Three-way valve for heating with thermostat: connection diagram, types and principle of operation. Features of three-way mixing valve for heating system Dividing valve

Adjusting the heat supply is the most important component of any heating system. This function is performed by a tee designed specifically for redistributing the coolant - a three-way valve on the heating system. The main distinguishing features of this device are ease of operation, functionality and compact size.

The product is equipped with one outlet pipe and a plug with holes, with the help of which the coolant flow is regulated.

What is the difference between a three-way valve and a two-way valve?

Unlike a two-way valve, the operation of a three-way valve has a completely different principle. In this case, the rod does not block the constant flow of the hydraulic mode. It is constantly open and tuned to a certain volume. As a result, consumers receive a certain volume in quantitative and qualitative equivalent. In other words, the valve is not capable of blocking movement on the regular hydraulic flow circuit. At the same time, it can block the variable direction, which allows you to control flow and pressure.

A three-way valve on a heating system was obtained by combining a pair of two-way devices. Only both must work sequentially - when one closes, the second begins its work.

Areas of use

Thanks to its functionality, this device can be found in almost every home, in particular, in every home equipped with an individual heating system: a three-way valve for a boiler, for heated floors, etc.

In addition, these plumbing devices are installed on branched circuits of heating systems, where periodic redirection of flow and changes in the state of the environment are required. Also, industry cannot do without them.

Three-way valve: operating principle

In general, the operating principle of this plumbing device can be described in a few sentences. The return and supply pipelines connect to the two inlets of the tee. The required temperature regime is adjusted using regulatory mechanisms.

During the first pass, the coolant flows as expected. On the way back it is already cooled, which immediately affects the overall temperature of the coolant. Within a few seconds, the sensor reacts to temperature changes and increases the hot water content in the system. He will open the valve until the water in the heating system reaches an acceptable temperature.

The main advantage that a three-way valve has is its operating principle: this device is autonomous and unpretentious, as it works independently. All that is required is configuration and testing of its functionality during the installation process.

Advantages

Easy to install.
Durability.
Functionality.
Practicality.
The ability to regulate the state of the system through simple actions.

Flaws

The three-way valve on the heating system is not designed to work with dirty media.
The cost of this device is at a high level.

Mixing type

These plumbing devices have two main subtypes. Each of them performs its own function: separation and mixing. In general, you can understand by the name what the meaning of their work is.

The mixing type device consists of one output and two inputs. Its main function is to mix two flows, which is required to reduce the temperature of the coolant. This is achieved by changing the ratio of hot and cold water. This option is indispensable when installing a heated floor system and is considered ideal equipment, as it is capable of creating the required temperature.

The temperature of the outlet stream is quite easily regulated. To obtain the required temperature at the outlet, you should know what temperature the incoming flows are, and try to calculate the proportions of each as accurately as possible.

If the three-way valve is installed and connected correctly, it can also serve as a flow separator.

Dividing type

The dividing type of three-way valve is designed to separate the main flow into two parts. For this purpose, the device has two outlets and one inlet. This option is required to distribute the coolant flows into two flows. If you include boilers and convectors in the system, then you cannot do without such a valve. A separation type valve functions in a system for the purpose of separating liquid. Quite often it is used in air heater piping.

Manual and electric actuator of three-way valve

According to the control method, three-way valves are divided into devices equipped with manual and electric drives. The manual version is considered the most popular. Externally, it looks like a classic ball valve; it has three pipes (outlets).

In private households, you can most often find automatic systems with electrical heat distribution. For example, you can set the temperature for rooms and distribute the coolant depending on the distance of the room from the heating equipment (boiler). Can be combined with a heated floor system. All-terrain devices are installed on heat pipelines between buildings.

Like any other device, a three-way valve on a heating system is selected depending on the coolant pressure and the diameter of the supply pipeline. Therefore, it must be used in accordance with GOST. Failure to comply with GOST requirements is a gross violation.

Connection

Before purchasing, it is advisable to familiarize yourself with its characteristics. These include:

Possibility of installing a servo drive (if the crane is installed to operate in automatic mode).
pipelines.
The diameter of the pipeline to which the valve is planned to be connected (2-4 cm).

When connecting a three-way valve, it is necessary to take into account the direction of the coolant. There is an arrow mark on the body of this device. The valve can be installed both horizontally and vertically. The location of the device will in no way affect the performance of its direct function.

