Safety valves for heating systems. Check valve for heating: connection diagram, types and operating recommendations

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Modern heating equipment for homes should be reliable, safe to operate and ensure uninterrupted operation. Any design must use safety valve for heating.

• Mixing taps;
• Safety kit ;
• Collectors and sludge collectors;
• Temperature controllers;
• Various safety valves;
• Auto-feed;
• Circuit balancing.

Among the listed safety valves, the most important element is a special kit that ensures the safety of the boiler.

Safety valves and shut-off valves

The main elements of the kit that ensures the safe operation of the boiler are:

• Safety valve for heating systems;
• Pressure gauge (for in the system);
• Air vent (to remove excess air).

During the operation of the heating main, various kinds of failures can occur, which lead to a sharp jump in pressure. As a result of improper operation of the installation, other elements may also occur, which in turn can pose a danger both to the structure itself and to people's lives. Therefore, it is very important to have a safety kit that allows you to regulate the pressure of the system.

Thus, the main function of the safety valve in the heating system is to protect the heating equipment at high pressure. Basically, such a need arises when using boilers with. However, one should not exclude such an emergency situation with other types of heating.

Boiler safety group

Causes overpressure in the heating system:

• The appearance of steam as a result of a sharp increase in temperature (descent of water);
• Use of a large amount of coolant. This mainly applies to private houses, in case of failure of the automatic system.

The temperature of water heating in radiators is not more than 90 degrees. The initial temperature when filling the installation does not exceed 15 degrees. Heating occurs, which leads to expansion of the volume. Therefore, a safety valve is used as protection.

It is one of the composite heating structure and acts as a protective element. The principle of operation of heating is based on the discharge of excess coolant in the event of excessive pressure. The most widespread are spring-loaded safety valves. It is the spring that counteracts such jumps.

The safety valves used for heating are open and closed.

The difference between these two types of valves is that the open safety valve works without backpressure, while the closed type works with backpressure.

When needed correct installation safety valves, according to the attached normative documentation, which takes into account the corresponding power and operating pressure of the selected device.

mixer taps

Mixing taps are located in front of the heating ring. They are used to regulate the heating in the system. When turning the handle three-way valve opens, the pump retracts cold water, after which it is mixed with the hot coolant in the system. Thanks to this device, the principle of operation of taps - mixers regulates the temperature of the water.

The safety valve is installed both on the heating medium supply pipeline, and mounted at the outlet of heated water, if heating is carried out using hot water.

When installing a safety valve in a heating system, the following conditions must be met:

Safety valve installation rules

• Absence of foreign devices in the valve-pipeline system;
• The diameter of the control valve is larger than the diameter of the pipe;
• Use of a special safe room for the withdrawal of discharge pipes;
• The selection of the required diameter should be carried out by specially trained people using the relevant approved regulatory documents;
• the pressure difference between the valve and the installation must be between 15 and 25%.
• Carrying out mandatory regular checks of the operation of safety devices. Checking is carried out during their forced opening. The recommended verification of instruments should be carried out at least once a year. Preferably before heating.

These are pipes large diameter. Equalize the pressure in the pipeline. Such a collector is installed in a special distribution heating cabinet.

To remove sludge from the system, ball valves embedded in the manifolds are used. In addition to ball valves, magnetic separators are used in the installations. Dirt separators have a special mesh arranged in the form of a fan. Due to this protection design, a delay is produced different kind particles and small debris in the water, their separation and removal to a collection designed for this.

Overview of thermostats

Heating regulators include a valve and a thermocouple. The heat transfer is controlled by means of a valve. The principle of operation is based on the distribution of water flow, which depends on the external temperature. The valve includes a spool, the height of which is determined throughput. Depending on the height of the movement, there are low-lift and full-lift.

Low-lift have a height of 0.05. For full-lift - is more than 0.25. The first type of temperature controllers is recommended to be used where there is a small throughput (usually a liquid medium), the second type is most suitable for a gaseous medium.

