water heater safety valve leaking quotation

2023-05-21 21:22:12

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.

water heater safety valve leaking quotation

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.

water heater safety valve leaking quotation

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.

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.

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.

water heater safety valve leaking quotation

If a recently replaced T&P relief valve starts leaking again, it probably means that the relief valve is only doing it"s job; it relieving excess pressure in the water heater. When this happens, the fix gets a little bit more involved. I"ll explain.

When a water heater heats up the water in the tank, the water expands. When this happens, the water typically ends up expanding back out the cold water inlet, all the way back to the water supply coming in to the house. The municipal water supply for the house acts as a gigantic expansion tank… and nobody notices. This is illustrated in the diagram below.

What would happen if a one-way valve, or check valve, was installed on the water supply piping for the house? The water wouldn"t have anywhere to go. As the water heater heats the water, it expands, which builds up pressure in what is now essentially a closed system. When the pressure builds up enough, the T&P relief valve on the water heater just does it"s job and relieves the excess pressure by leaking a little water.

In Minnesota, it"s rare for a check valve to be installed on the water supply line for the house, but it"s fairly common to have a pressure regulator installed. When the pressure from the water supply coming in to a house is too high, a pressure regulator needs to be installed on the water main, to prevent damage to the plumbing components in the house. The problem that these regulators can create is that they will act as a check valve; they"ll allow water in to the home, but they won"t allow water back out. This creates what is called a "closed system".

When this happens, the T&P relief valve for the water heater can leak. This doesn"t happen every time a pressure reducing valve is installed, but there may be other problems that show up in the house, such as the toilet fill valves randomly re-filling toilets, or faucets chronically dripping.

The FixWhen a closed system exists on the water distribution piping in a home, an expansion tank needs to be installed somewhere on the plumbing system. This is a fairly simple and straightforward fix; an expansion tank will give the water somewhere to go when it expands, and the T&P relief valve on the water heater will stop causing problems.

This rule also applies to hot water heating systems; when a boiler heats the water in a hydronic heating system, the expansion tank allows for the water to expand without the pressure relief valve leaking. If the pressure relief valve on a boiler system chronically leaks, even after replacement, it probably means there is a problem with the expansion tank.

water heater safety valve leaking quotation

Everybody knows that electricity and water don’t mix. It’s no different when your hot water heater is leaking. Having a gas water heater doesn’t necessarily protect you from this risk, either. Many gas heaters use electricity to keep thepilot light ignited. You can’t always tell this is the case by simply looking for a plug leading from the heater to an outlet, either; some gas heaters that use electricity don’t rely directly on the mainline.

This is less of a step and more of a precaution to keep in mind as you handle your hot water heater that’s leaking. Unlike water softeners (you can read about water softener leaks here), the water in your heater is, well, heated. Most water heaters in Phoenix ship with a default setting of 140 degrees Fahrenheit. If you’ve ever had the system adjusted by a professional, they likely only turned it down to 120 degrees, which is the recommended temperature.

You can read the very detailed steps for doing this in our article on cleaning water heaters. As a general overview, this process involves switching the thermostat off, opening your faucets to avoid creating a vacuum, connecting a hose to your drain valve, activating the valve, and allowing the tank to drain into a container or floor drain.

water heater safety valve leaking quotation

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.

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

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This article describes the causes of leaks, drips, or discharges from pressure relief valves, temperature/pressure relief valves, or TP valves found on heating boilers, water heaters, or the simpler pressure relief valves found on water pressure tanks.

We list the wide variety of possible TP Valve leaks and how to find and fix each of those problems, including how to fix a leaky pressure relief valve or leaky TP valve on a boiler, water heater, or water tank - what are the possible causes of leaks at these safety devices. Safety Hazard Warnings About Dripping or Leaking Pressure Relief Valves.

How to use an expansion tank to relieve high water pressure. T&P Valves Installed on Gas Sidearm Heaters: special problems. Closed Hot Water System & Thermal Expansion Problems.

So if you see water actually spilling or even if it"s just dripping at the temperature/pressure relief valve on your heating boiler or water heater, the cause needs to be found and fixed promptly, and it may be appropriate to install a new T&P valve (also called TPR valve) after those repairs are complete.

