Ignoring the need to install a safety valve may threaten the explosion of an electric boiler. Some people are trying to simplify the circuit and remove a much-needed device from the connection.

The cause of the boiler explosion may be an uncorrected safety valve for water heater.

Why are water heater safety valves important?

We will deal with the device of the safety device for the water heater and the principle of operation.

Device

The device itself is very simple. The design consists of two cylinders. One is large and the other is smaller. The cylinders are arranged perpendicular to each other.

1. big cylinder. It has a poppet valve, which is pressed by a spring. It provides water flow in one direction. A poppet valve is essentially a check valve. On both sides, the cylinder has a thread for connecting to a pipe and a heater.
2. Small cylinder. It is placed perpendicular to the first and has a smaller diameter. The cylinder is equipped with a drain socket with a poppet valve inside. It works in the opposite direction.

Principle of operation

There is nothing difficult in the operation of the safety valve for the water heater.

To clarify the operation of the device, we will simulate several situations.

• Let there be no valve at the heater inlet, which would block the return flow cold water flowing into the tank. Even with a stable pressure in the water supply, such a unit will not be able to work. The fact is that along with the heating of water in the tank, the pressure increases. At some point, the pressure in the tank may exceed the pressure in the plumbing, and hot water will begin to flow into the plumbing system. For example, hot water can flow from a cold water faucet or from a toilet bowl.
• There are times when in plumbing system pressure drops(often this happens at night, when the load on the water station decreases). In this case, the water from the tank is drained into the water pipes. TENY empty heat an empty tank, which leads to inevitable burnout. Of course, in theory, automation should prevent the process of overheating. However, not all models are equipped with this feature. Yes, and automation can simply fail in the most difficult moment.

Having considered both situations, one would say that this can be avoided by installing a simple check valve. There are craftsmen who do just that. But they do not even suspect that they are planting a time bomb in their house.

It is terrible to think what consequences can be expected if the thermostat fails.

There is no outlet for boiling water from the tank. The pressure rises, and with it the boiling point of water rises. If you open the tap, the pressure may drop, the boiling point also drops. This will cause water to boil instantly, as a result, a huge amount of steam is formed, which can cause a violent explosion.

Dangerous situations can be avoided by installing a serviceable valve for the water heater.

The main advantages of the safety device for the water heater.

1. Blocks the return flow of water from the heater to the water pipe.
2. It does not allow a sharp change in pressure in the plumbing system.
3. When the pressure rises, it releases excess water from the boiler.
4. If the safety device is equipped with a lever, the water can be drained for maintenance work.

Installation on a water heater

Choosing the right model

Usually boilers are already sold with a safety valve of a certain parameter. If the valve is missing, then you have to purchase it yourself. approximate price for a safety device - 250–450 rubles.

When buying a valve for a water heater, pay attention to the threaded part. If everything is in order with her, then you should pay attention to what operating pressure valve calculated. This value can be found by looking at the technical passport for the equipment. If it is below the prescribed pressure level, then water will constantly flow from the safety device. A valve with a pressure level higher than set in a critical situation may not save the boiler from overheating.

Correct installation

Some users try to hide the safety valve for the water heater and place it as far away from the heater as possible.

This approach is not forbidden if two conditions are met:

1. It is forbidden to install locking devices of any kind between the boiler inlet and the safety device.
2. It is forbidden to carry the boiler and valve at a distance of more than two meters.

If there is abundant water leakage through the drainage pipe until the water is very hot, then this indicates too high pressure in the plumbing system. This rarely happens. In this case, it is worth installing a gearbox.

At the same time, it does not interfere with checking whether the acquired the valve has a low pressure indicator and does not match the heater model. If it is normal, then it is worth checking the spring - perhaps it has “sat down” a little, and it needs to be replaced.

You should be wary if the valve remains dry at maximum heating rates. In this case, with a high degree of certainty, we can talk about its malfunction. You should not play Russian roulette, it is better to purchase a new device.

Conclusion

The safety of property and your own safety depend on the operation of the safety device for the water heater. When buying this device, be sure to check:

Safety devices for the water heater designed for smaller parameters must not be installed. It is also impossible to install valves whose threaded connections not suitable for installation.

If in doubt that you can install a safety valve for a water heater yourself, then it is better to entrust the work to qualified specialists.

Why do you need a safety valve in the water supply? How is this valve set up? What other types of fittings are used in water supply and heating systems? Let's figure it out.

Device and varieties

A typical valve has two branch pipes - for connection to the water supply and drainage. In this case, the drain pipe can be smooth or threaded.

In the body there is a spring with a normally closed (that is, in the absence of external influences in the closed position) valve hermetically closing the seat. Water presses against the seat side of the valve.

At a certain pressure level, the valve opens and remains open until it falls below the threshold value. Water all this time is drained through the drain pipe.

It is curious: most of the inexpensive valves do not allow you to change the factory setting and work at a pressure of 1.5 - 7 kgf / cm2 set by the manufacturer. However, they can be opened manually. However, there are also adjustable devices that allow you to set the response pressure in the range of 1-16 atmospheres.

What else is useful to know about this type of reinforcement?

• The difference between valves of the same type (adjustable and non-adjustable) comes down mainly to differences in diameter and type (external or internal) of the thread for connecting to the pipeline;
• The typical price of an unregulated device with a size of DN15 is 300-400 rubles, an adjustable one is 50-80% more expensive;
• Some manufacturers offer models with a built-in pressure gauge that allows you to visually monitor the current pressure in the pipeline.

