Operating principle of a three-way valve in a heating system, types, design, application

In heating, water can reach 80-90°C. And if this is still normal for pipes with radiators, then for a heated floor this temperature is too high. To ensure normal standing on the floors, a three-way valve is used. Although it is not installed only for these purposes, it is indispensable in a system with almost any solid fuel boiler. Let's figure out what this mechanism is, what it is needed for and how to choose the right three-way valve for the heating and water supply system.

Installation and operation rules

Three-way dividing valves with an electric drive are installed in pipelines and radiators using American union nuts with seals.
Thermal valves (no matter with or without electric drive) are very easy to install:

Mounted into the hole in the plug of the upper radiator hole.
The bypass is connected to one outlet pipe, and the coolant supply is connected to the other.

The connection of a three-way mixing valve with an electric drive to the heated floor system is made in the manifold cabinet. The supply of hot coolant from the boiler is connected to one inlet pipe, and the cool return flow is connected to the other. Warm water (45 °C) is supplied to the outlet pipe and then to the pump using an electric drive for the heated floor pipeline.

In the piping scheme of a solid fuel boiler, three-way separating valves with an electric drive are also required. When the boiler is turned on, warm water from the supply pipeline is directed through the bypass into the boiler - this protects the boiler chamber from condensation.

As the water warms up to 50-60 °C, the valve gradually adds cold water from the return line to the water entering the boiler. After the system has completely warmed up, the valve switches to supplying return water to the boiler (at a temperature not lower than 50 °C). When the return water cools more strongly, the valve is turned on again by the electric drive and mixes hot water into the return.

Frequent errors and problems during installation

The most common installation mistake is connecting pipelines to the wrong connections. For example:

Connecting a bypass to the inlet pipe when connecting the thermal valve to the battery.
The valve location is not in accordance with the arrows indicating water flow.

Typically, such connection errors occur when the type or shape of the electric valve is incorrectly selected.

Expert advice

Electrically driven thermal valves should not be installed on cast iron radiators - they have a very high thermal inertia, and practically adjusting such radiators is pointless. In case of overheating, it is easier to screw on a regular valve at the coolant inlet to the radiator.

Installing thermal valves with a single-pipe heating system and in multi-storey buildings is quite ineffective (we don’t heat until it gets hot, and if it happens, it’s easier to temporarily cover the radiator with a blanket or cardboard).

But connecting underfloor heating pipes without a three-way valve can lead to very unpleasant consequences - overheating of the system and floor structures (in some cases, even cracking of the screed).

Even more unpleasant consequences are the absence of an electric valve in the piping system of a solid fuel boiler. The ingress of cold water from the return into the combustion chamber of a solid fuel boiler will lead to condensation on the heat exchanger and the walls of the boiler and, as a result, will quickly disable the boiler.

The best known manufacturers and models: characteristics and prices

Now I want to talk about the most popular and reliable three-way valves to make it easier for you to choose the right model.

TIM

Manufacturer from China. It offers fairly high-quality products for heating and water supply at a relatively low price.

Photo	Model	Specifications	Peculiarities	Cost, rub.
	(ZEISSLER) BL3110C04	Material: brass Temperature range: 35-60 Operating pressure: 2-5 bar Diameter: 1 inch	Mixing, for heating and hot water supply	2 300-3 000
	BL8803	Material: brass Temperature range: 38-60 Operating pressure: 3-10 bar Diameter: ¾ inch	Mixing, external connection via American connection	2 800-3 500
	BL8804A	Material: brass Temperature range: 38-60 Operating pressure: 3-10 bar Diameter: 1 inch	Mixing, electrically driven	2 000-2 600

Esbe

This Swedish company produces various models of valves and controllers. I believe that the products from this company are of the highest quality. Although expensive.

Photo	Model	Specifications	Peculiarities	Cost, rub.
	VTA321	Material: brass Temperature range: 35-60 Operating pressure: 2-10 bar Diameter: ¾ inch	Mixing, for heating and hot water supply	6 000-6 500
	VTA372	Material: brass Temperature range: 20-55 Operating pressure: 3-10 bar Diameter: 1 inch	Mixing, high throughput	7 000-8 000
Read also: 9 ways to determine whether you can drink water from a well on your property	VTC511	Material: cast iron Temperature range: 60-75 Working pressure: 3-10 bar Diameter: 1 inch	For solid fuel boilers	8 000-9 000

STOUT

Joint production of Russia, Italy, Spain and Germany. The products are perfectly adapted to Russian conditions.

Photo	Model	Specifications	Peculiarities	Cost, rub.
	SVM-0120-164325	Material: brass Temperature range: 20-43 Operating pressure: 3-10 bar Diameter: 1 inch	Mixing, for heating and hot water supply	4 500-5 000
	SVM-0125-186520	Material: brass Temperature range: 30-65 Operating pressure: 3-10 bar Diameter: ¾ inch	Mixing, for heating	4 000-4 300
	SVM-0120-256025	Material: brass Temperature range: 35-60 Operating pressure: 3-10 bar Diameter: 1 inch	Mixing, high throughput	5 200-5 800

WATTS

One of the largest manufacturers of heating equipment in Europe. Huge range of products.

