What is the Difference Between Thermostatic and Tempering Valves?

Whether you’re a plumbing enthusiast or just want to understand your home better, knowing the differences between a thermostatic and a tempering valve can be useful.

These often-overlooked pieces of hardware each serve a vital role in the installation, protecting the safety and efficiency of your hot water system.

While their purposes are similar, thermostatic mixers and tempering valves have some distinct differences worth exploring.

The Function of a Tempering Valve

A tempering valve, sometimes called a mixing tool, is primarily used in residential hot water systems. It mixes hot and cold water to output water at a safe temperature. It’s installed to make sure no scalding hot water could harm users.

Water is stored at 60°C in a storage tank to prevent the growth of dangerous bacteria. However, if hot water was delivered at that temperature it would cause third-degree burns. That’s why a tempering valve is used to reduce the hot water to about 50°C.

It is mandatory around Australia to have a tempering valve or mixing tool installed in any bathroom, particularly for showers and baths.

Signs of a Bad Tempering Valve

Detection of a malfunctioning tempering control valve might prove challenging to an untrained eye.

Signs of a bad hot water tempering valve are fluctuating water temperature, a lack of consistent hot water, or an absence of hot water altogether.

Moreover, an observable decrease in water pressure could result from a defective tempering valve. The valve could restrict the flow of hot water to a particular outlet, such as the outlet of a shower or a tap.

The life expectancy of a tempering valve is typically around 5 to 10 years. However, this varies based on the quality of the stored water, water usage and the installation.

If you’re having problems with the temperature of your hot water, make sure you consult with a qualified plumber.

A woman tests the temperature of the water in a shower.

Tempering Valves vs Mixing Valves

To clarify, a tempering valve, also known as a hot water tempering valve, is a type of mixing valve.

It specifically blends cold water with hot water from a storage system to achieve the desired water temperature.

Mixing Valve Defined

A mixing valve is a component used in plumbing to combine hot and cold water to reach a specific water temperature. It’s made up of a temperature-sensitive element that adjusts the flow of both hot and cold water based on temperature changes.

Thermostatic mixing valves (TMVs), a specific type of mixing valve, are designed to maintain constant water temperature in showers and baths. They protect shower users from potential scalding. They also help limit the growth of harmful bacteria by storing water at high temperatures.

When there’s a sudden drop in cold-water pressure, the valve’s temperature-sensitive element will stop the supply of hot water. This mechanism guarantees that the water from the tap or shower is never dangerously hot.

In a nutshell, mixing valves are vital for maintaining a safe, constant water temperature and the overall safety of a home’s hot water system.

Introducing Thermostatic Systems for Hot and Cold Water

A thermostatic system mainly operates based on a thermostatic mixing valve (TMV). It blends hot and cold water to secure a consistent, safe outlet temperature, serving as a top-notch safety feature to prevent scalding.

The TMV responds automatically to pressure or temperature changes in the water supply, adjusting the mix of hot and cold water.

The key part of the valve is a temperature-sensitive element, which expands or contracts based on the water temperature, influencing the water mix. Therefore, the thermostatic system keeps the balance of hot and cold water, delivering a stable outlet temperature.

Distinguishing Thermostatic and Non-Thermostatic Mixers

A non-thermostatic mixer merely combines hot and cold water depending on the user’s manual setting, without automatically adjusting to keep the temperature constant.

However, a thermostatic mixer system has an in-built thermostatic valve that stabilises the temperature, irrespective of any water pressure fluctuations.

A steaming hot shower

What is a Thermostatic Shower?

A thermostatic shower, incorporating a thermostatic mixer, has been touted as the best quality showering solution for those seeking safety and control. Its rock-solid temperature stability, even when other outlets are in use, makes it a favourite pick.

Furthermore, the addition of a thermostatic mixer means these showers can act swiftly to neutralise any harmful bacteria that may breed in stored water. With this, a safer and healthier shower experience is guaranteed.

Debunking the “Thermostatic = Electric” Myth

While the term “thermostatic” might seem like it’s associated with electricity, it’s not. It refers to the ability of the device (in this case, a valve or mixer) to regulate temperature with impressive accuracy.

However, some thermostatic showers or mixers do use electrical components to enhance their performance, but this is not a necessity.

Final Thoughts

While the features of thermostatic mixers and tempering valves diverge to some degree, both are indispensable in regulating water temperature for safety and comfort. The choice between the two often comes down to a user’s preferences and specific needs.

Consulting with a licensed plumber will further guide you in navigating the world of thermostatic mixers and valves and making the best selection.

Remember, whether it is the installation of a new shower, bath, toilet or entire bathroom, it is critical to appreciate the roles these valves play.

After all, even the smallest parts can make the biggest difference in delivering the best quality for your home.

Please note: This information is provided for advice purposes only. Regulations differ from state to state, so please consult your local authorities or an industry professional before proceeding with any work. See our Terms & Conditions here.

Published: 2023-11-07

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