Every week we have clients asking why we are required to install a TMV or tempering valve to their hot water system. The short, simple answer is because it’s the law.
The longer answer is because it’s about safety. A TMV or tempering valve reduces the risk of scalding. This is because storage type gas, electric, solar and heat pump systems are storing hot water at between 60° C and 75° C. You need to be aware a severe hot water burn can occur in one second when the water is delivered at 60° C or higher. Hot water burns like fire because:
- 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 happen after 5 minutes
What is a TMV?
TMV or thermostatic mixing valve installed by Whywait Plumbing
A TMV is a thermostatic mixing valve but is commonly referred to as a TMV. The role of a TMV is to mix hot and cold water together to provide you with hot water delivery at your tap that is at a consistent temperature.
When we install your TMV, we set the temperature to deliver the hot water in all bathrooms at 45°C in aged care or childcare facilities or 50°C in all other bathrooms.
A TMV is compulsory for use when used in common areas for aged care or childcare. A TMV is very accurate and very responsive to fluctuations in incoming water temperatures keeping the temperature to within 1° C of the temperature that it has been set at when we install it.
Accuracy of temperature in the TMV is delivered by a thermally sensitive element which expands and contracts in response to the temperature fluctuations of the incoming cold and hot water. This expansion and contraction regulate the temperature by controlling how much cold water mixes with the hot water. An added safety feature of a TMV is that if cold water flows become too low, they shut down to prevent 60°C plus water being delivered.
What is a Tempering Valve?
Non-compliant tempering valve installation connected with flexihoses replaced by Whywait Plumbing
A tempering valve’s role is also to mix hot and cold water together to provide you with hot water delivery at your tap that is at a consistent temperature.
The tempering valve is a simple three-way valve that is temperature actuated to mix the hot and cold water. These days most come preset at 50°C and when we install them, we test them by measuring the temperature of the water from your hot taps in the bathroom.
A tempering valve is commonly used in residential homes as a one-off valve at the hot water service. A tempering valve is slower to respond to temperature fluctuations compared to a TMV plus it will deliver water to within 3°C of the temperature that it has been set at when we install it.
Which Valve do you Require?
The Plumbing Code of Australia in AS/NZS 3500.4:2018 is very specific about water temperature is section 1.11, which states:
- To avoid the likelihood of legionella bacteria growth, an installation shall store water at a temperature of not less than 60°C
- All new heated water installations shall deliver heated water not exceeding 45°C for the aged, the sick, children or people with disabilities in healthcare, aged care, early childhood, schools and nursing homes. For all other situations, heated water shall be delivered not exceeding 50°C.
Ultimately when we are installing a temperature control device, we are legally obliged to comply with the requirements above and much more as they are prescribed in AS/NZS 3500.4:2018.
Overall a TMV is more expensive to install initially compared to a tempering valve. However, a TMV has a much longer working life span compared to a tempering valve as they are more accessible to service and replace the working parts. A tempering valve, by comparison, is usually just replaced when it stops working as they are not easy to service or replace parts in.
In Queensland, all work undertaken on a TMV or tempering valve is reportable to the QBCC and must have a compliant Form 4 submitted. For your protection always demand a copy of your Form 4.
Replacing Your Hot Water Service – How Will You Know What’s Right For You?
When replacing your hot water service the most common question asked is what will it cost?
Whilst price is always an important consideration, at Whywait Plumbing believe that there are other equally important factors. This article will help you make an informed decision.
Should The Price of the Replacement Hot Water Service Be The First Consideration?
Besides renovating your home, replacing your hot water service is a major cost. It is often an expense that occurs with very little warning.
Unfortunately, unless you like cold showers, this gives you little time to carefully review available replacement options.
Hot water systems are not all created equal and the choice you make today will be one that lasts for the next ten to fifteen years. With ever-increasing energy costs impacting household budgets, having an efficient and well maintained hot water service has never been more important. A cheap hot water service may cost you a great deal more in ongoing expenses.
With So Many Hot Water Systems On the Market How Do You Know Which One To Choose?
With modern technological advances and the push for energy-efficient heating solutions, it’s no longer a matter of just replacing your hot water system with like for like. So how do you know which hot water service to buy?
Hot water services are available in electric, gas, solar and heat pump models, and all come in a huge range of sizes. Purchasing the right hot water service for your needs is something you should seek advice about from a qualified hot water specialist. With a little help from Whywait’s Hot Water Specialists you will be able to select the system that best suits your situation.
