Hot water is a useful and pleasant function in a person's home. But there are times when there is no such central communication, or the liquid flows barely warm. I have to buy a water heater. This apparatus combines a liquid close to boiling and electricity. Therefore, measures must be taken to prevent the danger.

A storage heater tank is a hermetically sealed tank in which water is heated. During this process, steam is generated and the pressure rises. That is why among specifications the unit has a maximum pressure indicator. For household appliances, it is usually equal to 10 bar.

When in the evening all family members took a shower, a bath and washed the dishes, the hot water was used up, and the tank was filled with cold liquid. While people are sleeping, the water heater heats the water, and the pressure inside the housing rises. All taps are closed, there is no return flow to the system. So the pressure builds up in the boiler itself.

Having reached the set heating parameter, usually it is 60o - 65o, the thermostat should turn off the device. At the same time, the pressure in the water supply system is 2.7-3 bar, plus the steam from the heated in the tank total in the heater body is about 4 bar. The situation is within the normal range.

Let's imagine that the sensor did not work. According to the laws of physics, the boiling point rises in proportion to the pressure. For water at 10 bar, this parameter will be 180 ° C. The volume of liquid in the tank is about 80-100 liters, now all this mass has turned into steam. If the hull fails, an explosion will occur. A safety valve for the boiler can protect in such a situation. This mechanism performs two functions:

  1. Prevents spontaneous flow of fluid from the heater into the system when there is no water in the communications.
  2. Relieves excess pressure from the tank in automatic and manual modes.

Operating principle

Two valves are placed in one housing.

  • The first, non-return valve, is located on the cold water supply side. As the tank empties, the pressure in the water supply becomes higher than in the tank and the pressure of the inflow presses the saddle away from the inlet. The path through which water enters the boiler is freed. When the device is filled and the pressure in it and the pipes is equalized, the spring returns the seat to its place, thereby blocking the exit from the boiler back to the water supply network.
  • Second, safety valve for the boiler , during normal operation device is closed, and in the event of excessive pressure, the jet from the unit acts on the valve, the calibrated spring is pressed out and the outlet channel opens, which ensures the discharge of excess fluid.

Installation

  1. The device is mounted directly on the inlet pipe of the water heater.
  2. During connection, the direction of fluid flow must be observed. To do this, an arrow is applied to the valve body, which should point towards the boiler.
  3. Some models may have an internal installation limiter. Such safety valve for boiler can be screwed up. If this option is not available, then twisting the mechanism should be done no more than 4 turns. Violation of this rule may lead to narrowing of the safety channel.
  4. Having mounted the mechanism on the heater, look inside its body from the side of cold water inlet. The seat must be visible. check valve. Try to lightly press on it with a blunt object. If the installation is done correctly, the barrier should move forward, and after releasing, return to its place. If the saddle does not move, then the work is not done correctly.

Attention! Cannot be replaced boiler safety valve simple check valve. In this case, only the tank empty warning function will work. Excess pressure will not be released.

Examination

This procedure will take several hours to complete. During the entire inspection period, the taps must not be opened. hot water.

  • After fully connecting the water heater and filling it with water, set the heating limit on the control panel to about 80 O .
  • As the temperature rises, closer to the maximum, a trickle or drops of escaping liquid should appear from the nozzle.
  • If this does not happen, wait until the thermostat turns off the water heater.
  • Depending on the characteristics of your model, increase the limit to the maximum possible.
  • When the heating process is completed, liquid should drip. In the absence of leakage, or the ability of the device to reach a level of more than 80 O it is recommended to check the valve in a workshop or replace it with a new protective mechanism.
  • Put a hose on the fitting of a working mechanism and secure with a clamp. The other end must be taken to the sewer.
  • In the case when water starts to flow immediately after filling the tank, the device is defective, it must be replaced with a new mechanism.

If the safety valve is not installed on the boiler, operation is prohibited.

