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. Safety valve for a water heater, which is mandatory included in 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 tank material is chosen correctly, then the following happens: the pressure and temperature increase, but the water does not boil, because at high pressure the point shifts. 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.

The operation of water heating equipment is directly related to a change in the pressure level in the system. Its adjustment is necessary for the safe operation of the electric storage boiler. Modern water heaters are equipped with automatic protection against high pressure in the tank. However, a safety valve for the water heater is essential to ensure safe work.

Purpose

The device of the storage boiler is based on maintaining a certain volume hot water, which is automatically replenished when it is used. In the absence of outflow from the tank, the electric heating element continues to work. Hot water expands, its impact force inside the tank increases.

Water is a substance that is practically incompressible. When the temperature rises to 80⁰ C, it increases in volume by 2-3%. Excessive pressure inside the tank can damage it, create an emergency situation.

To relieve excess water pressure, a safety safety device is used - a safety valve. Mounted on the branch pipe for entering cold water into the boiler. Through it, excess volume is removed to the outside. When the pressure inside the tank is normalized, the protective mechanism closes, the outflow of excess volume stops.

Design features

Safety valve device for water heater:

  • Frame
  • Relief fitting
  • release lever
  • Two poppet valves with opposite actuation direction
  • Relief valve spring
  • check valve spring

Structurally, the safety valve looks like two cylinders placed perpendicular to each other. The large cylinder has a threaded part at the ends for mounting to a water heater and a water pipe. Inside the cylinder there is a check valve pressed by a spring.

Perpendicular to the large cylinder is smaller in diameter. On one side, it enters the cavity of the large cylinder. On the other side there is a plug or forced pressure release handle. In the cavity of the small cylinder there is a drain pipe with a poppet valve in the opposite direction of operation.

Structurally, it looks like two cylinders placed perpendicular to each other. The large cylinder has a threaded part at the ends for mounting to a boiler and a water pipe. Inside the cylinder there is a check valve pressed by a spring.

Perpendicular to the large cylinder is smaller in diameter. On one side it enters inside the large one, on the other side there is a plug or a handle for forced discharge of water pressure. Inside the cavity of the small cylinder there is a drain pipe with a poppet design in the opposite direction of actuation.

Principle of operation

The safety safety valve is a direct acting device. When the tank of the water heater fills up, the force of the liquid will depress the poppet valve, making it possible to fill the tank.

After filling the tank, the water pressure inside will increase, under its influence the check valve of the large cylinder will close, preventing the outflow back through the plumbing system. As the liquid inside the tank decreases, its force of action gradually decreases. The non-return valve is pressed out, resuming the filling of the tank.

Increasing the temperature increases the pressure level. Under its influence, above the permissible value, the plate-shaped design of a small cylinder is triggered, a drainage hole opens, and the excess volume is brought out. The pressure inside the system equalizes, the reverse returns to its original position.

Functions

  1. Prevents backflow of fluid from the storage tank.
  2. Removes excess volume from the water heating tank to stabilize the internal pressure.
  3. Levels pressure drops inside the central water supply system.
  4. The forced reset lever can be used to drain when performing maintenance.
  5. Extends the life of the electric heating element, water heating equipment.
  6. Saves energy by preventing the heating element from running idle.
  7. Protects against an emergency situation of overheating, explosion of the storage boiler.

Kinds

They differ in the following points:

  • Release lever. It is needed to check the correct operation of the mechanism, it is advisable to check it once a month. By lifting the lever flag, you can empty the storage tank. It is important to pay attention to the device flag. Some models are made with a small screw attached to the lever - to prevent accidental opening, emptying the tank.
  • Arrow on the body, designation of the nominal working pressure of the safety mechanism. It is recommended to purchase devices with these designations on the case in order to choose the best option.
  • Drain plug. Produced different shapes. An oblong, stepped shape is preferable, so that it is more convenient to put on the outlet hose, crimp it with a clamp if necessary.
  • No release lever. When purchasing this modification, you should pay attention to the presence of a threaded cover. It will allow further maintenance (remove blockages, scale, pollution). This is the preferred option.
  • For large-capacity boilers (from 60 liters), other models are produced with additional mechanisms: a ball valve, a pressure gauge, a standard fitting thread. These models are more varied species composition. You can choose the option you like best. The cost of them increases significantly compared to standard counterparts, it can even reach the level of the price of cheap heating equipment.

Safety or reverse?

