by Gary Mays | Mar 25, 2023 | Hot water tempering valve
Why Do I Need A TMV or Tempering Valve?
Every week, our clients ask us why we must install a TMV or tempering valve to their hot water system. The simple and straightforward answer is that the law mandates it. However, we would like to emphasise that the underlying reason is the safety of the occupants.
A TMV or tempering valve is an essential safety feature that reduces the risk of scalding. This is especially important in storage-type gas, electric, solar, and heat pump systems where the water is stored at high temperatures, typically between 60°C and 75°C. Understanding that a severe hot water burn can occur in just one second when the water is delivered at 60°C or higher is crucial. Hot water burns like fire because of the following reasons:
At 60°C, a severe burn can happen in 1 second.
At 55°C, a severe burn would take 10 seconds.
At 50°C, a severe burn would occur after 5 minutes.
Therefore, it is clear that a TMV or tempering valve is essential in preventing scalding accidents, especially for children, older adults, and people with disabilities who may be more vulnerable to hot water burns. Therefore, installing a TMV or tempering valve is not only complying with the law but also a responsible action towards ensuring the safety of your household or building occupants.
What is a TMV or Thermostatic Mixing Valve?
A TMV or thermostatic mixing valve is a device responsible for mixing hot and cold water together to provide hot water delivery at a consistent temperature. The TMV achieves this by accurately regulating the temperature of the water delivered to your tap.
When we install your TMV, we set the temperature to deliver hot water at a consistent temperature of either 45°C or 50°C, depending on the specific application. For example, in aged care or childcare facilities, the temperature is set at 45°C, while in all other bathrooms, the temperature is set at 50°C.
In common areas for aged care or childcare, a TMV is mandatory to ensure the occupants’ safety. TMVs are very accurate and responsive to fluctuations in incoming water temperatures, maintaining the temperature to within 1°C of the temperature that it was set at during installation.
The temperature regulation accuracy in a TMV is achieved through a thermally sensitive element that expands and contracts in response to the temperature fluctuations of the incoming hot and cold water. This expansion and contraction control the temperature by adjusting the amount of cold water that mixes with the hot water.
In addition to accurately regulating water temperature, a TMV has an added safety feature that shuts down if cold water flows become too low, preventing hot water at temperatures of 60°C or higher from being delivered. This provides an additional layer of safety, ensuring that the water delivered to your tap is always at a safe and consistent temperature.
This photo illustrates a TMV installed in a duplex unit to regulate all hot water from the Rinnai instantaneous gas hot water unit at 45°C where the occupant is in a wheelchair due to multiple sclerosis
What is a Tempering Valve?
Like a TMV, a tempering valve’s primary function is to mix hot and cold water to provide a consistent water temperature at your tap.
A tempering valve is a simple three-way valve that is temperature actuated to mix hot and cold water. Most tempering valves come preset at 50°C, and during installation, we test them by measuring the temperature of the water from your hot taps in the bathroom.
Tempering valves are commonly used in residential homes as a one-off valve for the hot water service. Compared to a TMV, a tempering valve is slower to respond to temperature fluctuations and will deliver water to within 3°C of the temperature it was set at during installation.
While a tempering valve may not provide the same level of accuracy and responsiveness as a TMV, it is still an effective and essential safety feature in preventing scalding accidents. By providing a consistent water temperature, a tempering valve helps ensure that hot water delivered to your tap is at a safe and comfortable temperature.
This photo illustrates that the handyman who illegally installed this hot water system did at least attempt to install a tempering valve; however, it is non-compliant as it has been connected with flexihoses which ultimately burst and required Whywait Plumbing to completely repipe the system and lodge a Form 4 compliance certificate.
Which Hot Water Safety Valve do you Require?
The Plumbing Code of Australia in AS/NZS 3500.4:2018 provides specific guidelines for water temperature control in various settings. For example, section 1.11 of the code outlines that to prevent the growth of legionella bacteria, water should be stored at a temperature of no less than 60°C. Furthermore, for specific settings such as healthcare, aged care, early childhood, schools, and nursing homes, heated water should not exceed 45°C for the aged, sick, children, or people with disabilities. For all other situations, heated water should not exceed 50°C.
As plumbing professionals, we are obligated to comply with the requirements outlined in AS/NZS 3500.4:2018 when installing temperature control devices. While a TMV may be more expensive to install initially compared to a tempering valve, it has a longer lifespan and is more accessible for servicing and replacing working parts. On the other hand, a tempering valve is typically replaced when it stops working, as it is not easy to service or replace parts.
In Queensland, any work performed on a TMV or tempering valve is reportable to the QBCC, and a compliant Form 4 must be submitted. We recommend that you always demand a copy of your Form 4 for your protection. It’s essential to ensure that any work performed on your hot water system complies with the necessary standards and guidelines to maintain the safety and comfort of the occupants.