Photo	Model	Specifications	Peculiarities	Cost, rub.
	Aquamix 61C	Material: brass Temperature range: 32-50 Operating pressure: 3-10 bar Diameter: ¾ inch	Mixing, for DHW	5 200-5 700
	Aquamix 63C	Material: brass Temperature range: 25-50 Operating pressure: 1-10 bar Diameter: ¾ inch	Mixing, for heated floors	5 500-6 000
	V3GB Watts Classic	Material: brass Temperature range: 20-50 Operating pressure: 3-10 bar Diameter: 1 inch	Mixing, electrically driven	12 500-14 000

Features of selection and installation

A three-way valve for heating systems must match the diameter of the heating pipes. Typically this parameter varies from 20 to 40 mm. If a suitable size is not found, then it is worth purchasing additional adapters

It is also important to consider the pipe capacity. If the fittings are purchased for arranging a heated floor system, you can connect a servo drive

The arrows on the housing will help you carry out the installation correctly; they indicate the direction of flow.

When welding, it is important to avoid heating the element. It is necessary to select a location in such a way that the tap can be easily accessed in the future.

When it works with coolant containing impurities, it is important to additionally install filters.

The three way motorized valve can be positioned vertically or horizontally, it doesn't matter

It is important to observe only the direction of the flows. When installing a welded structure, it is necessary to prevent waste from getting on the internal surfaces

This will prevent the mechanism from jamming, as well as the accumulation of scale and impurities.

Blitz tips

Before starting the heating system, you need to check the serviceability and condition of the three-way valve and the entire heating system.
The tap should not be installed on pipes with a diameter greater than 40 mm.
In a hot environment, the tap must be opened very carefully to avoid failure of the hydraulic valve.
It is important that the rod, together with the adjusting device or the rotation handle, extends towards free access to them.
It is better to buy a faucet made of brass. It will last slightly longer than other materials.
The best option is a crane with pneumatic control of operation.
To avoid mistakes , consult a specialist first.

Features of a three-way heating valve

The problem is solved in two ways. The first is the quantitative regulation of the coolant. Part of the flow is directed in addition to the radiator using a bypass - a bypass pipe.

The bypass regulates the pressure in the heating network so as not to disrupt the operation of the circulation pump. If we shut off the radiators in one of the rooms, the pressure in the heating network increases, so the water flow is not blocked, but directed in addition to the radiator.

The second way to solve the heating problem is high-quality regulation with coolant recirculation. Cooled water from the return pipeline is mixed with the flow entering the battery. A three-way valve is used to manipulate the coolant.

Working principle and use

Depending on the installation orientation, the crane can perform different tasks:

mix two streams into one;
redistribute one flow into two pipelines.

The control system fittings have three pipes for connection to the coolant flows and a tap that regulates the water supply in two of the three pipes. The task is not to block the flow, but to redistribute it. Depending on the position, the valve completely shuts off one of the flows or partially shuts off two of them, regulating the outlet temperature by mixing in a colder flow.

How many positions does the mixing device have in the heating circuit:

completely open - the coolant temperature corresponds to the temperature level at the boiler outlet;
completely closed - a flow of return network water is supplied through the tap;
intermediate position - the return is mixed with the direct in different proportions.

The three-way mixing valve is the connection point between the bypass and the control valves and allows you to easily and smoothly control the temperature in a single room.

This control method is widely used in heat exchange points of entire microdistricts. High-quality regulation leads to fuel savings.

Disadvantages of a quality regulatory system:

difficulty in distributing the same amount of coolant across different branches of the heating network;
reduced temperature at the inlet to the extreme heaters.

“Witches’ rings” in urban heating networks are an example of erroneous regulation of coolant supply to an object. Entire microdistricts are covered by the circulation of reverse network water, passing in a circle, bypassing the heat source.

When the coolant flows are mixed, the return temperature at the outlet of the heating unit increases. The amount of coolant and speed remain the same, but the fuel supply to the boiler is reduced, since less heat is required to heat the warmer water. This is one of the ways to save fuel at power plants.

Three-way valve device

Faucets are made of brass, stainless steel and cast iron.

Cast iron is used in heating systems with pipes with a diameter of more than 40 millimeters, which is rarely used in private homes. Brass taps are the most popular. They are durable, small-sized and light weight.

The mixer resembles a tee with a thickening at the junction of the pipes. According to their design, they are either rod or ball.

In a ball valve, there is a cylinder or ball inside, bounded by Teflon walls. The ball rotates around a central axis and has a hole in it. When the ball is rotated, the hole partially or completely opens. When fully opened, one of the incoming flows closes; if the ball hole partially opens into two pipes, it becomes possible to adjust the temperature when mixing flows.

The advantage of a ball valve is precise installation, but over time, the smooth surface of the ball facing the flow becomes covered with salt deposits. When the ball moves, the soft Teflon partitions wear out, which leads to a violation of the seal.