A special case

The so-called safety group for a boiler consists of two different valves mounted in one housing - a safety and a check valve. This device is easily recognizable by the two threads for connecting to the water supply and by the arrow on the body indicating the direction of the water flow.

Functions

Safety valves for plumbing and heating systems prevent pressure from rising above their actuation level and protect pipelines, fittings and other fittings from damage.

It is worth clarifying: they are not used in cold water systems, centralized hot water supply with water supply from heating mains and central heating. Club members - DHW with water preparation in a storage water heater (electric boiler or indirect) and independent heating.

DHW

Any type of storage water heater must be equipped with a non-return valve at the inlet.

Yes, simply because without this valve, water will pour out of the boiler when the main water supply is turned off and reset. You see, its inlet pipe opens into the tank just above the bottom level: such a device allows you to achieve stratification of water by temperature.

Note: in addition to financial costs, the discharge of water from the tank will mean a high probability of exiting the heating elements of the electric boiler.

Now imagine what happens after filling and turning on the boiler, separated from the cold water supply by a check valve.

• The water temperature will start to rise;
• As it heats up, its volume, in full accordance with the laws of physics, will increase;

• An increase in the volume of an almost incompressible liquid in the closed space of the tank will cause a rapid increase in pressure.

This is where the safety valve installed on the water supply comes to the rescue: it will dump excess water into the drainage and thereby reduce the pressure level.

Heating

On heating, our hero is included in the boiler safety group and performs the same function as on hot water supply: it dumps part of the coolant with a dangerous increase in pressure.

The valve works in tandem with a membrane expansion tank and duplicates its functions: in normal mode, the excess coolant accommodates the expansion tank by compressing air separated from water by an elastic membrane. If the pressure continues to rise due to an incorrect calculation of the volume of the tank or overheating of the coolant, the valve is activated.

By the way: the installation is also practiced with boilers of a significant volume. It significantly reduces the cost of water supply: without an expansion tank, with each heating of water in a 300-liter indirect tank from 10 to 70 degrees Celsius, 6 and a half liters will be drained into the drainage hot water.

Installation

Are there any subtleties in installing a safety valve with your own hands?

• On DHW, it is mounted in front of the boiler inlet and after the check valve (of course, if the valves are not united by a common body);

• On heating, the safety group including the safety valve stands at a minimum distance from the outlet pipe of the boiler - where the pressure first begins to rise when the coolant overheats;

However: most heating elements of electric and wall-mounted gas boilers are equipped with their own safety group located inside the case.

• To seal the threads on the connection to the water supply, you can use any heat-resistant winding - flax with paint or sealant, FUM tape or polyester thread with silicone (for example, Tangit Unilok);

• The drain pipe is directed to the outlet internal sewerage or any plumbing fixture connected to it. If necessary, the drainage is increased by a tube.

Service

The only type of maintenance our hero needs is a periodic (monthly) health check. The fact is that the valve can stick to the seat, which will increase the response pressure. The test instruction is extremely simple: just open the valve forcibly for a couple of seconds.

Who else

Let's get acquainted with a few more varieties of the most popular sanitary fittings.

Name and photo	Description and functions
	Shuts off water with a ball valve when the stem is turned. It has only two working positions - "fully open" and "fully closed". Head and shoulders above its predecessors - plug valves and screw valves - in terms of fault tolerance.
	The throttle, which is also a balancing valve for water supply and heating, allows you to limit the throughput of the pipeline to equalize the temperature of the heating circuits or the water flow on the branches of the water supply. Similar in design to a screw valve, but with a needle valve and a wear-resistant stem seal.
	mechanical or electronic thermostat controls the position of the shutter of the control valve depending on the temperature working environment or indoor air. The shutter comes into motion when the volume of the working medium of the thermostat changes (liquid or solid material with a high coefficient of thermal expansion) or when the servomotor is started.
	Mechanical device for lowering water pressure to standard values ​​(1.5-4.5 kgf / cm2). The most common piston gearboxes operate due to the difference in the area (and, accordingly, in the force of the working medium acting on them) of the valve blocking the water and the piston located after it along the water flow.
	Comb with several outlets for parallel connection of heating or plumbing appliances. The so-called collector wiring allows you to independently adjust the flow of the coolant through several heating circuits. In addition, it equalizes the pressure on plumbing fixtures when water flows through the water fittings of one of them.
	Carries out a rough water filtration, detaining large suspensions on a stainless grid. Filtration is especially important if you use sanitary ware with ceramic closures: the ceramic chipped when you try to close the sand-jammed cartridge in single lever mixer or kranbuks.
	The device already familiar to us is a steel tank with an elastic pear-shaped membrane separating it into water and air compartments. The tank holds the excess of expanding water as it is heated in a closed circuit.
	Twin brother of the expansion tank, designed for cold water. It is used as a reserve tank and for pressure stabilization during pump operation.
	Limits the movement of water or coolant in one direction. Most common spring valves block the water with a brass or plastic valve with a return spring.
	Removes air pockets and steam formed during boiler overheating from DHW circulation systems and heating systems. Mounted at the highest points of the circuit or after the circulation pump. Works by changing the liquid level in working chamber: the valve opens and closes with a float.

Conclusion

Of course, our miniature review of fittings does not pretend to be complete: we have described only some of the most popular types of fittings. To learn more about why you need to put a safety valve on the water supply, the video in this article will help you. Good luck!

