hot water tank safety valve leaking quotation

So how much will water heater repair cost? The exact amount varies depending on the issues you’re facing, the time it takes to repair, and even the technician you hire.

The dip tube carries cold water to the bottom of the tank for heating. If the dip tube is corroded, blocked, or leaking, water heating won’t occur as efficiently.

The pressure relief valve makes sure your water tank pressure remains at safe levels. If pressure builds up too much, this valve opens to relieve some of that pressure.

If you notice that the valve is consistently leaking, it may mean that the tank’s pressure is too high, or you might simply have a faulty/clogged valve.

The function of the anode rod in your water tank is to prevent corrosion. It does this by taking on corrosion first—as long as the anode rod is corroding, your water tank and heating element won’t.

The thermostat regulates the temperature in your water heater. If there is more heat needed, it will turn on the heating elements. Once water is warm enough, the elements are turned off.

Electric heaters use a conductive metal element to heat the water. Therefore, if the element is corroded or stops functioning, you don’t get hot water.

Tankless water heatersare a relatively new technology that helps save you on water heating costs. Since they function quite differently from conventional water heaters, they will have their own unique issues.

Tankless water heaters require periodic flushing to keep mineral and sediment from building up inside the unit. Cleaning this buildup out will allow the unit to run more efficiently, so it’s recommended that you get your water heater tank flushed about once per year.

A leak from your water heater’s pressure relief valve is a major concern, especially if it’s the first time dealing with this problem. While some people tend to panic and get help immediately, others may just shrug their shoulders and assume that the leak is a common occurrence. However, there are many causes of leaks in water pressure relief valves. And all these must be addressed immediately given the high risks of property damage and hazards that can occur if the issue is ignored.

The pressure relief valve gives steam and water a chance to escape when either the pressure or temperature in the water tank gets too high. A malfunctioning valve can cause the water heater to explode and is the major cause of water heater explosions. In water heater pressure relief valves, the valve is set to open when the pressure exceeds 150 psi.

A leaking valve is not always a broken valve. In some cases, a water heater’s pressure relief valve may leak because it is functioning as intended. As excess pressure is relieved out of your water heater system, some water may leak. This necessitates the need to test the pressure in your water heater.

The process is not complicated. However, if you are not comfortable checking the water pressure, you can always contact your technician. To test the pressure, use a pressure gauge and attach it to either the cold-water pipe or the hot water pipe. However, one of the easiest places to connect the pressure gauge is the outdoor hose faucets. For this, ensure you purchase a pressure gauge that is designed for garden hoses.

Turn off all water outlets and faucets. The pressure reading should be between 40 psi- 80 psi. If the gauge shows a psi reading of 150 and above, then the cause of the leak could be high pressure. If the water pressure is normal and the leak is persistent, then high water pressure is not the cause of the leak.

If you get a high-pressure reading, then you could be dealing with a closed plumbing system issue. This means that when the water is heated, the pressure increases as it should. But with nowhere to go, the valves open to relieve the pressure. Luckily, this can be solved by installing an expansion tank that gives the pressure an outlet other than a pressure relief valve.

Although rare, your water heater’s pressure relief valve could be leaking as a result of excessively high temperatures. However, the water has to be near the boiling point. To check the water temperature, ensure you turn on the hot water faucet. Run the water for one minute and use a meat thermometer to take the temperature reading. The temperature should be around 120 degrees. If more than this, then you need to have the water heater checked. The water temperature would need to be close to 212 degrees to set off the relief valve.

While this is an uncommon occurrence, it is not far-fetched. Your technician could have used a pressure valve for another appliance since they have the same function. However, these other pressure relief valves are set to go off at a lower psi. For instance, boiler pressure valves go off at 30 psi. If installed in a water heater, you are likely to get leaks immediately after installation. As such, if you have had your water heater for years and only experienced the leaks after a long period, then this is an unlikely cause of the leak.

A slight leak may occur if your water heater’s pressure relief valve has not been opened for a while, say a few years. While this leak is normal and may not be an indicator of a problem with the water heater system, you may need to replace the valve if the leak becomes more serious. It is cheaper to replace the entire valve than to repair it and have to deal with the same problem later on.

A leak in your water heater’s pressure relief valve could also be caused by a faulty pressure relief valve. While pressure relief valves barely break down, excessive wear and improper installation can cause extensive damage. Unfortunately, a faulty pressure valve can not be repaired and must be replaced. However, the cost of pressure valves is affordable and ranges around $30.

Know your water heater and how it functions– Water heaters can be intimidating, especially for people with less technical know-how.  Understand what every part of the system plays in heating water such as the water shutoff valve, drain valve, thermostat, and pressure relief valve. This eases the maintenance routine and ensures you have a fair understanding of any malfunctions.

Insulate the pipes and the water heater– By insulating both the cold water and hot water pipes, you get to prevent condensation while also reducing heat loss. Also, insulating the water heater helps to keep water hot when surrounded by cold air.

Carry out regular maintenance– Inspect your water heater monthly, ensuring that all valves and pipes are in good shape. This also helps you catch corrosion and leaks early enough before they turn out to be bigger problems. And every year, carry out a water heater flush. Given that you cannot pinpoint all problems, have a qualified technician inspect the system annually.

Regardless of the possible cause of a leak in your water heater’s pressure relief valve, please contact a qualified plumber as soon as possible. And if you think it’s a problem that you can solve without getting help, ensure you have a qualified plumber confirm that the system is performing optimally after. Water heater issues should not be taken lightly as they can cause more issues, even explosions.

Any water-related system in your home is at risk of leaking, even your water heater. Traditional water heaters, as well as those used in RVs, are always at risk of leaking, especially when they are subjected to neglect. In fact, this is one of the most common issues that a water heater owner will face.

If you don’t properly maintain the water heater you have, leaks will be the least of your worries. Your unit may produce weird noises, not drain, or worse, it may even explode. It’s the same way that you need to ensure proper maintenance is undertaken to avoid roof leaks.

But if your only concern is leaking on your unit, whether it is from the topor bottom, it may go both ways. This may either be easily fixed by a professional, or it is a sign that your water heater is about to fail.

