Water heaters are installed not only in private houses not connected to the central water supply, but also in city apartments. The ability to independently regulate the temperature and a comfortable existence during the period of scheduled repairs are the advantages of apartments and houses with boilers. Self-installation of such complex equipment requires strict adherence to all connection and safety rules. Since the electricity in the water heater is combined with practically boiling water, a safety valve is necessary.
Peculiarities
A water heater safety valve helps prevent excess pressure from building up inside the unit. When the liquid is heated to certain temperatures, the device must turn off the heating based on a signal from the thermostat, but in rare cases the sensor may not work or simply break. The design of the boiler requires tightness and closed taps, so if the water overheats and steam forms, occupying a larger volume, an explosion may occur. In this case, the safety valve allows you to relieve pressure to the standard level of 10 bar and normalize the operation of the entire system.
The functionality of the safety valve is not limited to this alone. It also prevents water from the water heater from flowing back into the supply system when it is empty. Any fuse consists of a body, a rod with a handle at the top, a spring and a plug. Both ends of the body have pipe threads ranging in size from 1⁄2" to 3⁄4" depending on the type of product.
Kinds
There are practically no special differences between the many types of safety fittings for a water heater.
Most often they are divided into three groups depending on the volume of the heating apparatus.
- Valves for boilers with a volume of no more than 50 liters. This category includes standard disposable valves. They are almost always non-removable and their service life is very short. But their low cost allows, without any difficulties, to simply change such devices once a year.
- Valves for boilers with a volume of no more than 200 liters. More serious devices that professionals recommend installing even on boilers with a volume of up to 50 liters. They consist of several valves for various purposes and an additional nozzle for the sewerage supply.
- Valves for boilers with a volume of more than 200 liters. These are serious, complex devices, including a pressure reducing valve, a device for draining water and various adapters. Most often, such shut-off valves are installed on large industrial heaters and are rarely installed even in large private houses.
In addition, safety valves may vary in the presence and operation of additional structural elements. For example, release handles.
Using this pen, you can check the operation of the valve as follows:
- The lever is installed vertically.
- He pulls the spring behind him.
- The spring opens the flow of water.
This check should be carried out at least once every couple of months. The release lever is also used to completely drain the water from the tank. The handle must be held until the water drains completely.
For some models of safety valves, such a lever can be secured with a special screw, which prevents spontaneous opening when the spring is weakened. There are also valves without a discharge structure for forced drainage of water. Most often they have a lid mounted on a thread. Through it, the valve can be cleaned of scale and blockages.
The high quality of the purchased product is indicated by the markings applied to it. For example, an arrow should be engraved or drawn on the body to indicate the direction of fluid flow. Also on the body there must be information about the maximum permissible pressure that the valve can withstand. Even professionals will not be able to distinguish between a four and six bar valve if information about this is not in the accompanying documentation. Of course, such a device will have a higher cost, but the priority should still be the quality of the entire system, and not its price.
In addition to the above, differences may be in the shape and length of the fluid outlet fitting. A long non-linear fitting without expansion at the end will be more convenient, since it is easier to put a hose on it and secure it with a clamp. In addition, sometimes instead of a safety valve, a blast valve is installed on a home boiler. It is designed to quickly remove water in an emergency and should not be drained multiple times. Although the functionality of these locks is largely similar, one cannot replace the other.
A boiler safety valve is often called a check valve, but in reality it is a completely different device, although they are similar in appearance. The check valve is responsible for the unidirectional flow of water, and the safety valve protects the pipe and water heater from damage when excess pressure. Reverse installation locking device instead of a safety measure, it can cause damage to the property and health of residents. A device for unidirectional water flow will not be able to stop the heating of the liquid above the boiling point if the thermostat fails and will not prevent an explosion inside the device, which will destroy not only the boiler, but also the walls of the room.
Principle of operation
Standard water heater fuses consist of three independent valves:
- the safety valve itself (in rare cases, explosive);
- check valve;
- drain valve.
The safety valve includes a metal rod, a plug at its end, a powerful spring and a fitting for draining the liquid. As soon as the pressure inside the boiler exceeds the value specified in the documents, the device is triggered, the rod will compress the tight spring and it will allow water access to the fitting, through which it will flow out. This happens so smoothly that the flow of water is simply a large number of drops.