The service life of the storage boiler, as well as the safety of using the device, depends on the correct strapping. One of the important nodes is the safety valve for the water heater, installed on the inlet pipe of cold water.

To understand why a valve is installed on a water heater, it is worth remembering school curriculum. According to the law of physics, water expands when heated. The liquid is inside a sealed container. If there is no water analysis, the pressure rises, and the tank may burst. A safety valve for the boiler, which bleeds excess liquid from the tank, will help prevent an accident.

On the forums you can find information where it is advised to simply not install a check valve. Then the installation of the relief valve overpressure no need to make water. In their opinion, when there is an excess of pressure, part of the water will go back into the pipeline. Part of the advice is correct, but the system will work as long as the plumbing is stable. The advice is wrong for three reasons:

• there are no stably working water pipes without breakdowns;
• without a check valve, all the water from the tank will go into the empty pipeline;
• a bare heating element will heat the air inside an empty container.

Now consider the end result of the problem. In the event of a plumbing failure, the pipes remain empty. There is no non-return valve on the inlet pipe, and water with storage tank flows freely into the system. The thermostat will turn on the heating element when the temperature drops. Without water, the heater will simply burn out, but that's only half the problem.

There is another danger. The heating element is hot, and water appears in the water supply. Inside the tank, it sharply forms a large number of steam and excess pressure that does not have time to bleed back into the pipeline. The tank is guaranteed to break in several places. Boiling water will pour into the apartment. For this reason, it is better not to be smart, but simply install a water relief valve.

Device and work

There is nothing complicated in the installation of a safety valve for a water heater. Most often, the safety assembly is made in one piece. Inside one housing is a safety and check valve.

The scheme of a standard product looks like this:

• The bronze case has two chambers inside. The design resembles the letter "T". On the body of the check valve chamber, two threads are cut for attachment to the water supply. The body of the safety valve chamber is equipped with a fitting for water discharge.
• Inside the check valve there is a spring holding the stem, on which a round plate is fixed. When closed, it prevents the back flow of water from the tank into the empty water pipe.
• A safety valve similarly has a stem with a spring and a round plate. Most models are equipped with a forced water release lever. This element is directly connected to the stem.

Complete with a water heater are usually the cheapest safety valves without a lever. It is better to throw them away and buy a quality product.

In general terms, the principle of operation of the safety valve is as follows:

• During the analysis of water, the pressure inside the tank drops. The safety valve is closed. Due to the pressure difference, the check valve opens and the tank is replenished. When the pressure of the water supply and inside the container is equal, the check valve closes.
• The boiler thermostat turns on the heating element. The liquid begins to heat up, increasing in volume. If the pressure has reached a critical level, and there is no water analysis, the safety valve is activated. Hot liquid is drained through the fitting. After normalizing the pressure, the spring returns the mechanism to its original position.

The thermostat constantly monitors the set temperature and periodically turns on the heating element. If there is no analysis, the pressure will constantly increase with each increase in water temperature. During this period, liquid drips from the nozzle. This is normal working time. To prevent water from pouring onto the floor, a transparent reinforced hose is fixed to the fitting with a clamp, diverting its end into the sewer.

Types of security groups and the principle of choosing the appropriate model

The standard safety valve for a boiler may differ in several design features. These nuances do not change the functionality of the device, but only simplify the use and maintenance. To choose the right safety unit, you need to know what kind of safety valves for boilers are and how they differ.

Lever models

The most common type of standard safety knot is the lever model. Such a mechanism can be activated manually, which is convenient when checking or draining water from the boiler tank. They do it like this:

• horizontally located lever is installed vertically;
• direct connection to the stem actuates the spring mechanism;
• the plate of the safety valve forcibly opens the hole and water begins to flow from the fitting.

Even if complete emptying of the tank is not required, a control drain is performed monthly to check the operation of the safety assembly.

Products differ in the design of the lever and the fitting for discharging water. If possible, it is better to choose a model with a flag fixed to the body. Fastening is made with a bolt preventing manual opening lever by children. The product has a convenient herringbone shape with three threads, which ensures a secure fit of the hose.

The cheaper model does not have a flag lock. The lever can be accidentally caught by hand and unnecessary draining of water will begin. The fitting is short, with only one threaded ring. Fixing the hose to such a ledge is inconvenient and can be torn off with strong pressure.

Models without lever

Relief valves without a lever are the cheapest and most inconvenient option. Such models often come with a water heater. Experienced plumbers simply throw them away. The nodes work similarly to lever models, only there is no way to manually perform a control drain or empty the boiler tank.

Models without a lever come in two versions: with a cover at the end of the body and deaf. The first option is more convenient. When clogged, the cover can be unscrewed to clean the mechanism. A deaf model cannot be checked for performance and descaled. The liquid discharge fittings for both valves are short with one threaded ring.

Safety knots for large water heaters

Improved safety valves are installed on water heaters with a storage tank capacity of 100 liters or more. They work in a similar way, only they are additionally equipped with a ball valve for forced draining, as well as a pressure gauge.

Particular attention should be paid to the fluid outlet fitting. He's carved. Reliable fastening prevents the hose from being torn off by strong pressure and eliminates the inconvenient use of the clamp.

Models of the original performance

For lovers of aesthetics and comfort, manufacturers offer safety nodes in the original design. The product is completed with a pressure gauge, chrome-plated, gives an elegant shape. Products look beautiful, but their cost is high.

Case marking difference

Quality products on the case must be marked. The manufacturer indicates the maximum allowable pressure, as well as the direction of water movement. The second marking is an arrow. It helps to determine which side to put the part on the boiler pipe.