By its design, a rod valve is a device consisting of a saddle with two passages; a rod with valves moves in the center of the saddle, which can completely block one of the flows or, in the middle position, open both. The disadvantage of the design is the high hydraulic resistance, which is created by the narrowed saddle of the crane. If valves are selected incorrectly, hydraulic resistance increases, which leads to overload of the circulation pump and excessive energy consumption.

https://youtube.com/watch?v=2Y2N2p-8M0s

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.

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 use in water-type “warm floors”.
Finally, there is the pipeline capacity. This concept refers to the volume of liquid that can pass through it in a certain time.

The valve on the radiator is on the return line, you need

Well, as I understand it, there will be no heating in the whole house until you return the radiator or close the system. Again, as far as I understand, frequent flushing of radiators (systems) is not advisable, but I don’t care.

Frequent flushing is beneficial to the system, but only if you then fill it with prepared water. And yes, until you fix it, you won’t turn it on.

If the system is on water, the water is the same year after year, it is better than fresh because

1 it is degassed - there are few gases dissolved in it, which can create air pockets. 2 it is already neutral in relation to the system - it has dissolved what could be dissolved, where it was possible to deposit a precipitate - it has already deposited.

And if instead of water there is antifreeze, then God himself ordered to save it. It is more expensive than taps.

Of course, if installed, the taps are full bore.

It's better to put it in, of course. It’s not a fact that you will rarely use it, because... Now in a crisis, radiators can be molded from such a thing. draining the system in a couple of minutes?! Yes, you can go to the sewer, if there is one. Is it necessary to overfill the septic tank or have a capacity of 300 or more liters?

If the system is on water, the water is the same year after year, it is better than fresh because

And if instead of water there is antifreeze, then God himself ordered to save it. It is more expensive than taps.

Of course, if installed, the taps are full bore.

I decided to install a return valve. Somewhere I came across an article on adjusting two-pipe systems if there are several radiators in the CO branch using a valve on the return line. I can't find this article right now. But as I remember, the point is that as you move away from the manifold, the valves are clamped less and less tightly. I'm right? I can find ball valves without any problems - will they fit? Or do you need a non-ball one?

Operating principle and design of a three-way valve for heating systems

The design of a three-way valve is based on a conventional T-shaped tee. Two inlet pipes (in the diagram on the right and above) serve to supply cold and hot water. The outlet pipe (in the diagram on the left) removes the mixed flow. In the central chamber, the regulating sector rotates on an axis, partially blocking the incoming pipes. The figure shows how a sector three-way valve works

Figure 2. Operating principle of a sector valve

The overlap can be from 0 to 100%. The peculiarity of the design is that the more the lumen opens for one of the incoming pipes, the smaller the lumen becomes for the other. If the sector is in the middle position, 50% of each flow is passed through. By shifting the sector, for example, to the upper pipe, you can get the cold/hot proportions:

And so on until cold water is completely shut off (0/100%), in which case only hot water will flow into the outlet pipe

The valve can be controlled manually or using a bimetallic thermostatic device.

Figure 3. Diagram of operation of a thermostatically controlled valve.

This function can be performed using two two-way valves and a conventional tee used together. This is exactly what happens in two-valve mixers. To ensure constant pressure and accurately control the proportion of mixing of hot and cold flow, it is necessary to ensure that two taps open in antiphase (one opens, the other closes proportionally), for example, by placing them on a single axis.

Three-way valves are divided into two large groups. They can be:

Separating. They serve to proportionally divide the incoming flow into two outgoing ones.
Mixing. Designed to mix two incoming streams into one summing

Figure 4. Diagram of operation of a mixing and separating three-way valve

From the diagram it can be seen that the design of the mixing and separating valve is almost identical. They differ only in the directions of the flows. If installed correctly, the mixing valve will also work as a separating valve. You just need to configure the control system correctly. In case of manual control there will be no problems. It will be more difficult, but also possible, to configure electronic control. But the thermostatic control module, if connected via a separation circuit, will distribute flows depending on the temperature of the incoming flow. This will have to be taken into account when designing the heating system.

How many positions a sector valve with an electric drive has is shown in Fig. 5

Figure 5. Options for using an electric crane

In addition to sector three-way valves, saddle valves are also produced. Their operating principle is the same, but there are design differences.

Figure 6. Saddle or ball type valve

The mixing seat valve has a spherical working body moving on a rod; it locks the seats in turn, through which mixed flows pass into the chamber and then into the outlet pipe. The separating valve is equipped with two working bodies, mounted on a single rod and blocking the outlet flows. The more one is blocked, the more the other is open. Seat valves cannot be interchanged.

In addition, three-way devices are divided according to the control method:

Electrical. The sector is rotated using an electric motor with a gearbox. Such devices are connected to a computerized control system that reads temperature sensors and controls the flow in accordance with the built-in algorithm.

Figure 7. Electric crane

Manual. They are used in simple circuits with a constant proportion of distribution or mixing of flows. The angle of rotation of the sector is set manually by turning the flywheel.

Figure 8. Manual control

Thermostatic. Control is carried out by an autonomous thermostat. It is set to a certain temperature when setting up the system, and then it independently maintains it by passing part of the incoming flow from the radiator through the bypass pipe.