Selection


The main rule that should be observed when choosing this device is the correspondence between the response pressure of the mechanism and the characteristics of the heater. This parameter is indicated on the case or in the accompanying documents. Models that set the limits of action is better not to buy.

Pay attention to the presence of a forced liquid discharge lever. Inspect the threaded connections, and make sure that they are of good quality and that there are no thread defects.

The drain fitting must be placed so that it is convenient to put a hose on it.

Possible malfunctions and solutions

  1. If, when the boiler is cold, water flows out of the emergency discharge hole, this means that, most likely, foreign elements have entered the valve. Open the drain channel completely using the lever and let the liquid flush the mechanism liberally. When a clean, clear liquid flows through the hose, close the outlet with a lever. The leak must stop, otherwise the device must be replaced.
  2. Water is constantly flowing from the valve. Such a malfunction indicates that the spring pressing the seat has weakened. Since this part is calibrated, you need to buy a new valve. An extraneous cause of such a nuisance may be a significant increase in pressure in the cold water supply system, but this is unlikely and will be noticeable when using other plumbing fixtures. Unfortunately, there is another possibility of this defect - the absence or insufficient volume of the expansion tank in the boiler. The best option The solution to the problem will be the replacement of the water heater with products from another manufacturer. If this solution is not possible, install an additional expansion tank at the outlet of the heater.
  3. If no liquid comes out of the fitting at all, and all taps are in good order and there are no leaks in the hot water distribution system, flush the device as described in paragraph 1 or replace the mechanism.

Adjustment


Boiler safety valve, adjustable

Having bought a safety valve for the boiler, which is adjusted manually, install the mechanism in the manner described above.

  • Perform complete installation, connection and filling of the water heater.
  • Turn on the device in a mode close to the maximum in accordance with the manufacturer's instructions.
  • Immediately after reaching the set temperature, turn the adjusting screw or knob, depending on the valve model, until water begins to flow from the fitting.
  • Drain some of the liquid from the tank. A space will be released in the tank, which will be filled with cold water. Accordingly, the temperature inside the heater will drop. Turn on the limit mode of the boiler again. Now the water from the discharge channel will flow automatically. If this does not happen, loosen the spring until a thin trickle appears. Check with another drain and reheat cycle.
  • Set the operating mode to order 60 O . Do not constantly use a higher temperature regime unless absolutely necessary. This can cause increased wear of the heat exchanger.

Service

During use, depending on the intensity of hot water consumption, it is necessary to rinse boiler safety valve from scale, rust fragments from pipes and other foreign matter in the water. To do this, you just need to sometimes open the emergency discharge channel for excess fluid using a lever.

Do not use this mechanism to empty the water heater. Particles settling on the bottom of the tank passing through the bleed spring will get stuck and interfere with its further normal operation.

Observing all the rules for using the water heater and monitoring the correct operation of the safety valve, you will confidently and safely use hot water.

A safety valve for a water heater, boiler or a check valve device is one of the main elements responsible for the safe operation of the device in conditions of pressure drops when heating water.

Purpose

In the process of heating water in the storage tank of water heating equipment, the volume of liquid increases by about 2-3%. In accordance with the law of thermodynamics, even with a slight increase in temperature, a closed system is characterized by an increase in pressure.

The temperature control devices and thermostats installed in the boilers make it easy and efficient to control temperature regime liquids, but when they fail, the pressure increase inside the system becomes critical.

Safety valve for Ariston water heaters

The result of an avalanche-like increase in the pressure level is a rupture of the boiler body and an explosion of water-heating equipment.

In order to prevent exceeding the permissible pressure limits, a safety valve is installed that is capable of dumping part of the liquid to the outside in a critical situation.

However, the functional purpose of the water pressure relief valve for the water heater in water heating equipment is not limited solely to the protection of the boiler, but is also presented:

  • preventing the return of heated liquid from the storage tank to the plumbing system;
  • smoothing water pressure surges or the so-called water hammer at the inlet to water heating equipment;
  • discharge of an excess amount of heated water from the tank in conditions of a critical increase in temperature and pressure levels;
  • the ability to drain the liquid from the water-heating tank in order to carry out preventive maintenance and repair measures.