On cheap Chinese models, markings are often missing. You can figure out the direction of the liquid without an arrow. The check valve plate must open upwards in relation to the boiler nozzle so that water from the water supply enters the tank. But it will not be possible to determine the permissible pressure without marking. If the indicator does not match, the safety unit will constantly leak or, in general, will not work in an emergency.

Other types of valves

When trying to save money on the security group, they try to install a blast valve designed for the heating system on the water heater. The nodes are similar in functionality, but there is one caveat. The blast valve is not able to gradually release the liquid. The mechanism will work when the excess pressure reaches a critical point. The blast valve can only bleed all the water from the tank in case of an accident.

Separately, it is worth considering the installation of only a check valve. The mechanism of this node, on the contrary, locks the water inside the tank, preventing it from draining into the pipeline. With excess pressure, the working plate with the rod is not able to work in reverse side which will cause the tank to rupture.

Installation and adjustment of the safety node

Any person can install a safety valve on a boiler without the help of a plumber. correct wiring diagram indicates that the safety assembly is attached to the cold water inlet pipe to the water heater. Below are taps, filters and other piping elements.

The valve is installed on the water heater in the following sequence:

• The safety valve is installed directly on the cold water inlet pipe going into the water heater. Often a detachable adapter is placed between them - an “American” for ease of dismantling during maintenance.
• Fum tape is wound on the thread of the pipe or adapter to seal the connection. The safety knot is wound so that the arrow on the body is directed towards the boiler.
• When winding the safety valve onto the water heater, you need to stop when you feel the stop. On cheap models, there is no mounting fuse. The part is screwed in four turns. You can't rotate anymore. The thread of the pipe will close the channel of the fitting for draining the water.

After installation, it is worth looking inside the body from the side of the check valve. Inside the hole you can see the saddle and the plate of the locking mechanism itself. To check the performance with a finger or pencil, press the plate. It should go inward, and when released, return to its original place.

When the entire circuit is assembled, proceed to adjust the safety node:

• The water heater is filled with water, voltage is applied and the maximum temperature is set on the thermostat. You have to wait until full heating occurs, and the automation will turn off the heating element.
• Drops of liquid should appear from the nozzle. If not, turn the adjusting screw until a positive result is obtained.
• After adjusting the lever, a little water is bled from the tank, after which the mechanism is returned to the closed state. The dripping from the nozzle will stop. A new portion of water will enter the tank. The heating element will heat it up, and the liquid will again begin to drip from the fitting.
• The mechanism adjusted to the maximum temperature will always work when the permissible limit is exceeded. Now you can set a smaller value on the controller operating temperature, for example, 50–60 ° C. When this threshold is reached, liquid will not drip from the fitting.

The safety group is checked for operability of the forced drain lever and operation at maximum temperature once a month. If there is no adjusting screw and the mechanism does not work according to the required parameters, the part is replaced.

Faults and solutions

A faulty boiler safety valve is detected by constantly flowing liquid from the fitting or when there are no drops at the maximum heating temperature. A breakdown is the absence of a forced drain when the lever is raised.

Consider possible malfunctions:

• Liquid constantly flowing from the fitting appears at high pressure in the water supply. If the safety group is designed for 6 bar, then at 7–8 bar in the line, the excess will be constantly bled off. You can check by forced draining using the lever. If the drops stop after bleeding, then the problem is the high pressure of the water supply. It is necessary to put a reducer at the entrance to the house.
• When water continues to flow after the pressure is released, the cause is a clogged working spring. If the safety group can be disassembled, all elements are cleaned of dirt and put in their place.
• The absence of a drop and a forced drain indicates a clogged fitting or the entire working mechanism. There is only one way out - to disassemble and clean.

If a part is not separable or cannot be repaired, it should be replaced immediately.

The water heater safety group is not a node that is saved on. Boiler repairs will cost more.

The constant availability of hot water in a house or apartment - for most people this has long become a familiar norm, without which it is difficult to imagine a normal, comfortable life. If water supply is extended to housing or an autonomous uninterrupted water supply is organized, for example, , then there’s nothing to think about - you need to install a water heater of one type or another.

Probably the leading position in terms of popularity among domestic water heating appliances are electric boilers. They are extremely easy to operate, their installation does not require any additional conciliatory procedures or formulations individual projects. Installation of such a boiler is quite feasible for independent implementation. That is why the information that will be presented in this publication is necessary - each of the home masters must clearly understand how important the safety check valve is for

How would employees of housing and communal services, emergency and rescue services, regulatory bodies of state technical supervision did not warn what would plots with the consequences of accidents were not shown on television, all the same, with frightening regularity, there are “wise men” who need all these technical recommendations and just good advice is not a decree, they themselves "know how easier and better." Alas, ignoring a very small, inexpensive, easy-to-install, and at the same time extremely important object for tying an electric water heater can turn into very big troubles, and it is possible that even a tragedy.

First of all, it is necessary to immediately make a very important reservation. Though very often, in order to obtain information, those interested in driving in the search query “check valve for a water heater”, it will be much more accurate, more correct to talk about a safety valve that combines several functions. These devices have a certain similarity, but there is also a huge difference, which predetermines the main task - security safe operation of the electric heater.

For comparison, consider the device of a conventional check valve:

This is how a normal check valve works. But for a boiler it is not enough!