During the valve welding process, it is necessary to ensure the safety of the internal cavities from the ingress of welded soil and scale. At the junction of the valve and the pipeline, the temperature of the coolant should not exceed 100°C.

In a heating system, a three-way valve is installed in front of the circulation pump.

Valves must be checked periodically for stability and performance. At the facilities, their maintenance is carried out by the relevant organization in a certain order.

It is important that the device is used in strict accordance with the instructions.

Before you buy this plumbing equipment, you need to make sure that you understand the diagram of the three-way valve, you understand its characteristics and decide on the type of design. Many also pay attention to manufacturers. And indeed, how can a manufacturer with a good reputation afford a bad product or a defective product? He's just not interested in it.

Features of the valve design and mechanism do not significantly affect the choice. The choice of a specific metal depends entirely on your preferences. Bronze and brass are expensive, but they do not corrode and are more durable. Steel is cheaper and stronger, but everyone knows the consequences of its interaction with water. Cast iron is characterized by high weight and low cost.

The most important point is the choice of drive type. Manually operated valves are cheaper but have fewer functions. They are more expensive and can break, but most consumers are delighted with their many functions.

Among the huge variety of shut-off valves that are used on the heating system, there is a rather rarely used element - a three-way valve for heating with a thermostat. It is similar in shape to a tee, but it is designed for completely different functions. How a three-way valve with a servo drive works and why it is needed will be discussed in this article.

Operating principle of three-way valve

A three-way mixing valve is installed in those sections of the pipeline where it is necessary to divide the main coolant flow into 2 circuits:

with variable hydraulic mode;
with constant.

Often a constant flow is necessary for those who are supplied with high quality coolant and in specified volumes. Its adjustment corresponds to quality indicators. Regarding the variable flow, it is used for objects where quality indicators are not key. Here the quantity coefficient indicator plays an important role. In other words, the supply of warm fluid in this case is carried out according to the required quantity.

Note! One of the elements of shut-off valves is an analogue of the device that we are talking about in this article, which is called a two-way valve. What makes it different? It differs from the three-way one in the principle of its operation. The fact is that one of the elements of its design, the rod, cannot block the flow of liquid, which has constant hydraulic parameters.

The rod is constantly open, it is adjusted to a certain volume of liquid. Based on this, users have the opportunity to obtain the required volume, both in terms of quantity and quality. In general, this device cannot stop the flow of fluid for a network with a constant hydraulic flow. But it is capable of blocking a variable flow, which makes it possible to regulate the pressure/flow.

You can create one three-way valve by connecting a pair of two-way valves. But they must work in reverse mode, that is, when one opens, the other must close.

A three-way valve for underfloor heating or other purposes operates with the following sequence:

hot water flows to the collector, which is one of the elements of the heated floor;
the degree of heating of the liquid is determined as it passes through the thermomixing valve;
in the case when the temperature exceeds the set level, a passage opens from where the cooled liquid flows;
both streams mix internally;
Once the temperature drops to the set limit, the cold water passage is closed.

The disadvantages of three-way valves include the likelihood of sudden temperature changes that can occur when heated water is started, which can have a negative impact on the condition of the pipeline during mixing.

The three-way thermostatic mixing valve is used to:

if necessary, redirect flows from different pipelines;
mix flows of diametrically different temperatures to obtain a flow of a set temperature;
dynamically control the direction of flows to obtain a flow with a constantly set temperature;
in a plumbing system, this is obtaining a flow with a given stable temperature;
in a heating system, this means obtaining a separate mixing unit with a consistently constant circulation temperature.

Using a conventional ball valve, it can be adjusted manually. In appearance, it is similar to a regular valve, but has such a feature as an additional output. This type of valve is used for forced manual control.

For automatic adjustment, a special three-way valve is used, which is equipped with an electromechanical device to change the position of the rod. It must be connected to a thermostat in order to be able to regulate the temperature in the room.

Types of valves for heating

Without further introduction, let's say that the device comes in two types, which differ in the principle of operation. It happens:

dividing;
mixing.

The principle of operation of the device is clear from its name. The design of the mixing device has two outputs and inputs. This is necessary in order to mix different flows of liquid to reduce its temperature. By the way, this is the best option for setting the required mode for a “warm floor”.