Water heaters have intricate systems, but all these are not failproof and that’s why they leak in various places. If you are familiar with your plumbing system, you know that the leaks on it are often found on the piping and fixtures only. But in the case of water heaters, they can be found in various parts, such as the overflow pipe, hot water outlet, drain valve, cold water inlet, and temperature and pressure relief valves, commonly known as T&P relief valves, among others.

Since there are many parts that are at risk of leaking, identifying the source becomes much more complicated. But for this article, we will just concentrate on leaks coming from the pressure relief valve.

If you already have a professional to check the leak on your water heater and it is determined that the leak is coming from the relief valve, this can also mean one of two things: either it is doing its job or it is actually leaking.

T&P valves have an important job – that is, they are responsible for keeping a water heater safe for use. They are designed to release water when the pressure or temperature inside the tank is already too high and has reached dangerous levels. This water deliberately removed from the unit is what many people mistake as leaks.

Despite this feature, pressure relief valves are not immune to malfunction, including leaking. Oftentimes, only professionals can make the distinction between a leak on the pressure relief valve or water released as a result of this standard safety measure. A malfunctioning valve is usually the culprit if the professional confirms that it is indeed a leak. Luckily, this is a replaceable part.

If you have had your pressure relief valve replaced, yet it is still leaking, this may still be either a safety precaution and you need to have some settings of your water heater adjusted, or there is a problem with one of the components related to it.

Any kind of leak on a water heater must be resolved immediately, including those that come from pressure relief valves. That is, if it is a confirmed leak.

Confirmatory tests are important if the pressure relief valve is suspected to be leaking; a plumber needs to know whether the water heater is just doing its job or it really has an issue that needs to be remedied. You don’t want to have your pressure relief valve already tampered with or replaced prematurely just because it is doing its job.

Unlike in other leaking components, there are plenty of tests to confirm whether a leak is due to the pressure relief valve working properly or not. If you are curious about these tests, fret not. We have a guide on how contractors usually do this:

Open the faucet that is nearest the water heater and allow it to continuously run until the temperature of the water is at its highest; this will take a minute on average. The contractor will then get the water temperature and if it is below 200 ˚F, it is functioning well. Otherwise, this is a sign that the valve might open soon because the standard set temperature for them to open is 210 ˚F.

Observe the physical appearance of the pressure relief valve. Signs that a contractor will look out for include the formation of limescale or other sediments on the valve, the presence of rust within close proximity of the valve, or the valve letting off steam intermittently. If these are present, the leak is likely a result of a failing pressure relief valve.

Using a water pressure meter, the contractor will gauge the amount of pressure available in the water system. He or she will attach the device to a hot water faucet in the same room or location where the unit is located, such as the basement, and turn it the maximum level.

The meter will show the pressure as water flows, and it should be around 60 to 80 psi (pounds per square each). If the meter shows a higher reading, reaching around 150 psi, this is a warning sign that the T&P valve of your unit may open soon.

A contractor will also test the actual valve through its rocker arm; he or she will test if water is released when it is raised up. This part should also snap back to its original position once he or she lets it go and water should also stop flowing from it. If all these conditions are not met, the culprit for the leak is a malfunctioning valve.

Another test is to measure the pressure while hot water is being used. To do this, the hot water in the tank must be used up and only half should remain afterwards. The contractor will measure the pressure on the valve while it reheats the water remaining inside the tank. If the pressure is 80 psi or above, thermal expansion is taking place and this may be the likely source of the leak.

The contractor will also check the connections that are directly connected to the pressure relief valve. Leaks that may seem to originate from the pressure relief valve may actually come from loose connections and nearby parts. If all connections seem to be in order, the fault lies on the pressure relief valve.

Other methods may be done by your contractor to determine if the leak is indeed a result of a failing pressure relief valve. Once the leak is confirmed to be coming from this valve, the water heater must be completely shut off as a safety precaution.

Have you ever heard of horror stories of basements being flooded, which can also cause water damage to hardwood floors among other things? Would you believe that a common culprit for this is a small leak that has been underestimated and left unattended or unrepaired?

Unfortunately, this is not the only thing that can happen when you overlook having leaks on your water heater repaired. Aside from being an inconvenience, as you may have to frequently mop up puddles of water, they do possess some real dangers and may also result in you having to shell out large amounts to repair not only your water heater but also the damages it brings to your home.

Fires may start when water from these leaks come into contact with electricity– we all know that mixing water and electricity is always a bad idea. Your electrical appliances and wirings may experience a short circuit when they come into contact with water, and this may cause fires. You should periodically have your wiring checked by a licensed electrician since mice and other animals could be eating away at them.

Puddles of water may cause accidents– leaks are the most common culprit why you see puddles of water all over your floors. If you leave it there, anyone who fails to notice it may step on it and slip up. And if you didn’t know, this is actually the most common accident that occurs at home.

Leaks may be a sign that your water heater is at risk of exploding – if you remember, we mentioned that water heaters may explode and not a lot of homeowners know about it. What they also don’t realize is that leaks may also act as a warning signal that this will happen if you do not get it fixed the soonest.

It will also cause a lot of damage… to your budget – let’s face it. Doing maintenance and repair works on any water heater can be expensive, that’s why a lot of people hold off doing so. They believe leaks are not a serious issue and they can postpone doing repairs on them without affecting their everyday lives. What they don’t know is that the longer they put it off, the more expensive it will be to repair them. Leaks will worsen if left untreated. It’s not unheard of for people to be charged thousands of dollars for it if serious water damage happens.

These are just some of the major risks involving leaks on water heaters, in general. Most leaks will not have that much of an effect in the beginning, but this is not the case for leaks originating from the pressure relief valve.

For this type of leak, you need to address it as soon as you discover its presence. This valve is responsible for the safe use of water heaters, and leaks coming from it may be a sign that it can no longer do its job properly.

Leaks coming from the pressure relief valve are actually the primary indicator that it may not be functioning as well as it used to, compromising its ability to properly regulate pressure and temperature. Most importantly, it serves as the signal if a water heater is at risk of exploding.

In general, leaking parts of water heaters are repairable by a professional; this includes pressure relief valves. These repairs may be as simple as tightening the parts where the leaks are coming from, or replacing them altogether.

