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Thermostatic Mixing Valves

Image Source: Caleffi

In many modern plumbing and heating systems, comfort and safety are paramount to the end users and are often emphasised in design considerations. One vital component that plays a crucial role in achieving these objectives is the Thermostatic Mixing Valve (TMV). TMVs are devices capable of regulating water temperature, preventing scalding burns and maintaining optimal comfort levels in hot water systems. By understanding the capabilities of such valves, designers would be able to know the importance of these devices and to include them for their positive impact towards system design.


Understanding Thermostatic Mixing Valves

The basic functionality of a thermostatic mixing valve is for blending hot and cold water to produce a consistent, predetermined temperature at the outlet. This temperature is typically set at a predetermined point to ensure user safety and providing comfortable warmth, whilst preventing water from reaching scalding temperatures that could cause injuries. The working mechanism of TMVs is based on a temperature-sensing element, usually a wax or liquid-filled cartridge, which expands or contracts in response to temperature changes at the mixed outlet. This element then adjusts the valve to regulate both the inlets flow of hot and cold water, maintaining the desired output temperature. Controlling the temperature of hot water supply line itself is not feasible, as hot water must be stored at a temperature of at least 60 °C to prevent the growth of Legionella bacteria.


Applications Across Systems

One of the main reasons for the need for TMVs stem from the fact that hot water supply lines needed to be kept at high temperatures and as such controlling the temperature of hot water supply line itself is not feasible. Water that are not above 50 °C can lead to the growth of Legionella bacteria, and as such must be stored at a temperature of at least 60 °C to prevent the growth of Legionella bacteria. This in turn poses safety risks as water temperatures above 50 °C can lead to scalding, hence requiring TMVs to ensure a safe controlled outlet of hot water supply.

TMVs are thus used in many hot water systems, from domestic plumbing to commercial buildings and even in industrial processes. Although not common in Singapore, residential spaces with a dedicated hot water supply line can have TMVs installed in showers, baths, sinks, and other fixtures to prevent scalding accidents, particularly in households with children or elderly individuals. By maintaining a safe water temperature, these valves offer peace of mind to homeowners while ensuring a comfortable bathing experience. Similarly in commercial buildings such as hotels and hospitals, TMVs serve as an important device for ensuring safety from scalding incidents as well as providing a suitable temperature range for comfort. Not only that, TMVs can also play a key role in industrial applications such food processing, pharmaceuticals, and manufacturing that rely on precise water temperature control for various processes—ensuring consistent temperatures, safeguarding product quality, and promoting worker safety.

By precisely blending hot and cold water to achieve the desired temperature, TMVs can even help in conserving energy by reducing the need for excessive heating, potentially saving on operational costs.


Choosing Thermostatic Mixing Valves

Thermostatic mixing valves are the unsung heroes of plumbing and heating systems. From preventing scalding accidents to promoting energy efficiency, these valves play a crucial role across all sectors residential or commercial. As awareness of safety and sustainability continues to grow in today’s world, the importance of TMVs in ensuring reliable water temperature regulation cannot be overstated. Investing in quality TMVs from notable brands such as Caleffi not only enhances user experience but also demonstrates a commitment to safety and well-being in any built environment.

We at Val-Technik would be able to provide professional opinion on the appropriate uses for thermostatic mixing valves and suggest optimal sizing for the valves to function effectively in hot water systems.

For more information and consultation regarding the different types of thermostatic mixing valves and their suitability for a system, please email us at or call 6742 2770.


1.     Caleffi

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