Current trends The development of heating systems is increasingly leaning towards low-temperature floor and radiator systems, in which the temperature of the coolant supply is significantly lower than the temperature produced by the boiler. How to achieve flexible control of coolant temperature in conditions of constantly changing outside temperature?

For low temperature systems heating and “warm floor” systems need to be taken as follows technical solutions, in which chilled water from the return line is mixed into the supply pipe. This process is called high-quality regulation of the heating system, that is, regulation in which the coolant flow remains the same, but its temperature changes in the direction we need, and at the same time we do not interfere in any way with the operation of the boiler and its circulation pump. Quantitative control of the heating system differs from qualitative in that with it the temperature of the coolant does not change, but its flow rate changes, that is, a valve is simply installed on the pipe, the closure of which increases the hydraulic resistance and the circulation is slowed down or stops completely, and the coolant flow through the heating devices decreases accordingly.

High-quality regulation is carried out using a three-way valve and a bypass or a four-way valve located directly in front of the low-temperature heating ring (Fig. 26).

Rice. 26. Schematic diagram of high-quality regulation of coolant temperature

Turning the handle of the three-way valve to a certain position opens the bypass, and the circulation pump draws chilled water from the return into the supply, where it mixes with hot water submissions. Thus, the coolant supply temperature can be adjusted to the desired value. Three way valve can work very flexibly, it “knows how” to shut off the bypass or supply pipes or work to mix return chilled water with hot supply water. In other words, if the three-way valve closes the bypass, then the hot supply water completely enters the heating ring, if the valve closes the supply, then the heating ring works “on itself”, the coolant will spin in it through the bypass until it cools down, if the valve is open in the intermediate position, then the cooled water enters the tap through the bypass and mixes with the supply water, then it enters the heating circuit at the temperature we need. A three-way valve installed to regulate the temperature of the coolant, in this case, is called a three-way mixer (Fig. 27). Supply temperature hot water the heating system can be adjusted manually using a scale on the mixer or using a temperature sensor and an electric servomotor.

Rice. 27. Three-way mixers

The use of four-way valves makes it possible to do without a bypass pipe, but these valves differ in operation: some, for example, with X-shaped valves, can only close and open the supply and return, but cannot mix water, others, for example, with rotary valves, water mix. When using taps with X-shaped dampers, hot water enters the heating ring and the tap closes, and the pump drives the coolant around the inner ring, as soon as the coolant cools down, the tap opens and a new portion of hot water enters the inner ring from the boiler, and the cooled water is discharged into the return line . A four-way valve of this design divides each circuit into two parts; its operation is reminiscent of adjusting the coolant temperature by turning a circulation pump on and off. But unlike pump regulation (turning the pump on and off), regulation here occurs in a softer mode, since the pump does not turn off and the circulation of the coolant does not stop. Of course, the use of four-way valves with X-shaped valves is only possible in automatic mode, since manually turning the valve every time the coolant in the internal circuit cools is simply impossible.

Rice. 28. Four-way rotary mixers

Four-way mixers with rotary dampers (and some others) provide a constant and equal flow of hot and cooled coolant and at the same time allow you to set the desired coolant temperature both manually and automatically (Fig. 28). Such a heating system does not require the use of a differential bypass; the mixer automatically passes the required amount of water, in other words, the total amount of water entering the heating system and water flowing back will be constant. The presented control system is one of the simplest: depending on the position of the valve, the four-way mixer allows a certain amount of water flowing from the boiler into the primary circuit; exactly the same amount of coolant is displaced into the return line.

Rice. 29. Example of a connection node solution " heated floors» and operation of the rod mixer

Typically, low-temperature heating systems are equipped with automatic controllers that measure the temperature of the coolant or the air temperature of the heated room, and issue commands to electric servos that “turn” the valves of three- or four-way mixers. In addition to rotary valve mixers, there are other control valves based on rod (Fig. 29) three- and four-way valves. Regulation (closing and opening of the mixer channels) occurs due to the lowering and raising of the rod with a cone valve. The mixer is controlled by a sensor based on the thermal expansion of certain materials, such as paraffin. A capsule with paraffin is placed on the pipe of the heating system; when heated from the pipe, the paraffin expands and closes or opens the thermocouple contacts, that is, the capsule works as a switch that transmits an impulse to a servo drive that moves the rod of a three- or four-way mixer. Then the temperature in the heating pipe decreases, the paraffin decreases in volume and opens the contacts - the mixer rod takes its previous position.