Installing the opposite instead of the safety one can lead to unpleasant, life-threatening consequences.

The reverse will prevent the outflow of hot water from the boiler tank through the plumbing system. The liquid is heated to maximum temperature, its impact force inside the tank increases. If the thermostat fails, the temperature will continue to rise along with the pressure, which will increase the boiling point.

When excess volume is discharged through the water tap, the boiling point will return to 100⁰ C, but the temperature in the tank will still be much higher. Instantaneous boiling of the remaining liquid, the release of a large amount of steam will lead to a strong explosion that will damage the water heating equipment, the walls of the room.

If the safety valve is not installed

Without a safety mechanism installed, the water heater will not work properly.

With a constant volume inside the storage tank, an increase in temperature will cause an increase in the impact force. Having reached a value that exceeds the pressure level of the central water supply network, it will begin to push hot liquid through the water supply. If you do not open the hot water tap, normal pressure inside the tank will be regulated by its ejection into the pipe with cold air. Water heating equipment will waste electricity.

If the pressure in the water supply system decreases (load reduction at water pressure stations at night, accident, repair work), the supply pipe will be empty. Hot water from the storage tank of the water heater will pour out through the empty pipe. For models without automatic control of the operation of the electric heater (or with malfunctioning automation), the heating element will heat idly, which will lead to its burnout.

  • You should choose a spring mechanism. It is reliable and has good resistance.
  • It is recommended to take into account the features of the water supply system, if necessary, install a reducer to adjust the pressure of the water supplied from the central water supply network.
  • Need to consider throughput defense mechanism.
  • It is necessary to correlate the maximum allowable pressure level in the water heating system with the operating pressure of the safety mechanism. If the pressure of the latter is low, water will constantly flow from it. If high, it will not work when the water pressure rises above the allowable level.

Installation

  1. The water heater must be disconnected from electrical network, empty the storage tank.
  2. Install the valve mechanism on the pipe with cold water. Connect one end to the pipe, mount the other into the boiler. It is necessary to follow the direction of water movement (indicated by an arrow on the body).
  3. If necessary, install a water reducer up to the valve structure to stabilize the water pressure from the central water supply system.
  4. Connect the drainage outlet of the mechanism with a flexible hose to the sewer system. To monitor proper operation, it is recommended to supply a transparent hose.
  5. When hidden installation behind water heating equipment is prohibited:
    - install locking devices between the boiler and the safety valve mechanism;
    - make the distance from it to the boiler more than two meters.

How to check the correctness?

You can check the serviceability by turning on the water heater (faucet with hot water while not opening) wait for the water to heat up to the maximum possible temperature. After a while, excess water should drip from the protective protective mechanism.

The valve will not operate if:

  • the hot water faucet is faulty (pressure will be released through it);
  • the thermostat is set to 30-40⁰ C (the water will not warm up to the extent that the pressure inside the reservoir tank reaches an acceptable level);
  • operating pressure valve protection device is high, does not correspond to the productive capacity of the water heating equipment (the maximum allowable pressure in the storage tank will not be sufficient to trigger the safety valve mechanism. May have dangerous consequences).

Water from the valve device must be periodically discharged. If this does not happen and all the listed cases are excluded, the fuse itself is faulty. It must be replaced with a new one, after checking its performance.

A safety mechanism must be installed on water heating equipment to ensure long, uninterrupted, safe operation of the device. You should choose the most suitable option for all design and functional parameters, otherwise its activity will be inefficient, and even dangerous. In this case, it is necessary to periodically check its serviceability, about once a month. If a malfunction is detected, the inoperative valve must be replaced with a new one.

It is very dangerous to independently improve it, replace it with a check valve mechanism. This will lead to unpleasant consequences, due to which, it is likely that you will have to replace the purchased water heater with a new one.

Friends! More interesting stuff:


How to make a solar water heater for your home with your own hands?

For modern people hot water is the norm, providing a comfortable life. If there are problems with hot water supply, heating devices can be installed. The most popular designs are electric boilers. The safety valve for the water heater is an important component when installing the unit. The level of safe operation and the service life of the device depend on this part.

The operating time of the system elements depends on this device.

Part assignment

The non-return safety valve for the water heater prevents sudden pressure drops inside the device. The reason for such jumps is due to the fact that the liquid in the process of heating increases in volume and expands. Due to the tightness of the tank, the formed surplus has nowhere to go, because the tap is closed.