In addition, valves can be spring and lever-load. In the lever-cargo spool is combined with the lever. A load is hung on the lever. Due to the movement of the load, which is carried out along the entire length, the force of pressing the spool to the seat is regulated.

When there is a difference between the pressures of the medium and the lever, an automatic opening occurs and the flow of the coolant into the discharge pipe is ensured.

In addition to the safety element, bypass and check valves are used, with the help of which the pressure in the heating system is also regulated. The principle of operation of these devices is similar to the principle of operation of the safety element. The only difference is that they are connected to the return line. They ensure the movement of water into the pipeline in the opposite direction when the pressure exceeds the allowable level.

The main parameters that must be considered when choosing these devices are the working pressure. Their job is to let water through in one direction and prevent movement in the opposite direction.

bypass valve

Other types of locking equipment

Other types of shut-off heating equipment include a needle valve, a solenoid valve, compensators, a servo drive:

• The needle valve acts as a shutter. Regulates the flow of the coolant when the pressure in the system begins to rise.
• The simplest and most accessible of the safety elements that provide control and equalization of the water flow is a solenoid valve.
• Compensators reduce vibrations that can lead to deformation of the pipeline at high temperatures.
• The necessary dosing of water volumes, voltage and temperature is ensured through the use of a servo drive.
• Another component included in the design is a water heater or heat exchanger.

Water in the heating system is heated by boilers. The choice of boiler design depends on the water heater, due to which heat is transferred from the hot coolant to the cold one.

The use of safety valves for heating systems and other control equipment avoids many problems associated with high pressure, which can damage the heating installation and lead to the destruction of equipment components.

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A modern heating system is a complex, finely balanced system. Its main task is to provide indoor comfortable conditions regardless of the weather outside. And this means that a technologically advanced heating system must be able to adapt to changeable weather and change its operating modes. By-effect such flexibility and sensitivity - overloads that can lead to a decrease in heating efficiency or emergency depressurization of the circuit. In order for the heating to work flawlessly, a special type of shut-off and control valves is used - safety valves.

Why you need a safety valve

Valves are devices that constantly or when specific conditions are reached, regulate or completely close the flow of the substance transported in pipelines. Safety valves for heating, as the name implies, must protect pipes, heat exchangers and vessels (device cases) from harmful effects.

For example, the pressure in the heating system rises in the following cases:

• When the coolant reaches operating temperature and increases in volume.
• If the water is heated too much - until steam is formed (the volume increases several hundred times).
• In case of malfunctions or complete failure of the automated make-up unit. In this case, the pressure usually rises to an emergency mark, but sometimes the valve of the device stops holding, and the coolant flows in the opposite direction, respectively, the pressure in the heating installation drops sharply.

The valve for the boiler is a combined device, it prevents backflow and discharges excess water

Basically, we are talking about the pressure increasing to a critical point. But this is far from the only problem requiring an instant solution. There are also valves that prevent the backflow of water or eliminate the airing of the system. All safety valves in the heating system, in fact, perform the same job, but are mounted in different places and can protect individual components and devices / devices. They are installed:

• For the protection of self-contained closed-circuit heating installations in which boilers using all types of fuel, as well as heat pumps or solar collectors, are used as a heat generator.
• For steam heating.
• In systems with tanks that accumulate heat.
• In DHW circuits, which are equipped with flow-through, storage or electric heating elements.

Safety valves in heating installations function according to different principles and solve different tasks. Therefore, it is customary to divide them into several types:

• regulating,
• bypass,
• waste,
• reverse,
• air.

Types of valves for heating and hot water systems

Air valves

The air inside the circuit is compressed by the coolant into “plugs” and interferes with the circulation process, without which the operation of water heating is impossible. It enters the pipes during the filling of an empty system, or when replenishment is carried out (a certain amount of air is contained in the water in dissolved form). Partially, it penetrates through seals at joints and joints, as well as through diffusion through the walls of pipes and heat exchangers. In any case, the formation of traffic jams must be prevented.

To do this, “Mayevsky taps” are placed on the radiators - manually operated valves (you need to unscrew the screw). But there are also automatic air vents that, without human intervention, react to the air in the pipes. The air valve for heating has a float in its body, which, moving up / down, moves the needle through the rocker and opens or closes the discharge hole. Mount it in places where air accumulation is most likely (collector, top point of the riser, pump with air separator).

check valve

They are installed on pipelines to prevent the coolant from going in the opposite direction. Check valves are mounted at the inlet to the heating or storage tank, they can also be seen on the main line of the bypass interchange. The device is an indispensable part of the automatic make-up unit, where it stops the flow of coolant into the water supply pipes if too low pressure is set there.

The check valve for heating is arranged very simply. The seat inside the body is covered by a spring-loaded diaphragm. In the direction of travel, water / antifreeze compresses the spring and raises the membrane - the duct is open. If the water flows in the opposite direction, then the spring will press the membrane against the seat (the liquid itself will also contribute to blocking) - the duct will be closed. In another design, the control element of the device is a hollow ball made of metal or heat-resistant rubber. This "loose" ball is buoyant and is easily lifted by the flow above the orifice, but when it moves back, it fits tightly into the saddle.

For boilers, special check valves are used with a tap for water discharge. In fact, the “spout” is another valve that dumps the excess volume of liquid that appears when the water is heated and in the absence of parsing. It can also release water at too high pressure in the water supply.

Relief valve

It is triggered when the pressure in the heating system exceeds the set value. The device simply drains the "extra" coolant, thus bringing the pressure back to normal. The main elements of the relief valve for heating are:

• locking assembly (seat + bolt);
• sensitive mechanism that sets the actuation pressure (spring or loaded lever device).

In spring and lever valves, the coolant with set pressure exceeding the force of the load / spring, undermines the pressed down membrane and goes into the sewer, collecting tank or pit. Then the force of the loaded gate will begin to overcome the falling water pressure, and the valve will close.

The relief valve (left) is part of the boiler safety group

bypass valves

In their design, this type of device is similar to reset models. Only they do not remove excess coolant from the system, but redirect it to the return pipeline. In what cases is it necessary? Now users are actively using automatic and manual thermostats on radiators. But, by "clamping" the flow in order to reduce the heat transfer of the battery (usually - at all at once), we reduce the speed of the coolant and increase the pressure in some areas. But the circulation pump works without slowing down, which negatively affects its durability. To prevent such problems, a heating system bypass valve is needed, which allows water to flow along a short ring. Unlike vents, this device functions to drain water long time, not in individual moments when the likelihood of an accident is high.

control valve

This device designed to control the flow of the coolant by changing the cross section of the passage. This is a two-way actuator that can be operated by manual setting or by means of different kind drives (most often electric). According to the type of locking element, control valves are divided into:

• saddle,
• ball.

Some types of control valves for heating can be used not only to balance the flow of water, but also to control pressure. There are many applications for such devices, but most often they are installed on radiators and on the DHW circuit with a tank indirect heating.

The valve, mounted at the inlet to the battery, allows you to limit the flow through the heat exchanger and direct the coolant to other heating devices

Safety valves increase the efficiency and safety of the heating system. These are as important elements as batteries, pipes and a heat generator.

Video: safety valve

The bypass valve of the thermostat of the heating system is a simple mechanism designed to reset working environment(heat-conducting liquid) operating in return heating systems with a significant increase in pressure in the liquid supply circuit.

Cause and effect

Often, an increase in the pressure level in such systems is associated with the normal functioning of thermal valves that are installed on radiators or a thermal head. When the maximum temperature set in manual mode is reached, the supply of hot coolant to one or another radiator is reduced, which ensures an increase in pressure, and in some cases even a whistle of the radiator shut-off valves.

Of course, that this is reflected, in addition to the level of comfort in the room, also on the performance, as well as the durability of the heating system, its individual components. To avoid such situations, professionals recommend equipping heating systems with thermostatic valves.

Equipping the system with bypass valves will make it possible for its normal functioning, and it will be guaranteed to ensure the stabilization of the pressure inside it.

Where to mount and why

The thermostatic valve is mounted by inserting it into the system at a short distance from the pump supplying liquid, between the return line and the supply circuit. The setting mode of the maximum allowable pressure limit of the working medium allows the owner to make manual settings.

Currently, the range of these products, offered trading network big enough. But as practice shows, it is better to pay attention to such well-known trade marks like Mankenberg, Valtec, DANFOSS. They have proven in practice efficiency, reliability and durability in operation.

Purpose

Adjusting bypass thermostatic valves are designed to ensure a stable pressure difference between the return and supply pipelines in closed-type heating systems. If the heat load decreases, the thermostatic radiator valves close. This leads to an increase in the pressure drop between the return and supply pipelines.

Using a bypass valve provides the following benefits:

• reduces the load on the pump;
• protects the boiler from rust;
• prevents the occurrence of noise unnatural for normal operation;
• increases the temperature of the working medium in the return pipeline.

By closing the thermostatic valves on the radiators, we will get an increase in the resistance of our heating system (an increase in the pressure drop between the return and supply pipelines). This will increase the load on the pump and lead to noise.

If the pressure reaches the maximum level that corresponds to the settings of the bypass valve, it opens, forming an adjustable bypass. Also, a bypass valve is installed behind the circulation pump between the return and supply pipelines.

Types of valves for boiler and bypass

To understand the installation and selection of an element for radiators, you must first find out what safety bypass valves exist and what function they are designed to perform.

The principle of operation of the thermostatic safety valve is quite simple and is as follows. The working medium (water) exerts pressure on the plastic area, which compresses the spring and opens the passage. But when the pressure exceeds 20 bar, the plastic plane reaches the stem, which opens the outlet to the outside.

This valve is mounted for radiators in heating systems on containers in which the liquid is under high pressure. For example, this could be electric boilers. The valves installed on electric boilers have a special hole to provide local drainage.

They are a mechanism that is equipped with a double-sided thread and located with outside gasket. The device operates on the basis of a spring holding the rod. After applying force, the rod, pressing in, opens the passage. When pressure is applied from the back side, the blocking provides an increase in pressure.

These items are made from brass. The stem plate inside is made of heat-resistant plastic, and the spring is made of stainless steel. The mechanism works due to the fact that water under pressure is supplied to the damper, which rises, freeing the way for the flow. When the pressure drops, the stem drops, eliminating the possibility of flow return.

Three way valves

A three-way valve in the heating system is necessary to allow the coolant to cool. They can have mechanisms with manual control, electric drive and servo drive. They have enough simple design, outgoing and incoming openings.

Flow control is provided by a special damper, which has the form of a rod or a ball. When rotated, it orients the flow in the right direction. Such a valve also applies to safety fittings mounted on circuits with a low temperature. For example, in places where warm floor adjacent batteries operating from the same heat source.

They are used in places where it is necessary to lower the temperature on one of the parts of the circuit. With its help, the temperature of warm floors is reduced in comparison with batteries.

Mixing of the working medium can be carried out both in manual and automatic modes. For the valve to operate in automatic mode, it is necessary to equip the low-temperature circuit with special sensors, information from which will be fed to the servo drive. The three-way valve is made from different materials, but the main ones for their production are cast iron, steel.

The four-way valve is often made of bronze. It has three openings, one of which is an outlet and two are inlets. The regulating element in it is a corrosion-resistant rod.

When moving in a vertical direction, it does not completely block the flow of water, which makes it possible to redistribute the flows.

The heating system often includes control mechanisms and mechanisms that ensure the safety of operation. In another way they are called valves of heating systems. With the help of these adjustment elements, the parameters of heat supply change, they also ensure stable operation and produce automatic tuning. Consider the valves and regulators of the heating system, since they have different purposes and functions.