Figure 9. Esbe three-way valve with thermostatic control

If necessary, you can change the set temperature by turning the handwheel. It is often installed at the inlet of heating radiators to adjust the comfortable temperature in each room.

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 when 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.

It is not recommended to connect the valve to a pressure manifold or heating networks in the absence of devices that can throttle excess pressure. Otherwise, the coolant flow will fluctuate seriously.

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.

How to choose

The choice of a three-way valve is made based on the parameters of the existing heating system, the sizes and types of pipeline connecting devices, as well as other criteria:

Mismatch of any elements will either make it completely impossible to install a three-way valve, or will require the use of various adapters, for example, to attach a union type to a flange

Standard connection dimensions are in the range of 20–40 mm, but for high-pressure systems designed to serve large buildings with a large number of consumer devices, three-way valves with flanged connections are used. It is important to ensure that the diameters of the pipes and the valve match, otherwise the pressure in the system will be changed, which will entail a change in all design parameters. For large and extensive systems, such a change can cause failures or malfunctions, a drop in coolant temperature and other problems.

It is also necessary to purchase taps designed for the pressure existing in the existing system. When purchasing, you need to have an accurate idea of whether you need a servo drive, a pneumatic regulator, or whether the mode will be set manually. This is important, since replacing a three-way valve during operation is a difficult task, requiring disconnection from the coolant supply. In winter, this event can cause pipelines to defrost and fail. It is recommended to purchase three-way valves in brass or copper bodies. In practice, they have shown their superiority over steel and cast iron devices in terms of durability and reliability. It is best to choose products from well-known companies. The cost of such cranes is higher than that of less famous or Chinese models, but the quality and compliance of the operating parameters with the declared passport values will be guaranteed. Three-way valves are not purchased every day, so you can pay more once.

Consequences of problems with return flow

This article has already mentioned that problems with the return flow must be corrected as soon as possible. Now we will provide you with a list of reasons that explain the consequences of slowness in this matter.

Poor battery heating. It is logical that in this situation the quality of heating will suffer first. The room will not warm up properly and the rooms will have a low temperature.
Dissonance between temperatures, that is, a very large difference between the temperature at which water is supplied and the temperature at which it returns back to the boiler. This leads to the formation of condensation inside the boiler, which, entering into a chemical reaction with the released carbon dioxide, turns into acid. This acid will destroy the inner walls of the boiler, which will eventually lead to its failure.

Types of three-way valves

Since distribution valves for various purposes are now on sale, it is necessary to understand the difference between them and know the design features of these devices. In this case, it will be possible to make the right choice of a three-way valve. Below we will look at how the products of different models differ.

By purpose and principle of operation

Externally, different types of taps are no different, since they have 3 pipes, but their operating principle is exactly the opposite:

Mixing tap (adjusting). Mixes two coolant flows. The inlet is carried out through two pipes, and the outlet through one. Inside the device there is a rod with a valve.
Distribution valve (shut-off valve). It does not mix, but divides one stream into 2 parts. Valves are installed in the pipes. When one valve opens the passage for coolant, the second closes its line. The coolant enters the faucet through one pipe and exits through two. Such devices are often used for piping water heaters, in systems with installed boilers, to distribute heat to several rooms.

Manual ball three way valve

Housing material

Brass. This is the most popular metal alloy, which is reliable and practical.
Steel. Can be found much less frequently. It is characterized by increased strength, but less durability than brass.
Cast iron. Not used in everyday life. It is used for installation of industrial heating systems in which pipes have a diameter of more than 40 mm.

According to control principle

A three-way faucet for home heating may differ in the control method:

1. Manual control. Products of this type have rotary knobs that control the flow of coolant. Turning the knob changes the proportion of water supplied from different lines. The disadvantage of such mechanisms is uneven and long heating of distant radiators. Such fittings are characterized by a simple design and low cost.

2. Automatic control. Automatically controlled faucets make it possible to heat rooms to the desired temperature without human intervention. Moreover, heating becomes more efficient, radiators heat up evenly, and there is no need to constantly monitor the operation of the heating circuit. The distribution valve can be controlled by a servo drive, as well as by a hydrodynamic or pneumatic thermostat. Below we will look at the features of each of these devices.

Three way valve with electric drive

A servo drive, which is an electric motor, is used as a control element. A command is sent from the electronic control unit to the servo drive, according to which the motor changes the position of the ball or rod inside the device. The control unit determines the temperature at the outlet of the valve or calculates the optimal setting based on the return temperatures and water coming from the boiler.

Three way valve with servo drive

Of course, it makes no sense to install a three-way valve for an electric heating system without a control unit.

Distribution valve with thermostat

Such a device is a valve with a thermal head in which gas or a special liquid is placed. These components respond to changes in ambient temperatures. As a result of temperature fluctuations, the volume of liquid or gas changes, which leads to automatic operation of the valve.

When installing the device, careful adjustment is required. Temperature limits are determined and associated with the extreme positions of the valve. This determines the operating range within which a three-way heating valve with a thermostat will change the temperature of the coolant. For this purpose, the pressure in the thermal valve is manually adjusted.