Gas sidearm heater TP valves: The T&P valve is installed on a sidearm gas heater that is causing an overheat condition at the sensor point of the valve (This thermal expansion is discussed

Expansion tank defects or problems: if the expansion tank or compression tank on a hydronic heating system boiler or on other thermal expansion systems is itself defective (waterlogged, leaky, damaged internal bladder) system pressures will be excessive due to otherwise normal pressure & temperature variations during system operation, resulting in spillage at the relief valve.

Leaks into the heating boiler or water heater: leaks into a heating of water from a higher pressure building source can cause recurrent TP valve leaking. For example, if the tankless coil in a heating boiler is leaky, higher pressure water inside the tankless coil may leak out of the coil into the heating boiler.

Similarly, an internal leak in the heat exchanger coil of an indirect water heater can send water from the water heater"s potable water into the coil and thence into the heating boiler.

This same leak problem can cause high water pressure in a heating boiler that is used to heat water in an indirect-fired water heater. In that case, a coil containing boiler water (typically at 12-29 psi) that develops a leak may accept higher building pressure water from the building water supply to the indirect water eater tank (or cylinder) that is typically between 20 psi and 70 psi.

Diagnose this problem by observing that when the boiler is left OFF and its own water feeder is left OFF but building water supply is left ON into the tankless coil on the boiler or ON into the indirect water heater, boiler pressure will creep up several hours. With a reader we discuss this possible TP valve leak cause in the FAQs section of this article.

Watch out: under normal conditions, because building water supply pressures are above boiler pressures, an internal leak in the tankless coil or indirect water heater"s heat exchanger coil will cause boiler pressures to rise. But there can be exceptions in the direction of water leakage, as we explain

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. A brittle piece of gasket can be spit out of the valve and it will then keep leaking.

The wrong T&P valve has been installed or set to too-low a working pressure. (Proper set pressure is at least 20-30 psi above the working pressure of the equipment to be protected).

Thermal expansion problems: A closed water system with thermal expansion and no means of relief can cause leaks at the pressure/temperature relief valve, such as

Can occur on a hot water heater (hot water cylinder, calorifier, hot water tank) with some building piping arrangements, particularly where a check valve or pressure reducing valve are used.

See THERMAL EXPANSION TPR VALVE LEAKS for an explanation of why thermal expansion leaks occur at the relief valve on hot water systems & what to do about it

Can occur also a hot water heating boiler (used for building heating) at which the boiler"s thermal expansion tank has become waterlogged or has a ruptured internal bladder.

Water expansion pressure (thermal expansion) increases in any closed plumbing system, particularly where a check valve installed close to the water heater.

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: The building plumbing system suffers from water hammer. Water hammer in buildings causes surging in the water piping that in turn can cause leaks at pressure/temperature or other pressure relief valves, particularly at the pressure safety valve found at water pressure tanks.

Water heater temperature too high: The water heater temperatures are excessive. For example on an electric water heater a malfunctioning control can overheat the water e.g. the water heater thermostat is not working properly and is not shutting off the heat source when it should -

Water pressure too high: The building water supply pressure is too high or periodically water pressure fluctuates and is too high at times. Pressures over 70 psi in a typical building tend to cause leaks at plumbing fixtures and higher pressures are likely to cause or contribute to leaks at TPR valves.

Water pressure reducing valve / water feed valve problems: On a hot water hydronic heating system, if the water pressure reducer/feeder valve is not working properly it may over-feed water into the heating system causing overpressure.

Combinations of factors causing TP Valve Leaks: OK so this is more than 12 causes of TPR valve leaks, but keep in mind that the temperature/pressure relief valve leak causes listed above can also occur in combination. For example high incoming water pressure alone may not cause a TPR valve to leak but if we add water hammer then the valve may be leaky.

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.

The impaction of the relief valve spring with copper and calcium salts in this photo means that the valve is almost certainly not going to open should the heater"s internal pressure become unsafe.

The drip shown at the mouth of this relief valve demonstrates that a relief valve can drip and leak for a long time without anyone observing this dangerous condition.

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. The result is a clogged valve as we explain above - a dangerous situation that risks an explosion.