The process of adjusting the temperature is quite simple. You only need to know what the current temperature of the incoming liquid streams is in order to accurately calculate the required proportions of each stream in such a way as to obtain the required output indicators. By the way, if installed correctly, this control device can also work to separate the flow.

A dividing valve divides one flow into two, so it has one inlet and two outlets. This device is used mainly for separating the hot flow in domestic hot water systems. Although quite often it can be found in the piping of air heaters.

In appearance, both options are quite similar to each other. But when examining the drawing, where the devices are shown in section, you can see the main differences. In the mixing device, the stem has one ball valve. It is located in the center and blocks the main passage.

The rod of the separating devices is equipped with two such valves installed at the outlets. They work as follows: one of them is pressed against the saddle, closing the passage, while the other opens the second passage.

The control method of modern models is:

manual;
electric.

The most commonly used device is a manual control method; in appearance it is similar to a ball valve, but has three outlet pipes. But models with electrical control have automatic control, which is used mainly in private homes. Its job is to distribute heat. For example, the user can adjust the temperature regime in the rooms, and the coolant will flow according to how far the room is from the heating device. As an option, you can attach it to a warm floor.

Three-way valves, like other devices, are divided according to the pressure in the system and the diameter of the inlet. All this is determined by the regulatory acts of GOST. And if these requirements are not met, this can be regarded as a gross violation, especially in cases where it concerns the pressure indicator inside the line.

Where is this device used?

The three-way valve, whose operating principle was discussed earlier, is used quite widely. For example, such variations as an electromagnetic device or a device with a thermal head can easily be found in modern pipelines, where proportions need to be adjusted when mixing two separated liquid streams, but the volume or power should not be reduced.

In everyday life, the most popular is the thermostatic mixing device, which, as mentioned earlier, helps regulate the temperature of the coolant. It can be supplied both to the underfloor heating pipeline and to heating radiators. And if the valve is equipped with automatic control, then temperature control will be carried out without any problems.

Note! Using a three-pass heating system to balance temperature changes is beneficial not only in terms of creating convenience and comfortable conditions, but also saves your money.

The bottom line is that by regulating the temperature of the coolant at the “return” of the heating device, you can quite significantly reduce the volume of fuel consumed, and in addition, the efficiency of the system itself will increase. On some systems, installing a valve is simply necessary. For example, in a “warm floor” system, this device prevents the floor covering from overheating higher than necessary for comfortable conditions, thereby relieving users of unpleasant sensations.

Regulating devices of this kind are also used in water supply systems in order to obtain a permanent flow at the desired temperature. The most common example is a regular faucet, which allows you to regulate the water temperature by opening and closing valves.

Selection criteria when purchasing

You need to remember that when purchasing, be sure to pay attention to the technical characteristics of the device, which include the following:

Diameter of connection to the heating main. Most often, this parameter ranges from 2 to 4 centimeters, although most of it depends on the characteristics of the system. If you cannot find a device of the required diameter, then you need to use a special adapter.
Possibility of mounting a servo drive on the device to ensure its automatic operation. This is especially important when the valve is planned to be installed on a warm water floor system.
Finally, there is the pipeline capacity. This concept refers to the volume of liquid that can pass through it in a certain time.

There are many manufacturers of three-way valves on the domestic market. The choice of one model or another depends, first of all, on:

type of mechanism (and let us remember, it can be mechanical or electrical);
areas of use (DHW, cold water, “warm floor”, heating).

The most popular device is rightfully considered Esbe - a Swedish valve from a company that has existed for more than a hundred years. This is a reliable, high-quality and durable product that has proven itself in many areas. A combination of European quality and modern technology.

Another popular model is the American Honeywell - a true brainchild of high technology. Simple operation, convenience and comfort, compactness and reliability - these are the distinctive features of these valves.

Finally, relatively “young” but promising devices are valves from the Valtec line - the result of joint cooperation between engineers from Italy and Russia. All products are of high quality and are sold with a seven-year warranty. They differ in that they have a very affordable price.

DIY valve installation

We present to your attention several schemes for installing a mixing valve.

A scheme that is used mainly in boiler rooms of heating systems that are connected to a hydraulic separator or to a free-flow collector. The pump, which is located in the second circuit, ensures the necessary circulation of the coolant.