Three-way valve for heating system with thermostat

The coolant circulates through the device until its temperature changes to the set value. As soon as the temperature goes beyond these limits, the proportion of mixing cold and hot water in the tap will change.

The advantage of a faucet with a thermostat is that it does not require a control unit to operate. Such devices operate autonomously and also have an acceptable cost.

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.

Types by control method

Types of control depend on operating conditions and purpose. Fixing heat main sensors transmit commands to controllers, who coordinate the actions of energy suppliers.

There are different types of drives:

with thermostat;
electric drive;
pneumatic;
hydraulic.

A manually adjusted drive is much less common.

With manual control

Manual valve

The rod is driven by a rotary handle or valve. For convenience, a control panel is installed with marks on it. Risks correspond to certain thermal hydraulic regimes.

The positive points include:
low cost of manual drive;
direct control of regime indicators;
the ability to instantly change the order of work.

With thermostat

Valve with thermal head allows you to regulate coolant flows

A three-way heating valve is equipped with a thermostat in which liquid or gas is present. The internal environment reacts to all changes in the temperature of the flows. Heating to the specified parameters activates the thermal valve piston system and the flow of hot flow is blocked.

Three-way units with a thermostat can be mechanical or electronic. Mechanical ones operate autonomously, while electronic ones require connection to electricity or battery power. The disadvantage of the second type is compensated by absolute automation. Electronic regulation allows you to set changes in the heating order by day of the week or time of day.

Electrically driven

An electromagnet (solenoid) is installed or a combination servo drive is used, mounted on an electric motor with a transmission mechanism. The drive is coordinated by temperature or pressure meters, which are placed in the piping circuit. The unit is immediately equipped with a servo drive or supplied without it, which makes it possible to optimally select the device for actuation.

Technical characteristics of current, voltage, power, and overload capacity are taken into account

Choose an economical and reliable one, without high operating costs, pay attention to the surrounding operating conditions and safety requirements

Hydraulic

The three-way heating valve with thermostat is equipped with a thermostat installed inside the housing. The device operates according to the outlet water temperature parameters, which are set at the factory. The hydraulic drive includes a housing with a plate-shaped diaphragm.

The positive aspects of use include the low price. The negative side is the need to select a hydraulic drive according to the temperature of the fluid in the heating line. The second disadvantage is the impossibility of changing the heating mode set at the factory.

Pneumatic

The pneumatic actuator automates the operation of the distribution valve and is used for remote control. The drives are a cylinder with a piston that moves under the influence of compressed air.

Advantages of using pneumatic drives:

fast control when environmental conditions change;
simplicity of design and interchangeability;
the change in force is achieved by simply limiting the air pressure in the drive.

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Tap selection

The correct choice of a three-way valve depends on its technical parameters, as well as the features of its installation and use.

First of all, you should consider what diameter of the product is needed to connect to the pipeline. Typically it is 2-4 cm depending on the heating system. If it is impossible to select a device of the required diameter, adapters are used.

It is equally important to know the volume of working medium that each pipeline can pass through itself over a certain time period. Possibility of installing a drive with automated control

This property is necessary when choosing a device for use in a water-type “warm floor” system

Possibility of installing a drive with automated control. This property is necessary when choosing a device for use in a water-type “warm floor” system.

It is worth paying attention to the base from which the device is made. Brass taps are considered the best because they are less susceptible to corrosion.

Regardless of what type of product you choose, it is worth checking the operation of the shutter mechanism, as well as the surface of the tap for damage and traces of rust.

Installation recommendations

To achieve maximum performance from a three-way valve, it must not only be selected correctly, but also connected properly.

Installing this product is no different from installing other fittings. It is advisable to take into account the following recommendations during the work:

You don’t have to think about the spatial location of the crane. The operation of the device is not affected by its vertical or horizontal position;
To position the faucet in the desired direction, take a look at its body. An arrow will be visible on it indicating the direction of coolant flow;
The control device of the tap must be located so that it can be easily accessed;
If the installation is carried out using a welded method, it is important to prevent scale or other debris from getting into the pipeline;
During welding work, it is necessary to protect the valve from heating. To do this, you can provide it with some kind of heat sink;
Before the start of each heating season, it is necessary to check the operation of all control and shut-off valves.

By installing a high-quality three-way valve into the circuit of your heating system, you will be able to regulate the temperature of various heating devices at will, control and change the temperature in individual rooms.

How does a three-way valve work?

Externally, it looks like a bronze or brass tee with an adjusting washer on the top, and the design of the three-way valve depends on the model.

Option 1. In a cast body with three nozzles there are three chambers, the passages between them are blocked by disc elements mounted on the rod. The rod comes out of the body at the top. The principle of operation is as follows: pressing the rod smoothly opens the passage for the coolant flow on one side, while simultaneously closing the passage for the coolant on the other side. As a result, in the central zone the coolant is mixed until the desired temperature is obtained and enters the circuit.

Option 2. The switching element inside the tee is a ball, part of which is figuratively selected. The drive rotates the rod with the ball attached to it, as a result of which the coolant flows are redistributed.

