• ico clock Open 7 days
  • ico clock 5 star service
  • ico clock Same day plumbing service
  • ico clock Open now
Phone icon Look no further. Call us now! 1300 13 80 80
October 29, 2021



For decades now, Tempering Valves have been a fairly standard item you’ll generally find adjacent to your hot water service. Tempering devices, much to the displeasure of some, are essentially the final line of defence against scalding water burns that, in principle, may occur during the usage of nearly all domestic washing fixtures.

So, what is a tempering valve? It’s a small tee-shaped device that diligently balances hot and cold water to deliver up to 50°C temperatures through to your showers, sinks and baths. As such, these valves have been a requirement by law due to years of case studies on domestic hot water-related burns that particularly affects children and the elderly.

How does a tempering valve work?

Tempering devices function on the premise of a sensitive element that expands and contracts based on the incoming supply temperature from the hot water unit. So, if your hot water cylinder is 70°C and after a 10-minute shower drops down to 60°C; Tempering devices will constantly adjust the hot flow to accommodate the loss of tank temperature whilst consistently balancing cold supply to regulate a safe 50°C property temperature range.

Why must you have a tempering valve?

‘But, we don’t have kids, and there are no elderly residents here….’

The simple facts are:  Third-degree burns can easily occur under unrestricted hot water temperature conditions.

Scalds can arise in the following temperature/time scenarios:

70°C+– 1 second

60°C– 5 seconds

55°C - 30 seconds

50°C and below – 2 to 5 minutes

The severity of a general scald or third-degree burn requiring medical attention is dependant on both contact time and sheer supply of heat which is precisely why The Pied Plumber, in these cases, leaves no stones unturned when it comes to hot water safety.

Why must you have a tempering valve?

Unfortunately, there’s road block in the form of Legionella bacterial growth within hot water tanks should the temperature be turned down. This is the exact reason why your hot water thermostat won’t operate below 60°C as ingested bacterial growth can eventuate into Legionnaire’s disease. So, if the hot water doesn’t send you to hospital, pneumonia might!

Are there different types of tempering valves?

Standard performance tempering Valves: Appropriate for most electric, gas and instantaneous hot water installations.

Blue – Ideal for most electric hot water systems

Black – Designed optimally for lower flow or gravity hot water systems

High-performance tempering Valves: Designed for higher demand tempering installations

Green – Manufactured mainly for instantaneous and high demand gas installs.

Yellow/Orange - Found on all solar installations along with most commercial boiler units. Yellow or orange caps indicate these variants of tempering valves.



Are there any exceptions to 50° temperatures set at tempering devices?

Absolutely, you can go under 50 degrees. Although, we wouldn’t recommend this! However, certain justifiable exclusions exist for kitchens and laundry tubs – these facilities are considered in the AS3500 Australian plumbing Standard as cleaning fixtures rather than wash down areas like baths, showers, and sinks. To attain high temperatures in these cases, special hot water pipelines must be installed straight from the hot water unit, essentially bypassing the tempering mechanism.  Oftentimes, when a new installation has been undertaken, these tasks are not achievable without significant pipe rerouting and is placed in the too hard basket for most properties. Where these exceptions apply are predominantly for new builds where plumbing can be appropriately designed and tailored to suit.

At The Pied Plumber, we love to chat – So if you have any queries related to tempering valves and their operation, we’re a call away! 1300 13 80 80