This is not the case for leaks that are confirmed to be coming from the tank of a water heater. If leaks of pressure relief valves are connected to the safety of water heaters when being used, leaks that are confirmed to be coming from the tanks of a water heater are involved not only in the safety but also its function.

A water heater tank is sturdy, yet it can also be considered as the most fragile part. It can last a long time and withstand constant use but when it gets damaged, you would already have to replace your entire water heater. That’s how vital this component is.

Fortunately, this is an easily preventable problem. All you need to do is have your water heater undergo periodic maintenance to remove the sediments that may settle inside and cause irreversible damage. Minerals and sediments found in the water are not something that you can take likely, as they are the biggest factors why a water heater breaks down.

Leaks from a water heater tank may also be mistaken as such, even if the water coming out is actually the result of the safety precautions of the unit. Just like the pressure relief valves, tanks leaking may just be an indicator that it is doing its job of safeguarding your unit properly. And if this is the case, a contractor will just have to set the thermostat to the right value to stop the leak.

For a leaking pressure relief valve, some basic troubleshooting may first be done by a contractor before doing the actual repair on a water heater unit. Among these are:

Gently raising the valve’s easing lever upwards for a number of seconds to possibly loosen up any sediments that may have gotten stuck. This is often done on leaks that are continuous and can be best described as dribbles. Leaks of this type are usually caused by sediments in the valve.

If the leak has a strong flow but only occurs when hot water is being used up, the water heater may just need to undergo a reset. For gas-powered ones, this is done by turning off the gas control via a knob found above the thermostat, while the switchboard will be used to turn off electric water heaters.

For leaks that seem to happen only at night and continuously flows, this may be attributed to pressure that is present that exceeds the amount the pressure relief valve can currently handle. To remedy this, a pressure relief valve may be installed, but never relief valves that have pressure ratings higher than the one used in your unit.

If these do not solve the leaking, a contractor will have to change the pressure relief valve, install an expansion tank to the water heater, or make use of both methods.

Drain it halfway, particularly up to the point where the water level is lower than the location of the pressure relief valve, by turning on a hot water faucet and letting it run continuously until the water flowing out of it is lukewarm.

Separate the drain valve and the T&P valve from each other using tools, such as a pipe wrench. Afterwards, you need to detach the actual T&P valve and separate the pressure relief valve.

Clean out any debris or residue that has settled inside the valve and a contractor will usually do this by soaking the temperature relief valve in a mixture of hot water and CLR cleaner. The pressure relief valve will not be soaked, since this will be replaced anyway.

Get the replacement pressure relief valve and wrap its threads with Teflon tape. Again, it is important that the new pressure relief valve has the same pressure rating as the one that will be replaced.

The T&P valve will be installed back to the water heater together with the drain valve, making sure that they are screwed into position as tightly as possible. Power and water may now be supplied back to the water heater.

If the issue persists despite replacing the pressure relief valve with a new one, the contractor will install an expansion tank to your water heater, especially if you use a closed loop system.

Do note that this may be done first or replacing the pressure relief valve may be completed initially; the order doesn’t really matter. Professionals are able to gauge which one will be more appropriate, but they will likely replace the pressure relief valve first.

Identify the ideal size of the expansion tank that will be connected to the water heater. They come in different sizes and will depend on the amount of water a water heater can hold. This means the more gallons a water heater can handle, the bigger the expansion tank that should be used.

Determine the ideal location where the expansion tank will be installed, taking into consideration the cold water line. Expansion tanks ideally should be placed in a wall or any sturdy location that is above and in close proximity to the cold water line, because this will allow water to be supplied to it much quicker.

Completely cut off the supply for power and water of the water heater. It is vital that only those who know how to will turn off the gas supply to avoid the buildup of fumes that can cause fires.

Mount the expansion tank to the chosen location, ensuring that the tank has been affixed properly to support its own weight. This is important because a poorly mounted expansion tank is likely to loosen up and drop, damaging the water heater itself and not just the expansion tank.

Identify which of the ends of the expansion tank’s threaded connector will correctly fit its tee fitting and wrap this particular end’s threads with Teflon tape.

An expansion tank will be able to help relieve the pressure on your water heater that causes water to leak out. More often than not, contractors will replace the pressure relief valve and, at the same time, install an expansion tank as an additional safety measure. In fact, some municipalities even require these tanks to be installed on residential water heaters.

Expansion tanks would normally be able to solve the issue at this point. But if there is still a leak, you may have to look into getting a pressure regulator installed.

Leaks that are still present, despite having a new pressure relief valve and expansion tank installed, is not considered a leak but an effect of the safety measures of the T&P valves. Water is still being discharged because of too much pressure on your water heater, and a pressure regulator is your best bet to already stop this.

Pressure regulators are capable of reducing the water pressure that gets inside the unit and maintain an ideal level of pressure to be used in the entire household. Pressure within safe levels will prevent water from being discharged as a safety measure of your unit.

If the leaking pressure relief valve has been resolved and is the only issue that your water heater is facing, there is no need for you to replace your unit just yet. Doing the different repairs and remedies we mentioned above will resolve leaks of this type.

However, there are some factors that you should consider to decide if doing these repairs are enough for your water heater or you need to look into just replacing it entirely. Among these are:

An aging water heater – if you’ve been using your unit for the longest time, maybe it would be best for you to replace it. Leaks may be the first sign of trouble for your unit and it will not be the only one as time passes, especially if you do not take steps to address it.

The leaking pressure relief valve is not the only issue– sure, you may have had all the issues on your water heater repaired. But, how long will you get headaches from it and keep having it repaired? If you think about it, having your unit checked out and repaired every now and then may already cost you nearly the same amount if you just get a new one.

It is no longer considered energy efficient – water heaters take up a huge chunk of your overall household bills and older units are generally not as energy-efficient and budget friendly as the new ones. If you believe that your water heater is consuming more resources than usual and forcing you to pay more than the usual amount for your bills, you should look into upgrading your unit to a more modern one that is much more efficient and budget-friendly.

If you noticed, a malfunctioning unit is not the only reason why you should think about getting a new water heater. Sometimes, it is actually a more economical option as well. You may believe that you get to save a lot if you use the same unit for the longest time, but the reality may be far from it.

In general, repairs on water heaters can be as low as $95 or reach as high as nearly $1500, averaging almost $550. They also typically range from $216 to $895, with the rate already including the cost of materials.