The absence of a valve does not prevent emergency the outflow of heated water from the boiler, so the exposed heating elements burn out in a short time.

The safety valve will prevent backflow of water into the conduit, prevent pressure surges and water hammer, and also allow excess liquid to be drained for maintenance purposes.

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Principle of operation

The safety valve is represented by the main body structure and several elements, which are located in a brass or nickel shell. Usually, this device has an inverted T-shape. A non-return valve is fixed at the bottom of the water heating tank, which prevents water from flowing out under the influence of a drop in the pressure level in the pipeline.

A valve device is located on the perpendicular branch, which operates when the pressure rises, and is also responsible for draining excess fluid through the fitting. A correctly installed device works in stages.

Check valve in the circuit

When the pressure level in the reservoir is lower than that in the pipeline, the filling process causes the poppet plate in the valve to be squeezed out under the influence of water pressure.

The normalization of pressure is accompanied by the closure of the plate and the limitation of the flow of water into the system. The active heating mode is characterized by a slow increase in the temperature of the water and an increase in pressure, which can reach maximum values. In this case, the defense mechanism is activated.

Periodic draining of liquid through the choke channel should not cause concern, as it indicates the functioning of the safety valve of the hot water boiler in normal mode.

Varieties

The safety valve device installed on domestic hot water equipment is most often represented by three main groups:

  1. Protective devices for water heaters with a volume of not more than 50 liters. in the form of disposable valves. A feature is the presence of a non-separable design, low cost and enough short term operation. However, some very well-known manufacturers of boilers are equipped with valves of higher quality characteristics.
  2. Devices for water heaters with a volume of not more than 200 liters, characterized by a 7 bar safety valve, a check valve and a shut-off ball valve, as well as a special nozzle for connecting to the sewer system.
  3. The safety device for water heating equipment with a volume of more than 200 liters is represented by mandatory elements in the form of a pressure reducer, a tap, a non-return and safety valve with a drain fitting.

Completely disassembled safety valves are equipped with special test points that facilitate diagnostics and maintenance of water heating equipment.

A lot of American manufacturers, as a rule, install closed-type valve devices on their water-heating equipment with no visual control of operation.

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Choice

Most often, all modern water heaters are sold with already installed system protection in the form of a safety valve with certain parameters. When purchasing the device yourself, you should pay close attention to the features of the threaded part, as well as the maximum operating pressure.

Installed valve

Each valve is designed for a certain level pressure, which must be indicated in the technical passport of the equipment. The total volume of the tank must also be taken into account. Produced protective systems can have a response threshold from 6 to 10 bar.

If the safety valve is incorrectly selected or installed incorrectly, there may be a constant leakage of liquid or a very strong overheating of the water heating equipment.

Installation

Self-installation of the device, as a rule, does not cause difficulties. Before proceeding with the installation, it is necessary to disconnect the water heating equipment from electrical network and drain all the water from the tank, then perform the installation, adhering to the following simple recommendations:

  • the safety element is installed at the cold water inlet to the boiler;
  • during installation, it is necessary to use a FUM sealing tape or traditional tow;
  • the second side of the fuse is connected to the cold water supply system;
  • in the presence of pressure drops in the water supply system, a reducer is installed in front of the valve.

Valve Installation Diagram

A flexible and transparent hose is used to connect the drainage pipe to the sewer system. It should be noted that sometimes a special safety valve is replaced by a demolition device designed to discharge liquid in emergency mode.

Despite the similarity of functions, the principle of operation of such devices is noticeably different, so you should not count on the correct operation of such a device.

It is forbidden to mount locking devices in the area from the entrance to the water heating equipment to the safety valve, and also to remove the protective element more than two meters from the boiler tank.