The Paramount Importance of Safe Hot Water
In the complex realm of plumbing and water systems, it’s easy to overlook the subtle components that play a monumental role in our safety. The TMV or Tempering Valve stands as a silent sentinel, diligently working to ensure that our hot water usage is safe, preventing potential scalds and burns.
As we’ve unravelled throughout this discussion, these valves aren’t just a luxury but a necessity for every household. They bridge the gap between comfort and safety. In a world where the unexpected can happen in the blink of an eye, having a reliable TMV in place offers more than just regulated hot water – it provides peace of mind.
Ensure your hot water system is equipped with a functioning TMV or tempering valve and embrace the assurance of safety it provides.
by Gary Mays | May 5, 2018 | Consumer Issues, Emergency Plumber, Gold Coast Plumbing, Health Issues, Hot Water, Hot Water Heat Pump, Hot Water Solar, Hot Water Temperature, Hot water tempering valve, Plumbers Gold Coast, Plumbing Emergencies, solar hot water
A common question we get asked this time of year concerning hot water repairs is “Why is my hot water not hot enough?”
We find our clients tend to notice this problem predominately when showering and in most instances, the temperature of the water hasn’t suddenly changed. It’s more than when the weather is fresher, and we tend to increase the ratio of hot to cold water, and therefore, any fault that affects the hot water becomes more apparent.
Hot Water Not Hot Enough, Common Causes
When customers ask “why is my hot water not hot enough” we always provide as much information as possible.
In our 42 years of plumbing experience and as hot water specialists, we have found the most common causes of this problem are:
Let’s take a closer look at each of these possible problems.
Malfunctioning tempering valve
Tempering valves are designed to blend hot and cold water to deliver water at a constant temperature that does not exceed 50’C. If water entering the tempering valve contains small amounts of sand or other debris, this can become lodged in the filters of the tempering valve and affect the operation of the valve resulting in lukewarm rather than hot water. Read more about tempering valves.
Faulty hot water service
If your hot water service is older (usually 10-15 years) or you have overlooked regular maintenance, it could result in a problem with the heating system.
A hot water system fails most commonly at these points:
The element is the mechanism within the hot water service that heats the water with the thermostat being responsible for switching the element on and off. Any problem with either of these parts can result in disruption to your hot water.
The relief valve is responsible for releasing built-up pressure as the water heats. If this valve is continuously leaking, then you will lose hot water which in turn is replaced with cold water that cools the hot water stored in the tank.
Hot water demand exceeds the capacity
Typically if a tanks capacity is over 125L, then you would connect to one of the off-peak tariffs, which means that electricity used by the hot water system will be charged at a lower rate. While this makes for a cost-effective solution, it does come with some limitations as you do not have an unlimited supply and if for any reason your demand for hot water increases there is always the possibility that you could run out of hot water.
If you are finding the hot water in your household is consistently not hot enough, and repairs are not required, then seriously consider a more substantial capacity, new hot water system.
Help Is On Hand
Here at Whywait Plumbing, we don’t consider hot water a luxury, it is a necessity. So if you are experiencing a cold shower and asking yourself why is my hot water not hot enough, call us now for Same Day Service.
by Gary Mays | Feb 26, 2018 | Bathrooms, City of Gold Coast, Consumer Issues, Gold Coast Plumbing, Health Issues, Hot Water, Hot Water Heat Pump, Hot Water Legionella, Hot Water Solar, Hot Water Temperature, Hot water tempering valve, Plumbing Legislation, Sanden “Eco®” Plus Heat Pump hot water system
Perception is reality and nowhere is this truer for us at Whywait Plumbing than when dealing with the issue of hot water temperature and the possibility of a 
serious hot water burn.
Everyone has a different perception of how hot they want their hot water whether it is for cleaning or sanitation or personal hygiene use.
Recent research in the United States from the Johns Hopkins Bloomberg School of Public Health, confirms hot water heater temperatures are too high.
In Australia, most manufacturers preset the thermostats for hot water heater temperature at 60-65 degrees. This is dangerously high for a significant proportion of homes, presenting a scald hazard particularly for young children and the elderly. This is because literally hot water burns like fire because:
At 60°C, a serious burn can happen in 1 second
At 55°C, a serious burn would take 10 seconds
At 50°C, a serious burn would happen after 5 minutes
It is estimated a serious hot water burn causes an estimated 1,200 hospital admissions and 50 deaths per year. Young children and elderly adults have thinner skin which burns more quickly putting them at increased risk.
In Queensland, it is the law that hot water delivered to bathrooms used primarily for personal hygiene purposes be regulated by use of a tempering valve or a thermostatic mixing valve that does not exceed 50°C. This is due to the fact that in 1995 the laws were changed requiring tempering valves to be installed on:
all new homes having a hot water system installed
replacement or upgrading of an existing hot water system
or when moving an existing hot water system to a new location on the property
However, homes built before 1995 will frequently still have hot water being delivered at 70°C. It is estimated that 37% of homes still have older electric or gas heaters delivering hot water that presents a scald hazard that will cause a serious hot water burn in one second.