Watch out, serious safety hazards can be caused by dripping at the TP discharge line: often the dripping is caused by thermal expansion of hot water.

For details please see THERMAL EXPANSION TPR VALVE LEAKS - an explanation of why thermal expansion leaks occur on hot water systems & what to do about it

Also 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

With a sidearm gas heater a common problem is frequent T&P valve opening even though there is very little hot water in the hot water storage tank. That"s because an overheated condition exists right at the sensor point of the T&P valve - most of the overheated water is "congested" at the top of the tank.

This problem can be caused by undersized circulation piping between the sidearm heater and the water tank. Undersized piping between the sidearm heater and the tank (supply or return) amounts to a restriction of the circulation area (or volume).

When this "too small" circulation area or volume is combined with a heater whose BTU input rate is higher than that undersized volume can carry, proper circulating does not occur through the tank nor through the sidearm heater coils themselves - the "congestion" referred to above occurs.

In turn this congestion (think of it as a hot water traffic jam) causes overheating right where the T&P valve sensor is located, thus causing the valve to spill hot water repeatedly.

Because there is just a small volume of "too hot" water where the valve is located, the valve opens, spills the small amount of hot water, then is cooled and closes after just a short interval.

[The system we used for years used 1 1/4" diameter copper piping - Ed.] Non-ferrous piping is preferred to reduce the chances of clogging from rust debris - a clue that warns us that even 3/4" piped gas sidearm heaters can clog from rust or scale formation and will then exhibit this problem if the piping is iron.

With an automatic gas storage heater installation, either the heater thermostat is acting abnormally (not shutting off when it should) or stacking temperature conditions are causing this TP leak. - paraphrased & adapted from information from the Watts Regulator Company. [10]

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

[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

[8] Rheem Electric Water Heater "Owners Guide and Installation Instructions", (Australian models) rheem.com.au/images/pdf/owners_dom-elec_121996C_0707.pdf

[9] Watts, 815 Chestnut Street, North Andover, MA, USA 01845-6098, web search 09/18/2010 original source: http://www.watts.com/pages/learnAbout/reducingValves.asp?catId=64

[11] "Four hurt as water heater explodes", Elaine Porterfield, Paul Shukovsky, Lewis Kamb, Seattle Post Intelligencer, 28 July 2001, web search 25 Sept 2010, original source: http://www.seattlepi.com/local/33094_boom28.shtml

In small scale testing, the Mythbusters started with a small six gallon water heater and disabled all of its safety features under the theory of poor installation or neglect. While the water heater eventually ruptured, it did not explode like a rocket. The Mythbusters then upgraded to larger thirty gallon water heater which exploded with significantly greater force, sending the water heater several hundred feet into the air. In order to confirm the stated myth, the Mythbusters obtained a full size fifty two gallon water heater and built a shack around it with a roof that followed standard California building codes. The water heater eventually exploded, shooting through the roof five hundred feet into the air and disintegrating the shack. In light of these results, and the fact that there is documented evidence corroborating the myth, the Mythbusters deemed it confirmed.

Because of built in safety devices most water heaters safely operate day in, day out without any major problems. But don"t let the excellent safety record of water heaters lull you into forgetting about the explosive potential of these marvels of convenience. When a water heater explodes, it releases a tremendous blast force which can easily demolish a building.

Randall Hilton and crew, with help from the Service Roundtable has prepared this video of a water heater explosion as a demonstration of the explosive power of a simple water heater. The hot water tank explodes using the steam pressure that any water heater can generate when the thermostat and temperature pressure relief valve (T&P valve or PT valve) malfunction. We were impressed by how far the tank flew after the water heater exploded. Click on the links below to view the video. Then, visit the Q&A page for warning signs as well as simple steps which can help you prevent your own water heater from exploding.

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Is your water heater pressure relief valve leaking? What is the cause, and what can you do to fix it? If you’re asking any of these questions, you’re in the right place. Read on to learn all you need to know to fix the problem.

There are some common reasons why your water heater pressure relief valve might leak. One is excessively high temperatures in the water tank. Either a gas burner or electricity heats the water inside the tank, and the pressure relief valve is a safety mechanism to make sure the tank doesn’t overheat.