Option 3. The principle of operation is the same as that of the design with a ball, but instead of a ball, a sector is fixed to the rod - its working part is capable of completely blocking one coolant flow, or partially blocking two flows.

3-way valve device

Thermal mixing valve drives

To control the coolant flows passing through the three-way valve, an external drive is required. The functionality and ease of use of the device depends on its type.

Three-way thermostatic mixing valve. The thermostatic actuator is designed to include a fluid medium that is highly sensitive to temperature changes. It is she who, expanding, presses on the rod. Such a drive is installed on small household devices; it can be replaced with a drive of another type.
Three-way mixing valve with thermal head. The thermal head is equipped with an element that is sensitive to the air temperature in the room. To adjust the temperature of the coolant, such a device is additionally equipped with a temperature sensor on the capillary tube, which is placed in the pipeline. In this case, the temperature regime of the circuit is more accurately regulated.
Thermal mixing valve
Three-way valve with electric drive. The electric drive acting on the rod is controlled by a controller, which receives information from sensors about changes in coolant temperature. This is the most accurate and convenient option.
Three-way valve with servo drive. The electric drive directly controls the rod, without a controller, in accordance with signals from sensors. Servo drives are usually equipped with sector and ball mixing devices.

Flow regulator

Having installed energy metering devices, the question naturally arises of how you can regulate and control the supply of coolant, limit or add its flow. For this purpose, there are all kinds of automatic regulators, the use of which allows you to save money; they operate from outside air temperature sensors and return pipeline sensors. Another advantage of temperature controllers is that they control the temperature directly at the radiator installation site, unlike other devices. This advantage gives priority in obtaining a uniform temperature background for a comfortable stay in the room. The regulator will prevent overheating of the air in the room, which sensors on centralized automation cannot always track. It is possible to adjust the temperature for each room separately. Sometimes, when solving the adjustment issue, ordinary taps are installed. Of course, this solution reduces financial costs, but deprives a number of useful advantages. The faucet has limited functionality to open and close. There is a danger of stopping or airing the riser. By adjusting the heating using taps it is impossible to achieve the required temperature. Using automatic regulators, you can adjust the system accurately and efficiently.

general information

It is no secret that the problem of uneven heat distribution in a room often causes a lot of trouble for owners. To get rid of this unpleasant phenomenon and create a comfortable temperature regime, you need to introduce a special device into the heating system - a thermal power regulator or a three-way valve.

The mechanism ensures recirculation of the coolant fluid by mixing a certain amount of cooled treatment with the main current. Currently, tees are installed in hot water supply systems, heating circuits and plumbing systems.

Three-way valve – multifunctional, durable

In most cases, three-way valves are installed in heating systems with many components and circuits, which is necessary to stabilize the temperature in all radiators. The use of the device allows you to control the flow of coolant, distributing it to different parts of the room (for example, in the kitchen, garage and living rooms). Among the main advantages of the invention are:

compact and ergonomic dimensions;
multifunctionality;
ease of installation, operation and maintenance;
high tightness;
long service life;
ease of switching between operating modes.

In addition to the advantages, tees also have disadvantages. These include the likelihood of valve jamming if operating rules are not followed and rapid wear of inexpensive products.

This video will tell you how to install a three-way valve correctly:

Pipes for natural circulation systems

When selecting the diameter of pipes, not only the size of the system and the number of radiators play a role, but also the material from which they are made, or rather, the smoothness of the walls.
For gravitational systems this is a very important parameter. The situation is worse with ordinary metal pipes: the inner surface is rough, and after use it becomes even more uneven due to corrosion processes and accumulated deposits on the walls. Therefore, such pipes are taken of the largest diameter. Steel pipes may look like this in a few years

From this point of view, metal-plastic and reinforced polypropylene are preferable. But metal-plastic fittings are used that significantly narrow the clearance, which can become critical for gravity flow systems. Therefore, reinforced polypropylene ones look more preferable. But they have restrictions on the coolant temperature: operating temperature is 70 o C, peak - 95 o C. Products made from special PPS plastic have an operating temperature of 95 o C, peak - up to 110 o C. So, depending on the boiler and the system as a whole, you can use these pipes, provided that these are high-quality branded products and not counterfeits. Read more about polypropylene pipes here.

Metal-plastic and polypropylene can also be used for installation of heating systems

But if you plan to install a solid fuel boiler. then no polypropylene will withstand such thermal loads. In this case, either use steel, or galvanized and stainless steel on threaded connections (do not use welding when installing stainless steel, since the seams leak very quickly)

Copper is also suitable (it is written about copper pipes here), but it also has its own characteristics and must be handled with care: it will not behave normally with all coolants, and it is better not to use it with aluminum radiators in the same system (they are quickly destroyed )

The peculiarity of systems with natural circulation is that they cannot be calculated due to the formation of turbulent flows that cannot be calculated. They are designed based on experience and averaged, empirically derived norms and rules. Basically the rules apply:

raise the acceleration point as high as possible;
do not narrow the supply pipes;
supply a sufficient number of radiator sections.