Rice. 30. An example of a heating system made according to the classical scheme

Thus, a heating system with a low-temperature underfloor heating circuit and a high-temperature radiator circuit may look like this (Fig. 30). The coolant, heating up in the boiler, enters the hot water collector, from where it is distributed over two distribution risers: radiator heating and “warm floors”. Radiator risers deliver water to the heating devices, where it is cooled and enters the chilled water collector connected to the boiler return pipe. The coolant, driven by the circulation pump, constantly circulates in this circuit and through the boiler. In the heating circuit of “warm floors”, a slightly different movement of the coolant occurs. The circulation pump does not pump coolant from the supply manifold constantly, but periodically, as the three-way mixer opens the supply. The rest of the time, the pump “spins” its own cooled water around the “warm floor” ring. It should be noted here that when manually adjusting a three-way mixer, the pump will constantly mix water from the supply manifold, and when adjusting the mixer automatically, two operating options are possible: with the “warm floors” completely disconnected from the boiler and with the addition of hot water. The fact is that manufacturers of three-way mixers produce two versions of these valves; in most cases, three-way mixers are configured in such a way that manually closing the valve, indicating “hot water supply is closed” on the device scale, does not actually completely close the hot water, but leaves it slightly open. This is the so-called foolproof protection. For example, having installed a radiator heating system with an error, the user completely cuts off the supply of “warm floors” to the heating system, while the boiler is running and heating water, pushing it into the system. And where should it flow if three way valve closed? The system creates overpressure and overheating of the coolant - a rupture of the boiler heat exchanger or pipeline is possible. A three-way mixer with a small hole, with seemingly complete closure of the supply, allows you to not stop the circulation and allow the coolant to flow through the low-temperature heating circuit.

This allows for somewhat automated control, but does not make it possible to constantly maintain a certain temperature at the inlet to the boiler (which is necessary for the safety and durability of the heat generator). Indeed, with large temperature differences, there is a possibility of condensation forming with subsequent corrosion of the heat exchanger, and the intensity of scale formation also increases. In case of use cast iron heat exchanger cracks may appear in sections of the heat exchanger. In addition, the stress at the connections of boiler parts increases, primarily at the joints and along the welds.

Therefore, for operational safety and durability of the equipment, as well as to achieve the required level of comfort, four-way valves are used to separate the heating and boiler circuits. In Fig. 2 presented typical diagram using solid fuel boiler and a hot water storage tank (one outlet from the boiler, after which the coolant is distributed to hot water heating and the heating system). The separation of the boiler circuit and the heating system circuit is carried out using a 4-way valve, which allows for constant circulation in the boiler circuit and, at the same time, in the heating system circuit.

Rice. 2. Installation diagram of a solid fuel boiler to a heating system with forced circulation coolant and 4-way valve:
1 - boiler; 2 - automatic boiler control unit; 3 - coolant temperature sensor; 4 - room thermostat; 5 - circulation pump; 6 - heat consumer; 7 - differential valve; 8 - four-way mixing valve; 9 - expansion tank; 10 - hot water boiler; 11 - boiler pump; 12 - shut-off valves; 13 - filter

At the same time, in addition to the extreme positions, in the middle position 50% of the coolant goes into the heating system, mixing with 50% of the coolant returning from the heating system, and the remaining part returns back to the boiler, mixing with the rest of the coolant from the heating system. It is also possible to maintain, in contrast to regulation with 3-way valves, a flow separation constant in other strictly defined proportions. For example, 30% of the coolant is in the boiler circuit, 70% is in the heating system. Or any other ratio (Fig. 3).

Rice. 3. 4-way valve positions

Such constancy of consumption is very important for a solid fuel boiler, since, as we noted above, when using it there are not such wide opportunities to influence the intensity of the combustion process as in gas boilers. The use of an automatic draft regulator allows you to regulate the temperature only at the outlet of the boiler, but not on the return line.

Features of using valves

Installed on 4-way valve electric drive, controlled by a controller, which, in turn, operates based on signals from temperature sensors. This drive allows the valve to be in any position, thereby accurately maintaining set temperatures. Four-way valves also allow the combined use of several heat sources in the boiler room, operating on various types fuel. For example, nowadays you can often find a combination of solid fuel and gas boilers (Fig. 4) or solid fuel and electric boilers. In this case, the gas boiler can be used as a backup. In the case of constant use of several heat sources (for example, the joint use of gas, electric, solid fuel boilers and solar power plants), it is necessary that all heat sources work on the storage tank (buffer tank), from which the coolant will be taken for the heating system and hot water supply.

