The crane is four-way. Three-way and four-way mixing valve What is a valve

A four-way valve is an element of the heating system, to which four pipes are connected, having heat carriers of different temperatures, used to prevent overheating of a solid fuel boiler. The thermostatic valve prevents the temperature inside the boiler from exceeding 110 °C. Already at a temperature of 95 °C, it starts cold water to cool the system.

Four way valve design

The body is made of brass, 4 connecting pipes are attached to it. Inside the body there is a bushing and a spindle, the operation of which has a complex configuration.

The thermostatic mixing valve performs the following functions:

• Mixing streams of water of different temperatures. Thanks to mixing, smooth regulation of water heating works;
• Boiler protection. The four-way mixer prevents corrosion, thereby extending the life of the equipment.

Diagram of a four-way mixer

The principle of operation of such a valve for heating is to rotate the spindle inside the housing. Moreover, this rotation must be free, since the sleeve has no thread. The working part of the spindle has two selections through which the flow opens in two passes. Thus, the flow will be throttled and will not be able to go directly to the second sample. The flow will be able to turn into any of the nozzles located on the left or right side of it. So, all flows coming from opposite sides are mixed and distributed over four nozzles.

There are designs in which a push rod works instead of a spindle, but such devices cannot mix flows.

Valve operation is controlled in two ways:

• Manual. Flow distribution requires the stem to be installed in one specific position. This position must be adjusted manually.
• Auto. Spindle rotation occurs as a result of a command received from an external sensor. Thus, the set temperature is constantly maintained in the heating system.

The four-way mixing valve provides a stable flow of cold and hot coolant. The principle of its operation does not require the installation of a differential bypass, because the valve itself passes the required amount of water. The device is used where temperature control is required. First of all, it is a radiator heating system with a solid fuel boiler. If in other cases the regulation of heat carriers occurs with the help of a hydraulic pump and a bypass, then here the operation of the valve completely replaces these two elements. As a result, the boiler operates in a stable mode, constantly receiving a metered amount of coolant.

Heating with four-way valve

Installation of a heating system with a four-way valve:

The connection diagram for a heating system with a four-way mixer consists of the following elements:

1. Boiler;
2. Four-way thermostatic mixer;
3. Safety valve;
4. Pressure reducing valve;
5. Filter;
6. ball valve;
7. Pump;
8. Heating batteries.

The installed heating system must be flushed with water. This is necessary so that various mechanical particles are removed from it. After that, the operation of the boiler must be checked at a pressure of 2 bar and with the expansion tank switched off. It should be noted that a short period of time must elapse between the start of full operation of the boiler and its check under hydraulic pressure. The time limit is due to the fact that with a long absence of water in the heating system, it will be susceptible to corrosion.

How to make a heating system with a four-way valve

The four-way valve for heating allows you to mix and direct 4 coolant flows. The principle of operation of the four-way valve lies in the possibility of mixing the coolant in different proportions.

Source: domotopim.ru

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News about "four-way valve for heating"

11.02.2015 - Electrotechnical market of Russia and CH

K200.M.0. The controller VT.K200.M Valtek is designed for measurement and automatic proportional-integral-derivative (PID) control of the heat carrier temperature in the mixing units of underfloor heating systems in accordance with a given schedule....

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Three-way valve for heating with thermostat

Properly executed piping of the heating circuit allows you to create the most comfortable temperature living conditions in the house. Equally important is the configuration of the heating main. So, for example, a three-way valve for heating with a thermostat, as well as other elements identical in functionality, play a significant role in the construction of a heat main.

1. What should the heating circuit be equipped with?
2. Mixing taps
3. thermostats

What should the heating circuit be equipped with?

Despite the fact that the main protection group for heating is selected directly by the employees of the store where the equipment is purchased, it will not be superfluous if you find out what exactly should be included in the set of intake fittings.

Mixing taps

Through these details, it is possible to carry out high-quality temperature control in the thermal block. The principle of operation of such a device is simple: when the handle of the heating three-way valve is turned, the bypass opens, which causes the cooled water to be drawn into the supply compartment, where hot and cold water is mixed.

According to this scheme, you can achieve the required temperature in the room. The three-way valve operates flexibly, without creating sudden temperature fluctuations in the heating installation. As a rule, almost all collector units of heating systems of private houses are equipped with such mixing blocks. This allows you to reduce the cost of consuming energy resources to heat a particular room, which, if necessary, can simply be disconnected from the main line.