Subsequent heating can cause pressure build-up. In this situation, it is highly likely that the permissible strength values ​​​​of the device will be exceeded, and its walls will break. To avoid such moments a check valve is being installed on the water heater.

Many owners are puzzled if a fuse needs to be installed if the check valve can be removed. Experts say that with high and uniform pressure indicators in the systems, this scheme will work, but not for long.

This does not mean that such actions are a way out. The error of the technique is that the pressure in the system is far from always stable. excess water leaves the devices in the water supply, thereby exposing the heating element. Heating the air, the unit will break down after a while.

In this video you will find out why it drips from the boiler:

Burnt out structures are not the worst problem. It is important that there is a possibility abrupt change pressure indicators in the system. The liquid quickly turns into a vapor state, which sharply increases the pressure. In this case, the walls of the water heater will certainly burst. A large number of hot water and steam will quickly fill the room, threatening severe consequences for the people in it.

Principle of operation

The safety valve consists of several elements. They are located in a brass or nickel case. Often, the part looks like an inverted letter T. A non-return valve is fixed on the bottom of the electric boiler, which prevents water from flowing out of the system when the pressure in the pipes decreases.


The working principle of this valve is easy to understand.

The perpendicular outlet consists of another valve, which is activated after an increase in pressure and discharges excess water through the fitting. The principle of operation of the check valve on the boiler is as follows:

  1. If the pressure in the tank is less than in the pipes, then when the tap is opened, the check valve plate is pressed out by the pressure of the water. When the indicators return to normal, the spring mechanism clamps the plate to the protrusion on the body, preventing the flow of fluid.
  2. During the period of active heating, the temperature of the water slowly rises, and the pressure increases. The mechanism is not activated until the indicators reach the maximum values.
  3. Upon reaching the limit level under the action of pressure, the safety spring is compressed, opening the inlet channel of the inlet on the fitting. Excess water flows out through this passage. After the values ​​are reduced to standard values, the spring closes the channel, and the liquid withdrawal stops.

From the described, we can conclude that water periodically flows from the fitting. This happens during the heating of the liquid, when the pressure in the water supply system decreases.

If water is regularly present in the fitting, then the drain valve for the water heater is fully functional. But at the same time, it is necessary to divert the flowing liquid. To do this, a tube of the appropriate size is fixed on the nozzle; a clamp can be used as a fastener. The normal operating pressure in the tank ranges from 6 to 10 bar. Without a strong fixation, the pipe will be torn off, so you need to choose this part carefully. It should be tightly tightened and brought to the drain in the sewer.

Features of different types

If we are talking about standard safety valves for a water heater, outwardly they do not differ much. But there are a number of nuances on which the ease of use of the part depends.


Do not forget about the nuances of these valves

Trigger lever

Some valves are equipped with a special lever. Periodically, you need to check its performance. To do this, you need to carry out the following manipulations:

  1. Move the lever from horizontal to vertical.
  2. Wait for the activation of the spring mechanism, because the lever pulls it along.

After carrying out these actions, a channel will open from which water will flow. This procedure should be carried out at least once a month. This is how water is drained from the water heater tank. After raising the flag, you need to wait a little until the liquid drains completely.

For some valves, the lever is fixed with a special bolt. This design eliminates the possibility of spontaneous opening and descent of the liquid. In addition, some products are completely without levers; they have a cap on the top of the thread that is needed to service the valve. As needed, it is opened and various contaminants and scale are removed.

The least preferred option is parts without any levers, dirt extraction holes or markers. These are the lowest quality products made in China. Rely on their strength and long term operation is not possible. Such devices can be used as a temporary replacement for stronger parts.

Connection and pressure value label

There are a number of device differences. On the case there is an arrow indicating the direction of water flow, as well as an inscription that reports the maximum possible pressure for a particular product. Such trifles may seem insignificant, but if it is not difficult to figure out the direction of the flow of water, then the situation with pressure indicators is much more complicated.

At first glance, it is difficult to say what values ​​\u200b\u200bexist for a particular valve, because they can only be calculated empirically . Suppliers distinguish them only by documents. Masters do not advise buying products without identification marks. Of course, the cost of marked parts is slightly higher than that of analogues, but in this case it is better not to save.