Possible breakdowns and causes

There are some of the most common problems that can occur during the operation of the safety safety valve of water heating equipment:

  • When the boiler is disconnected from the network and the water supply is turned on, liquid flows out of the drain hole. Cause - breakage of the safety element or elevated level pressure in the plumbing system.
  • When the boiler is connected to the network, there is a minimum water intake, prolonged heating of the water and a constant flow of fluid from the drainage hole. The reason is a malfunction of the safety valve.

All breakdowns associated with the safety valve are usually accompanied by frequent leakage of water or total absence fluid flow. In both cases, it is advisable to replace the device with a serviceable protective valve set to similar operating pressures.

It is very important to connect a flexible and transparent hose to the drain outlet of the device, which allows you to easily visually monitor the performance of the safety valve installed on the water heating equipment.

The correct operation of the safety valve installed on the water heating equipment is a guarantee of the safety of property and own security, therefore, when choosing and acquiring such a device, it is imperative to make sure that the operating parameters and rated power are in full compliance, as well as organize competent installation into the system.

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2016-12-04 Evgeny Fomenko

The answer to the most popular question: “Why do we need a safety valve for a water heater”, we will consider in this article? The safety or non-return valve in the water heater is needed for two functions, which are determined by its name. First - protection of the unit against excess water pressure.

Why is there excess pressure?

Everyone knows from the school bench that when heated, the liquid expands and increases in volume. The boiler tank is a closed volume, the excess pressure will seek weak spots it contains connecting gaskets, connecting elements of plastic pipes, seams on the container body.

Its second function- passing water in one direction into the boiler, it prevents hot flow from entering the water main, does not release it back. For example, even under the condition of normal pressure in the water supply, when a liquid is heated in a closed volume, its pressure increases.

For this reason, a moment comes when the water pressure in the tank will be higher than the supply pressure and the discharge will occur either into the water supply or into the toilet bowl. At the same time, cold water is supplied to the water heater, the heating element continues to work, expensive electricity is wasted.

The situation can become more unpleasant and costly with a sharp drop in pressure in the line, for example, during emergency or preventive work. If all the water from the boiler drains, the heating element will burn out. Some users who prefer to do everything with their own hands install a conventional non-return valve on boilers, not understanding the seriousness of the possible consequences.

It does not protect your appliance from pressure buildup, it only keeps the water in the tank. A water heater is not a kettle, but a complex heat engineering device; both automation and a thermostat can break down. If you are lucky and you have purchased a boiler in which the tank is made of high-quality material, boiling will not happen. Otherwise, if you turn on the tap, the pressure of the tank will drop sharply, immediately creating a stream of steam, which can lead to an explosion.

So why do you need a safety valve for a water heater, only briefly:

  • discharge of excess water when heated;
  • obstacles to the reverse flow of water;
  • normalization of pressure drops, protection against water hammer.

What is the function of the valve

In order to understand the principle of operation, consider its device. The safety device consists of two perpendicularly arranged brass cylinders forming a common cavity. In the inner part of the larger of the cylinders there is a disk element, which is pressed by a spring and allows the liquid to move in only one direction, preventing its outflow. The heater inlet and cold line pipe are connected to the two ends of the larger cylinder, which terminate in a threaded connection.

Inside the smaller cylinder is also a poppet element, which has a reverse actuation. At its outlet there is a forced discharge handle, at the bottom there is a pipe for draining excess water, which is connected to the sewer with a plastic tube. You can not use buckets, jars for draining.

How it works? The pressure in the water supply presses the plate spring, the liquid enters the tank. When the container is full, the pressure in the tank exceeds the water pressure, the valve closes, the water flow stops. In the process of water consumption, the pressure changes, the valve opens, the water begins to fill the boiler again. When the liquid in the container heats up and begins to expand, the protective disc device of the smaller cylinder is activated, the excess is drained through the side drainage hole, and the pressure in the tank is equalized.

Why do you need a forced reset handle?

When is it necessary to repair work, for example, to change the anode or in case of a long shutdown of the heater, you can make a forced drain of the liquid. How to use the check valve in this case? It is very simple to do this - raise or lower (depending on the model) the forced reset handle, after disconnecting the heater from the electrical network, the liquid will flow into the sewer.

