Is your hot water safe?

What is a tempering valve?

Tempering valves are control valves that maintain the hot water temperature at a set level. The valves consist of thermal sensors that react to temperature changes. Hot water from your heater flows through the tempering valve wherein the temperature is lowered by adding just the right amount of cold water. The valve closes and water is delivered to your tap.

Why are tempering valves mandatory?

Many fresh water sources naturally contain small amounts of a bacteria called Legionella which grows best between 20 – 60°C. To keep the water safe from the rapid growth of legionella bacteria and prevent Legionnaires’ disease in humans, hot water needs to be maintained above 60°C in storage. However, if the water is delivered to the tap fixtures at this temperature it can quickly cause scalding. That’s why tempering valves or TMVs are installed, to safely reduce the temperature of the water to 50°C or 45°C.

Legionnaires disease is a type of severe pneumonia which can be fatal in some cases. People above 65 years of age, smokers, chronic lung disease patients or people with a weak immune system are at high risk for Legionnaires disease.

Can I install a tempering valve myself?

Installing tempering valve requires expertise and it is definitely not a DIY job as it can be dangerous if done incorrectly. Only qualified plumbers can install tempering valves – Ryan Old Plumbers have expert plumbers who can do the job correctly the first time. Call us now for installation, testing or repairs for your tempering valve.

Regulations for tempering valves

• Tempering valves are required for bathroom renovations, new builds, hot water system installation and new pipings.
• According to the Plumbing Code of Australia, hot water tank temperature needs to be maintained at or above 60°C.
• Tempering valves are mandatory to comply with the AS/NZS 3500.4:2018.
• For bathroom taps:
  1. The temperature of hot water should not exceed 50°C – in this case, tempering valves need to be installed.
  2. The temperature of hot water should not exceed 45°C for hospitals, schools, aged care centres, any facility for children, disabled or sick individuals need to supply – in this case, TMV needs to be installed.
• Restricting the hot water temperature for laundry and kitchen is optional.

Difference between tempering valve and TMV

Both a tempering valve and TMV mix hot water with cold water to prevent burns and ensure a consistent delivery temperature. TMV restricts hot water at 45 °C whereas tempering valves restrict water at 50°C. TMVs are used in commercial applications as they respond faster to changes in water temperature and pressure compared to tempering valves.

Types of tempering valves

• Blue Cap tempering valves are used for electric hot water heaters. It is used with electric hot water heaters that supply water between 65-75 degrees Celsius.
• Green Cap tempering valves are used for gas hot water heaters.
• Orange Cap tempering valves are used for solar and heat pump hot water
• Black Cap tempering valves are used for large capacity systems.

Contact the tempering valve experts Brisbane & the Gold Coast

Our licensed plumbers can install, repair and test tempering valves throughout Brisbane, Moreton Bay, Logan, Redland and Gold Coast. Contact us today at 1300 055 940 or complete our online job booking form.

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