Attention! In the case where the valve is planned to be directly connected to the coolant source on the bypass, which is connected to port B, then it will be necessary to install a valve with hydraulic resistance, which will be equivalent to the same resistance of this source.

If this is not done, then the coolant flow in the segment A-B will fluctuate depending on the movement of the rod. It is worth noting that this installation scheme provides for a possible interruption of coolant circulation through the source if the installation is made without a circulation pump or hydraulic separator in the main circuit.

If the return is overheated, it is allowed to get rid of excess pressure using a jumper, which is mounted parallel to the valve mixture in the circuit.

Carrying out quantitative adjustment by changing fluid flow rates is the main function performed by this three-way thermal valve. It is used where it is possible to bypass liquid to the “return”, but stopping circulation, on the contrary, is extremely undesirable. We also present a diagram for installing a three-way separating valve:

Important! A similar connection scheme has become quite popular in water and air heating units connected from individual boiler houses.

In order to link hydraulic circuits, it is necessary that the consumer's pressure losses be equal to the losses on the valve - balancer in the bypass. The diagram shown here should be used for installation on those pipelines in which there is excessive pressure. The movement of liquid is carried out due to strong pressure, which is formed using a circulation pump.

Simplified mixing elements with temperature lock

An autonomous three-way valve of a simplified type can be installed in simple heating systems of country houses, where heat is obtained from a TT boiler. To function, it does not require a thermal head with a temperature sensor, and there is no rod there.

The thermostatic element, which is installed inside the housing, is adjusted to a certain temperature of the coolant at the outlet, for example. 50 or 60 °C (must be marked on the body).

The mixing valve of this sample always maintains the set temperature of the coolant at the outlet; this setting does not change. This gives rise to positive and negative aspects when using such fittings:

advantage - cheaper, unlike a unit with a thermal head. The difference is about 30%;
disadvantage - there is no possibility of adjusting the heating of the exiting coolant. If the factory settings are set to 55°C, then it will constantly supply water at this temperature ±2°C;
Before purchasing a valve of a simplified design, carefully study the documentation for the solid fuel boiler; it usually indicates the minimum return temperature.

A thermostatic three-way valve is a rather useful thing in the heating system of a private home, which makes it possible to efficiently use the heated liquid, and thereby save fuel. Moreover, this part allows you to increase the service life of solid fuel boilers, and also plays the role of a safety element. On the other hand, you should not sculpt the valve just anywhere; it is always better to consult with a specialist who is well versed in this.

In the wide range of shut-off valves used for heating systems, there is an element that is used quite rarely. Its shape resembles a tee, although the functions it performs are completely different. We are talking about a three-way valve, the operating principle of which will be discussed in this article.

Operating principle of three-way valve

What is this device and why is it needed?

How it works

The three-way valve is installed in those sections of the pipelines where it is necessary to divide the flow of circulating fluid into 2 circuits:

with variable hydraulic mode;
with constant.

In most cases, a constant flow is required by those who are supplied with liquid of high quality and in designated volumes. It is regulated in accordance with quality indicators. As for the variable flow, it is used for objects where quality indicators are not the main ones. There great importance has a quantity coefficient. Simply put, the coolant is supplied there according to the required quantity.

Note! Shut-off valves also include an analogue of the device described in the article - a two-way valve. How is it different? The fact is that the three-way option works on a completely different principle. The rod included in its design is unable to block the flow of liquid, which has constant hydraulic parameters.

The rod is open all the time, it is adjusted to a particular volume of liquid. Consequently, users will be able to get the volume they need, both in terms of quantity and quality. In general, this device is unable to stop the flow of fluid to a network in which the hydraulic flow is constant. In this case, it may well block a flow of variable type, due to which, in fact, the possibility of adjusting the flow/pressure arises.

And if you connect a pair of two-way devices, you can get one, but three-way. But it is necessary that both work in reverse, in other words, when one valve closes, the next one must open.

Video - Three-way valve operating principle

Valves classification

Without lengthy introductions, we note that the device can be of two types according to the principle of operation. It could be:

dividing;
mixing.

The features of each type of action are clear from their names. The mixing device consists of two outputs and an input. In other words, it is necessary to mix fluid flows, which may be required in order to reduce its temperature. By the way, this is the most optimal option for setting the desired mode in the “warm floor”.