Also watch this video for more information Additional information by valve:

How to replace (install) the valve in its place

As a rule, high-quality boilers are equipped with a safety device, taking into account the nominal working pressure indicated in the manual for the device. If the safety element is not included in the kit or it needs to be replaced, you can purchase it, it is inexpensive, the equivalent of $ 4-6.

The most basic selection criterion is compliance with the maximum possible pressure of your heater, indicated in the passport for the device. There are many different models on sale with an actuation moment of 6-10 bar in 0.5 bar increments. For greater security, it is better to purchase an element 0.5 bar below the maximum allowable.

The highest quality safety device on the market is considered to be the one on which the nominal value is indicated, the movement of the liquid flow is drawn with arrows, the outlet fitting consists of three sections for any size of plastic tubes, the reset handle is screwed in to prevent accidental pressing.


There are models without indicating pressure, in which case you should ask the seller what value it is designed for. Be careful, you can buy products - fakes made of silumin, you can determine them by weight. Models with a reset handle require periodic cleaning, at least once a year. To do this, you need to open and close it several times for washing.

Before you should drain the water from the unit, block access to it and disconnect from electricity.

The connection is made immediately under the water heater, to the cold water supply, taking into account the index arrow on the element, it shows the direction of flow. The thread on it, as a rule, is half an inch, twisted with a key for several turns using sealing materials.

If the pressure in the system is too high, a reducer should be installed in front of the valve. It is impossible to install an element with smaller parameters or with an inappropriate thread.

It is forbidden to put shutoff valves in front of it, only the installation of an "American" is allowed to allow the pipe to be disconnected.

All valves are factory set to nominal pressure and must not be changed, although some items are available with an adjustment screw.

A storage water heater (boiler) or simply a water heater is a device designed to heat water used in everyday life. Storage water heaters can have various design features, but in the vast majority these are metal containers completely filled with water, inside of which heating elements are located.

The water heater is designed in such a way that it constantly contains the same volume of water: when hot water is taken, the vacated volume is filled with cold water from the water supply system, which allows the device to be used continuously.

In the event that there is no hot water intake, and water heating continues, excess pressure may arise in the water heater tank, which can make it unusable.

Why in storage water heater is there excess pressure?

When heated, water expands by about 3% of the total volume occupied by the liquid. This means that in a 100-liter boiler, when the water is heated from 20 to 80 degrees, almost 3 liters of water turn out to be “superfluous”. If we remember that the liquid is practically not compressible, then it is easy to simulate a situation in which the metal tank of the boiler leaks and fails.

To prevent a possible emergency, water heaters are equipped with safety valves through which excess water is discharged to the outside.

In other words, a safety valve is a pipeline fitting designed to protect devices from destruction when excessive pressure occurs in them by automatically discharging excess liquid into the environment.

The safety valve operates under the direct influence of the working medium and is a direct-acting device. When the medium parameters are normalized, the valve returns to its original position. This means that as long as there is no excess pressure in the water heater, the valve is in its original position and does not let water out. When the pressure rises above the limit value, the valve opens and discharges excess liquid until the pressure drops below the set value.

How does a water heater safety valve work?

The water heater safety valve consists of two parts

    Non-return valve that prevents hot water from flowing back into the plumbing

    Direct acting spring valve

How a relief valve works can be seen in the example of a typical spring-loaded direct-acting valve set to a certain maximum allowable pressure. In the closed state, 2 forces simultaneously act on the sensitive element of the valve: one from the side of the pressure of the liquid in the boiler, and the other from the side of the setting device or the spring, which prevents the valve from actuating and opening.

If the fluid pressure force exceeds the force of the spring, the valve opens and water is discharged. When the pressure of the working medium decreases, the valve closes and the discharge of water stops.

With the help of the adjuster it is possible to change the settings of the safety valve.