Rice. 4. Schematic diagram operation of boilers using various types of fuel using a four-way valve:
TK - solid fuel boiler; GK - gas boiler; 1 - four-way valve; 2 - temperature sensor; 3 - boiler pumps; 4 - heat consumer; 5 - circulation pump; 6 - controller

4-way valves for heating systems presented on the Ukrainian market are usually made of cast iron with chrome plated internal surfaces. Their diameters range from 20 to 150 mm. Similar valves are offered by Afriso (Germany), ESBE (Sweden), Honeywell (USA), Oventrop (Germany), etc.

For example, Honeywell's V5442A series compact 4-way mixing valves (Figure 5) are designed for systems that use water or fluids containing up to 50% glycol as the coolant. They are designed for operation at temperatures of 2...110°C and operating pressures up to 6 bar. The valves are available with connection sizes of 20, 25 and 32 mm. Accordingly, the values ​​of the Kvs coefficient are from 4 to 16 m 3 / h. The valves are designed to work in conjunction with electric drives. For more powerful systems, the flanged valve series ZR...FA is used. Installation of 4-way valves is straightforward and provides many implementation options (Fig. 6).

Rice. 5. Four-way valves V5442A and ZR...FA (Honeywell)

Rice. 6. 4-way valve connection options

Resume

Thus, it can be argued that the use of 4-way valves is almost ideal for use in conjunction with solid fuel boilers, because they allow for more control possibilities than with 3-way valves.

The use of mechanical thermomixing valves (Fig. 7) does not solve the problems of controlling temperatures in the system and sharing several heat sources, but only allows you to maintain a pre-set constant temperature of the coolant at the entrance to the boiler, without taking into account the operating conditions of the boiler and the system itself.

Rice. 7. Use of a thermomixing valve to maintain a constant temperature at the boiler inlet

Also, the use of large-diameter thermomixing valves is not economically feasible, since their cost is significantly higher than the cost of a system using a four-way valve. At the moment, the cost of fully automated control using a four-way valve, for systems with a power of up to 80 kW, is in the range of 400-800 euros. The payback period for such a system is 3-5 years.

More important articles and news in the Telegram channel AW-Therm. Subscribe!

3 way air conditioner service valve

4 way air conditioner reversing valve

The diagram shows the principle of operation of a solenoid valve in a refrigeration system (showing the direction of movement of the refrigerant when switching from the “heating” mode to the “cooling” mode and back).

4 way reversing valve designed to change the direction of refrigerant movement in a reverse cycle circuit. It should be noted that replacing a four-way valve in an air conditioner is one of the most difficult and expensive repair operations. It is comparable in cost to replacing an air conditioning compressor, because... requires several solderings per hard to reach places in close proximity to the valve body, overheating of which can lead to deformation and jamming of the internal fluoroplastic sleeve. Therefore, before talking about the defect check valve, it is necessary to check the serviceability electrical diagram, and that the reversing valve solenoid valve coil is energized (presence magnetic field checked by a characteristic click when removing and installing the coil). You should also ensure that there is sufficient refrigerant in the circuit and that the compressor is operating at full capacity.
We offer several options for solving the problem in the operation of this valve: actually replacing the faulty 4-way valve with a new one, replacing it with a unit with a 4-way valve assembly, or removing it. In the first case, the mandatory use of heat-removing paste and all-round access to the pipeline will be required. Therefore, this procedure for replacing a 4-way valve is practically impossible on a wall-mounted air conditioner and will have to be dismantled external unit during repairs. When replacing the assembly, the number of solderings is reduced to two and they are performed at a considerable distance from the valve body, which means that overheating is eliminated. In both cases, after repair, uninterrupted operation of the air conditioner in both heating and cooling modes is guaranteed. If it is possible to continue using the air conditioner in only one mode (either heating or cooling), then the faulty 4-way valve can be excluded from the hydraulic circuit, leaving the air conditioner to operate either cold or warm at the customer’s request. In this case, the air conditioner will work uninterruptedly without a 4-way valve, but its repair will cost much less than replacing it. Before carrying out work to replace the reversing valve, remove all refrigerant from the system, and after the repair, evacuate the circuit, install a new filter drier and charge it with freon.

Air conditioner valve check
(serves to ensure optimal pressure drop between the condenser and the evaporator when switching from the “heating” mode to the “cooling” mode and back)

Electronic expansion valve
designed for use in air conditioners and refrigeration systems, in heat pumps.
The valve supports automatic refrigerant flow settings and optimizes system operation for rapid cooling or heating, providing precise temperature control and energy savings. The valve can also be used, for example, to suck in pressure in a control line.
These valves provide bi-directional control of refrigerants, regulating flow rates in heating or cooling mode.