This is a metal cylinder., on both sides of which there are threaded sections for "packing" into a straight section of a pipe of the corresponding diameter. The poppet valve is stopped inside - a disk with a rubber seal around the circumference, on the central axles - stock(shown in the figure with a green arrow). The disk is constantly in a spring-loaded state, blocking itself internal channel for the passage of water.

When water is supplied in the direction of the arrow (the direction of the allowable fluid flow is always indicated on the valve body - in the figure this mark is shown by a red arrow), the pressure in the pipe through the "plate" compresses the spring and slightly opens the passage. As soon as the pressure decreases, the valve automatically switches back to the closed state.

Such a precautionary measure, of course, is necessary so that the tank is constantly filled in the water heater, under any circumstances. However, such a measure is clearly not enough to ensure security - this will be discussed below.

The safety valve is somewhat more complicated:

In fact, these are two valves in one housing, placed perpendicular to one another.

In the larger cylinder (pos. 1), which goes along the course of the water, the same valve is installed to prevent the reverse flow of water. On the supply side, there is a “male” threaded section (pos. 2) for tapping into the plumbing system (in particular, it will be convenient to connect a flexible water hose here). On the opposite side, there is a “female” threaded coupling (pos. 3), which in some cases is screwed directly onto the standard cold water supply pipe in the electric heater.

In the figure, the "plate" of the check valve (pos. 4) with a sealing ring around the circumference, and the spring (pos. 5) that holds the valve in the closed state are very clearly visible.

And now - the main difference. Perpendicular to the cylinder with a check valve, there is another one, somewhat smaller in size (pos. 7). In fact, it contains the same poppet valve, but its spring is much more powerful - this is the very safety “stall” valve. Normal and even slightly increased pressure in the water supply system will not be able to compress the spring and open it - this requires much more serious efforts.

In the cavity of the cylinder behind the "plate" of the safety valve, there is necessarily a hole with a pipe (pos. 8), where, when the valve is triggered, excess liquid will be discharged.

A cylinder with a safety "stall" valve can be completely plugged, and sometimes it ends with a threaded plug (plug), behind which there is an adjusting screw (usually for an "internal" hexagon). But the most common safety valves with an additional lever:

The figure clearly shows the features of such a device. The lever (pos. 9) is intended for manual opening of the safety valve with water discharge through the pipe (pos. 8). Please note that the branch pipe may have a special relief design that allows you to put thin hoses on it to drain water into the drainage (sewerage). The function of manual control of the valve can be convenient, for example, to drain the contents of the boiler during repair or maintenance work. Nevertheless, one should not “get carried away” using such manual control - it can even be dangerous in some cases (this will be discussed below).

Any safety valve always has an arrow indicating the direction of cold water flow towards the water heater. (red arrow in the diagram). Very often, the limiting pressure of the “stall” valve operation is indicated on the body - in this case it is 0.7 MPa or 7 atmospheres (yellow circle in the figure).

How a safety valve works in different situations

In order to finally be convinced of the importance of the safety valve, it is best to consider the cases in which it works, as well as those situations that may arise if, for some reason, the valve is missing or defective.

For clarity, once again - the simplest, but also the most understandable scheme for tying a boiler with a safety valve. The blue and red arrows show the direction of flow, respectively, of cold and hot water. The green arrow points to the location of the safety valve.

1. After the electric is installed, completely “tied”, its filling follows. To do this, simply open the cold water supply and the hot tap on one of the mixers. The pressure in the water pipe is enough to open the check valve for unobstructed flow. As the volume of the water heater tank is filled, air is displaced. As soon as a stream of water comes out of the mixer - the entire container is filled up to the upper intake pipe, the supply can be turned off.

The pressure in the boiler at this moment is approximately equal to the pressure in the cold water main - it is, as it were, “supported” by it. However, it can even be slightly higher - due to the remaining compressed small volume of air in the upper part of the tank. Plus, when the power is turned on, the water starts heating - and this, of course, also leads to an increase in pressure.

2. Imagine a situation that the check valve is not installed, or is in a faulty condition. The balance that was reached when filling the boiler tank is sooner or later disturbed, since the pressure becomes higher than the pressure in the pipe. The "hot" taps on the mixers are closed, which means that the heated water will look for an exit in a different direction. This can cause hot water to suddenly start flowing from a “cold” faucet, or it may fill up the cistern on the toilet. Meanwhile, the boiler thermostat cannot understand the situation and does not give a signal to turn off the heating elements. Expensive electrical energy is completely wasted.

3. But this is not the saddest part either. It is no secret that the pressure in the water main, especially in high-rise buildings, often drops to critical values(from the tap, as they say, barely flows), or even disappears completely. There are a great many reasons for this, for example, an accident on the highway, preventive maintenance, planned pressure reduction, for example, at night, etc. What happens if the check valve is missing or defective? Yes, nothing good - the boiler will simply empty, since all the water from it will completely flow out into the supply pipes.

Well, if the boiler provides protection against "dry" heating, and it will work quickly! And if not? Powerful heating elements will idle heat the air in a closed volume, and this will end either with their burnout or cracking of the enamel - in any case, nothing good can be expected in such a situation.

4. A reasonable question may arise - is it possible be limited to installation of this same non-return valve? It would seem, judging by the description, he is able to solve all problems.

Do not consider it an exaggeration: such an installation is a bomb planted in your house!

No, by no means. The installation of a complex valve, combining both a check valve and a safety valve, is prerequisite safe operation water heater.