The procedure for adjusting the temperature regime is extremely simple. You just need to know about the current temperature indicators of the incoming liquid flows, accurately calculate the required proportions of each of them so as to obtain the required indicators at the output. By the way, this device, subject to proper installation and adjustment, can also function for flow separation.

But the separating valve divides one flow in two, therefore, it is equipped with one inlet and two outlets. This device is used primarily to separate the flow of hot water in hot water systems. Although quite often it is found in the piping of air heaters.

Externally, both options are almost identical. But if you look at their cross-sectional drawing, their main difference is immediately visible. The rod, which is installed in a mixing-type device, has one ball valve. It is located in the center and blocks the main passage.

As for separating devices, the stem has two such valves, which are installed at the outlets. They function according to the following principle: one of them is pressed against the saddle, closing the passage, and the other, in parallel, opens passage No. 2.

According to the control method, modern models can be:

electrical;
manual.

In most cases, a manual device is used, which in appearance resembles an ordinary ball valve, but is equipped with three outlet pipes. But electric models with automatic control are used mainly in private homes, namely to distribute heat. For example, the user can set the temperature regime by room, and the working fluid will flow in accordance with the distance of the room from the heating device. As an option, you can combine it with a “warm floor”.

Video - Device in a boiler group

Three-way valves, as well as other devices, are determined in accordance with the pressure in the system and the diameter of the inlet. All this is regulated by GOST. And if the requirements of the latter are not met, this will be regarded as a gross violation, especially when it comes to the pressure indicator in the line.

Areas of application

The three-way valve, the operating principle of which was discussed above, has a fairly wide range of applications. Thus, its varieties, such as an electromagnetic device or a device with a thermal head, are often found in modern pipelines, where it is necessary to adjust the proportions when mixing two separated liquid streams, but without reducing power or volume.

As for household use, the most popular here is considered to be a thermostatic mixing device, with which, as noted above, you can regulate the temperature of the working fluid. This liquid can be supplied both to the “warm floor” pipeline and to heating radiators. And if the valve also has automatic control, then you can control the temperature in your home without any problems!

Note! The use of a three-way valve in a heating system to balance temperature changes is extremely beneficial not only in terms of comfort and convenience, but also in terms of cost savings.

The fact is that by regulating the temperature of the liquid at the “return” of the heating device, you can significantly reduce the volume of fuel consumed, and this will have a positive effect on the efficiency of the system itself. In some systems, a valve is simply necessary. For example, in a “warm floor” system, this device prevents overheating of the floor covering above a given comfort level, thereby relieving users of unpleasant sensations.

Regulating devices of this kind are also used in water supply systems in order to obtain a permanent flow at the required temperature. The simplest example is an ordinary mixer, in which you can make water hotter/cooler by opening/closing a cold tap.

Adjusting the flow of working fluid. What to look for when purchasing?

Manual adjustment is made using a conventional ball valve. Visually it is very similar to a simple valve, but has an additional output. Fittings of this kind are used for forced manual control.

As for automatic adjustment, a special three-way valve is used here, equipped with an electromechanical device to change the position of the rod. It should be connected to a thermostat in order to be able to regulate the temperature in the room.

Remember that when purchasing a valve, it is imperative to take into account the technical parameters of the device, which include the following.

Diameter of connection to the heating main. Often this indicator varies from 2 to 4 centimeters, although much depends on the characteristics of the system itself. If a device of a suitable diameter cannot be found, you will have to use special adapters.
The possibility of installing a servo drive on a three-way valve, the operating principle is discussed at the beginning of the article. Thanks to this, the device will be able to work automatically. This point is very important if the device is selected for operation in “ warm floors» water type.
Finally, there is the pipeline capacity. This concept refers to the volume of liquid that can pass through it in a certain time.

Popular manufacturers

There are many manufacturers of three-way valves on the domestic market. The choice of one model or another depends, first of all, on:

type of mechanism (and let us remember, it can be mechanical or electrical);
areas of use (DHW, cold water, “warm floor”, heating).

The most popular device is rightfully considered Esbe- a Swedish valve from a company that has been around for over a hundred years. This is a reliable, high-quality and durable product that has proven itself in many areas. A combination of European quality and modern technology.