Then they use another one: from the place of the first branch and each subsequent one they lead with a pipe of a smaller diameter step. For example, a 2-inch pipe comes from the boiler, then 1 ¾ from the first branch, then 1 ½, etc. The waste is collected from smaller to larger diameters.

There are several other features of installing gravity systems. First, it is advisable to make pipes at a slope of 1-5%, depending on the length of the pipeline. In principle, if there is a sufficient difference in temperature and altitude, it is possible to make horizontal wiring, the main thing is that there are no areas with a negative slope (inclined in the opposite direction), which, due to the formation of air pockets in them, will block the flow of water.

Gravity single-pipe system with vertical distribution into two wings (circuits)

The second feature is that at the highest point of the system you need to install an expansion tank and/or an air vent. The expansion tank can be an open type (the system will also be open) or a membrane type (closed). When installing an open vent, there is no need to vent air; it collects at the highest point - in the tank and goes out into the atmosphere. When installing a membrane type tank, the installation of an automatic air vent is also required. For horizontal wiring, “Mayevsky” taps on each of the radiators will not interfere - with their help it is easier to remove all air pockets in the branch.

Video description

This video shows how to remove air from a radiator using various types of Mayevsky tap:
Using an automatic thermostat as an example, the following general rules for installation exist:

The tap is selected based on the type of heating system - one- or two-pipe.
Before installing the device, it is important to reliably determine the direction of movement of the coolant in the system. The arrow on the body of the mounted faucet must correspond to the flow movement.
The temperature sensor should be placed at right angles to the heated surface in order to remain as independent as possible from a nearby heat source.
Before supplying coolant, you must ensure the tightness of the adjacent surfaces of the tap and radiator.
Configuration and adjustment of the temperature sensor should be carried out by checking with an independent room thermometer.

Recommendation! The optimal solution to the problem of energy saving for a private home is an automatic control valve for the heating radiator. Such a device must be mounted on the supply line, while on the return line it is enough to install a standard ball device.

Manufacturers of three-way devices

There is a wide range of three-way valves on the market from both reputable and unknown manufacturers. The model can be selected after the general parameters of the product have been determined.

The first place in the sales ranking is occupied by valves from the Swedish company Esbe . This is a fairly well-known brand, so the three-way products are reliable and durable.

Three-way valves from the Korean manufacturer Navien . They should be purchased if you have a boiler from the same company.

Greater adjustment accuracy is achieved by installing a device from the Danish company Danfoss . It works completely automatically.

Valtec , manufactured jointly by specialists from Italy and Russia, are distinguished by their good quality and affordable cost

Honeywell are effective . These valves have a simple design and are easy to install.

Options for piping heating radiators

Installation of heating radiators involves connecting them to pipelines. There are three main connection methods:

saddle;
one-sided;
diagonal.

Connection options

If you install radiators with a bottom connection, you have no choice. Each manufacturer strictly binds the supply and return, and its recommendations must be strictly followed, since otherwise you simply will not get heat. There are more options with a side connection (more about them is written here).

Strapping with one-sided connection

One-way connection is most often used in apartments. It can be double-pipe or single-pipe (the most common option). Metal pipes are still used in apartments, so we’ll consider the option of tying the radiator with steel pipes on pipes. In addition to pipes of a suitable diameter, you need two ball valves, two tees and two bends - parts with external threads at both ends.

Lateral connection with bypass (one-pipe system)

All this is connected as shown in the photo. With a one-pipe system, a bypass is required - it allows you to turn off the radiator without stopping or draining the system. You cannot put the tap on the bypass - you will block the flow of coolant through the riser, which is unlikely to make your neighbors happy and, most likely, you will be fined.

All threaded connections are sealed with fum tape or linen winding, over which packaging paste is applied. When screwing the valve into the radiator manifold, much winding is not required. Too much of it can lead to the appearance of microcracks and subsequent destruction. This is true for almost all types of heating devices, except cast iron. When installing all the others, please do not be fanatical.

Welding option

If you have the skills/opportunity to use welding, you can weld the bypass. This is what the piping of radiators in apartments usually looks like.

With a two-pipe system, a bypass is not needed. The supply is connected to the upper entrance, the return is connected to the lower entrance, taps, of course, are needed.

One-way piping with a two-pipe system

With bottom wiring (pipes laid on the floor), this type of connection is made very rarely - it turns out inconvenient and ugly; in this case, it is much better to use a diagonal connection.

Strapping with diagonal connection

Installing heating radiators with diagonal connections is the best option in terms of heat transfer. In this case it is the highest. With bottom wiring, this type of connection is easy to implement (example in the photo) - the supply on this side is at the top, the return on the other is at the bottom.

A single-pipe system with vertical risers (in apartments) does not look as good, but people put up with it because of the higher efficiency.

Coolant supply from above

Please note that with a one-pipe system, a bypass is again required

Coolant supply from below

Strapping with saddle connection

With bottom wiring or hidden pipes, installing heating radiators in this way is the most convenient and least noticeable.

With a saddle connection and lower single-pipe wiring, there are two options - with and without bypass. Without a bypass, the taps are still installed; if necessary, you can remove the radiator and install a temporary jumper between the taps - a squeegee (a piece of pipe of the required length with threads at the ends).