If somewhere the reader comes across a similar picture - only a check valve at the inlet, then he should understand that this is comparable to the mortgaged powerful bomb, which is unknown when it explodes.

Another example of "suicidal creativity"

We consider the situation in detail. When the boiler is turned on, heating begins, and with the rise in temperature, according to the laws of thermodynamics, pressure begins to increase in a closed volume.

Constructors household appliances a certain operational resource is laid in each water heater, allowing the device to operate up to certain pressure values ​​​​in the tank - usually this value is indicated in the technical documentation. Typically, all boilers are very balanced thermodynamic systems, in which the optimal ratios of allowable temperatures and pressure levels are very accurately calculated. However, anything can happen. And as soon as the pressure level, for some reason, begins to approach the permissible upper mark, the spring on the safety valve is compressed, and the resulting excess liquid is discharged into the drain pipe. As a result, the system again enters a state of dynamic equilibrium.

Water escaping from the drain pipe is normal.

And now let's try to imagine what can happen in a situation where there is no emergency valve, and everything is limited only to the reverse

Water heating should be limited thermostatic regulator, but quite often these electromechanical devices are far from perfect, and can simply fail. In this case, heating continues uncontrollably.

The pressure inside the boiler tank is growing, but there is no way out for it - the mixers are closed, and the check valve reliably blocked the supply line. It would seem that the temperature will only reach 100 degrees, to the boiling point of water? Nothing like this! With increasing pressure in a closed volume, the boiling point of the liquid also rises sharply. For example, the data is shown in the table:

Pressure in a closed volume, atm (MPa)	Boiling point of water, °Ċ
1.0 (0.1)	99.09
1.033 (0.1)	100.0
1.5 (0.15)	110.79
2.0 (0.2)	119.62
2.5 (0.25)	126.79
3.0 (3.0)	132.88
4.0 (0.4)	142.92
5.0 (0.5)	151.11
6.0 (0.6)	158.08
7.0 (0.7)	164.17
8.0 (0.8)	169.61
9.0 (0.9)	174.53
10.0 (1.0)	179.04
20.0 (2.0)	211.38
25.0 (2.5)	222.90
50.0 (5.0)	262.70
100.0 (10.0)	309.53

When the word “bomb” was mentioned above, this is not at all an exaggeration! Under such circumstances, the water heater becomes really into an explosive device terrible destructive force.

Already at 4 - 5 atmospheres of pressure, the boiling point reaches almost 150 ° WITH, and continues to rise. An increase in pressure on the walls can lead to their deformation, chipping of the enamel or ceramic coating - but this will be the smallest possible evil. Another circumstance is terrifying - a sharp drop in pressure in this closed system, and this can happen when a crack appears in a weld, when a rubber seal breaks, or even just when you open a hot water tap on

A sharp decrease in pressure leads to a corresponding sharp decline boiling point of water. As a result, the entire volume of liquid (imagine all 50, 80 or 100 liters at the same time!) instantly boils, which, of course, is accompanied by the release of a huge amount of steam. No, even the most durable body can withstand this - a strong explosion follows, which is capable of demolishing everything in its path, including even brick interior walls. illustrative examples there are many on the Internet.

It's hard to believe, but these are the consequences of an explosion of an ordinary electric boiler.

So let's lead summary regarding the need for a safety valve.

- It does not allow back leakage of water from the tank into the supply pipeline, in the event of a decrease in pressure.

The presence of an inlet valve creates additional protection boiler from possible strong pressure surges in the water supply system, from hydraulic shocks.

- The safety valve will eliminate a possible flaw in other security levels - it will maintain the temperature-baric regime in the boiler within acceptable values.

— The safety valve, equipped with a lever, also allows you to drain the water from the boiler if necessary.

Video: Do ​​I need to install a safety valve on the boiler?

Recommendations for the selection and installation of a safety valve

Choosing the right valve is easy. Most often, boilers (especially from leading manufacturers) go on sale complete with a valve of the required rating. You will need to focus on the same value if, for some reason, you have to change the valve in the future.

The value of the limiting pressure in the boiler tank, in addition, must be indicated in the technical documentation of the product. If the water heater is not equipped with a valve, then you will have to purchase it yourself, based on the value indicated in the passport. It is important to choose the right value here - if you install a too “weak” valve, water will flow almost continuously from it. A valve with too strong a spring will not create absolutely safe conditions operation.

The valve can be “packed” directly on the cold water boiler pipe (always has the corresponding blue color marking. For reliable sealing during installation, it is best to use linen tow with modern sealing pastes. When twisting, 3-4 full turns are usually enough. flexible eyeliner, then there is enough rubber sealing gasket.

Sometimes a drain valve is inserted between the valve and the boiler itself - this greatly facilitates periodic maintenance work. Such an installation is quite acceptable, but only under one condition - the valve must be on the branch of the tee, but in no case should it interrupt the direct channel from the water heater to the valve. Any check valves on this straight section strictly prohibited!

Step-by-step instructions for tying an electric water heater

It makes sense to consider step by step how you can connect yourself electric boiler to the plumbing system. The table below shows two options as examples. Despite some differences, in both cases it will still be clearly demonstrated that the safety valve is an indispensable element of piping such a water heater.