How to install a mixing valve yourself

This installation scheme is used mainly in boiler rooms of those heating systems that are connected to a hydraulic separator or to a free-flow collector. And the pump located in circuit No. 2 ensures the required circulation of the working fluid.

Note! If the three-way valve will be connected directly to a bypass heat source connected to port B, then it will be necessary to install a valve with a hydraulic resistance equal to the same resistance of this source.

If this is not done, then the flow rate of the working fluid in the segment A-B will fluctuate in accordance with the movement of the rod. We also note that this installation scheme provides for the possible cessation of liquid circulation through the source if the installation was carried out without a circulation pump or a hydraulic separator in the main circuit.

It is not advisable to connect the valve to heating networks or a pressure manifold in the absence of devices that throttle excessive pressure. Otherwise, the fluid flow in section A-B will fluctuate, and significantly.

If overheating of the return is allowed, excessive pressure is eliminated by means of a jumper installed parallel to the valve connection in the circuit.

How to install a dividing valve with your own hands

Providing quantitative regulation by changing fluid flow rates is the main function performed by such a three-way valve. Its operating principle is extremely simple and was discussed above. It is used where it is possible to bypass liquid to the “return”, but stopping circulation, on the contrary, is not allowed.

Note! This connection scheme has gained wide popularity in water and air heating units that are connected from individual boiler houses.

In order to link hydraulic circuits, it is necessary that the consumer's pressure losses be equal to the losses at the balancer valve in the bypass. The diagram presented here is intended for installation on those pipelines in which there is excessive pressure. In this case, the liquid moves due to the strong pressure generated by a circulation pump.

Video - Three-way valve and its operating principle

A three-way valve (sometimes called a tee or three-way tap) on a heating system is a mixer for generating a stable flow of water at a given temperature. This unit is simple, but it plays an important role in the operation of various systems with water circulation circuits. This is explained by the need to compensate for the uneven distribution of heat throughout the volume of the building in general and along the heating circuit in particular. The most typical representatives of such products are ordinary household faucets.

Application area of three-way valve

Three-way valves can be used in water supply systems. Unlike heating circuits, such elements do not serve as mixers, but as flow separators.

However, there is one note: any three-way valve can work in different systems, it all depends on the connection diagram and selection of settings. But with all the many schemes, they have a common purpose - this is to protect users from burns and, most importantly, to divide the flow circulation into circuits.

In one circuit a constant hydraulic mode is maintained, in the other this mode is variable. In other words, consumers with quantitative indicators of parameter regulation are connected to the nozzles in the variable-mode circuit, while the constant-mode circuit serves consumers with qualitative regulation.

The mixer cannot shut off a permanent circuit, having a rigid setting. But if the mixer is equipped with a thermal head, then such overlap becomes possible. A tool for monitoring pressure and flow rates appears.

In addition, three-way valves are sometimes may be deprived of the temperature stabilization function. Then these nodes serve to simply redistribute fluid flows in the system.

Operating principle of a three-way valve

The operating principle of a three-way mixing valve in a heating system is to mix water flows:

hot;
cold.

From the description of the operating diagram of a three-way mixer, the conclusion follows: this the device must operate under the control of a control system, monitoring the amount of water heating.

Advantages of a three-way mixing unit:

ease of installation;
high functionality;
durability of operation;
ease of adjustment;
practicality of design.

Disadvantages of a three-way mixing unit:

high price;
sensitivity to coolant contamination.

Three way valve design

Three-way valves, the operating principle of which was discussed earlier, are conceptually a connection of a sequentially operating pair of two-way valves. Unlike them, it does not completely block the flow of water, only allowing you to adjust its intensity to ensure the required temperature parameters.

According to their internal structure, three-way valves are divided into two main types:

products with stem-seat adjustment;
products with ball-socket adjustment.

Products of the first type are mixing valves; the position of the rod is adjusted by moving it up and down. As a rule, the rod is controlled by an electromechanical drive, which makes it possible to achieve a high degree of automation of system adjustment.

Products of the second type are used as separating valves; the position of the ball is adjusted by rotating it. Such designs belong to the class of shut-off valves. However, in domestic heating systems with relatively low water consumption, these taps can also work as mixers, as well as their variety - valves with sector locking.

There are two types of rod drive:

electromechanical;
hydraulic;
pneumatic
manual.