The check valve includes a plastic rod with a rubber plug at the end and a weak spring. Unlike water valves, the boiler check valve is not designed to hold high pressure water and serves as an ordinary damper, which is why the spring is so weak. It just prevents water from leaking into the pipes in the event of an emergency or a water outage in the central water supply.
The last, but very important valve is the bleed valve. It consists of a check valve stem and a small spring. He works “on the safety net.” When the pressure approaches critical values, but does not exceed them, the release valve is able to normalize the pressure inside the heater during switching on water tap or toilet flush. When the water in the pipeline slightly reduces its pressure due to this, the drain valve opens and the excess almost boiling water goes back into the pipe.
Installation
Before installing safety valves on an installed water heater, it is necessary to study the supply of the construction market and choose a quality product.
Good valves have several distinguishing features.
- The body of a good unit is made of brass alloy using seamless casting. Sometimes it is plated with nickel to protect it from corrosion and scale formation. Unlike cheap copper or aluminum alloys, brass is heavier, making it easy to identify.
- When you press the quality rod shut-off valves You can see how the plug moves tightly inside the case. Even a slight jamming at the end is allowed.
- A bad valve can be identified simply by blowing into it. If, even with strong pressure on the rod, air comes out freely, then it is better not to take the product. At the same time, if water periodically drips from the fitting of the installed constipation, this does not mean that it is broken. Perhaps you just need to clean the sediment plug and everything will work again.
If you follow these tips, you can choose the right fuse the first time and start installing it right away. There are few requirements for it. The valve is always installed in the cold water line. It is placed between the shut-off valve and the pipe entrance to the boiler body. You can cut it directly into the water supply pipe or install a special tee at a distance of no more than 200 cm from the entrance to the heater.
Apart from the fuse, there should be nothing in this area. Most models are installed in such a way that water enters them vertically from below. There should be an arrow on the fuse body indicating this movement.
A polyvinyl chloride tube is attached to the fuse fitting, connecting it to sewer pipe. It is better if this tube is transparent - you can see whether the device is working properly.
The installation process itself is divided into several stages.
- Disconnecting the installed boiler from the power supply and draining the water from the tank. You need to make sure that the water supply to all pipes is shut off, otherwise, at the time of cutting the required area, you can simply flood all the apartments located below.
- The valve body is purged with air to remove any debris or dust. Tow or FUM tape is being prepared, which will serve to waterproof the threaded connection.
- The valve is screwed in with a wrench at the junction of the pipe and the boiler. The arrow on the valve body must coincide with the direction of fluid movement. The union nuts must be well tightened; the joint can be additionally coated with silicone sealant.
- Before connecting the boiler to the electrical network, it is worth crimping the connection using cold water. If after 5 minutes of liquid flow no drops appear at the connection site, then everything is connected correctly.
The safety and check valves are also checked “cold”. In the first case, you need to press the trigger flag weakly at first (the first drops of water should appear), and then with full force. When fully pressed, water should flow quickly through the transparent outlet tube. The check valve can be checked by filling the water heater reservoir completely and shutting off the central water supply. When you open a tap in the bathroom or kitchen, the flow of water should stop quickly. If water continues to flow from the faucet for several minutes, the check valve needs adjustment.
Sometimes individual elements of the water heater or the entire system stops working properly. This reduces the safety of the structure and can lead to dire consequences. In this case, you need to find out the cause and location of the breakdown as early as possible and either fix it yourself or call a specialist for this. Most often, thermostats, heating elements and safety valves fail. Moreover, a problem in the work of one of them can instantly affect the others. You should never install elements that do not match the parameters of the boiler or have different ways connections.
Problems cannot occur on their own; they have certain causes.
Most often they consist of the following.
- Late replacement of damaged parts. For example, the check valve should be replaced at least once a year. It's cheap and won't cost you much.
- Incorrect installation of the entire system. If the fuse is inserted into the pipe with insufficient waterproofing or at too great a distance from the entrance to the boiler, the system will not work properly.
- Voltage changes in the electrical network can lead to failure of the heating elements of the system.
- Presence of manufacturing defects or lack of preventive inspections. In order to choose the right heater and fuses, you need to carefully study all the information when purchasing. And even the highest quality device needs to be checked periodically.
- Scale formation or corrosion. Scale and corrosion on the check valve can cause water to leak back into the pipeline or “corrode” various connections, breaking their tightness.
The most basic faults can be divided into several types. Most often the broiler begins to leak. This can be either a manufacturing defect or a crack acquired due to corrosion. Such a tank cannot be fixed on its own; it will have to be completely replaced. Water dripping from pipe connections indicates they are leaking. On the contrary, water should sometimes drip from the safety valve. If it is always dry, it should be replaced.
Water heaters are the most common devices for organizing hot water supply in a private home; sometimes they are also installed in high-rise apartments.
For installation on a water pipe, you will need some tools and additional materials. One of the required fittings is a safety valve for a water heater. As a rule, this protective element is supplied with the main device, but some budget models may be sold without a valve.
Purpose of the fuse
There are three main tasks that a safety valve performs:
- ensures safe operation of the water heater;
- protects heating elements from dry heating;
- if necessary, allows you to drain water from the water heater.
A safety valve is installed on storage water heaters (boilers). To better understand its principle of operation, you need to know how the boiler is designed and how it works.
The storage water heater contains water throughout its entire operation. The heating element turns on depending on the temperature to which the thermostat is adjusted.
Cold water enters the water heater through a pipe at the bottom of the tank. Hot water flows out of the tank through a pipe that is built into the bottom and installed inside, so that its upper end almost reaches the top of the tank.
This allows you to first select the top layer, which has a higher temperature, while cold water flows from below.
If there is not enough backwater in the main, the water can be drained through the pipe, which is designed for filling.
If there is no water, the heating elements will simply overheat and burn out. Even if they do not have time to burn out before filling, the water, when it hits the hot metal, will quickly boil and form a large amount of steam, which will create very high pressure. This pressure will be enough to destroy the device.
To prevent an explosion from occurring, it is necessary to install a check valve for the water heater, which must be located on the inlet pipe for cold water. In this case, when the pressure in the cold pipeline decreases, liquid will always remain in the container, preventing overheating of the heating elements.
But installing a check valve alone is not enough. Moreover, if you install only it, the consequences may be even worse than without it.
The water entering the water heater will stop as soon as the pressure in the boiler becomes equal to the pressure in the cold pipeline. After heating begins, the water will expand inside, and when the taps are closed, hot water she simply will have nowhere to go and the pressure will begin to increase. All this is fraught with an explosion, the consequences of which can be the most unpredictable and tragic.
Obviously, for normal operation you just need to provide a drainage device that will produce an emergency release of water when the pressure reaches a certain threshold (excess value). It is implemented as a safety relief valve for the boiler.
Device and principle of operation
The device for preventing a serious accident looks surprisingly simple, and its dimensions are small - it fits in the palm of your hand. It is a small mechanism consisting of two perpendicularly located spring-loaded valves, enclosed in one metal body. Essentially, these are two cylinders (tubes), one of which is slightly larger than the other.
The first larger diameter tube, usually 1/2 inch, with two threads at the ends, has a check valve installed that allows fluid to flow in only one direction. The flap in it is located across the pipe and can move along it by several millimeters, opening or closing the passage.
Under the influence of pressure directed towards the water heater, the flap opens, compressing the spring. As soon as the pressure in the pipeline and behind the valve is equalized, the valve closes under the action of a spring.
In a tube of smaller diameter, located perpendicular to the first, a second valve is installed, the spring of which is adjusted to open at a certain pressure, exceeding the pressure for the first valve. This is a fuse that protects against explosion.
Thus, when the pressure rises and the check valve does not allow water to escape into the cold supply pipe, the second valve opens and it is discharged through the drain pipe.
The nozzle may have special notches that make it easy to put on a hose of a suitable diameter. This hose must be secured with a clamp and led either into the sewer or into a container that will have to be emptied from time to time. This will have to be done infrequently, since the amount of water squeezed out during operation of the water heater will be small.
Very often, a plastic flag is provided in the design to force the opening of the drain device. You can use it to check the functionality of the fuse. To do this, you just need to open it and make sure that the piston stroke is free, it is not clogged with rust and scale, and the spring force is enough to return the valve to the closed state.
The safety valve body is often marked with an arrow indicating the direction of water flow to facilitate installation. The small pipe is usually marked with a marking indicating the pressure in pascals at which the emergency valve opens.
Installation
The safety valve for the water heater is installed on the pipe that supplies cold water to the container. Due to the presence of threads at the ends of the device, it is installed without welding or soldering, its installation is simple. Be sure to follow the direction of the arrow on the body, indicating the direct flow of cold water. To seal the thread, you must use flax with packaging paste or FUM tape.
It is recommended to install a tap or drain valve between the inlet pipe and the safety valve. This is necessary because if you often drain water using a safety valve, the elasticity coefficient of the spring will decrease and the nominal opening pressure of the valve will change. Drainage will be needed when repairing a boiler, for example, in case of replacing heating elements or when preserving a house in winter, when liquid is drained from all systems to prevent it from freezing and destruction of pipes.
The tap must be placed on the side outlet of the tee in such a way that it is impossible to shut off the pipe between the water heater and the safety valve, otherwise the latter will not work. To ensure that air enters the water heater and does not create a vacuum that prevents draining, you can open one of the hot taps on the mixers.
Install a drain valve with a tee on a pipe with hot water inappropriate. It will be impossible to drain water through it, and there is no need for extra detachable connections in the water supply.
If you want to hide the safety valve, you can slightly lengthen the vertical section of the pipe. But the distance from the tank to the valve should not exceed 2 m.
If water drips through the valve without visible reasons(without heating), this may mean high pressure in the system (above normal). In this case, it is recommended to install a reducer on the water supply system and adjust the pressure. If the water in the tank is cold, the pressure is not higher than 4 bar, and the valve continues to drip, then this is most likely a defect and the device must be replaced.
Functionality check
After installing the safety valve, you must check its functionality. To do this, fill the container with cold water. You need to fill with the tap open so that air comes out of the boiler. After water flows from the hot tap, you need to turn off both taps.
Water should not drip from the safety valve, but when opened by hand, it should come out under pressure approximately equal to the pressure in the water supply. There is no need to measure it, since it is easy to determine visually.
After heating has started, you should not turn on the hot water taps for some time. This will create in the tank high blood pressure. Droplets will appear in the drain tube or simply from the valve hole (if there is no tube) as liquid begins to be displaced from the tank. This means that the safety valve is in working order and the water heater can be safely used.
The need for selection occurs in the event of a fuse failure, leakage or loss for some reason. If you need to buy a new safety valve, then pay attention to its response pressure. It is necessary to compare with the boiler pressure, which is indicated in the passport. Another indicator is the setup step. Typically it is 0.5 bar. You can choose a safety device with a slightly lower pressure than the boiler, but in no case with more.
A valve for a boiler should not be confused with a similar device for heating, since the latter is designed for lower pressure. It is also impossible to install a check valve instead of a safety valve, as it will not perform its functions and the heater may explode.
It is advisable to pay attention to the material of the case and choose brass, since it is more ductile, does not crack, lasts longer, although it is more expensive.
Not only the service life of the equipment, but also the safety of residents depends on the correct piping of an electric storage water heater (boiler). That's how serious things are. And its correct piping is a safety valve for a cold water supply water heater.
What is it needed for
Installing a safety valve prevents the pressure inside the device from increasing above the standard value. What causes blood pressure to rise? As you know, when heated, water expands, increasing in volume. Since the boiler is a sealed device, there is nowhere for the excess to go - the taps are closed, and there is usually a check valve at the supply. Therefore, heating the water leads to an increase in pressure. It may well happen that it exceeds the tensile strength of the device. Then the tank will explode. To prevent this from happening, they install a safety valve for the water heater.
This is what an installed pressure relief valve looks like in a water heater
Maybe there is no need to install a safety valve, but simply remove the non-return valve? At a sufficiently high and stable pressure in the water supply, such a system will work for some time. But the solution is fundamentally wrong, and here’s why: the pressure in the water supply is rarely stable. There are often situations when water barely flows from the tap. Then the hot water from the boiler is forced out into the water supply system. In this case, the heating elements will be exposed. They will heat the air for some time and then burn out.
But burnt-out heating elements are not the worst thing. It’s much worse if they get hot, and at this time the pressure in the water supply rises sharply. The water that gets on the hot heaters evaporates, a sharp increase in pressure occurs - with a jerk - which leads to a guaranteed rupture of the boiler flask. At the same time, a decent volume of scalding water and steam escapes into the room under high pressure. What this could mean is clear.
How does it work
It would be more correct to call a safety valve for a water heater a valve system, since there are two of them in the device.
Safety valve device for boiler
They are located in a brass or nickel-plated case, which looks like an inverted letter “T” (see photo). At the bottom of the housing there is a check valve that prevents the outflow of water from the water heater when the pressure in the system decreases. In the perpendicular branch there is another valve, which, if the pressure is exceeded, allows some of the water to be released through the fitting.
The working mechanism is as follows:
- While the pressure in the boiler is less than that in the water supply (when filling or when the tap is open), the check valve plate is pressed out by the flow of water. As soon as the pressure is equalized, the spring presses the plate against the protrusions of the body, blocking the flow of water.
- When the heating is turned on, the water temperature gradually increases, and with it the pressure also increases. As long as it does not exceed the limit, nothing happens.
- When the threshold level is reached, the pressure compresses the safety valve spring, and the outlet to the fitting opens. Some of the water from the boiler is released through the fitting. When the pressure drops to normal, the spring closes the passage and the water stops flowing.
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Based on the principle of operation, it is clear that water will constantly drip from the fitting. This happens when the water heats up and the pressure in the water supply decreases. If you periodically see water on the fitting, then everything is working normally. But the draining liquid must be drained. To do this, put a tube of a suitable diameter on the pipe and secure it with a clamp. The normal operating pressure of the boiler is from 6 Bar to 10 Bar. Without mechanical fastening, the tube will be torn off in no time, so we select a high-quality clamp and tighten it well. Place the tube into the nearest sewer drain.
One more point: the tube for the fitting needs to be transparent and preferably reinforced (the so-called “herringbone”). Why reinforced is understandable - because of pressure, and transparent - to be able to monitor the performance of the device.
Types and varieties
If we are talking about conventional safety valves for a water heater, then they look almost the same, only the nuances differ. But it is these small details that are responsible for ease of use.
Safety valve for boiler with forced pressure release option
The photo above shows two safety valves with release levers. They are needed for periodic performance checks. The lever flag is lifted up. It pulls the spring behind it, freeing it to release water. This check should be carried out approximately once a month. You can also empty the boiler tank by raising the flag and waiting for everything to drain.
The difference in the presented models is that the model in the photo on the left has a lever secured with a screw. This eliminates the possibility of accidental opening and complete discharge of water.
Two more differences are striking. This is an arrow on the body indicating the direction of water movement, and an inscription showing what pressure the device is designed for. Seemingly minor details. But if you can figure out the direction of water movement (look in which direction the poppet valve is turned), then the nominal value is more difficult. How to distinguish, for example, whether it is 6 Bar or 10 Bar? Only checks. How will sellers differentiate them? No way. By boxes. What if they put it in the wrong box? In general, it is better not to take it without markings on the case. These are usually the cheapest of the Chinese designs, but the difference in price is not so great that it is worth the risk.
Also pay attention to the shape of the water discharge fitting. The model on the left has a long fitting and has a non-linear shape. The hose fits on it quite easily and is long enough to install a clamp. The shape of the fitting on the model on the right is different - with an extension towards the end, but more importantly, the fitting is short. You can still pull the hose onto it, but the clamp is questionable. Unless you crimp it with wire...
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The following photo shows the safety valves without a forced pressure release flag. The one on the left has a threaded cap at the top. This is a serviceable model. If necessary, you can unscrew the lid to remove clogs, scale and other contaminants.
Safety valves - serviceable and not
The model on the right is the worst option. No markings, forced resets or maintenance. These are usually the cheapest available, but this is their only advantage.
All of the above models are suitable for water heaters with a volume of up to 50-60 liters. For boilers bigger size There are other models available, many of which have built-in additional devices. Typically this is a ball valve and/or pressure gauge to control pressure.
For boilers up to 200 liters
The water drain fitting here has a standard thread, so there will be no problems with fastening reliability. Such devices already have a fairly high price, but their quality and reliability are much higher.
With pressure gauge and original
Not everyone likes appearance I like these devices. For those who attach aesthetics great importance Very attractive devices are being produced. Their price, however, is comparable to the price of an expensive water heater, but it’s beautiful.
Is it possible to install other valves?
Sometimes, instead of a special safety valve for a boiler, a blast valve is installed, which is intended for the emergency release of heating water. Although their functions are similar, the main mode of operation is fundamentally different. The demolition device should only be used in emergency situations. It is designed for volley discharge of a large volume of liquid. It is not suitable for constantly bleeding small portions of water. Accordingly, it will not work correctly.
Another case is to install only a check valve. It will not allow water to drain when the pressure in the water supply decreases, but it will not save you from increasing pressure in the boiler. So this option doesn't work either.
How to choose and install
Select a safety valve for a water heater based on the pressure for which the unit is designed. This number is in the passport. The volume of the tank also influences the choice. They produce devices with operating limits of 6, 7, 8, 10 Bar. Basically, all units are designed for this pressure. So everything is simple here.
Installation is simple: flax tow or fum tape is wound onto the threads, after which the valve is screwed onto the pipe. Twist it all the way by hand, then another one or two turns using keys. It is much more important to choose the right place to install it. When installing a water heater, this valve is installed directly on the cold water inlet pipe.
Buying your first electric boiler is a significant event. It is impossible to forget it, if only because for the first time you have to figure out why the water heater needs a power cord, as well as how to connect and install the entire system.
Subsequently, as a rule, no questions arise, so when replacing the boiler with a new one, reading the accompanying instructions is often skipped. Today we will talk about why a safety valve for a water heater is needed and what will happen if you “forget” to install it.
Laws of physics
Every person knows from childhood that when heated, objects expand, increasing in volume. The value depends on the material of the object, temperature and conditions environment- these are the laws of physics. And water is no exception. If there is an increase in volume in a sealed enclosed space, then mechanical damage to the boundaries is quite possible - they will simply be torn apart. The safety valve for the water heater, which is necessarily included in the boiler installation kit, serves to protect the walls of the tank from destruction.
If it is missing, it must be purchased and installed separately. To understand the operating principle of a water heater safety valve, let's mentally assemble a model of the tank and connect it to the system.
Experiment
Two pipes are connected to the boiler: the supply of cold water and the return of already heated water. While the taps on the outgoing line are closed, the volume of the tank will be filled with cold water, which will begin to be heated by the heating element to the set temperature. As soon as you open the tap, hot liquid rushes out of the tank, squeezed out by portions of cold liquid coming from the system. However, there are several points that do not allow the boiler to be operated with this switch on. Firstly, since the entire mass of cold water (in the tank and pipe) is not divided by anything, the heating element will constantly work, trying to heat the entire available volume. Secondly, if for some reason the water disappears in the supply pipe or the pressure drops significantly (not uncommon in domestic systems), then the stored and heated liquid from the tank will partially flow by gravity back into the supply pipeline. To prevent this from happening, a check valve is installed on the connection pipe. The spring-loaded plate allows water to flow in only one direction, mechanically separating the two media - a simple but incredibly effective solution. Why do you need a safety valve for a water heater? Let’s mentally complicate the task by adding to the design the usual one installed on the feed. In this case, heating will occur without losses, and the disappearance of water in the supply pipeline does not threaten anything.
But what happens if the heating value is set not to 20-30 degrees, but to 60-80, as often happens? In accordance with the well-known law of physics, the water will begin to expand, and since all the taps are closed, the internal pressure will increase. If the walls of the tank are of poor quality, they will be locally damaged (burst). And if the tank material is chosen correctly, then the following happens: pressure and temperature increase, but water does not boil, since when high blood pressure the point moves. As a result, it turns out that the boiler may well contain water with a temperature of over 100 degrees. But then someone opens the water tap. The pressure drops sharply, returns to the usual 100 degrees, an avalanche-like release of steam occurs, which sharply increases the pressure and the tank bursts. If you manage to avoid injury, it can be considered lucky.
Safety valve for water heater "Ariston"
To prevent such accidents, they are designed in such a way that when a certain value of internal pressure is exceeded, part of the water is automatically discharged (usually a few milliliters). The layout of these elements is the same, so there is no difference whether they are installed on an Ariston, Termex, or other boiler. There are two spring-loaded plates inside: one of them functions as a simple check valve in the supply, and the other holds water in the tank until until the pressure exceeds a certain limit.
Owners who have installed a storage water heater in their home often have questions about the operation of its safety valve. Is water leaking from this device normal or a breakdown? And if the water circulation must take place, then in what quantities and how often? We have already considered the design and principle of operation of a safety valve for a boiler. Now we will tell you how to determine the malfunction of this device and how to solve the problem of its leakage.