Professionals may charge from $45 to $150 for every hour of work for basic repairs, and their rates will also depend on whether the water runs on gas or electricity. Gas-powered units are a bit more expensive to repair than electric water heaters.

For leaks, the cost will depend on the complexity of the repair and a contractor may even charge as much as $1000. Leaks coming from the pressure relief valve are much cheaper, since a replacement valve costs around $20 only and the maximum rate a contractor may charge for the entire work, including checking the condition of the water heater and doing some maintenance work on it, is $200.

From the previous section, you can see that the main reason why repairs cost that high has something to do with the professional fees or rates being charged by a contractor. This might even be the most important deciding factor for you to go and have your water heater checked out or not.

By taking the time to fill out the form on this page, we’re going to connect you with the most relevant contractors in your area, that will then be able to provide you with free estimates or quotes for your water heater repair or replacement job, at absolutely no obligation to you — and it only takes 2 minutes to fill out the form.

This article explains hot water thermal expansion that can cause leaks, drips, or discharges from pressure relief valves, temperature/pressure relief valves, or TP valves found on heating boilers, water heaters.

Watch out: a dripping or frequently spilling T&P valve is dangerous because those very leaks can eventually cause the valve to clog and then to fail to open when it should.

See HOT WATER PRESSURE EXPANSION RATE - for an explanation of just how much pressure increase to expect when heating water. In explaining why the relief valve on a water heater may be dripping, American Water Heater Co. [1] explains:

Note: While a 125 psi pressure relief valve on cold water supply piping is fine to protect piping from rupturing, if building incoming water pressures are too high, rather than relying just on a relief valve (wasting water) we prefer to install a pressure reducing/control valve at the building entering water supply piping. Limit incoming water pressure to 60 psi at a typical one or two story residential home.

Watts (2011) suggests two methods for testing for thermal expansion of hot water as the cause of a TP valve drip. The text below is adapted from that source.

If the TPR valve is leaking due to thermal expansion of hot water, simply opening a water faucet or fixture anywhere in the plumbing system will immediately stop the drip.

That"s because opening the hot water faucet reduces the system pressure back to normal operating levels - we are no longer heating water in a "closed" piping and tank system.

Why would opening either a hot or cold water faucet work? Because when no water is running, the entire plumbing system is "closed" - unless there is an expansion tank already installed on the hot water heating system to accommodate thermal expansion, heating water in the water cylinder (water heater for Yanks) causes an increase in system pressure.

Install a pressure gauge on a convenient hose bib such as at the washing machine hook-up or if weather permits, outdoors. Install & use the pressure gauge to monitor system water pressure over at least a full 24-hour period. You don"t have to sleep by it.

If you select a pressure gauge with a re-settable "telltale" needle, the gauge"s re-settable indicator will indicate the highest pressure that has been reached by the water system since the water pressure test gauge was installed.

SeeMEASURE WATER SYSTEM PRESSURE & PRESSURE MAXIMUM for tips on how to make or buy an inexpensive recording-type water pressure test gauge for this purpose.

where we describe both hot water expansion tanks and hot water expansion relief valves designed to handle thermal water pressure increases and thus to stop dripping TP valves.

Watch out: get advice from a licensed plumber and your local water supplier. Never remove or plug a leaky pressure/temperature relief valve on a water heater - doing so risks dangerous or even fatal

See RELIEF VALVE LEAK DUE TO EXPANSION TANK where in a series of steps a homeowner figures out that a leaky TPR valve is due to the failure of the internal bladder of an expansion tank attached to the boiler.

If the building water pressure gauge reading is ever found at 80 psi or higher, you will want to install a water pressure regulator at the point where water supply enters the building.

If your building already has a water pressure gauge installed, it may be defective or it may be set too high. The articles listed just below discuss how to adjust a water pressure regulator:

An alternative to installing or changing a water pressure regulator when building water pressure is occasionally 80 psi or higher is the installation of an expansion tank to temporarily absorb that pressure increase.

Proper use of an expansion tank can help avoid unnecessary opening of the pressure/temperature relief valve on a hot water heating tank or a hot water heating boiler.

You go through alot of effort to explain how heated water expands and the resulting increase in pressure. All that is well and good for theory. In a domestic (North American) water supply system, to the best of my knowlege there is nothing to prevent the expanding water/pressure from the hot water heater from just backing up into the supply plumbing and hence the water pressure in the hot water heater would NEVER exceed the supply pressure. Or is there a required one way valve somewhere in the system I am not aware of say in the hot water heater?

Domestic water systems in most cities are required to have a backflow preventer or check valve on the system. So when no water is being run the system is in effect closed.

My original interest and intent was to show that the actual expansion in volume from heating water is actually very small. Nevertheless, on some systems, the water heater can cause enough of a pressure increase that some installations include a small water heater expansion tank.

Where expanding hot water pressure is causing trouble the common solution is the installation of a small expansion tank, usually on the hot water supply line above the water heater, though it could go almost anywhere so long as it"s not isolated from the heater by a shutoff valve.

Thermal expansion occurs as domestic water is heated. Left unchecked, the resulting pressure increase can cause relief valve discharge and other potentially hazardous conditions. Therm-X-Trol® expansion tanks absorb this expanded water, keeping water pressure at a safe level.

Water heater manufacturers and plumbing codes require the installation of an expansion control device if a backflow preventor, pressure reducing valve or check valve is installed in the domestic supply line.

Watch out: a leaky relief valve on a water heater, heating boiler, or any other closed vessel is dangerous. Leaks ultimately can lead to relief valve clogging, failure, and worse, BLEVE EXPLOSIONS. Beginning at RELIEF VALVE LEAKS we describe all of the causes of and cures for leaky relief valves or TP valves.

ANSI BS 7074-1:1989, Application, selection and installation of expansion vessels and ancillary equipment for sealed water systems. Code of practice for domestic heating and hot water supply (British Standard)

This standard covers the test methods and performance requirements applicable for waterheater supply shutoff valve with a thermal expansion control valves for use on closed plumbing systems.