In turn, electromechanical drives are divided into groups:

Thermostatic. Often found in an easily removable version in valves of household heating systems.
Thermostatic head with a remote temperature sensor installed in the pipeline. Usually, Such heads are installed upon customer request to three-way valves instead of standard thermostatic actuators. By the way, this scheme is widely used in underfloor heating circuits.
Electric drive controlled by a controller with temperature sensors. Being the most common, this type of three-way valve drive is also the most accurate.
Servo. Servo-actuated valves are essentially a simplified version of similar designs with controllers. In contrast, a servo drive directly controls a three-way valve without a controller. More often, such a system is used in designs with a ball or segment flow regulator.

Manual drive is carried out by rotating the plastic cap.

Information about products from major manufacturers

Three-way mixers equipped with an Esbe electric drive

They are used not only in heating, but also in refrigeration systems. 3MG Series made from a special brass alloy, which allows the use of such mixers in systems with high sanitary and hygienic requirements. Brass VRG devices are used in general purpose systems. The VRG131 product, for example, can be purchased for $65-70. The F series consists of compact cast iron mixers.

In general, mixers in this line have long been have proven themselves to be of high quality, durability and reliability.

Faucets manufactured by Valtek

Valtek was created as a result of close and successful cooperation between Russian and Italian developers. Despite its youth, the company quickly gained popularity for its high quality products combined with reasonable prices. A handmade sample can cost $40-50. Valtek products have a seven-year warranty.

Mixers from Danfoss, Honewell and Heimeier

Danfoss products can be purchased for $40-70. In terms of popularity, the company is approaching Valtek. As for products from Honewell, then this line is also durable their products. Control of mixers from this company is simple and reliable. Honewell mixers are also compact.

Heimer faucets with a thermostatic head cost $35-40. The German quality of this product will not disappoint the buyer.

In heating systems, a three-way valve is indispensable as a temperature regulator. With the correct selection of the model and the optimal system installation scheme, the expected effect will certainly be achieved.

Further development of three-way mixers are four-way with increased functionality. But the description of these products goes beyond the thematic scope of the article.

Modern water heating is not only a boiler, pipes and radiators. Every time we talk about the design of a heating system, “shut-off and control valves” are always mentioned as an integral element of the heating installation. This includes several types of devices, each of which performs a specific function and contributes to the creation of a practical and efficient system. One of the most important are devices for regulating heat flow.

Why and how to regulate heat flow

Before starting heating design, a thermal calculation is performed. Taking into account the possible heat loss of the facility, the developer determines the required performance of the heating system and draws up a heat balance of all rooms. Based on these data, heating devices of the required type and power are selected that can maintain optimal temperature conditions in the rooms. However, the conditions under which radiators will operate during operation may change. There are several influencing factors: fluctuations in air temperature outside, wind strength, solar activity, heat generation by household appliances, etc.

But we can’t remove or turn off certain sections when the rooms get hot. It turns out that if the main goal is to maintain a comfortable temperature regime, then you need to learn how to manage the energy that comes from the heat generator differently. This can be done in two ways, but in both cases manipulations are performed with the liquid circulating through the pipes:

Qualitative change in the properties of the coolant. If necessary, colder or hotter water is supplied to the radiators - the heat generator is simply switched to a different operating mode (it doesn’t matter if it’s a boiler room for an entire microdistrict or a wall-mounted boiler in the kitchen of a country cottage).
Quantitative control of heat flow. In this case, we use special devices to limit the amount of coolant that will pass through the heating devices. Thus, the battery, with the same surface area, will release less or more heat into the room (within limited limits). For these purposes, three-way valves for heating and temperature regulators on radiators are used.

In autonomous heating systems of apartments and private houses, a combined control method is used as the most effective.

Scheme of using a three-way valve to regulate the water temperature in an indirect heating boiler

Important! By adjusting the heat flow, we can lower or increase the temperature of the heating device, but only to a given limit. This limit is set technical characteristics a specific radiator - more precisely, its maximum heat transfer.

Three-way valve in a heating system

Device

At first glance, this device resembles a regular tee made of yellow metal (brass is used, sometimes steel/cast iron), since its body has 3 separate pipes. But inside there is a mechanism that automatically controls the flow of coolant. There are valves with two types of actuators:

saddle (with a rod that progressively moves up/down);
rotary (with a rotating ball/sector).