Heating device safety group

The heater protection unit includes a safety valve, a pressure measuring device and a throttle for venting air from the heating unit. Thanks to these elements, it is possible to prevent both the breakdown of the equipment itself and to avoid an emergency in the event of an increase in pressure in the line. After all, this can lead to a rupture of the pipeline and, as a result, anyone who is nearby at this moment can be seriously injured.

Regardless of the choice of the type of heating system, it must necessarily be equipped with a safety hydraulic valve for the boiler.

The safety throttle can be made in two versions - open and closed. The first option is characterized by the absence of back pressure and the removal of excess fluid from the heating circuit. Whereas by means of a closed control valve, excess liquid is discharged into the pipeline. At the same time, counter pressure also works.

In order to increase the efficiency of the heating unit, it is necessary to correctly install the group of protective fittings. The entire set of rules is present in a special document SNiP. And it is not possible to present it to your attention in full, since everything depends on the specific equipment, its power and other individual factors. But at the same time, we can still consider the basic principles of the installation of valves.

A three-way valve for heating with a thermostat, as well as other elements of the heating system, are determined solely by pressure indicators and pipeline diameter. This imperative requirement determines GOST and any deviation from the norm is a violation, which can eventually lead to an emergency.

Features of the installation of valves

1. The safety valve is installed on the supply pipeline in close proximity to the heating unit.
2. In thermal circuits that are supplied with hot water, a hydraulic valve is placed at the hot water outlet at the highest point of the boiler.
3. The arrangement of the water heating system is characterized by the absence of various devices between the shutoff valves and the thermal circuit.
4. Drain valves for heating should be connected to main pipes of a relatively large diametrical size. And their withdrawal is carried out to any safe place or sewer network.

During the installation of the heating unit, it is strictly forbidden to narrow the pipes by a diameter smaller than the existing diameter of the valve.

VIDEO: Three-way valve in the system

When connecting heating in two-story houses, shut-off valves are installed separately on each floor. Experts recommend installing it as much as possible, so the boiler will be easier to maintain.

1. Chokes are adjusted by 15-25% more than the operating pressure in the thermal circuit.
2. It is necessary to carry out a functional check of the valves at least once a year, preferably after the start of the heating season. And this is done very simply: you need to make a forced opening of the throttle.

Bypass and non-return valves

To stabilize the pressure in the system, a check valve for heating is required. In addition, another structural element is also used - the bypass valve of the heating system. The principle of its operation is the same as that of the safety one, but in that case the pipe is connected to the return. With an increase in pressure, this device turns on and transfers the coolant to the return circuit. And in order to balance this characteristic, a reverse hydraulic valve is used.

The principle of operation: by means of a check valve in the heating system, the liquid moves in one direction, preventing its reverse movement.

thermostats

The thermostat is characterized by the use of two main structural elements - a valve and a thermoelement. The first is used as a heat transfer regulator. This is due to the change in the flow rate of the coolant depending on the air temperature. In turn, the thermoelement allows you to control the temperature of the coolant and, if necessary, heat or cool it.

Depending on the movement of the spool, which is equipped with a hydraulic valve, this design is made in two versions: low-lift and full-lift. In the first case, the lift height of the spool is equal to 0.05 of the diameter of the seat. As a rule, low-lift chokes are used in those blocks in which there is no need for high bandwidth. But as for full-lift throttles, they have a spool height equal to 0.25 of the diametral value of the saddle. Such parts, for the most part, are used in thermal mains with a gaseous medium.

Other shut-off fittings

In addition to the above structural elements, needle throttles are also used. They are a shutter in the form of a narrow cone and contribute to reliable shutoff and regulation of coolant flows at elevated pressures.

There are also electromagnetic valves, which are a primitive and most affordable option for automating the regulation of the movement of hot water through the pipeline. However, in order to use such parts, it is essential to use water with a minimum hardness and the absence of solid particles.

Many heating units are also equipped with compensators, due to which deformations of pipeline lines are compensated for under the influence of high temperatures. In addition, such devices help to reduce vibrations in the system, which also eliminates possible damage to the thermal circuit.

In fact, the installation of heating equipment is quite a feasible task even for someone who has never performed such processes in his life. And if you correctly approach the implementation of the goal and perform the work in accordance with all requirements, then you can reduce the likelihood of emergencies and the need for repair and restoration measures.

Here, in fact, is the entire set of valves that is used in the construction of heat blocks. Now that you know what should be included in the heating unit, you can perform high-quality piping of thermal equipment that will last you for decades.

