Any boiler equipment installed in a private home or business 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 wiring diagrams, provide many protective devices and systems. One of the simplest and at the same time common devices is a safety valve in a heating system. This will be discussed in this material.

Where is the safety valve installed?

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

• leaks and ruptures of heating pipelines, most often at connections;
• 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 you from all these troubles. Based on the fact that pressure increases to a critical limit in the boiler, the safety valve must be installed as close to it as possible, 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 heat source in the house is a gas or electric boiler, then a reset device is not required. The reason is the presence of automatic safety 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 switched off and heating stops almost immediately.

Another thing is a solid fuel boiler or stove with a water circuit, installation here safety valve required. When the firewood in the firebox has flared up and the water in the network has reached the required temperature, you need to reduce its heating. The access of air to the combustion chamber is closed and the flame dies out, but the red-hot firebox continues to rise in temperature by inertia. If the process proceeds 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 out for the formed steam and release it, thereby reducing the pressure to normal. Then the device will close on its own and will be in standby mode again.

Design 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 is shown in the figure:

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

This whole simple mechanism works like this. In normal (standby) mode, as long as 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 prop up 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 from it out through the side hole.

When some water leaves the system, the pressure will drop so much that it will not be able to resist the spring and the membrane will close the passage again. It happens that the mechanism operates cyclically, especially if the heating unit is operating at its limit and the coolant temperature is close to the maximum (90-95 ºС). In practice, when the burst valve for a boiler is triggered very often, it loses its tightness and begins to leak.

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

Since not all manufacturers heating equipment If they complete their products with a safety group, you often have to make the choice of a safety valve for the heating system yourself. To do this, you must definitely study specifications boiler installation, namely to know it thermal power and maximum coolant pressure.

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

The best option is to purchase a valve with pressure control that covers a certain range. The regulation limits must include the value for your boiler. Then you need to select a product according to the power of the thermal installation, but it’s difficult to make a mistake here. The manufacturer's instructions always indicate the limits of the thermal power of the units with which a valve of a particular diameter can operate.

It is strictly forbidden to install shut-off valves on the section of the pipeline from the boiler to the place where the excess pressure relief valve is installed. In addition, you cannot place 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, outlet valve, it is recommended to connect a pipe that drains the discharge into the sewer. If you want to visually control the process, then vertical section tubes, you can install a special drain funnel with a visible break in the stream.

Conclusion

The pressure relief safety device is considered 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. Equally important is the correct setting of the valve for the maximum pressure of the boiler installation.

When sudden changes in coolant temperature occur, excess pressure occurs in the pipes, which can lead to their rupture or deformation. In addition, during operation heating system Various failures may occur, which can also lead to a pressure surge in the heating network. This situation can be eliminated by installing a safety valve in the heating system.

The device belongs to a security group heating devices and serves to prevent various damages. With the help of such mechanisms, the temperature of the liquid in the heating network can also be adjusted.

Fuse types

The safety valve for heating systems has several varieties, differing in operating principles and performing different functions:

• waste;
• back;
• air;
• regulatory;
• bypass

Discharge

Relief-type devices are pre-calculated for a certain pressure, above which excess coolant is removed. To relieve excess pressure, a special drain hole is provided, which is closed under normal conditions. When the pressure rises above a safe one, the membrane is raised by the pressure of the coolant above the emergency pressure release hole, and the excess liquid is simply removed from the system.

Back

The device serves to prevent a change in the direction of fluid movement in the circuit. The essence of the fuse is simple. A special locking mechanism allows water to move in only one direction - into the heating tank. In addition, when the pressure in the pipelines increases, excess water is discharged through the “spout” of the valve. To prevent water from spilling onto the floor, it is recommended to put a discharge pipe on the outlet of the valve and drain it into the sewer.

Spring loaded

In spring-loaded check devices, the through-hole flap is closed using the clamping force of a spring. The flow of water presses on the membrane, lifting the spring and opening the passage hole. In case of return flow of liquid, which is unacceptable if used closed circuit heating, the spring presses on the membrane from above, closing the hole. Pressure from reverse side further enhances downforce, preventing a change in the direction of flow.

Ball

It is based on the same principle, but instead of a spring and a shutter, a steel ball is used that closes the drain hole under the influence of gravity. This imposes some restrictions. For example, it can only be used on horizontal heating areas.