Illustration	Brief description of the operation to be performed
	To begin with, a few words about installing the water heater itself on the wall. Of course, the place is thought out in advance, before the purchase of the device, so that the boiler fits in the space allotted to it and does not interfere with the normal operation of the room. To the installation site is usually carried out in advance power cable power supply connected to a separate machine. Insertion points into the plumbing system are immediately provided. To accurately hang the boiler on the wall, its height is measured.
	Knowing the height of the water heater, it is easy to determine the lower point of the position of the device, which it will take after installation.
	On the back side of the body of the water heater there are devices for mounting on the wall. V this case- this is a regular mounting plate (bracket) that will cling to hooks. There may be other options - in the instruction manual of the device, usually all this is described, and often 1: 1 templates are also applied to simplify the marking process.
	In this case, it is necessary to determine the location of the line on the wall along which the hooks will be mounted. To do this, we measure the distance from the lower end of the water heater to the mounting plate.
	The same distance is laid vertically on the wall from the previously planned point of the planned lower edge of the boiler.
	With control over building level a horizontal line is drawn along which hooks-hooks will be located.
	The next step is to measure the required distance between the hooks. In this case, 200 mm will be optimal - the hooks will be placed closer to the edges of the mounting plate, but there will remain the possibility of a slight backlash to the left and right to align the water heater.
	This distance is transferred to the intended horizontal line - the centers of the holes for the hooks are marked. In the example shown, they fell rather unsuccessfully - exactly on the seams between the ceramic tiles. If there is such an opportunity, then it is better to mark the holes away from the edge of the tile - there is much less chance of a crack appearing when drilling holes.
	Powerful hooks were chosen for hanging the boiler: the outer diameter of the polymer dowel-plug is 14 mm, the length of the dowel is 80 mm, the diameter of the metal hook is 8 mm. Often, the kit of an electric water heater already includes the fasteners recommended for installation.
	At the marked points, the corresponding holes are drilled with a perforator, into which the dowel-plugs are hammered. Then the hooks themselves are screwed in.
	The hooks are screwed in to such a depth that a reliable, stable fit of the water heater is ensured, without play, but also without jamming.
	Everything, the boiler is hung on the wall. Two pipes are clearly visible from below, through which the device will be connected to home system plumbing. Branch pipes are marked color coding: blue - cold water supply, red - hot water outlet.
	A corresponding tie-in has already been made into the water supply - here are two polypropylene pipes, to which it is necessary to connect the water heater piping. On the left is the hot water pipe, on the right is the cold water pipe.
	In this example, the master decided to equip the entrance to the boiler with an optional element - an additional tap, which will be used when it is necessary to empty the boiler. To do this, a tee will be installed on the inlet pipe of the water heater. The recommended preliminary “fitting” is carried out - how many revolutions are needed for the retractor of the reel to take the required position. In general, it is advisable to carry out such fittings before assembling any fixed assembly - there is less chance of making a mistake.
	After that, the tee is packed on a winding of tow, smeared with Unipak sealing paste.
	The tee is packed, it is given the intended position.
	A compact valve will be mounted on the side branch pipe of the tee.
	Tow is rewound, sealing paste is applied.
	The tap is screwed in, tightened with a key, at least three turns, it is given a planned position for easy access to the handle.
	And now the turn has come to install an obligatory element - a safety valve. Be sure to pay attention to the arrow showing the direction of water flow.
	The safety valve will be installed on the lower branch pipe of the already installed tee. The basic rule is fully observed - between the valve and the water heater there are no locking devices. A tap installed on the side branch pipe of the tee does not have any effect on the safety of operation of the device.
	The valve is packed on a tee - in the illustration, this entire assembly is assembled.
	It is advisable to make the boiler piping collapsible - this will make it possible to turn off the device to remove it, for example, for prophylaxis or for replacement heating element or an anode rod. Therefore, the master decided to install shut-off valves at both entrances. Ball Valves with a union nut - "American". A sample of such a crane is shown in the illustration.
	The faucet itself will be rigidly packed on the lower branch pipe of the safety valve. And on the fitting with the union nut itself, a fitting will be mounted to switch to a polypropylene pipe. That is, it will not be difficult to disconnect the boiler from the pipes of the regiment.
	The second tap of the same type is placed on hot water, but already directly on the outlet pipe of the water heater. And it is also assumed that a fitting will be packed to a removable fitting with an "American" to switch to a polypropylene pipe.
	Here is the fitting mounted to the fitting of the crane, trying on the installation site. In this case, a 90-degree fitting was used to immediately leave the pipe closer to the wall.
	Next, another branch will be welded in - and the pipe will go down along the wall.
	On the fitting of the second tap, for hot water, a conventional fitting is mounted for switching to polypropylene. But this was done solely for reasons of aesthetic appearance of the strapping - so that the “step” of the transition to a level closer to the wall on both pipes is located at the same height. Further, the usual welding and installation work with polypropylene pipes is carried out.
	This is how neat the common water heater piping turned out.
	And this illustration shows how the supply pipes are welded into the previously left water pipes. The water heater installation is complete. You can open all the taps (except for the drain), fill the boiler with water, connect to the power supply. If necessary and possible, a transparent PVC tube is put on the drain pipe of the safety valve, which is drained into the sewer, cistern toilet bowl or any container - the drained excess water will not fall on the floor.
	Now consider possible variant boiler piping with installation of flexible piping. The illustration shows that the water heater is already hung on the wall. The arrow shows one of the "water outlets" - branch pipes hidden in the wall under the decoration of cold and hot water pipes.
	Conventional ball valves will be packed on these nozzles. In this case, there is no particular need to use taps with a union nut - the piping will be collapsible due to the use of flexible piping.
	Linen tow is wound on the branch pipe. Some craftsmen use FUM tape, but there are still many more supporters of reliable sealing with tow.
	The winding is smeared on top with Unipak type sealing paste.
	Then the crane itself is screwed on - first it is baited manually ...
	... and after that - it is tightened with a key, so that the "lamb" is located in a place convenient for use - on top.
	A similar operation is completely repeated with the second crane. This is over for now.
	We proceed to operations directly on the boiler itself. Two of its branch pipes are ready for further installation.
	A sealing winding is performed at the inlet pipe - a safety valve will be installed here.
	In this case, the master decided to limit himself only to the valve, that is, to do without installing a drain valve on the tee. It is quite a normal solution - you can also drain the water from the boiler through the valve - a special lever is provided for this. Draining will take a little longer, but the installation is simpler and cheaper, and you still have to resort to emptying the boiler not so often.
	The valve is screwed on and then tightened with a wrench so that the lever and drain pipe are in a position convenient for the user. In fact, this was the last connecting node that required winding up with tow.
	The safety valve is installed in its regular place.
	Flexible hoses are connected. In this case, the master used high-quality corrugated stainless steel hoses, which are considered “eternal” according to their characteristics. A flexible hose made of a rubber or plastic hose in a metal braid, of course, is significantly inferior in terms of reliability, and attracts only at a low price. The principle of installation is absolutely identical. Hoses in length are purchased taking into account the distance from the boiler to the "water outlets". The gasket that comes with it is inserted into the union nut of the hose, then the nut is inserted onto the thread of the branch pipe (in this case, the outlet). No rewinding is necessary if the end of the pipe along the entire circumference is in a normal state - the gasket will provide the necessary level of sealing of the connection. The union nut is first screwed on by hand - until it stops ...
	... and then tightened literally another ¼ ÷ ½ turn with a wrench. You should not overtighten the connection - you can pinch the gasket and thereby achieve just the opposite result.
	The second end of the flexible hose is connected in the same way to the threaded fitting of the tap on the corresponding “water outlet”.
	The installation of the second hose is carried out in a similar way, with the only difference being that it is connected with its upper end to the branch pipe of the safety valve. Now you can open the water and check all connections for leaks. If a “tear” is found, you can still slightly tighten the connection with a key, without applying much effort - the leak should disappear.
	If there are no leaks, you can proceed to the full operation of the water heater. The illustration shows the "lower node" of the boiler piping: the flexible connection is connected to the taps of the "water sockets".
	And these are the same hoses, but connected from above to the safety valve (for cold water) and to the hot water outlet pipe. Boiler installation completed.