Three-way valve for heating with thermostat

A three-way valve for heating with a thermostat, as well as other elements identical in functionality, play a significant role in the construction of a heat main.

• About the principle of the valve
• Practical use
• Conclusion

Anyone who has ever tried to study various schemes of heating systems must have come across those where the supply and return pipelines miraculously come together. In the center of this node there is a certain element, to which pipes with a coolant of different temperatures are connected from four sides. This element is a four-way valve for heating, the purpose and operation of which will be discussed in this article.

About the principle of the valve

Like its more “modest” three-way counterpart, the four-way valve is made of high-quality brass, but instead of three connecting pipes it has as many as 4. Inside the body, a spindle with a cylindrical working part of a complex configuration rotates on the sealing sleeve.

In it, from two opposite sides, selections are made in the form of flats, so that in the middle the working part resembles a damper. It retains a cylindrical shape at the top and bottom so that sealing can be performed.

The spindle with the sleeve is pressed against the body by a cover with 4 screws, an adjusting handle is mounted on the outside of the shaft end or a servo drive is installed. How this whole mechanism looks like, the detailed diagram of the four-way valve shown below will help to visualize well:

The spindle rotates freely in the sleeve because it has no thread. But at the same time, the samples made in the working part can open the flow through two passes in pairs or allow three flows to mix in different proportions. How this happens is shown in the diagram:

For reference. There is another design of the four-way valve, where a push rod is used instead of a rotating spindle. But such elements cannot mix flows, but only redistribute. They have found their application in gas double-circuit boilers, switching the flow of hot water from the heating system to the DHW network.

The peculiarity of our functional element is that the coolant flow, connected to one of its nozzles, can never pass to the other outlet in a straight line. The flow will always turn into the right or left branch pipe, but will not fall into the opposite one. At a certain position of the spindle, the damper allows the coolant to pass immediately to the right and left, mixing with the flow coming from the opposite entrance. This is the principle of operation of the four-way valve in the heating system.

It should be noted that the valve can be controlled in two ways:

manually: the required distribution of flows is achieved by setting the rod to a certain position, guided by the scale opposite the handle. The method is rarely used, since the effective operation of the system requires periodic adjustment, it is impossible to constantly do it manually;

automatically: the valve spindle is rotated by a servomotor that receives commands from external sensors or a controller. This allows you to adhere to the specified water temperatures in the system when external conditions change.

Practical use

Wherever it is necessary to ensure high-quality control of the coolant, four-way valves can be used. Quality regulation is the control of the temperature of the coolant, and not its flow. It is possible to achieve the required temperature in the water heating system in only one way - by mixing hot and cooled water, obtaining a coolant with the required parameters at the outlet. The successful implementation of this process is just ensured by the device of a four-way valve. Here are a couple of examples of setting an element for such cases:

• in a radiator heating system with a solid fuel boiler as a heat source;
• in the underfloor heating circuit.

As you know, a solid fuel boiler in the heating mode needs to be protected from condensate, from which the walls of the furnace are corroded. The traditional scheme with a bypass and a three-way mixing valve that does not allow cold water from the system to enter the boiler tank can be improved. Instead of a bypass line and a mixing unit, a four-way valve is installed, as shown in the diagram:

A logical question arises: what is the use of such a scheme, where you have to put a second pump, and even a controller to control the servo? The fact is that here the operation of the four-way valve replaces not only the bypass, but also the hydraulic separator (hydraulic arrow), if there is a need for such. As a result, we get 2 separate circuits that exchange coolant with each other as needed. The boiler receives chilled water in doses, and the radiators receive a coolant with the optimum temperature.

Since the water circulating through the heating circuits of underfloor heating is heated to a maximum of 45 ° C, it is unacceptable to run the coolant directly from the boiler into them. In order to withstand this temperature, a mixing unit with a three-way thermostatic cock and bypass is usually placed in front of the distribution manifold. But if instead of this unit a four-way mixing valve is installed, then in the heating circuits you can use the return water coming from the radiators, which is shown in the diagram:

Conclusion

It cannot be said that the installation of a four-way valve is simple and does not require financial investments. On the contrary, the implementation of such schemes will result in tangible financial costs. On the other hand, they are not so great as to give up the advantages of such systems - work efficiency and, as a result, economy. An important condition is the availability of a reliable power supply, since without it the valve drive will stop working.

cotlix.com

How to make a heating system with a four-way valve

A four-way valve is an element of the heating system, to which four pipes are connected, having heat carriers of different temperatures, used to prevent overheating of a solid fuel boiler. The thermostatic valve prevents the temperature inside the boiler from exceeding 110 °C. Already at a temperature of 95 °C, it starts cold water to cool the system.