Air

In addition to excess pressure in the heating system, there is also the problem of possible formation of air locks. Basically, this problem occurs if the coolant is water. The point is that in the water room temperature contains a certain amount of dissolved air, which is released during the heating process. Installing an air relief valve for heating in a closed system will prevent air from building up and blocking the flow of water.

Operating principle

The device works according to to the following principle: there is a float in a special capsule; when there is no air in the system, it is in a raised state. When the heating network becomes airy, the water level in the capsule drops and the float lowers, opening the valve that releases air from the heating system. Emergency air release can be carried out manually or automatically.

Regulatory

The control valve is installed in front of the radiators. It performs the function of temperature control. It works on the principle of narrowing the passage opening as the temperature of the coolant increases until the flow directed to the batteries is completely blocked. This makes it possible to adjust the temperature of heating systems, which allows you to reduce energy waste and maintain the room temperature at a comfortable level.

Bypass

Control thermovalves for heating help maintain the temperature within specified limits, preventing the room from overheating by narrowing or blocking the flow of coolant leading to the radiators. This principle can lead to a number of problems.
For example, if the heating scheme in a house includes several rooms with radiators, and the coolant flow is blocked, then its circulation stops, which can lead to uneven heating different rooms, or damage to the pump forced circulation. To solve such problems, a bypass valve is used.

The bypass valve performs the task of maintaining a uniform coolant flow. To do this, when the pressure in the pipes increases, it redirects its excess to the return circuit. The coolant is not removed from the heating system. The bypass fuse is capable of operating in a constant mode, and not like a reverse fuse, which relieves pressure only at peaks in the increase in coolant volume.

Therefore, installing a safety valve for a heating system closed type extremely important. The choice of a suitable device depends on the functions that will be assigned to it.

The main purpose of a safety valve in heating systems is to protect the pipeline and connections from sudden changes in coolant parameters: pressure and temperature. Its installation prevents ruptures and deformation of pipes during operational failures, and reduces the risk of emergency situations. This type shut-off valves are part of the so-called safety group, recommended primarily as a component of the circuit individual heating. But in an apartment with centralized heating it will also be relevant, it all depends on selecting the correct parameters of the safety valve.

The safety mechanism consists of a durable housing, an adjustment block and an outlet for discharging excess coolant (or an element for return outlet). The flow acts on the valve shutter, the position of which is changed by a spring or weight; when a certain pressure value is exceeded, the rod rises and water is released into the outlet pipe. After the parameters have stabilized, the safety valve type returns to its original state, and the coolant begins to circulate inside the system again. To check the functionality, a rod is used to manually retract the spring or another mechanism that changes the position of the shutter (forced opening). After installation and adjustment, the device operates fully automatically.

Types of valves

The main difference concerns the locking mechanism (control block). There are safety valves for heating of spring and lever-load type. The first ones consist of a spool with a seat, an elastic spring, a disk diaphragm for measuring pressure and a rod. This is the most common type of safety relief valve in individual heating systems. The advantages are: availability, reliability, small size and weight, safety and ease of use. The disadvantage is frequent compression of the spring, which leads to rapid failure of the device, which is not recommended for systems with large volumes of coolant.

Lever-load, on the contrary, is suitable for pipes with a diameter of over 200 mm. In this safety mechanism, the spool directly depends on the position of the lever with the load. The latter controls the force of contact of the spool with the seat, and, accordingly, the reliability of coolant passage. The main purpose of this safety valve is heating industrial facilities, its cost is not suitable for use in private construction.

Safety heating fittings are divided, depending on the lifting height of the locking mechanism, into low- and full-lift. The first has low throughput, the second opens in the process of draining excess water or releasing steam to at least a quarter of the seat. Full lift fittings are also suitable for gas heating. The last classification concerns the type of reset: devices are divided into closed (reverse) and open.

When selecting a safety valve for heating, the following parameters are taken into account:

1. Maximum permissible temperature coolant (the more, the better).
2. Pressure: operating, when connecting, opening and closing. The main (first) characteristic is determined by the difference between the parameter value at the moment the rod moves and at full passage. For heating in a private house, safety valves with an operating pressure exceeding 3 bar are rarely needed.
3. Nominal diameter (no less than that of the hot water supply pipe).
4. Future installation location: horizontal or vertical.
5. Availability of additional functions: built-in pressure gauge, check valve.