This European Standard specifies, dimensions, materials and performance requirements (including methods of test) for expansion valves, of nominal sizes from DN 15 to DN 40, having working pressures 1) from 0,1 MPa (l bar) to 1,0 MPa (10 bar).Expansion valves are intended for fitting to the cold water supply of storage water heaters, having a maximum distribution temperature of 95 °C, for all energy sources.

Expansion valves do not control the temperature and alone does not constitute the protection required for storage water heaters. Expansion valves limit pressure, in the water heaters to what they are fitted, that is produced by thermal expansion of the water .NOTE : The use of the device specified in this Standard does not override the need to use controls (e.g. thermostats and cut-outs) which act directly on the power sources of water heaters.

"THERM-X-TROL® Water Heater Expansion Tanks", [web page] Amtrol,1400 Division Road, West Warwick RI USA 02983, Tel: 800-426-8765, Website: www.amtrol.com, retrieved 2017/01/08, original source: http://www.amtrol.com/thermxtrol.html

"THERMAL EXPANSION TANKS for POTABLE WATER, Installation & Operation Instructions" [PDF], Models ST-5 through ST-201V & Models T-5 through T-12, Amtrol, Op. Cit., retrieved 2017/01/08, original source: http://www.amtrol.com/media/documents/thermxtrol/9015087_06_16_Thermal_Expansion_Tank_IO_.pdf

the red-circled valve is a combination of cold water inlet shut-off valve and a drain intended to provide relief against excessive pressure in the water heater due to thermal expansion - as discussed on this page.

the red-circled valve is a combination of cold water inlet shut-off valve and a drain intended to provide relief against excessive pressure in the water heater due to thermal expansion - as discussed on this page.

Similar products manufactured by Watts are described at WATER HEATER THERMAL EXPANSION PRODUCTS - WATTS [PDF] https://inspectapedia.com/plumbing/Watts-Thermal-Expansion-Products.pdf

My hot water tank has a Thermal Expansion Control Valve installed on the cold water intake line (rather than an expansion tank). In the past 2-3 days, I have noticed that there is a small amount of water constantly draining out of this Valve/Tube.

The leakage is constant, even during/after a long hot shower, which presumably would drain a lot of the hot water out of the tank and temporarily stop any thermal expansion/condensation. It is important to note that the T&P valve on the water heater itself is fine, there is no leak or release of pressure/water happening there.

(Why else would it still leak when the hot water tank is being drained and cold water is entering the tank?). Wondering if anyone has any thoughts on this? I"m pretty sure I should be calling in for a repair, but unsure how urgent. (Am I at risk of a BLEVE explosion given the leak is constant, even when the tank should not be up to temp/pressure and even the pipe between the tank and the valve feels cold?).

It is possible on SOME water heaters to set the temperature above 210°F (99°C) but in my experience that would be unusual - you"d have probably scalded everyone using the hot water system.

1. It is already telling us that (usually) there is an unsafe condition such as pressure too high (water tank can blow up in a BLEVE explosion) or temperature too high (someone can be scalded - burned)

2. If it"s dripping just because the valve itself is old and defective the risk is that scale clogs the valve, it stops relieving, and then you"re missing a critical life-safety device.

the hot water heater has been shut down about one year , I lit the polite then went back a few hours later when I noticed the pressure relieve valve was spraying water out. so I shut the gas off. not sure what"s going on. ?

Continue reading at HOT WATER EXPANSION TANKS for a solution to thermal expansion leaks at relief valves on water heaters, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

THERMAL EXPANSION TPR VALVE LEAKS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

[1] "Residential Electric Water Heater Installation Instructions and Use & Care Guide", American Water Heater Co., October 2001, American Water Heater Co., Johnson City, TN, [manufacturer of residential & commercial water heaters, also manufacturer of Polaris/Commercial water heaters], Tel: 800-999-9515, web search 1/12/2012, original source: americanwaterheater.com/support/manuals/res-elect.pdf [copy on file] [Technical review requested 1/25/2011]

[3] Pounds of lime deposited vs. temperature and hot water usage: see Purdue Bulletin #74 (also provided by A.O. Smith in the article below). Purdue"s chart shows the number of pounds of lime deposited per year as a function of the water usage in gallons per day, with an assumed 10 grains of water hardness.

[4] "When, Why, and How to Remove Water Scale from Tank Type Glass-Lined Water Heaters (for non glass-lined tanks, consult water heater manufacturer)" PDF provided by A.O. Smith Water Products Company - hotwater.com/lit/training/4800r9.pdf 800-433-2545 - 01/07/2009.

[6] A.O. Smith"s Form No. 4778* All about Deliming Coil-Type/Tube-Type Commercial Water Heaters and Hydronic Boilers *Normally supplied when ordering Part No. 4930 Motorized Deliming Pump Kit

[7] "Building Owner Water Heater Safety Notice", Building Department, City of Colleyville TX, web search 09/24/2010, original source: http://www.colleyville.com/dmdocuments/Building%20

Water heater safety is imperative to the occupants of a building or structure. If improperly installed, water heaters can be detrimental to the structure, as well as being potentially fatal to its occupants. The proper installation of a water heater is so important that according to Texas State Law all water heater installations must be inspected by a state licensed plumbing inspector.

TECHNICAL REFERENCE GUIDE to manufacturer"s model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop Weldon & Associates

Here at we discuss temperature and pressure relief valves used on residential water heaters. We explain the function, inspection, and maintenance of temperature & pressure relief valves on water heaters used to produce hot water for washing and bathing.

We describe how to diagnose and cure just about every problem with T&P valves on water heaters and we describe how to inspect the hot water supply system for unsafe or improper Temperature & Pressure Relief Valve installation.

Here we provide ANSI and water heater standards and advice: water heater relief valve requirements. Water heaters: how to inspect, test, adjust, repair, and choose among types of hot water heaters.

We offer suggestions for Testing the Water Heater Temperature Pressure Relief Valve (TP Valve or "Safety Valve" or T&P valve or TPR valve) on a Water Heater.

We also describe Water Heater Safety Inspections - how to check the TP Relief Valve, and we warn about BLEVEs: Boiling Liquid Expanding Vapor Explosions at Water Heaters (or heating boilers).

To reduce the risk of abnormally high and dangerous pressures in the hot water system and to reduce chances of a dangerous explosion, water heater manufacturers, building codes, and independent standards require that a temperature and pressure relief valve be installed on the water heater - a T&P Relief Valve.