In addition, you should pay attention to the shape of the water outlet. On some details, it is long and has a non-linear shape. It is easy to fix the tube on such a device; its size is quite enough to securely fix the clamp. If the products are expanded at the end, then the size of the fitting is the main thing. It is better to refuse such an acquisition. This is due to the fact that it will be difficult to fix and secure the handset on the device. Handicraft methods do not guarantee the quality of work, and in the future there may be problems with water drainage.


Don't forget the pressure mark

Products for large appliances

All devices described are intended for small storage water heaters, the capacity of which is 50-60 liters. For large tanks, other parts are used, each of which has specialized equipment integrated - a valve or a ball pressure gauge that controls pressure.

The fitting for draining the liquid they have is equipped with a standard thread. This is necessary for better fixation and the absence of problems with clamps. Such devices are expensive, but their level of quality is much higher than that of other systems.

Many consider it a major disadvantage appearance crane. For such people, fuses are specially produced, which are not only useful in practice, but also decorate the interior of the room. Often their price is equal to the cost of a water heater, so everyone evaluates the feasibility of such an acquisition for themselves.

Other devices

There are situations when, instead of factory safety systems that prevent pressure surges, a blast valve is installed. Its main purpose is emergency draining of liquid into the heating system. In terms of functional characteristics, such products are very similar, but the principle of their work is diametrically opposed.

Products of subversive type function in case of accidents. They are necessary for emergency draining of water from the water heater and are not suitable for periodic bleeding of small portions. Such elements should not be expected to work correctly.

In addition, many install only a check valve. Its mechanism at low pressure does not allow liquid to escape, but it does not save from sudden changes in the tank. Practice shows that such a device is also non-functional.

Selection and installation

It is necessary to choose a bypass valve for the boiler, based on the pressure value that the product can withstand. Often this figure is fixed in the data sheet. In addition, the choice is influenced by the capacity of the tank. There are systems whose response threshold varies from 6 to 10 bar. These are the most common indicators for valve actuation. The installation process of the valve is quite simple, if you follow the step by step instructions:

  1. Wrap FUM tape or tow on the thread for a tight connection.
  2. Fix the valve on the nozzle.
  3. Tighten the product until it stops by hand, and then make a few turns with a wrench of the appropriate size.
  4. Do not forget about the place of installation of the installation. Masters advise placing it on the cold water inlet pipe.


After that, you can install a check valve, otherwise called constipation. Such manipulations are reinsurance measures, because a design with identical functions is already present in the fuse system, in addition, it is often integrated into water meters.

Then it is necessary to place a ball valve, which is used to remove water from the tank during dismantling or conservation of the product for the winter. Also, these actions will need to be performed during preventive cleaning or repair. Often, the crane is mounted on a tee - the link between the product and the safety system.

The safety valve is an indispensable part for the correct functioning of the water heater. It is undesirable to neglect this design, because an inattentive attitude can be fraught with serious consequences.

If there are difficulties with the choice or installation, it is better to entrust this matter to experienced craftsmen who will make the boiler completely ready for correct and safe operation in a short time.

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, 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 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 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 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 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.

When arranging an alternative hot water supply system, a safety valve for the water heater is installed, the principle of operation of which is very well known to specialists.

If you need to install hot water equipment yourself, you need to know not only the design features, but also the basic rules for installing such fittings.

Storage boilers are popular household appliances designed to heat water.

Storage type water heating equipment may vary design features, but predominantly, most of these devices are represented by metal water tanks with installed heating elements in the form of heating elements.

Water heating equipment is designed in such a way that the same amount of water is constantly inside the tank, the volume of which is replenished as needed.

In the process of heating, a natural expansion of water occurs and an increase in the initial volume of liquid by about 2.5-3.0%. Thus, the amount of water in a tank designed for 100 liters, as a result of heating to 80 ° C, will increase by about three liters.

Safety check valve for boiler on 1/2″ thread without flag

The absence of a pronounced compression of the liquid can provoke a rupture of the walls of the tank and the formation of a leak of varying severity.

Among other things, the reason for the failure of the water heater may be too high pressure in the water main. If the water supply network is characterized by a pressure level above 6 atm., then it becomes necessary to install a special gearbox.

In the absence of hot water consumption and while maintaining the level of heating, problems can occur represented by overpressure, which often causes the failure of hot water equipment.

What is the function of the valve?

What is a water heater safety valve and how does it work? Many consumers independently upgrade water heating equipment by removing the check valve.

Of course, under conditions of a sufficiently high and stable pressure inside the plumbing system, this option will function correctly for some time, but the very first failure causes the device to go out of working condition.