In the first version, a seat is installed inside the body, which is covered by a cone attached to the end of the working rod. In another design, the rod does not move vertically, but is rotated by the drive so that the ball with an opening (as in ball valves) opens or partially blocks the communication between the nozzles. Valves with a ball or a locking working part in the form of a sector are used mainly in domestic systems where high throughput and resistance to very high temperatures are not needed.

Operating principle of a mixing rotary valve with a sector regulator

type of drive

The working rod moves using an external drive. It comes in several types. Most often used in domestic installations:

Thermostatic direct or indirect action. When the temperature of the coolant changes, the expanding liquid of the heat-sensitive element, the “bellows”, presses on the rod (an attached thermal head can also be installed here). In some cases, a probe located inside the pipeline is used as a thermostatic three-way valve sensor.
An electric drive, which is an electromagnet or a servo drive based on an electric motor. The command to the actuator is supplied either directly from the temperature sensors or from the control controller. This drive option allows you to most accurately regulate heat flows.

Important! Often such devices are sold without a standard drive, and the user himself chooses the most suitable option for his conditions.

Electrically actuated three-way valve

The three-way valve is not intended to reduce coolant flow; its circulation does not stop at any position of the rod. This is its main difference from two-way devices (taps, regulators). The task of such a valve is to mix flows or separate/distribute them.

The separating valve allows for quantitative regulation, since it releases part of the water not along the main direct path, but through the bypass. Two of its pipes are output, and one is for input.
A three-way mixing valve usually mixes colder coolant with a hot coolant (sometimes vice versa), changing quality characteristics heat flow. The level of temperature change is determined by the established proportion of connected jets. There are two ports (pipe) for entry and one for exit. These same devices can perform separation functions under certain conditions.

Three-way heating control valves are used in several circuits. For example, in order to temporarily cut off the cold return water and let part of the already heated coolant flow through a short circuit (relevant for solid fuel boilers, in the chamber of which condensation falls at the beginning of the firebox). These devices are also installed to feed the hot water supply circuit by dividing flows or to prevent overheating of individual branches of water-heated floors. Using three-way devices, bypass piping of radiators is often carried out.

Creating a short circuit for preparing the return

Temperature regulators

What are they needed for

These devices are installed directly on the radiator plugs. Their direct “duty” is to block the flow of coolant passing through the battery - if necessary, even completely. Approximately the same as a faucet does, only here the user can set the required values once, and the thermal valve for the heating radiator will then itself maintain the set temperature. It is pointless to use regulators only with cast iron batteries due to high thermal inertia.

Electronic thermal valves have increased accuracy and functionality

How do thermostats work?

These are two-way devices that consist of a valve and a thermal head. A valve (“valve”) is a locking mechanism consisting of a standard set of elements: seat, cone, stem. When the working rod retracts, the gap between the seat and the cone decreases - the coolant flow decreases, and vice versa.

But the thermal head controls the rod. The principle of its operation is based on the expansion of a liquid or gas when heated. A heat-sensitive substance, enclosed in a special cylinder (“bellows”), under the influence of too hot coolant, expands and pushes the spring-loaded piston, which, in turn, moves the rod with the cone towards the seat. When the coolant flow decreases, the active substance cools and decreases in volume, and the spring returns the piston, rod and cone to their place - the flow increases. The cycle is repeated over and over again, so the heating of the battery can be controlled with great precision. The more accurately and quickly the thermal head responds to settings and changes in modes, the better it is (but will cost more).

Types of radiator regulators

According to the method of setting the temperature and controlling the temperature regime, thermostatic valves for heating are:

Mechanical. A handle with divisions performs presetting; the rod moves under the action of a bellows and a return spring.
Manual. They are not much different from a regular faucet, but such a thermal head can be quickly replaced with a model for automatic operation of the valve under changing conditions.
Electronic. Equipped with a digital panel and battery powered. Allows you to take into account the temperature of the coolant and program time modes.

Depending on the type of active substance in the bellows, regulators are:

gas,
liquid.

By purpose:

for two-pipe systems,
for single-pipe wiring diagrams.

By connection method:

corner,
straight.

Devices for regulating the flow will not increase the power of the heating system, but will allow you to properly manage the generated heat. It is thanks to these “soldiers of the invisible front” that heating becomes comfortable and economical.