When water is heated, thermal expansion causes pressure to build up inside of the water tank. If the temperature gets too high, the valve will open up and drain out some of the hot water, replacing it with cooler water to lower the temperature.

This is a sign that the valve is working correctly and occasional leaking is normal.Temperatures inside the water tank rangefrom 120 to 140 degrees.The pressure will be released if the temperature inside the tank gets to about 210 degrees and 150 psi (pounds per square inch).

Another possible cause of leaks is the valve not being appropriately sealed at the point where it connects to the water heater. Another potential issue is that the valve itself is faulty. For example, if the seal is damaged or the valve sticks to the open position.

If the water heater pressure relief valve is truly damaged and is causing the leakage, why is it a good idea to fix it right away?The high-pressure buildup could cause the tank to rupture or explode.

What are some of the signs that your water heater pressure relief valve is leaking?No water pressure. Just as with low or fluctuating water pressure, no pressure is a sign that something may be wrong with your pressure relief valve.

Loud noises coming from inside the walls.If you hear loud banging or humming noises inside your walls, this may be a sign that your pressure relief valve is leaking. To make sure the sound is coming from the valve, go close to it and see if the sounds become louder.

What to Do When You Find a LeakAssess the leak. Find out whether or not the leak is from normal pressure release or a bad valve. Replace the valve if needed.

Do a valve test to see if the pressure relief valve is functioning properly. If a lousy valve causes the leak, contact a licensed plumber to replace the valve if you don’t have the skills to do it yourself.

Check the frequency of the leaks. If you often have leaks due to the valve opening. You may have unsafe pressure levels, and your water tank is at risk of rupturing or exploding.

Check the valve opening to make sure it can close properly. Minerals in the water may become encrusted on the valve opening over time. If the valve is leaking because it is stuck in the open position, open and close the valve a few times quickly to get it unstuck. If the valve still sticks, you know that you need to replace it.

Check the pressure gauge. If the valve has no pressure, it could be due to a broken spring or the valve not fitting correctly. Controlling the pressure is a vital function of the valve, and replacement is a must.

If the leakage is severe, immediately turn off the water heater. If your water heater uses gas, locate the gas line, which is usually near the water heater. Turn the gas valve clockwise until the gas is entirely off.

If your water heater is powered by electricity, locate the appropriate switch in your breaker box and set it to “off.”Next, turn off the water supply to stop more water from building up in the tank.

Use caution with a leaky tank, as the water is hot and could cause burns and serious injury.Replacing a leaking water heater pressure relief valve can be a DIY project, depending on the cause of the leak.

The valves are inexpensive, and you can do a quick fixin a few simple steps:Turn off the water heater breaker (allow 24-48 hours for the water to cool).

If the water heater pressure relief valve is often open and leaking, there could be an issue with your water heater. If your water heater is constantly at a high temperature, there is a high-pressure buildup.

If your water heater pressure relief valve is leaking, there’s no need to panic. A simple replacement of the valve can easily fix the issue. Testing your valve regularly can prevent costly repairs in the future.

Pay close attention to the frequency and the level of the leaks so that you know when it’s time to call a professional. Test valves regularly and replace them when necessary to avoid costly repairs in the future.

Replacing a pressure relief valve is far cheaper than repairing one after something has gone wrong. CPV Manufacturing recommends replacing your pressure relief valve every 4-5 years, but you also need to factor in some other things.Location – Certain climates, particularly desert climates, can be hard on pressure relief valve seals. Heat and dryness can cause the seals to crack, so users need to replace them more frequently.

Debris in your water – Debris in your water may be a sign of blockage or corrosion in the valve. If the pipes undergo a thorough cleaning process and the debris remains, it’s time to replace the valve.

Age of the valve – The spring mechanism in the valve loses tension as the valve ages. This is why it’s essential to test your valve about every six months and replace the valve every 4-5 years.

Frequency of use – If your water heater pressure release valve is in high use, it may need to be replaced more frequently due to the wear and tear caused by this usage.

Water quality – Minerals build up on the water heater pressure relief valve over time. If you live in an area with hard water, mineral deposits may build up quicker. Mineral buildup on the valve can cause the

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