As you can see, the design of the safety valve is extremely simple, but at the same time, a properly functioning valve is a guarantee safe work water heater and reliably protects against such troubles as overheating of the device and possible boiling of water in it, which can happen when the thermostat is not working.

How to check if the valve is working or not?

Checking the operation of the safety valve is easy: you just need to turn on the water heater and do not open the hot water tap until the water is heated to the limit. allowable temperature. In this case, through the safety valve should be discharged (drip) excess water.

If the water in the boiler heats up, but the valve does not work, then it is faulty, and it must be replaced with a new serviceable valve, and after installation, check its operation.

But before proceeding with the repair, you need to make sure that the hot water intake faucet is working and not leaking. If it is faulty, then the “extra” water from the boiler will flow through it and the situation in which the valve can work simply will not arise.

Also, the valve will not work if the thermostat of the device is set to incomplete water heating (30-40 C) or hot water is taken from the water heater, which also reduces the pressure level in it.

Precautionary measures

Summing up what has been said, it should be noted that the safety valve is a mandatory device for installation in pressure devices, especially if they are used in everyday life.

Without it, the water heater should not be operated. It is especially dangerous to independently improve the device and replace the safety valve with a check valve.

User Questions:

  • Hello, during a preliminary check of the connections between the tees, pressure gauge, safety valve, reducer and valves before connecting to the boiler, it turned out that the safety valve passes water in the opposite direction, i.e. not through but
  • Is it necessary to unscrew the screw on the lever to open the drain hole after installing the water heater?
  • I have a valve without a lever, and on the thread from which water leaks. how to set it up
  • Hello! Please tell me, everyone and everywhere says that the safety valve serves to prevent excessive pressure from entering the EWH tank and to relieve excessive pressure (when water is heated to the maximum allowable temperature) from the EWH tank. Question: how
  • I have a water heater hightag 50 liters how many atmospheres to buy a valve. sometimes he squeaks at me
  • Why does the valve actuate when the heater is off and water flows from it?
  • Hello! I have water flowing from under the nut of the flexible connection, which is screwed to the safety valve, which is screwed directly to the EWH. Water flows through the center of the nut, through a hole into which the eyeliner enters the nut. What's wrong?

Buying your first electric boiler is a milestone event. It is impossible to forget it, if only because for the first time you have to figure out why you need a power cord for the water heater, as well as how the entire system is connected and installed.
Subsequently, no questions, as a rule, arise, therefore, 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.

The laws of physics

Everyone knows from childhood that when heated, objects expand, increasing in volume. The value depends on the material of the object, temperature and conditions environment- such 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 a mandatory part of the boiler installation kit, serves to protect the walls of the tank from destruction.
If it is missing, then it must be purchased and installed separately. To understand how a water heater safety valve works, let's mentally assemble a tank model and connect it to the system.

Experiment

Two pipes are supplied 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. It is worth opening the tap, as hot liquid rushes out of the tank, squeezed out by cold portions coming from the system. However, there are several points that do not allow the boiler to be operated with this inclusion. Firstly, since the entire mass of cold water (in the tank and pipe) is not separated by anything, the heating element will constantly work, trying to heat the entire available volume. Secondly, if for some reason water disappears in the supply pipe or pressure drops significantly (not uncommon in domestic systems), then the stored and heated liquid from the tank will partially flow out 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 pass in only one direction, mechanically separating the two media - the simplest but incredibly effective solution. Why do you need a water heater safety valve? Let's mentally complicate the task by adding a conventional one installed on the feed to the design. In this case, heating will occur without loss, 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 is often the case? 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 material of the tank is chosen correctly, then the following happens: the pressure and temperature increase, but the water does not boil, because when high pressure the point is moving. 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 faucet. 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 injuries, then this can be considered luck.

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 scheme of these elements is the same, so it makes no difference whether they are installed on the Ariston, Termex or other boilers. There are two spring-loaded plates inside: one of them acts as a simple check valve at the supply, and the other holds the water in the tank until then until the pressure exceeds a certain limit.