Also pay attention to the material of the housing and membrane. Modern high-quality safety fittings are made of brass with minimal thermal expansion, the internal control unit is made of special heat-resistant plastic. You should not buy devices with a body made of cheap Chinese alloys; they are destroyed at the slightest excess of operating pressure. If you have any doubts about how to select a valve, it is better to contact a specialist.

Installation technology

The installation conditions depend on the boiler power and the nominal pressure in the heating system. For large volumes of coolant, two are duplicated in succession safety devices A. The recommended installation location is the section of the supply line at the outlet of the boiler (with extreme parameter values). The valve has an internal thread for secure fastening to the pipes; you will need pliers and adjustable wrenches. There is a special arrow on the body, its purpose is to indicate the correct direction.

Also during the installation process a number of rules are observed:

• A discharge for the discharged coolant or steam into the sewer is provided, taking into account maximum safety for people. The drain hose should not have more than two bends and should not be too long.
• It is not allowed to narrow the pipeline between the valve and the main line to a size that exceeds the nominal diameter of the excess shut-off and control valves at the inlet or drain (no exception is made even for filters).
• It is undesirable to install a fuse without other elements of the safety group (in particular, a pressure gauge); in this case, it is impossible to accurately adjust the set pressure.
• To minimize water hammer, the mounted valve sometimes has a slope only towards the boiler.
• The load on the control unit is unacceptable.
• To enhance the tightness at the joints, tow or silicone sealant is used.

Adjustment

Each safety valve of the heating system is configured to certain parameters by the manufacturer, but nothing prevents you from carrying out this procedure yourself. Typically, adjustment is made downward using a pressure gauge; the water flow increases by an average of 25% of the rated operating pressure. When the desired value is reached, the spool is installed in a new position (by turning a special cap for spring valves, moving the load for lever valves).

This process, as well as checking for full opening, is recommended to be repeated at least once a year in order to prevent emergency situations. Optimal time making adjustments - before starting heating at the beginning of the season.

[contents]Due to improper operation or certain failures in the equipment, a sharp increase in pressure in heating networks is possible. This can lead to the destruction of system elements, and in the worst case scenario, to the destruction of buildings and even pose a threat to the life and health of people. To eliminate such situations, heating and hot water supply system diagrams must include a device such as a safety valve.

As mentioned above, the valve is designed to protect heating systems from excessive pressure build-up. Systems with steam boilers, but a sharp increase is possible in the most common water heating type for heating houses, as well as in hot water supply networks. Most often this happens in the following cases:

1. A sharp increase in coolant temperature and, as a result, the formation of steam (most often when draining water from the system);
2. Heating replenishment with excess water (in case of failure of automatic systems);

Principle of operation

There are two types of safety valves - spring and lever-load. Let's look at each type separately.

The lever-load protective mechanism is a locking device, the spool of which is connected to a lever on which the load is hung. The weight can be moved along the length of the lever and thus adjust the force with which the spool is pressed against the seat. When the pressure of the medium on the lower surface of the spool is greater than the force from the pressure of the lever, the valve opens and water from the pipeline into which it was embedded leaves through the discharge pipe;

A spring safety valve differs from a lever-load safety valve in that the pressure on the spool rod is carried out not by a lever with a weight, but by a spring. Its adjustment is carried out by changing the degree of compression of the spring, but the principle of operation is no different.

Spring devices are most common for small heating systems, this is due to their following advantages:

1. Smaller dimensions;
2. Inability to change the setting without using a tool;
3. The spool rod does not have to be in a vertical position;
4. Possibility of combination with other devices (for heating systems small house valves are produced that combine the functions of a de-airing device).

Where and how to properly install a safety valve

For reliable and safe work heating systems, it is important to follow the rules for installing safety devices. They are described in regulatory documents and may differ depending on power and operating pressure. But the basic principles remain unchanged, we present them below:

1. The safety valve must be mounted on the supply pipeline immediately after the boiler (at a certain power, two devices are installed to duplicate each other);
2. In hot water supply systems, the valve is installed at the outlet hot water at the top of the boiler;
3. Between protective devices and the main pipes of heating systems, it is not allowed to install any additional shut-off or control devices, as well as narrowing the pipelines to a diameter smaller than the nominal diameter of the valve (more on selection and adjustment below);
4. Discharge pipes are connected to a pipeline line of sufficient diameter and lead to a safe place or sewer networks. In this case, it is not allowed to install shut-off valves on these lines:

Nominal diameter and adjustment

The selection of the nominal diameter of the safety valve is carried out according to methods developed and approved by state technical supervision authorities, therefore, to select it, it is advisable to contact specialists. If this is not possible, you can use online calculation programs that are available on the websites of specialized companies.