Valve on the water heater

For example, with insufficient pressure inside the pipeline, a process of natural displacement of cold liquid by hot water occurs with its movement back into the plumbing system. The result is the exposure of the heating elements and their inevitable, fairly rapid overheating.

Burnt-out heating elements are not capable of completely compromising the safety of operation of a water heater, but highly heated heating elements cause a sharp rise in pressure in the plumbing system.

In this case, the ingress of water onto a hot heater causes its evaporation, a lightning-fast increase in pressure and a guaranteed strong rupture of the water heater reservoir, with the release of boiling water and steam to the outside. To prevent such problems, a safety valve device is used.

Boiler safety valve device

It should be remembered that the safety device prevents the supply of water from the heater to the water supply system, smooths out possible pressure fluctuations and prevents the formation of powerful hydraulic shocks, facilitates the discharge of excess water through the fitting and ensures the safe operation of water heating equipment.

Valve design

The safety valve device for a water heater or the so-called "safety group", depending on the design, may have some features.

The following devices are available:

  • intended for water-heating equipment with a volume of not more than 100 l;
  • service boilers with a volume of 100-200 l;
  • built-in water heaters with a tank capacity of 200 liters or more.

The features of valve devices of the first category are affordable cost and a non-separable type of housing. They will be different short term operation, but may well be replaced quite often. It is these devices that are most often equipped with budget models of water heaters.

The second type of "safety group" is complemented by a ball valve and a special pipe for connecting to the sewer system. Most often, such devices are made in a collapsible case, which makes it possible to replace individual faulty elements.

The most expensive and most modern valve devices are "safety groups", which are used in hot water equipment with an increased tank capacity. Such devices are characterized by the addition of standard equipment, in the form of a pressure gauge, pressure reducer, strainer and a special sump.

During the installation of a water heater, it is unacceptable to replace the safety valve device with a blast or emergency valve intended for installation in heating systems.

Why do you need a forced reset handle?

Often, the safety valve device is equipped with a special lever, through which water is drained from the reservoir of water-heating equipment in manual mode.

The valve with a drain handle allows for easy and convenient emptying of the storage tank of the water heater during any repair work and for the purpose of routine inspection of the inside of the tank or cleaning it from accumulated scale.

Water supply to the water heater

The principle of operation of the safety valve

The safety valve device used in hot water equipment would be more correctly designated as an effective valve system. A pair of such elements is located inside a brass or nickel-plated perpendicular-shaped body.

The lower part of such a body is represented by a check valve, which helps to prevent the outflow of water from the water heater tank under conditions reduced pressure in the plumbing system. Inside the perpendicular branch of the volumetric body, another valve device is installed, the task of which is to release a certain amount of water at elevated pressure.

Valve with emergency lever

The principle of operation of the safety valve device is quite simple:

  • in conditions of filling the tank with water and with the hot water supply tap open, the pressure indicators inside the water-heating equipment are below the water level, which causes the disc plate to be squeezed inside the check valve device;
  • when equalizing the pressure indicators inside the water-heating equipment and the plumbing system, the plate is pressed against the body walls with the help of a spring, which helps to block the flow of water into the water-heating unit;
  • in the conditions of the switched on mode for heating, a relatively smooth increase in the temperature indicators of water is carried out, and, accordingly, an increase in pressure inside the system to the limit values;
  • the achievement of threshold pressure indicators stimulates the compression of the built-in spring on the safety valve, which is accompanied by the opening of the outlet to the fitting. In this case, the water is partially drained until the indicators are normal, after which the spring device closes the outlet and the water does not flow out.
  • the principle of operation of the safety valve device is determined by the dripping of water from the fitting, which accompanies heating and lowering the pressure level inside the plumbing system. Draining water needs to be drained, so a special transparent pipe is used, which is fixed at the outlet with a well-tightened clamp.

The tube installed on the fitting must be reinforced, but transparent, which will allow it to easily withstand overpressure and control the constant performance of the valve device.

The safety valve device refers to pipeline fittings, which are intended to protect water heaters from destruction, under conditions of excessive pressure.

Such an element allows automatic discharge of excess fluid into the sewer system.

The performance of the valve device may be impaired by dirt entering the internal part or as a result of damage to the disk part of the equipment.

It is for this reason that it is necessary to provide the valve with regular preventive inspections, and, if necessary, timely replacement of worn parts with similar new elements.

Related video