Why is the safety valve leaking?
As you already know, the safety valve for a water heater is used to relieve excess pressure from the tank that occurs while heating the water. In this case, a leak can occur in several cases, each of which we will consider in more detail.
Leaking when the boiler is off
Let's simulate the following situation: the water heater is disconnected from the network, the water supply from the water supply is turned on (the tap on the pressure line is open). Water is flowing from the boiler drain hole. The cause of this phenomenon may be either a malfunction of the safety valve or increased pressure in the line.
To find the cause of a leaking safety valve, you need to know the water pressure in the water supply
To determine the culprit of the leak, you need to measure the cold water pressure in the water supply. The fact is that if the main pressure exceeds the accepted SNiP, the valve will open and perform its functions of discharging excess water into the sewer. Most water heater safety valves that manufacturers equip their products with are set to a pressure of 6 to 8 atmospheres. The maximum pressure allowed by SNiP in main water pipelines should not exceed 6 atmospheres. In fact, it often happens that actual indicators exceed standard values by 1 - 2 atmospheres. Naturally, the safety mechanism will work.
The second cause of leaks may be the valve itself. Wear of its plate or seat, weakening of the spring - these are the factors that can lead to leaks. Cheap Chinese products are often susceptible to such malfunctions.
The possibility of particles of scale or debris getting under the locking mechanism plate, which can happen during an emergency pressure release or after draining water from the boiler during maintenance or repair work, cannot be discounted.
If the safety valve leaks, do not under any circumstances remove this part from the water supply system to the water heater. Remember that operating a storage water heater without a safety valve is prohibited and can lead to its explosion.
Video: What does operating a boiler without a safety valve lead to?
Valve leakage during water heater operation
If the water heater is connected to the network and heats water for a long time without significant water intake, then the cause of the constant leakage is most likely a faulty safety valve. The fact is that during the initial heating of cold water, its volume in the boiler will increase by about 2-3%. This excess liquid will be discharged from the tank. In the future, the boiler simply maintains the temperature of the hot water, so there should be no leaks, so the cause should be sought either in a breakdown or in a clogged safety valve.
A completely different picture should be observed with increased water consumption, for example, while taking a shower: the constantly leaving volume of hot liquid will be continuously replaced by cold water. But when it heats up, the excesses indicated above will begin to appear. Therefore, the flow of a certain amount of water from the drainage hole in this case is quite logical.
Safety valve device for water heater
And the third option is for a small, extended water withdrawal. For example, washing dishes or cooking. With such a flow rate of hot water, there should not be a constant leak from the drainage tube, but the periodic leakage of liquid drops will indicate the correct operation of the water heater.
How to troubleshoot
If the cause of the leak is a faulty valve, then it is replaced with a working part adjusted to the same operating pressure. When replacing, or better yet, while installing a water heater, try not to use cheap Chinese products. Remember that the safety of your family directly depends on the valve. Good Italian safety valves with the same non-separable design, although they cost several times more, are purchased once. As practice shows, there are no problems with them in the future. Connect a flexible transparent hose to the drain outlet of the device. This will help you visually evaluate the performance of the part. Lead the end of the hose into the sewer or a suitable container.
Products from well-known manufacturers are reliable and durable
To remove the valve for replacement or cleaning, you will need a plumber's wrench and an adjustable wrench. The work is performed in this order:
- Disconnect the boiler from the network;
- Turn off the cold water supply tap to the water heater;
- Open the hot water taps and completely drain it from the container;
- Press the lever on the safety valve and remove any remaining liquid from the tank;
- Disconnect the cold water pipeline from the safety valve;
- Remove the valve.
After cleaning or replacement, the part is put back in place in the reverse order.
Important note: you can connect the water heater to the network only after its tank is completely filled with water, otherwise the tubular electric heater may fail.
If the input pressure of your water supply system exceeds the nominal pressure for which the storage water heater is designed (this can be found in the technical data sheet for the device), a pressure reducer is installed at the water inlet to the apartment.
Installing a reducer at the inlet of the water heater will not only reduce the water pressure, but will also prevent the occurrence of water hammer, which adversely affects the coating of the internal tank of the boiler.