In extreme cases (you'll end up with a substantial supply), you can take a valve with a diameter no smaller than the boiler outlet pipe.

The valves are adjusted to a pressure of 15-25% more. The operation is checked by forcing it to open (it is advisable to carry it out constantly), and the opening pressure is checked and adjusted at least once a year (before the start of the heating season).

Any heating system must include adjustment and safety elements. With their help, heat supply parameters change - operation stabilization, automatic adjustment. For these purposes, valves for heating systems are used: balancing, non-return, three-way.

Purpose of valves for heating

Standalone or district heating must adapt to the current parameter values ​​- pressure and temperature in the system. To perform this task, you need a bypass valve in the heating system, mixing valve, safety valve and others.

Unlike shut-off valves, they operate in automatic or semi-automatic mode. All must comply with the parameters of a specific heat supply.

The main criteria are:

• System operating temperature. The heating shut-off valve must function normally even under critical thermal influences;
• Pressure – nominal and maximum. Each heating system pressure reducing valve has certain response limits, which should be 5-10% below the maximum;
• Type of coolant - water or antifreeze. In the latter case, malfunctions are possible, since the air valve for heating is not designed for a liquid with a higher density than water.

A suitable valve for bleeding air from the heating system is selected at the calculation stage. The operation of this device and similar components should stabilize the state of the system in the event of a risk of emergency situations. Therefore, it is necessary to know the operating principle and types of valves for heat supply.

Some performance characteristics are indicated directly on the body of the heating bypass valve. If this is not the case, professional advice is required.

Heating bypass valves

Often during heat supply operation there is an excess temperature regime. This provokes an increase in pressure and, as a result, destruction of system components. To remove part of the coolant in a timely manner, a heating bypass valve is required.

The operating principle of this component is simple - the seat of the bypass valve in the heating system is constantly exposed to coolant pressure. When the spring force is less than the external pressure, the rod moves and some of the hot water is released. After the pressure stabilizes, the saddle returns to its original position.

There are two types of heating control valves - with a constant response pressure and the ability to manually set this parameter. For autonomous systems heating systems, installation of the second type is recommended, since they can be adapted to any parameters.

The heating pressure valve has the following functions:

• Reduces hydraulic load to the circulation pump;
• Prevents rust. When the temperature is exceeded, oxygen is released. It is the main cause of oxidation of metal heating components;
• Reduces the noise level of heating supply. Without a pressure valve for heating, water circulation may increase and, as a result, vibration and noise will increase.

This item is installed only for closed systems. In gravity heating, a pressure valve for heat supply is not needed. If the temperature is exceeded, the expansion of the coolant is compensated by using an open expansion tank.

The bypass valve in the heating system is included in the mandatory safety group. It is also installed at the highest point of the circuit and in critical areas.

Types of control valves for heating

Normal operation of heat supply is impossible without minimum set control valves. They are designed to stabilize heating parameters and change their values ​​depending on the settings.

The operating principle of heating system pressure reducing valves is based on limiting the flow of coolant by changing the cross-section of the pipeline. For this purpose, the design has an adjusting head and shut-off valves. Bypass valves for heat supply are divided into the following types:

• With manual flow adjustment;
• With mechanical thermal head. When the thermal element is exposed to temperature, it expands and puts pressure on the valve seat. As a result of this, the rod lowers, limiting the flow of coolant;
• With servo drive. To operate this type of heat supply control valve, the control element is connected to a control unit (programmer) or temperature sensor. When a control command is received using a servomechanism, the position of the rod changes and, as a result, the volume of coolant inflow is regulated.

These types of pressure reducing valves for heat supply systems allow you to change the main parameter - the operating temperature. Installation of regulators is carried out in the piping of radiators, radiators, and in the collector units of the heated floor.

The control valve must be installed in such a way that the outgoing heat from the batteries does not affect the thermocouple.