Usually, the boiler automation cannot meet the demand for water with different temperatures for multiple heating circuits. The three-way thermostatic mixing valve of the heating system comes to the rescue, which maintains the necessary thermal parameters of the coolant in the circuits of the heating system, as well as in the small circuit of the system.
In appearance, the valve looks like a simple tee, the metal is bronze or brass. At the top of this tee, an adjusting washer is installed, under which there is a material sensitive to temperature differences. And if necessary, it presses on the working rod coming out of the housing. The main task of the valve is based on keeping the temperature of the coolant at the outlet within the specified limits by adding cold or hot water. In case of unsuitable temperature changes, the external actuator of the valve presses on the stem. Further, the cone leaves the saddle and a passage opens between all channels. During work, control three-way valve according to the temperature, it is executed by an external drive.

Heating check valve

AT complex system heating is present enough a large number of auxiliary elements, the task of which is to ensure the reliability and uninterrupted operation. One of these elements is the check valve of the heating system. check valve set so that there is no flow in the opposite direction. Its elements have a very high hydraulic resistance. In connection with this circumstance, there are restrictions on the use of check valves in the system. There is too little pressure in such a system. At minimum pressure it is necessary to install gravity valves with a butterfly valve, some of them can operate at a pressure of 0.001 bar. The main part of the check valve is the spring used in almost all models. It is the spring that closes the shutter when changing normal parameters. This is the principle of operation of the check valve.

It is necessary to take into account the operating parameters in a particular heating system. In this connection, select a heating system valve that has the necessary spring elasticity.
Applied in heating systems ah shut-off valves are usually made of the following materials: steel; brass; stainless steel; gray cast iron.
Check valves are divided into the following types: poppet; petal; ball; bivalve. These types of valves differ in the locking device.

Control (shut-off and control) heating valves

Regulating and lock-regulating heating valves systematically change the flow of the coolant, from maximum to minimum, with the valve open and closed. Shut-off or shut-off valves control the coolant discretely with the valve fully open or fully closed. The control valve consists of three main blocks: the body, the throttle assembly and the valve actuator. The locking and regulating element of the valve is the throttle assembly. When choosing a bushing, seat, plug, you should pay attention to the operating conditions of the valve. The medium and its temperature, the presence of impurities, and throughput are taken into account. Main and important in the operation of the valve is the correct direction of supply of the working medium. Usually it is marked with an arrow on the working surface of the case.

thermostatic valve

In modern realities, a thermostatic expansion valve is a preliminary norm for modern and reliable equipment in a heating system. The temperature of the valve is automatically regulated. The operation of the mixing valve of the heating system for radiators is to limit the supply level to a separate one. The valve stem makes movements to open and close the hole. Through this hole, the coolant enters the radiator. When the valve with a thermostatic head is heated, the inlet is closed, as a result of which the coolant flow rate is reduced. The thermostatic valve constantly changes its position. And an important factor is the quality of the materials on the basis of which this product is made. The product may fail due to stem sticking, as well as significant corrosion and breakthrough of sealing materials. But even if the thermostatic valve fails, you can extend its life by replacing the thermostatic element.

Heating system valves with thermal heads differ depending on the shape and type of supply to the heating system. They can be angular when approaching the radiators from the floor, they can also be straight, which connect the pipes to the battery relative to the wall surface. Axial, mainly when connecting pipes from the wall to the battery. When batteries are connected sideways, a special kit is required. It uses thermostatic heads and valves. Obviously, batteries coming with a bottom connection are equipped with valve-type liners.

pressure regulator

The operation of the batteries and the pump is disrupted due to high or low pressure levels. Correct control in the heating system will help to avoid this negative factor. The pressure in the system plays a significant role, it ensures that water enters the pipes and radiators. Heat loss will be reduced if the pressure is standard and maintained. This is where water pressure regulators come in handy. Their mission is, first of all, to protect the system from too much pressure.. The principle of operation of this device is based on the fact that the valve of the heating system, located in the regulator, works as a force equalizer. From the type of pressure, regulators are classified into: static, dynamic. It is necessary to choose a pressure regulator based on throughput. This is the ability to pass the required volume of coolant, in the presence of the necessary constant pressure drop.

Heating bypass valve

To discharge the working medium, the bypass valve of the thermostat of the heating system is used, which functions in the return direction with a significant increase in pressure. As a rule, the pressure increases due to reaching the maximum temperature set in manual mode, the coolant supply to the radiator decreases, as a result of which the pressure rises. The bypass valves of the heating system are basically designed to ensure a stable difference between the return and supply pipes. As the heat load decreases, thermostatic valves closed, resulting in a pressure drop between the pipelines. As a result of using a bypass valve, the load on the pump is reduced, the return temperature increases, and the boiler is protected from corrosion. The scope of the bypass valve of the heating system is quite wide, it is also used to prevent the noise generation of thermostats. The installation of bypass valves is carried out not only at the unregulated pump, but also on the jumpers of the risers.

Safety valves

Any source of danger is. Boilers are considered explosive, as they have a water jacket, i.e. pressure vessel. One of the most reliable and widespread safety devices, minimizing the danger is the safety valve of the heating system. The installation of this device is due to the protection of heating systems from overpressure. Often this pressure occurs as a result of boiling water in the boiler. The safety valve is placed on the supply pipe, as close as possible to the boiler. The valve has a fairly simple design. Body made of brass good quality. The main working element of the valve is the spring. The spring, in turn, acts on the membrane, which closes the passage to the outside. The membrane is made of polymer materials, steel spring. When choosing a safety valve, keep in mind that full opening occurs when the pressure in the heating system rises above the value by 10%, and complete closure when the pressure drops below the actuation by 20%. Due to these characteristics, it is necessary to choose a valve with a set pressure higher than 20-30% of the actual one.

balancing valve

The balancing valve of the heating system is designed to regulate the flow of coolant. The liquid is consumed depending on the pressure. The greater the pressure, the more liquid is consumed. The installation of this device takes place on the risers. A balanced system ensures uninterrupted operation. The manual valve is used as a diaphragm, the automatic maintains pressure and consumption in risers. The manual balancing valve can shut off the system. The design is a valve type device. Manual valves can be installed in tandem with stop valves.

Flow regulator

Having installed energy meters, the question naturally arises of how to regulate and control the supply of coolant, limit or add its consumption. For this, there are various automatic regulators, the use of which allows you to save money, they work from outdoor air temperature sensors and return pipeline sensors. Another advantage of temperature controllers is the temperature control directly at the radiator installation site, unlike other devices. This advantage gives priority to obtaining a uniform temperature background for a comfortable stay in the room. The regulator will prevent overheating of the air in the room, which can not always be tracked by sensors on centralized automation. It is possible to regulate the temperature for each room separately. Sometimes, when solving the issue of adjustment, ordinary taps are installed. Certainly this decision reduces financial costs, but deprives a number of useful benefits. The faucet has limited opening and closing functionality. There is a danger of stopping or airing the riser. By adjusting the heating with taps, it is impossible to achieve the required temperature regime. Using automatic regulators, you can adjust the system accurately and efficiently.

Any boiler equipment, installed in a private house or at an enterprise, is a source of danger. The water jacket of the boiler is the same vessel under pressure, and therefore it is considered explosive. To minimize the danger, modern heat generators, as well as their piping schemes, provide for many protective devices and systems. One of the simplest and at the same time common devices is a safety valve in a heating system. It will be discussed in this article.

Where is the safety valve installed?

To answer this question, we must first understand what it serves. The purpose of installing this simple device is to protect heating systems, prevent high blood pressure coolant in them. This can occur as a result of overheating of the water in the boiler, especially for units that burn solid fuel. When the coolant in the boiler tank boils and vaporization begins, this is followed by a pressure jump in the system. The consequences may be:

• leaks and breaks in heating pipelines, most often at joints;
• destruction of polymer pipes and fittings;
• explosion of the boiler tank, danger of electrical short circuit in the boiler room.

One small valve of a simple design can protect against all these troubles. Based on the fact that an increase in pressure to a critical limit occurs in the boiler, the safety valve must be placed as close as possible to it, on the supply pipeline. Some manufacturers of boiler equipment complete their products with a so-called safety group, which includes a relief valve, a pressure gauge and an automatic air vent. The group is mounted directly into the water jacket of the unit.

