maximum outlet water temperature, which is standardly used for circulation in heating systems, is 50 °C. Many new systems regulate the water temperature to 48 °C, to prevent scalding and thus cause serious injuries. Another serious danger that mixing valves are able to prevent is the risk of Legionella Pneumophila. For this reason, the water must be heated to 60 °C, which prevents these bacteria from forming. However, this temperature is dangerous for humans - it can cause burns. The most common solution is a thermostatic mixing valve, which can be used to control the entire system. Recommendation: Whenever you are asked to check an old water supply or to make a new one, perform the following easy test: Is there a mixing valve that limits the temperature? Is it working? Does it maintain the correct water temperature - a maximum of 50 °C? If not, install a new thermostatic mixing valve. ESBE Basic 35-60 °C has the right temperature range and scald protection that stops hot water if cold water pressure is lost.

TMVs are usually very reliable, service life will typically depend on the method of installation, operating conditions and maintenance - the key factor is, for example, water hardness. Standard service life is 5 years, during this time they should be serviced. And then possbly replaced after this period - depending on their condition.

Yes, the lowest adjustable range is 20-43 °C.

TMV responds quickly to changes, which is ensured by the certification that ESBE valves have. This certification is regularly verified by third parties, thus ensuring that scalding does not occur even during a sudden change in temperature. However, it may happen that a sharp change between the minimum and maximum temperature will increase by about 7 degrees above the set maximum. Modern mixing valves are able to suppress this extreme above the maximum for 1.2 and 0.5 seconds, respectively - a time for which temperature extremes can occur by 7  (50 degrees).

It is important to perform the installation exactly according to the instructions, typical errors that arise during the installation of TMV are:

1) Flow regulators are not used when installing the mixing valve in the boiler. This can cause problems in the winter months.

2) Failure to remove flow regulator when installed in an open system may reduce water flow. If you have any doubts regarding the installation of the product, contact the ESBE manufacturer or contact us here.

Heat from solar is cheap, but irregular. Because of this, a heat storage is used and its subsequent redistribution to heating systems. When only one circuit is installed, the system draws hot water from above. If you install a second circuit and two ESBE Basic 35-60 °C valves, the valves will take hot water from the middle as long as possible to keep the water at the top of the tank hot. With two circuits and with ESBE Basic 35-60 °C on the primary side, solar energy is better utilized even on colder days. In this way, the water from the solar panel is released in the lower part of the tank, so as not to disturb the warmest layer of water in its highest part. The longer the storage system can maintain a higher temperature, the faster the return of costs. At the same time, the valves ensure that the hot water system is protected against scalding.

Wide range of thermostatic mixing valves on our site