Thermostatic valve
The expansion valve is used to dose the amount of freon supplied to the cooler and is a throttle with a variable cross-section.
Connects after the filter, on the liquid line.
The thermostatic valve reduces the pressure and temperature of the freon so that when it enters the cooler, it boils off and effectively transfers heat. Special hole reduces the pressure of freon entering the expansion valve. The refrigerant coming from the condensing unit is a liquid, under high pressure. Passing through the expansion valve, freon turns into liquid dust, while its main parameters decrease. All these points improve the process of freon boiling away in the cooler.
The dosing of the amount of freon passing through the compressor-condensing unit occurs as follows: The expansion valve cylinder is in contact with the cooler manifold. There is freon inside the cylinder. When the freon temperature in the block increases, the refrigerant pressure in the expansion valve increases and the bellows stretches. The bottom of the bellows, through the rod, presses on the ball or needle, which, moving, increases the amount of freon passing through the thermostatic valve, while the temperature of the outlet tube and evaporator decreases. The freon pressure of the expansion valve drops, the bellows contracts, the ball closes the throttle, causing a decrease in gas volume.

IN wide range Shut-off valves used for heating systems contain 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 does this work

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 for whom the liquid is supplied high quality and in the indicated 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 value has a quantity coefficient. Simply put, the coolant is supplied there according to the required quantity.

Pay attention! TO shut-off valves This also includes 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 best option in order to set the desired mode in the “warm floor”.

The adjustment procedure itself temperature regime 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 as a flow separation device.

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 into DHW 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.

By control method modern models may 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 having 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 be supplied in accordance with the distance of the room from 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 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!

Pay attention! 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 flooring above a given level of comfort, 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 carried out using the usual ball valve. Visually it is very similar to a simple valve, but has 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 this throughput pipeline. 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. Combination European quality and modern technologies.

Another popular model is the American Honeywell - a true brainchild high technology. Simple operation, convenience and comfort, compactness and reliability - these are distinctive features 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, sold with warranty period at seven years old. They differ in that they have a very affordable price.

How to install a mixing valve yourself

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

Pay attention! 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 of working fluid will be segment A-B will oscillate according to the movement of the rod. We also note that this installation scheme provides for the possible cessation of fluid circulation through the source if the installation was carried out without a circulation pump or 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 consumption per 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 yourself

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.

Pay attention! 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

Schemes mixing units(this is what the assembled heated floor unit looks like):

Mixing unit for Valtec floor heating for 1 circuit (up to 20 m2.)

Valtec underfloor heating manifold from 2 to 4 circuits (20-60 m2.)

Our online store offers to buy thermostatic mixing valves and servomotors for organizing heating and water supply systems. As a certified distributor of the world famous trademark Valtec, we deliver reliable engineering plumbing, in demand in private and mass construction, during the reconstruction of buildings and premises for various purposes.

Control mixing valves are components modern systems heating, hot and cold water supply. They are designed to allow cold and warm water flows to mix, delivering liquid at the required temperature at the outlet. These valves (valves), both three-way and four-way, are in demand when organizing water supply with or without circulation of hot liquid in classical radiator, floor, panel and ceiling heating systems, serve as return limiters, and also ensure exchange between the incoming and return lines . The valve body can be steel, brass, cast iron. The Valtec product line includes mixing valves whose bodies and control parts are made of brass - this metal does not form corrosive layers. The rod is sealed by a pair of rings made of Epdm Perox synthetic rubber. The valves are fully repairable; it is possible to replace the upper ring without the need to completely disassemble the part.

By mixing coolant from two streams with different temperatures (in water supply this is hot and cold water, in heating - supply water and return), Valtec control valves create a flow with a given level of heating.

In our online store you can buy three-way and four-way mixing valves Valtec. A three-way part will be needed when installing a “warm floor” system, as well as for heating warm liquid from a high-temperature coolant in a heating structure. Four-way variations are needed in order to create two control circuits at once, each with personal temperature parameters. For example, this is necessary to protect boilers from cold temperature in the return line. Valtec three- and four-way mixing valves can be controlled in either manual mode, and by means of a servomotor. You can also order the latter on our website. The servomotor controls the valve using a controller or thermostat. The company supplies models with analog and pulse control, with the ability to switch to manual adjustment.

The term "thermostatic" in mixing valves means that they maintain optimal level temperatures in DHW systems and protect against the possibility of getting burned.

The Valtec brand's range of valve product offerings contains control parts for all kinds of applications, made from high-quality, reliable materials. Valves (gates) for heating systems can be operated at coolant temperatures reaching 120°C and at a pressure level of no more than 10 Bar. Products serve without the need for replacement or repair for 20-25 years (the specific service life depends on the model).