Saddle connection for one-pipe system

With vertical wiring (risers in high-rise buildings), this type of connection can be seen rarely - the heat losses are too large (12-15%).

Operating principle

For the product to work, cold and hot water flows must be connected to it simultaneously. The installation diagram itself is presented in the form of arrows indicating the direction of flow. The hot water flow acts as a coolant (supply that comes from the boiler), and the cold water flow acts as a return.

A valve is installed between the tap pipes, which regulates so that water flows into two of the three holes. According to the installation position and its connection, two functions are divided:

mixing cold and hot water flows;
division from one line into two outputs.

Depending on the position of the valve, the following situations are possible:

the valve is half open - the outlet flow has an average water temperature;
the valve is fully open - the hot flow comes directly from the boiler and the water has the maximum temperature;
the valve is closed - only cold water flows into the outlet flow.

Briefly about the main thing

Taps on heating radiators perform the following number of tasks:

De-energize a separate section or battery.
Reduce or increase coolant flow.
Protects the system from pressure surges.
Allows you to drain the coolant.
Bleeding out the air.
Save energy resources.

By design, they are divided into ball, valve balancing and thermostatic manual or automatic, as well as air-bleeding. When choosing a faucet, several criteria are taken into account - the type of heating system, the type of device itself and its purpose, technical parameters and compliance with their system, type of connection and method of activation - manually or automatically. Determining its location in the house heating circuit and the installation procedure is best left to a specialist.

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Classification by type of mechanism control

The three-way valve is controlled either manually or electronically. In the latter case, additional equipment is used - sensors or thermostats.

Manual control mode	A cheap device that looks like a standard ball valve. Mixes the flows in approximately equal proportions. The main disadvantage is the unevenness and duration of heating of heating batteries remote from the boiler.
Automation	Allows you to regulate the heating of the coolant automatically and does not require human intervention. It is characterized by a more effective action and ensures uniform heating of all areas. Control is carried out via a servo drive, pneumatic or hydrodynamic thermostat.

Using drives

In addition to the thermostatic head, the valve can be controlled in other ways. The first of them is manual, when the depth of pressing of the rod is determined by turning the handle outside the body. Not the best option and is only suitable if the temperature of the water entering the pipes is constant. Another option is control using a servo and electric drive, receiving commands from the controller. To work together with different drives, another type of valve is used - rotary valves, whose device is shown in the figure:

This 3 outlet valve is very similar to a regular motorized ball valve

There is a certain similarity here with a ball valve, only the working rotary element has a different hole shape to allow coolant to flow in two directions at once. The operating principle here is simple: the axis rotates to the required angle, rotated by the drive. The latter is controlled by a controller that receives impulses from one or more sensors. Typically, valve actuators are installed in complex or automated heating systems with weather control.

Features and diagrams of a beam system in an apartment building

The main difficulty of using a collector-radial circuit in an apartment building, in which the coolant is supplied according to a traditional vertical two-pipe circuit, is the influence of the radial circuit of an individual apartment on the heat load of the apartments above, in which this circuit is not implemented. Such apartments will not receive enough heat.

There are some ways to connect the collector to the common house system without harming the neighbors.

Use of a heat exchanger in a radiant system

The heat exchanger has no hydraulic resistance and is connected like a simple radiator through which the coolant passes without the participation of a circulation pump.

Heat flows passing through the collector circuit in which the heat exchanger is installed do not mix with the central heating coolant.

Connection with primary-secondary rings

With this connection, the central heating system of the house serves as the primary ring, and the collector-radiant heating system plays the role of the secondary ring.

The connection is made to the pipeline coming from the convector.

The algorithm for constructing such an insert is as follows:

To directly supply coolant to the collector, the first cut is made at a distance of 30 cm from the radiator jumper.
The return contour line is cut in at a distance of 60 cm from the jumper.
Shut-off valves are mounted on the tie-ins.
A three-way valve and pump are installed.
A valve is mounted on the return pipe, through which coolant flows in only one direction.

Hot water passes through the collector through loops of the circuit, then part of it is supplied to the central heating return pipe, and part is returned to the collector through a three-way valve. This valve is responsible for the distribution of coolant.

With this scheme, the coolant is withdrawn evenly, without creating a vacuum in the central heating pipeline and without changing the heat balance of the apartments.

To insert into the common heating riser of a residential building, individual design and permission from the management company are required.

Air valves and radiator fittings

Almost all modern radiators provide the possibility of installing Mayevsky manual valves for air discharge. Some manufacturers even complete their products with them. If desired, instead of a manual air vent, you can install an automatic one, but in practice it does not look very presentable.

Recently, laying heating lines below floor level and using radiators with bottom connections has become increasingly popular. Then there remains a small gap between the battery and the floor, where it is not always possible to place any fittings. For this case, there is a special connection headset with built-in taps, shown in the picture (left):

On the right is a headset for the bottom connection of a conventional radiator with side plugs; it also has valves plus the ability to connect a thermal head. Such solutions look very aesthetically pleasing, but will require maximum financial costs. More information about the headset is shown in the video: