Having hot water is essential to have in every household or business. When hot water works efficiently, cooking, cleaning, and general washing are easy. It all starts with the water temperature and hot water systems.
A hot water unit is built to produce heated water throughout your property safely and economically. Your tank has many components allowing water to flow to every tap and fixture.
When you have your hot water system installed, one part that is crucial in ensuring the safety of your water tank is a TMV or Tempering Valve.
The tempering valve has a temperature-sensitive element that mixes hot and cold water at an adjustable ratio and then is piped to the bathrooms or house. The hot water mixing valve mechanism is a sliding valve within the tempering valve that works to vary the ratio of hot and cold water allowed to pass. Hot water stored in a hot water storage system should be kept at a minimum temperature of 60°C. However, water should be delivered through a faucet at a maximum of 50°C. It also maintains a constant outlet temperature, reducing the risk of accidental scalding and bacterial infection in your storage tank.
Homes that use tankless continuous flow models hot water don’t need a hot water mixing valve as there is no stored hot water prone to Legionella bacteria growth.
Usually, hotels, schools and other high-risk locations, including health and aged care facilities, are the only establishments that install a Thermostatic Mixing Valve (TMV). A Black Cap Tempering Valve is most commonly used for large-capacity systems.
When your tempering valves fail, like any mechanical item, this can cause various issues and may even prompt you to hot water system replacements. You can encounter a complete loss of hot water supply, a lack of pressure or a reduced hot water temperature. You can also experience leaking around the tempering valve connections, which can be challenging for the untrained to detect this problem.
How Does A Tempering Valve Work?
The hot water tempering valve works by mixing both hot and cold water. It produces the safest water temperature in your hot water unit. If the valve works correctly, people are not burned or scalded by the temperature of the water, also for personal hygiene purposes. This means the hot water system should have a tempering valve installed.
According to Australian Standard AS3500.4.2 Clause 1.6, the water temperature from the taps must not exceed 50 c. To prevent bacterial growth, like legionella bacteria, from developing inside the tank, the tank temperature must always be at 60 c. This includes solar, electric, gas and heat pump hot water systems with storage tanks.
Tempering valves work by allowing the 60 c water inside the unit to be mixed with cold water and then safely flow out of the faucet with a water temperature of 45 c to 50 c.
For some institutions such as young, aged, sick and disabled facilities, e.g., nursing homes, the maximum delivery temperature should not exceed 45 c.
Where Are Tempering Valves Located?
A tempering valve is located externally on the hot water system. It is installed between the cold line and the hot water line.
Coldwater comes through the inlet valve from your water supply, travels to the hot water tempering valve, mixes with the hot water, and then releases tempered water to your bathroom, kitchen and laundry taps.
Do You Need A Tempering Valve?
You do need a tempering valve on your hot water system. In the late '90s, regulators made fitting tempering valves mandatory on new installations of water heaters or replacement hot water systems, a legal requirement that ensures your tank complies with the Plumbing Code of Australia. The plumbing code is a great idea, as it helps stop kids from being scalded by hot water. Young skin can be burnt by water at 60 degrees in seconds. Water at 50 degrees would take minutes to inflict a severe burn.
Your trusted plumbing company will be able to install the correct valves for you with any new hot water tank installation.
What Is The Difference Between A Tempering Valve And A Thermostatic Mixing Valve?
A tempering valve and thermostatic mixing valve or TMV combine hot water with cold water to provide a safe temperature for water usage. And although they both work with the same idea, there are some differences between them. These are,
- There is a price difference, with tempering valves being cheaper than TMVs
- To install a TMV, a licensed plumber must carry a licence specific to installing thermostatic mixing valves
- A tempering valve is slower to respond to changes in temperature than TMVs. This is why facilities like nursing homes and hospitals can only have a TMV installed. They need a lower temperature of 45 Celcius, so a tempering valve is not suitable
- TMVs do not last as long as tempering valves
So if you suspect the tempering valve could be the problem or if you notice your hot water tap is immediately running hot, don’t wait for it to go to boiling point and endanger anyone. It’s time to contact a plumber or your trusted hot water specialists. TMVs must be tested annually to ensure the hot water temperatures remain suitable and safe. And to also see if the valves are fully compliant and functioning correctly. The good news is replacing a tempering valve is much cheaper than the entire hot water system. Call a professional and licensed plumbing company to assist you with your hot water tank repairs and hot water system replacement. Call Fixed Today if you need to install a new hot water system. We can install gas, electrical or solar hot water systems correctly.