The T&P Valve installed on your water heater must be marked with a "set pressure" (the pressure at which the valve will open to relieve pressure) must be equal to or less than the maximum working pressure of the water heater.

This is an unsafe condition as the operation of the temperature or pressure relief valve may be interfered with by the insulation and also because the valve cannot be inspected for evidence of leaks or failure.

The water heater temperature/pressure relief valve is installed into an opening directly on the water heater at a location marked for that purpose, usually at or near the top of the heater (where water temperatures will be greatest).

For conventional residential and commercial water heaters of size 15L (4 US Gal) and larger, a pressure relief alone cannot prevent a water heater tank explosion.

Pressure relief valves are only intended for protection of tanks that are not heated - such as a well water pressure tank or a cold water storage tank. Where a pressure-only relief valve is to be used it should be installed as close as possible to the equipment it"s protecting.

The operating pressure and temperature ratingof a temperature/pressure relief valve must be matched to the input BTUh, temperature and pressure capacity of the calorifier, geyser, water heater and its physical volume.

On some very small point of use electric water heaters (1.5 - 3 KW heating capacity, and up to 15L / 5 USG water capacity) the relief valve may operate only on pressure and may be set to open at 6 bar (87 psi).

Question: I went and looked at a house today. On the water heater, there was a tag, it was red and white. It stated "notice of unsafe condition". However on the check boxes there was nothing checked IE stuff like CO or ignition risk. However, on the bottom it said "no water, copper through floor".

Christian, Without some photos or other details, I don"t know, but I speculate that if the discharge tube on the relief valve is piped down through the floor to a non-visible location, that"s improper & unsafe and may be what the tagged meant.

All pressure/temperature relief valves include a tag or label that indicates the valve discharge capacity in BTUs - heat energy discharge rate. The installation or technical data or data tags for all modern water heaters include the water heater"s BTU input rate capacity (and some indicate the specifications for the TP valve too.)

The Temperature/Pressure relief valve for a water heater must have a BTUh discharge rate (BTUs per unit time, such as BTUs per hour) that isequal to or greater thanthe BTU input rate of the heating appliance the valve is supposed to be protecting.[10]

at BLEVE EXPLOSIONS, it is the release of heat (or "temperature" or "energy") that prevents a water tank from exploding when it is being overheated, not the release of pressure.

The Temperature/Pressure relief valve mouth must point down, and a 3/4" I.D. (or greater) discharge tube must be attached to the T&P Valve"s opening and routed down close to but not touching the floor level, typically near a floor drain and stopping 6" above the floor.

Our photo above illustrates a T&P valve installed on the water heater top and connected to a discharge tube that passes outside the building through the wall.

This Tucson Arizona home installation disposes of any water heater T&P discharge outside to about 6" from the ground surface - not to a hidden location. And because there is no freeze risk in this climate the local installation was approved.

T&P valve discharge tubes are permitted to discharge below the floor of a structure but should not be piped to a hidden location where you won"t notice that the valve is dripping or leaking.

What is the minimum clearance distance that is required from the bottom of the countertop to allow the temperature relief valve adequate clearance? Is there a code spec for this?

Julie a look at installation details for TP valves on water heaters didn"t come up with an over-head clearance, though some common sense would indicate you"d need enough space for the test lever to be operated AND enough space to remove and replace the valve when needed.

Since a top-mounted TP valve has a temperature sensing stem that protrudes downwards into the water heater the removal space will be more than you think

On a small water heater (cylinder) the extension of the sensor is about 3" while on larger water heater cylinders that added length could be as much as 9" below the inlet.

Adding that 9" of sensor to the TP valve body and lever height (anywhere from 5 5/8" to 9 1/4") means the minimum (for the smallest valve size) valve total length is about 9" and the larger valve could be much larger.

Now we can slightly tip a valve to get it out of the heater, buy - I"d like to see 12" or more to give both working space and space to remove the valve.

Relief valve missing its discharge tube or drip line, also called an extension tube: this is an unsafe condition - someone may be scalded should the relief valve open.

do not install a temperature & pressure relief valve through any intermediary plumbing fittings. Doing so can cause the T&P valve to fail to operate safely when it should. For example, an air pocked in a coupling can prevent proper sensing of water temperature.

We inspected a hot water tank installation at which the installer actually cut off the temperature sensing probe from the T&P valve so that he could install it through an elbow. This was a stupid and dangerous modification. - Ed.

The discharge tube attached to the water heater pressure/temperature relief valve should be the same diameter as the opening of the valve itself. In our photo someone has fastened a 1/2" pipe discharge tube onto a 3/4" diameter relief valve.

Watch out: As our photo shows (above left), mineral salts left behind as hot water evaporates from the mouth of a pressure or temperature relief valve can completely clog the spring that is intended to allow the relief valve to open under excess (unsafe) pressure.

Water temperature: the water heater temperatures are excessive. In this case the TP valve is doing its job - find and fix the cause of too-high water temperatures in the system.

Incoming water pressure: the building water supply pressure is too high (over about 70 psi) or periodically water pressure fluctuates and is too high at times

at THERMAL EXPANSION TPR VALVE LEAKS A closed water system with thermal expansion and no means of relief can cause leaks at the pressure/temperature relief valve, such as

A deteriorated gasket inside the relief valve or corrosion on the valve seat can cause leaking at the valve; we find this mess occurring when someone lifts the "test lever" on a older P/T valve that has not been tested or operated for some time.

The increase in plumbing system pressure to a level that opens the TP valve is called "thermal expansion pressure". Watts suggests installing a bypass model water pressure regulator that lets the excessive pressure head back to the street main or building water supply system - a solution that only works if the supply pressure is lower than the T&P relief valve spill pressure - which it usually is.

Water hammer: water hammer or "banging pipes" can also be a source of relief valve drips and leaks. Water hammer causes a momentary very high pressure in the water piping system, sufficient to open a TPR valve for a brief time.

Watch out: a dripping or frequently spilling T&P valve is dangerous because those very leaks can eventually cause the valve to clog and then to fail to open when it should.