It should be noted that safety valves for heating are not always used in circuits. For example, when the source of heat in the house is a gas or electric boiler, then a relief device is not required. The reason is the presence of safety automation in these types of heat generators and the absence of any inertia. That is, upon reaching set temperature coolant gas-burner or the electrical element is turned off and the heating stops almost immediately.

Another thing is a solid fuel boiler or a furnace with a water circuit, here the installation of a safety valve is mandatory. When the firewood in the firebox flared up and the water in the network reached the required temperature, it is necessary to reduce its heating. The access of air to the combustion chamber is closed and the flame dies out, but the red-hot firebox by inertia continues to raise the temperature. If the process goes near the limit values ​​​​(temperature 90-95 ºС), then vaporization at such moments is inevitable.

As mentioned above, boiling is followed by an increase in pressure, which can be prevented by the safety valve of the heating system. It will automatically open the way to the outside for the formed steam and release it, thereby lowering the pressure to normal. Then the device will automatically close and will be in standby mode again.

The device and principle of operation of the valve

The design of the valve is extremely simple. The body is made of high-quality plumbing brass using hot stamping technology from two cast parts in a semi-solid state. General device safety valve shown in the figure:

The main working element of the valve is a spring. Its elasticity determines the force of pressure that must act on the membrane that closes the passage to the outside. The latter in the normal position is in the seat with a seal, preloaded by a spring. The upper stop for the spring is a metal washer attached to the rod, whose end is screwed to the plastic handle. It is used to adjust the valve. The membrane and sealing elements are made of polymeric materials, the spring is made of steel.

This whole simple mechanism works like this. In the normal (standby) mode, while the coolant parameters are within the specified limits, the membrane closes the entrance to the inner chamber. As soon as a situation close to an emergency arises and the pressure in the heating system of a private house increases, the steam-water mixture begins to support the membrane. At a certain moment, the pressure force of the coolant overcomes the elasticity of the spring, opens the membrane, enters the chamber, and out of it through the side hole.

When some water leaves the system, the pressure will decrease so much that it cannot resist the spring and the membrane will close the passage again. It happens that the operation of the mechanism occurs cyclically, especially if the thermal unit operates at the limit and the temperature of the coolant is close to the maximum (90-95 ºС). In practice, when the blast valve for the boiler is activated very often, it loses its tightness and starts to leak.

If you find fresh traces of drips from the safety mechanism, then this is a clear sign of the heat generator operating in extreme mode or the presence of malfunctions in the heating system, for example, in the expansion tank.

Since far from all manufacturers of heating equipment complete their products with a safety group, you often have to make the choice of a safety valve for a heating system yourself. For this, it is necessary to study specifications boiler plant, namely, to know its thermal power and the maximum pressure of the coolant.

For reference. Most well-known brands of solid fuel heat generators have a maximum pressure of 3 bar. Exception - boilers long burning STROPUVA, whose limit is 2 bar.

The best option is to purchase a pressure-controlled valve covering a certain range. The control limits must include the value for your boiler. Then you need to choose a product according to the power of the thermal installation, but it is difficult to make a mistake here. The instructions from the manufacturer always indicate the limits of the thermal power of the units, with which a valve of one or another diameter can work.

On the pipeline section from the boiler to the place where the overpressure relief valve is installed, it is strictly forbidden to install stop valves. In addition, you can not put the device after circulation pump, do not forget that the latter is not able to pump the steam-water mixture.

To prevent splashing of water in the furnace room, it is recommended to connect a pipe to the outlet of the valve, which discharges the discharge into the sewer. If you want to visually control the process, then on vertical section pipes, you can put a special drain funnel with a visible break in the jet.

Conclusion

The pressure relief safety device is considered to be very reliable due to its simple design. When making a choice, you should pay attention to the quality of the material and not chase a cheap product. No less important is correct setting valve according to maximum pressure boiler plant.