Hot Water Service FAQ’s
Before making any decisions about a hot water service replacement you will need to think about:
- What size is your current hot water service and have you ever run out of hot water with your current hot water system?
- Does your current hot water service operate on an off-peak electricity tariff?
- Are your hot water needs likely to increase, decrease or stay the same over the next five years?
- Do you intend to remain in your current property for at least the next five years?
- What is more important to you the initial up-front installation cost or the ongoing running costs?
- Is the quality of the product and length of warranty a consideration when comparing hot water services?
Once you have answered the above points it will be time to consider the available options.
If you are reading this because you have no hot water and wondering if having no hot water is a plumbing emergency, read on.
Generally speaking if you have time to look a problem up on a website it’s probably not a plumbing emergency (yet) so technically speaking, having no hot water isn’t exactly a plumbing emergency, but still……
Having no hot water is considered a same day guarantee situation for our plumbing business, but this may not be the case for other local plumbing companies.
Even though no hot water usually isn’t an emergency, at our Gold Coast business, Whywait Plumbing, we made the decision many years ago that we don’t consider hot water to be a luxury, so for this reason we offer a same day guarantee for situation where a household is without hot water.
So why haven’t you got hot water?
In our 40 year history at Whywait Plumbing, we have found the most common causes of having no hot water are:
- Faulty element or thermostat (possibly both)
- Relief valve constantly leaking
- Faulty tempering valve
- Off-Peak relay switch failing to activate
- Insufficient sunlight to heat solar hot water
- Demand exceeds capacity
- Leaking hot water service
Hot Water Troubleshooting Checklist
Follow the DIY check list below before calling for help
Locate your hot water service and check the following:
- Check for any leaks at the tank especially around the electrical box. (Do not remove the cover as doing this will expose live wires)
- If the relief valve is leaking activate lever until water runs out in a continuous flow, then return lever to original position and see if the leak stops.
- A faulty tempering valve usually results in tepid water rather than no hot water, you can test this by activating the relief valve and checking if the water in the tank is hotter than the water delivered at the taps.
- If your hot water service is connected to off- peak electricity check with your energy supplier to see if there has been any problems, in your suburb, with transmitting to the relay switch at your home.
- For solar hot water check for foliage blocking sunlight to panels, that panels are clean and if cloudy or wet that the booster switch is on.
Locate the meter board and check the following:
- Check the hot water switch is in the on position.
- Check for a tripped circuit breaker or blown fuse.
Emergency or not, having hot water that is not hot enough, or no hot water, can be unpleasant and inconvenient, however you will be happy to hear in most instances it is a simple fix.
If you’re thinking about replacing your hot water service and not sure what is best to suit your family then look out for next weeks Blog – Choosing a New Hot Water Service – How do I know what’s right for me?
Whywait Plumbing recommends that all adults residing in a household should at a bare minimum know:
- Where the main water isolation valve for the property is located.
- How to turn off the water at the water meter (usually located in a turf box on the property boundary).
- How to turn off the water at the hot water service.
- How to isolate the power to the house at the meter board.
Should an emergency arise where any of the above is required having this prior knowledge will allow the situation to be handled quickly and calmly allowing you to make the situation safe and minimising damage to the property.
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.
It is normally the routine of a knock on the door by a friendly “salesman” stating they were in your neighbourhood doing some work and that a neighbour had suggested they do the same “free check” on your hot water service.
This unsolicited pitch or a variation of it is a signature of rip-offs who prey on gullible homeowners, especially the elderly. They commonly show a great deal of empathy and concern and are only doing the “free check” of your hot water service as your neighbour had already had theirs repaired and were concerned for you.
In the photo on the left the anode on the left was replaced by Whywait Plumbing with the one on the right with the differences between old and new perfectly illustrated.
Take it from me knocking on your door and cold-calling is not a professional or viable way to market or operate a plumbing business. And yes to work on your hot water service you must be a licensed plumber. In all likelihood the person knocking on your door is not a licensed plumber or a licensed plumbing contractor and in our experience they are ordinary old con artists who have no experience or knowledge in servicing a hot water service.
Yes your sacrificial anode on your hot water service should be checked at least every 5 years. But if it has never been checked and your hot water service is over 7 years old you are wasting your time replacing it as the damage has already been done to your steel storage tank.
By Gary Mays