In 2020 five people, including a child, were killed after a hot water pipe exploded during the night, flooding a basement room with boiling water. The accident occurred on 20 January 2020 in the Mini Hotel Caramel, located in the basement of a residential building in Perm, Russia. - "Around the World", The Times of India, Times Global section, l p. 1, 21 January 2020. The Times added that at least three other people were hospitalized in the accident.

However there is at least one exception: it may be "normal" to see dripping from the relief valve of certain small 2-5 gallon point of use electric water heaters.

Some small point-of-use water heaters, such as some of Ariston"s Andris Lux point of use electric storage water heaters, include this statement in the water heater"s IO Manual:

Watch out: As our we cited above, mineral salts left behind as hot water evaporates from the mouth of a pressure or temperature relief valve can completely clog the spring that is intended to allow the relief valve to open under excess (unsafe) pressure. Ariston recommends that the water heater shown here be protected from hard water (water high in mineral content).

ariston.com retrieved 2020/04/12, original source: Ariston, Op. Cit., https://www.ariston.com/uk/Electric_Water_Heaters/media/files/830_Andris%20Lux%20UK%20Manual%202017.pdf

Technical note: why must the TP Valve point "down"? Take a look at the photo above. If a relief valve is dripping the deposit of minerals inside the valve will accumulate still more rapidly if the valve points to the side or upwards.

At RELIEF VALVES - TP VALVES we explain that in the photograph above where you see the plaster wall and the foam insulation sprayed around the lever, these form blockages of the test lever on the TPR valve.

Watch out: If the lift/test lever on a temperature/pressure relief valve is blocked from movement that prevents the valve from being tested - a step recommended at least annually by relief valve manufacturers.

Watch out: Depending on the relief valve model and design, a blocked relief valve test lever may prevent the valve from opening in response to pressure or temperature:

The pressure-relief component of a TP valve or of a separate additional pressure-relief valve should be at least 20 to 30 psi above the maximum working pressure in the system. Otherwise you will find occasional "nuisance dripping" at the relief valve due to normal water pressure variations or due to water hammer.

The standard opening pressure for TP valves on residential water heaters is usually 150 psi, and most water heater tanks also have a standard operating pressure of 150 psi.

If the building water supply pressure is above 125 psi, Watts recommends that a pressure-reducing valve be installed to reduce pressure to 40-45 psi so that a standard TP valve set can be used.[10]

Note: we recommend that for most conditions residential water pressure inside the building should not exceed 70 psi. We observe an increase of leaks and drips at faucets and toilets at higher building pressures as the pressure may exceed the design pressure of some plumbing fixtures.

Watch out: as we discuss above, dripping TP relief valves are unsafe. The hazard is that minerals in the water supply accumulate inside the valve during the passage of hot water through the valve assembly.

That accumulation of scale will eventually block operation of the relief valve, causing the relief valve to fail to operate properly if unsafe pressure or temperature occurs in the water heater in the future. The risk, ultimately, is a water heater tank or heating boiler explosion.

The water heater relief valve must be capable of discharging energy (as BTUs) at a rate greater than the input rate of the water heater"s energy source

You can easily verify the TPR valve on your 40 gallon water heater by looking at the information on the relief valve data tag and comparing that with the INPUT BTUH rating of your water heater.

Watch out: the typical water heater relief valve capacity rating and sizing charts assume that the heater is supplied with water at no less than 30 psi.

Because very low supply pressure means low pressure in the water heater tank which means that the valve may not open even at unsafe water temperatures or pressures for the equipment installed in your home.

Water heater relief valves must be listed or approved for their use according to the standards accepted by the country where you live. In North America those are SME, ANSI and CSA (AGA) standards.

Watts WATER HEATER TEMPERATURE & PRESSURE RELIEF VALVE SELECTION CHART [PDF] (1996) Watts Regulator, Water Product Division, Safety & Control Valves, retrieved 2020/11/15 original source: http://media.wattswater.com/F-SF.pdf

For gas, electric or oil storage water heaters under 200,000 BTU/hr. ratingand for compliance with any applicable water heater labeling requirements: Use3⁄4" T&P Valves tested under ANSI Z21.22 with ratings as certified and listed by CSA.

For gas or oil-fired storage water heaters between 200,000 and 730,000 BTU/hr.rating; and for compliance with any appli-cable water heater labeling requirements: Use 1" and over T&P valves tested under ANSI Z21.22 with ratings as certified and listed by CSA.

For ASME installations of gas or oil-firedhot water supply boilers heating domestic water for a storage tankover 730,000 BTU output; and for ASME installations of steam coil storage water heaters: Use 11⁄2" and over, T&P valvestested under ANSIZ21.22 with ratings as certified and listedby CSA.

These are abnormal and potentially dangerous conditions. First, they respond to excessive pressureby opening at the pressure set point of the valve, typically 150psi, to prevent further pressure increase.

Second, they respond to excessive temperature. When the temperature of the water in the water heater reaches 210°F, the T&P relief valve’s internal thermostatic element expands, lifting the valve’s disc off its seat to discharge the overheated water.

We can understand the huge energy release involved in a BLEVE explosion by a quick review of the extra energy required to change the state of water from a liquid to a gas.

At SEER RATINGS & OTHER DEFINITIONS in our discussion of BTUs (British Thermal Units, a measure of energy), we point out that while only 180 BTUs of energy are needed to raise one pound of water at 32 degF to 1 pound of water at 212 degF, a much larger amount of energy, 970 BTUs, are needed to raise 1 pound of water at 212 degF to 1 pound of steam vapor at 212 degF.

This figure is the latent heat of vaporization, the number of BTUs of energy used to raise one pound of water at 212 degF to one pound of steam vapor at the same temperature; in other words, the temperature is unchanged but the state of matter is changed from liquid to vapor. State changes involve large amounts of energy.

But if the safety valve has been damaged, modified, or even omitted (as we saw on our neighbor"s water heater), that condition, combined with overheating can cause a water tank to explode, creating a BLEVE - Boiling Liquid Expanding Vapor Explosion that releases tremendous force and causing extreme damage to a building.

Because repeated heating of the water tank bottom may combine with other conditions (such as corrosion or excessive heating due to mineral deposits on the tank bottom) to produce a weak water heater tank bottom, that is the part more likely to fail in an overheat and overpressure condition.