Purpose of a balancing valve in heating

Another type of control valve is a balancing valve in a heating system. Structurally, it is similar to the adjustment one, but has a number of operating and installation features.

The purpose of a balancing valve for heating is to regulate the volume of coolant depending on its temperature. Their installation is optional for systems with short lengths or without problems with thermal distribution. They are mounted on each heating circuit.

After installation shut-off valve For heating, the following heat supply indicators will improve:

• Even heat distribution throughout all heating circuits;
• Ensuring hydraulic stabilization of the system, no sudden pressure drop;
• Reduced heating costs– fuel consumption is optimized, thermal operating conditions are stabilized;
• After installing a balancing valve in the heating system, it becomes possible to partially or completely disconnect individual circuits from the general heat supply.

To monitor current readings of pressure and temperature, the valve design provides fittings for installing a thermometer or pressure gauges. Depending on the design, adjustment of coolant flows is carried out manually or automatically.

Balancing valves are installed in the collector systems of private houses or in the two-pipe heating system of an apartment building.

Heating safety valves

In addition to the heating bypass valve, the normal operation of the system requires the installation of other types of control and safety valves. During heating operation, excess air may appear and the coolant will move back. To prevent these phenomena, it is necessary to provide in advance the installation of an air valve for heating and return.

Depending on the functional purpose, there are two types of safety valves - to remove air from the system and to prevent the reverse movement of water in the pipes. Without these elements, the operation of the system may be unstable, which will lead to a violation of the temperature regime, destabilization of pressure and the creation of emergency situations.

Installation of safety valves is carried out in the following areas of the system:

• In places with the highest probability of excess pressure - after boilers, circulation pumps, on collectors;
• A petal equivalent must be mounted on the return pipe. It is also necessary to install this component in the circulation pump piping;
• At the highest point of the circuit - to remove air from the system. A Mayevsky tap is installed on radiators and batteries.

Safety valves must not impair the performance of the heating system. First of all, they eliminate possible malfunctions in the heat supply. In the “inactive” state, these system components should not impair the speed of movement of the coolant or affect the temperature regime.

To prevent a sudden drop in pressure in the make-up unit, it is necessary to install a heating drain valve. It will prevent a sharp rise in pressure.

Heating air valve

During heat supply operation, heat may form in pipes and radiators. air jams. The reason for this is the high oxygen content in the water and the coolant temperature above +100°C. As a result, oxidation of metal components occurs and the temperature distribution changes. To avoid these situations, it is necessary to install valves to bleed air from the heating system.

First of all, the air valve for heat supply is mounted in the safety group along with the drain and pressure gauge. In the heating circuit they are located on a straight branch leading from the boiler. This place is the most heat coolant, as well as maximum pressure indicators. In the manifold circuit, it is mandatory to install heat supply drain valves on each comb.

Air vents are divided into two types, each of which is designed for installation in certain areas of the system:

• Mayevsky crane. Installed in the radiator (battery) and needed to remove air pockets;
• Automatic air vent. Mounted at the highest point of the system, as well as in security groups. Air from the heating system escapes through it.

For the latest model, it is important to comply with the operating conditions. After a long period of inactivity, there is a high probability that some moving components will “stick” and then the air vent will not work. To avoid this, the structure should be regularly inspected and, if necessary, replaced with a new one.

Most valve models for bleeding air from a heating system are designed for pressures from 0.5 to 7 bar.

Heating check valve

Without a circulation pump, there is always the possibility of a change in the direction of water movement. In this case, the boiler heat exchanger may be damaged due to overheating, as well as failure of other components. To prevent such situations, a check valve is installed.

IN large schemes heating systems install a heat supply ball valve. Under the influence of the reverse flow of water, the polymer ball blocks the pipeline, thereby preventing the movement of the coolant. As soon as the direction changes, it falls down under the influence of gravity. The solenoid valve for the heating system works on the same principle. The difference lies in the control element - a solenoid or an electromagnetic coil is used for this.

The advantages of installing a solenoid valve in a heating system are as follows:

• Possibility of connection to the programmer;
• Setting the device operation mode depending on external factors– temperature or pressure;
• Reliability of operation.

The disadvantage of solenoid valves in heat supply is their dependence on the supply of electricity. IN autonomous heating A spring version of the check valve is used. The water pressure constantly acts on the saddle, compressing the spring. As soon as the direction changes, the movement of the coolant will be automatically blocked.