Tempering Valve

Hot Water Tempering Valve

A tempering valve restricts the temperature of hot water that is delivered into your home from your hot water system, which helps to prevent injuries such as scalding.

In many Australian states, you are now required by law to install a tempering valve when you install a new hot water heating system. While your tempering valve may have the ability to be set higher than 50^OC, this goes against Australian standards.

The tempering valve is fed by the hot water and cold water pipes and mixes the hot and cold water with a temperature monitor that makes sure that the temperature doesn’t go above 50ºC.

Using a temperature sensitive element submerged in water, the thermostatic element, the 3-way mixing valve can selectively open and close pipes to allow hot and cold water in. It does this by expanding and contracting in response to temperature changes. This controls a piston which opens and closes the hot and cold inlet pipes, thus regulating the temperature.

The ratio of hot and cold water is varied so a temperature of 50ºC can be achieved. Tempering valves are accurate within 3ºC.

Your plumber sets your hot water storage tank to heat water to a minimum of 60ºC and installs a tempering valve after this, set to 50ºC. By mixing cold water to temper your hot water down to 50ºC, you decrease your hot water usage and thus decrease your hot water demand.

Where You Will Find a Tempering Valve

Tempering valves are typically designed to be installed near the hot water system. Most can be installed in any orientation, vertical or horizontal, and have regulations related to installation distance depending on the type of water heater. Pressure reducing valves may be installed where necessary, and most tempering valves require isolating valves on both inlet sides as well.

Tempering valves are not needed on pre-set gas continuous flow hot water heaters because they are already set at 50ºC. Meanwhile, any storage system that heats water at a higher temperature must have a tempering valve. This is because the storage tank hot water heater must be set to at least 60ºC to kill off legionella bacteria.

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Professional Hot Water Maintenance

Only a licensed plumber, such as the experts at Metropolitan Plumbing, can install or replace a tempering valve. Due to the incredibly specific nature of fine tuning the part, you need an expert’s hand to set the hot water tempering valve to the correct temperature.

Plus, our technicians can also assess all aspects of a hot water system, including the pressure limiting valve.

The pressure limiting valve limits the pressure coming into the hot water system to 500 kPa. You only need this valve if the water pressure going into the system is too high. There is no need to limit the pressure that isn’t there.

24/7 Hot Water Service

Metropolitan Plumbing has experienced and local plumbing professionals who can service your current hot water system or put a new system in. If something goes wrong with your tempering valve we can be at your door within an hour* of your call – or any time of the day.

We also offer an exciting range of interest free payment solutions** so any hot water system repairs or installation can be done straight away. You can easily spread out payment options with either Humm, Zip Pay or OpenPay.

If you’re ready to get in control of a temperamental tempering valve, contact Metropolitan Plumbing today! We’ll have a plumber at your door in a flash.

How long does a tempering valve last?

You can expect your tempering valve to last somewhere between 5-8 years. However, regular inspections and maintenance will prolong the life of your tempering valve and identify problems before they can do any damage. Many tempering valve-related problems stem from a build-up of debris from your water heater. Water heaters should be flushed annually to prevent a build-up in your tank, and this will help prevent a build-up in your tempering valve as well. Furthermore, you can have an inline filter installed. This prevents debris from entering your hot water system in the first place! Older hot water systems are also prone to rust and build-ups which can affect your tempering valve.

What happens when tempering valve fails?

Tempering valves and the maximum 50^OC were introduced as an Australian standard to prevent scalds and burns caused by too hot water. As water temperature increases, the time to receive a third-degree burn decreases. Depending on the water temperature, you can receive a third-degree burn with varying contact times:

70^OC – 1 second for an adult, 0.5 seconds for a child
60^OC – 5 seconds for an adult, 1 second for a child
55^OC = 30 seconds for an adult, 7 seconds for a child
Less than 50^OC – approximately 5 minutes for adults and children

Most tempering valves have a thermal shut-off feature when there is a problem with the hot or cold inlet supplies. This will shut off the outlet and stop the mixed water from leaving the valve.

Is Thermostatic Mixing Valve another name for a Tempering Valve?

Thermostatic mixing valves do the same thing as a standard tempering valve. They keep the water below scalding temperature. But thermostatic mixing valves (TMVs) have a quicker response to pressure and temperature changes. Because they are more sensitive and reliable, TMVs have to be put in at places like schools, child care centres and nursing homes where they are set at 45 degrees.