A failure at the water tank bottom may explain why a BLEVE can produce a water tank explosion that behaves like a rocket, sending the water tank skyrocketing up through a building.

Some plumbers open the water heater pressure/temperature relief valve for this air-in purpose - but there is risk that you"ll later be unable to get the valve to shut fully again - debris can clog the valve seat - sometimes we can stop a relief valve from dripping by tapping on the valve lift rod that protrudes through the valve lift lever

Other plumbers simply remove the relief valve entirely - this is the process recommended by some water heater manufactures such as A.O. Smith. Removing the relief valve makes it easy to inspect this critical safety component itself, and it"s easy to clean or replace the safety valve at that time.

When replacing the relief valve use an approved teflon tape or pipe sealant and work neatly and with care so that there will be no leaks at this location.

One has to consider that the manufacturer would not be likely to include the test-lever feature on relief valves if it had no intended uses whatsoever.

Water heater manufacturers" installation instructions for at least some water heaters advise building owners or maintenance personnel to manually operate the TP valve at least once a year to make sure it is working properly.

Temperature and pressure relief valves should be re inspected at least once every three years by a licensed plumbing contractor or authorized inspection agency to ensure that the product has not been affected by corrosive water condition [sic] and to ensure that the valve and discharge line have not been altered or tampered with illegally.

Certain naturally occurring conditions may corrode the valve or its components over time, rendering the valve inoperative.Such conditions are not detectable unless the valve and its components are physically removed and inspected.

Contact a plumbing contractor for a re inspection to assure continuing safety. Failure to re inspect as directed could result in unsafe temperature or pressure build-up that can result in serious injury or death and/or severe property damage. - Watts Water Corporation, "T&P and ASME Safety Relief Valves", retrieved 8/22/14, original source: http://media.wattswater.com/PG-TP-ASME.pdf

Nevertheless, Ken, I agree with you that while the "easing lever" can be used to open or "operate" a TP valve, that does not promise that the valve will necessarily open at the rated pressure or temperature.

But by making this test you might find by that the valve is "stuck" or clogged and will not operate. Not finding that the valve is stuck is not a 100% promise of proper function but the risk is reduced.

Watch out: Opening or operating the pressure relief valve using the lever is not a complete test and it should not be used by home inspectors nor by anyone who is not prepared to shut down the water heater and replace the TP valve immediately should the valve fail to operate or should it fail to close and stop leaking or dripping after it has been tested using the lever.

52 Questions and their Answers [about] Hot Water [Heaters, Explosions & Water Heater Safety], Watts Regulator Company (1973) retrived anew 2018/10/27, original source: http://media.wattswater.com/f-52qa.pdf

"Residential Gas and Electric Water Heaters: Service Handbook", [PDF], A.O. Smith Water Products Company, 5621 W. 115th St., Alsip IL 60803 USA, Tel: 1-800-433-2545, Website: www.hotwater.com, Email: www.hotwater.com/parts, retrieved 15 March 2015, original source: : http://www.hotwater.com/lit/training/320991-000.pdf

This handbook provides service information for residential gas water heaters that are atmospherically vented and use a thermocouple as their electrical source and to residential electric water heaters having one or two heating elements and common wiring configurations for these water heater models.

"Residential Electric Water Heater Installation Instructions and Use & Care Guide", American Water Heater Co., October 2001, American Water Heater Co., Johnson City, TN, [manufacturer of residential & commercial water heaters, also manufacturer of Polaris/Commercial water heaters], Tel: 800-999-9515, web search 1/12/2012, original source: americanwaterheater.com/support/manuals/res-elect.pdf [copy on file] [Technical review requested 1/25/2011]

More water heater temperature & pressure relief valve (TPR) test recommendations are in the Residential Gas and Electric Water Heater Handbook [PDF] provided by A.O. Smith and linked-to at REFERENCES

A Temperature Limiting Valve that limits the outgoing water temperature to 50 °C in order to prevent scalding. This valve should be checked annually by measuring water temperature at a nearby water taps, making sure that the water delivered closest to the water heater is not hotter than 50 °C .

An Expansion Control Valve is used on water heaters in south and Western Australia where hard water is found, and in some other countries or other jurisdictions.

The purpose of this valve is to release pressure through a separate control so that the safety provided by the Temperature and Pressure Relief valve is not compromised by clogging from minerals should that valve frequently open.

The expansion control valve should be tested every six months, following the same procedure as for temperature and pressure relief valves as we described above.

see RELIEF VALVES - TP VALVES where we include additional relief valve information including for hydronic heating and steam heating boilers used for central heating.

At TUNDISH used in PLUMBING we describe special devices designed to provide an air gap in the relief valve discharge tube and piping: a feature that can permit visual detection of a spilling TP valve if its discharge has been piped to an otherwise not visible location, and a feature that can protect the potable building water supply system against contamination from cross connections.

If the building water pressure gauge reading is ever found at 80 psi or higher, you will want to install a water pressure regulator at the point where water supply enters the building.

If your building already has a water pressure gauge installed, it may be defective or it may be set too high. The articles listed just below discuss how to adjust a water pressure regulator:

An alternative to installing or changing a water pressure regulator when building water pressure is occasionally 80 psi or higher is the installation of an expansion tank to temporarily absorb that pressure increase. Proper use of an expansion tank can help avoid unnecessary opening of the pressure/temperature relief valve on a hot water heating tank or a hot water heating boiler.

A typical pressure/temperature relief valve for a water heater, like this Rheem ProTech TPR valve shown here, costs about $25. for the valve alone - not including paying a plumber for installation.

Note that this TPR valve has an extenstion that senses water temperature by being immersed into the hot water tank or calorifier (or geyser) hot water contents.

By replacing the TPR valve and observing that the new one leaks - i.e. not from the threaded fitting but from the valve"s discharge opening or mouth - you"ve demonstrated that there is an unsafe condition on the water heater itself - an over temperature or over pressure, or possibly a leak due to water hammer or abnormally high water system pressure and the need for a thermal expansion tank on the system.

Water heater temperature and pressure relief valves are not adjustable. You don"t change or set the relief or release pressure. The standard pressure is typically 150 psi.

While I haven"t seen an explicit prohibition against using flexible copper tubing on a relief valve dis