Video - Check valve on the water heater

Frequently Asked Questions (F.A.Q.)

And finally, it makes sense to answer some of the most frequently asked questions about the operation of boilers with a safety valve.

• People often ask how to deal with annoying water droplets protruding from the drain pipe?

But there is no need to fight them - they only say that the valve is functioning normally. The easiest way is to put a transparent tube on the nozzle (so that you can visually control it), and bring it out either into sewer pipe, or, for example, in the toilet flush tank.

• Can the valve be placed so that it is not visible?

By and large, if he is so annoying, then you can. But at the same time, certain conditions must be met:

- No additional elements are allowed between the valve and the boiler - shut-off valves, tees, etc.

- The length of the section from the valve to the entrance to the boiler should not exceed one and a half ÷ two meters. The fact is that the vertical column of water in the pipe will exert additional pressure on the safety valve spring, and it will not work correctly, with a strong undercut.

• Leakage from the valve is too frequent and abundant, even at low water heating temperatures. What can be done?

The reasons for this phenomenon may be different.

— The valve rating does not match the characteristics of the water heater.

— in the valve, the spring simply weakened over time.

In both cases, the valve should be replaced with a new one with the required actuation force.

Another reason may lie in the instability of pressure in the plumbing system. For example, frequent pressure surges with a large amplitude lead to valve operation even in the absence of heating. In this case, it is recommended to install a pressure reducer at the inlet of the water supply to the house (apartment).

• Can I try to adjust the valve myself using the adjusting screws?

Definitely - no! Adjustment of such devices requires " calibrated» pressure, and it is forbidden to carry out such procedures on your own. The valve is not such an expensive product that it is impossible to purchase a new one of the required denomination.

• I have never seen a single drop of water come out of the valve. This is fine?

But this is a very worrying sign.. Who knows, perhaps the valve simply “calms” with its appearance, but it is completely inoperative. For example, the chamber behind the belleville spring is overgrown or clogged with scale, the pipe is clogged, etc. If the valve is equipped with a lever, then you can try to check it manually (only better - at low heating temperatures, about 40 degrees, so as not to get burned).

It is possible that the valve rating is excessively high - it does not match the model of the water heater. In addition, a factory marriage cannot be completely ruled out.

The best way out of this situation remains the same - replacing the safety valve with a new one.

So it will be calmer!

Never skimp on your own safety!

Video - Tricks of connecting an indirect heating boiler

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.

Tank heater accumulative type It is a hermetically sealed tank in which water is heated. During this process, steam is generated and the pressure rises. That is why among the technical characteristics of the unit there is an indicator of maximum pressure. For household appliances, it is usually equal to 10 bar.

When in the evening all family members took a shower, 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 of the apparatus 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, ensuring 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 check valve seat should be visible. 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 test period, do not open hot water taps.

• After the water heater is fully connected and filled 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 operating 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 outside reason for 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. In the tank, a space will be freed up, which will be filled 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 level unless absolutely necessary. temperature regime. 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 at 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.