Frequently these homes are rental properties. Many landlords and real estate property managers are unaware that recent litigation has placed a ‘deed of care’ onus on them to ensure the safe delivery of hot water in domestic bathrooms used primarily for personal hygiene purpose.
The installation of a tempering valve is an acceptable solution to hot water scald prevention. Delivering hot water at a consistent temperature is difficult without a tempering valve. This is due to the fact that as a hot water tank is depleted through use then replenished and reheated, the water temperature will not be constant throughout the tank.
Despite a perception by many people, a hot water service thermostat is not designed to provide precise estimates of water temperature. Its purpose is to begin heating when the temperature drops below a set level and turn off when it reaches a set level. Without a tempering valve installed it is almost impossible to assess the exact temperature of hot water delivered from a tap.
The advantage of a tempering valve is that guesswork is eliminated as tempering valves are designed to blend hot and cold water to deliver mixed water at a constant temperature and thus reduce the risk of a serious hot water burn.
Unfortunately for plumbers, property managers, homeowners and property investors hot water has increasingly become a legal minefield with the duty of care provisions.
It is for this reason Whywait Plumbing recommend that you install a tempering valve and maintain it compliantly with annual testing.
by Gary Mays | May 26, 2012 | City of Gold Coast, Consumer Issues, Gold Coast City Council Plumbing Inspector, Gold Coast plumbers, Gold Coast Plumbing, Health Issues, Hot Water Heat Pump, Hot Water Solar, Hot Water Temperature, Hot water tempering valve, licensed plumber, plumbing inspectors, Plumbing Legislation
Gold Coast homeowners are increasingly subjected to allegedly “free compliance audits” by Gold Coast City Council plumbing inspectors. To justify their jobs in a depressed market with almost nil construction activity, Gold Coast City Council plumbing inspectors act like desperate door-to-door salesmen knocking on the doors of homeowners who have upgraded hot water systems. There is no legislative requirement for these audits to occur, and the homeowner does not need to allow them to enter their home.
To fill in time and justify their jobs, Gold Coast City Council plumbing inspectors are undertaking “audits” that are not requested and are unannounced. The plumbing inspectors are knocking on the door and stating they are there to inspect the hot water service. Legally they can assess the work if invited to do so by you. No Gold Coast plumber is asking them to evaluate the work, as none of us sees any value in doing so. Neither Gold Coast City Council nor its plumbing inspectors take any risk or responsibility, so their inspection is of no real value except to justify their jobs.
If Gold Coast City Council plumbing inspectors arrive unannounced at your door, he has no right of entry. He may request access by your invitation to inspect work that pertains to the form 4 plumbing contractors are legally obliged to lodge, but that is the absolute limit. If you refuse him entry, then he must immediately depart.
Unfortunately, the plumbing inspectors are loose with the truth and make out that they are legally obligated to undertake this audit. They do not inform homeowners that it is optional and not a legislative requirement.
The individual plumbing inspectors are not to blame for these events but are forced to do so as they work in an appalling atmosphere at Gold Coast City Council. It has been common knowledge within the plumbing industry for many years that the Gold Coast City Council plumbing inspectors are a deeply troubled organisation with bullying, abuse of power, nepotism, cronyism and double standards a daily occurrence.
Several clients of Whywait Plumbing that have received these unexpected visits were shocked when we phoned to say their hot water service we installed six months ago has had a defect notice issued. In every instant, as long as Whywait Plumbing receives the defect notice, we undertake the “repairs”, which invariably are that the tempering valve legally required to deliver hot water at 50 degrees is over temperature. To date, every home we have returned to is between 1-3 degrees over temperature. To see more information on the requirements of tempering valves and your obligations, click here.
Many of our clients have told us that they do not want the plumbing inspectors returning to their homes to re-audit. This we have conveyed via email to Gold Coast City Council plumbing inspectors on behalf of our clients. As a result, we had a phone call from the Gold Coast City Council Plumbing & Drainage Supervisor, Brian Till, recently, who informed us we should be encouraging our clients to have the re-audit undertaken; otherwise, we will remain responsible for the defects despite our notifying Gold Coast City Council that rectification work has been conducted.
Furthermore, Brian Till advised that the property will have registered against the title that there are outstanding plumbing defects which can have severe financial repercussions if you wish to sell your home.
If you get an unexpected knock on the door from a Gold Coast City Council plumbing inspector, we recommend you decline to allow them entry to your home. However, declining access does not affect you as they walk away, and the file is closed.
However, suppose you have had a defect notice issued. In that case, we recommend allowing a re-audit at a time that is suitable for you to ensure no defects are registered against your property. If you desire, we will attend at no cost to reassure you and ensure that due process is complied with.