Four way valve design

The body is made of brass, 4 connecting pipes are attached to it. Inside the body there is a bushing and a spindle, the operation of which has a complex configuration.

The thermostatic mixing valve performs the following functions:

• Mixing streams of water of different temperatures. Thanks to mixing, smooth regulation of water heating works;
• Boiler protection. The four-way mixer prevents corrosion, thereby extending the life of the equipment.

Diagram of a four-way mixer

h3_2

The principle of operation of such a valve for heating is to rotate the spindle inside the housing. Moreover, this rotation must be free, since the sleeve has no thread. The working part of the spindle has two selections through which the flow opens in two passes. Thus, the flow will be throttled and will not be able to go directly to the second sample. The flow will be able to turn into any of the nozzles located on the left or right side of it. So, all flows coming from opposite sides are mixed and distributed over four nozzles.

There are designs in which a push rod works instead of a spindle, but such devices cannot mix flows.

Valve operation is controlled in two ways:

• Manual. Flow distribution requires the stem to be installed in one specific position. This position must be adjusted manually.
• Auto. Spindle rotation occurs as a result of a command received from an external sensor. Thus, the set temperature is constantly maintained in the heating system.

The four-way mixing valve provides a stable flow of cold and hot coolant. The principle of its operation does not require the installation of a differential bypass, because the valve itself passes the required amount of water. The device is used where temperature control is required. First of all, it is a radiator heating system with a solid fuel boiler. If in other cases the regulation of heat carriers occurs with the help of a hydraulic pump and a bypass, then here the operation of the valve completely replaces these two elements. As a result, the boiler operates in a stable mode, constantly receiving a metered amount of coolant.

Heating with four-way valve

Installation of a heating system with a four-way valve:

The connection diagram for a heating system with a four-way mixer consists of the following elements:

1. Boiler;
2. Four-way thermostatic mixer;
3. Safety valve;
4. Pressure reducing valve;
5. Filter;
6. ball valve;
7. Pump;
8. Heating batteries.

The installed heating system must be flushed with water. This is necessary so that various mechanical particles are removed from it. After that, the operation of the boiler must be checked at a pressure of 2 bar and with the expansion tank switched off. It should be noted that a short period of time must elapse between the start of full operation of the boiler and its check under hydraulic pressure. The time limit is due to the fact that with a long absence of water in the heating system, it will be susceptible to corrosion.

domotopim.ru

Four way mixing valve for heating

• Device and functions
• Manufacturers

The four-way valve is a plumbing element that performs important functions in the heating system.

Esbe four-way mixing valve

Device and functions

A four-way valve for heating rotates a spindle in the body itself. Rotation must necessarily be carried out in a free manner, because the sleeve does not contain threads. The functioning part of the spindle has a pair of selections, with the help of which the flow is opened in two passes.

As a consequence, the flow is regulated and unable to go directly to the second sample. The flow can turn into any branch pipe, which is located on the left or right side of it. It turns out that all the flows that pass from different sides are mixed and diverge through four nozzles.

There are devices where a pressure rod functions instead of a spindle, however, such designs are not designed to mix flows.

A four-way valve for heating is an element of the heating system to which four pipes are connected, having a heat carrier of different temperatures. Inside the body are the sleeve and the spindle. The latter has work with a difficult configuration.

The operation of the 4-way mixer can be controlled as follows:

1. Manual. In this case, for the distribution of flows, it is necessary to mount the stem in one specific position. And you need to manually adjust this position.
2. Automatic (with temperature controller). Here, an external sensor gives a command to the spindle, as a result of which the latter begins to rotate. Because of this, a stable specified temperature is maintained in the heating system.

Installation diagram of a four-way mixing valve in a heating system

The main valve functions of the 4-way valve are as follows.

1. Mixing of water streams with different temperature heating. The device is used to prevent overheating of a solid fuel boiler. The four-way mixing valve does not allow the temperature in the boiler equipment to rise above 110 °C. When heated to 95 °C, the appliance runs cold water to cool the system.
2. Protection of boiler equipment. The 4-way valve prevents corrosion and thus extends the life of the entire system.

Thanks to the 4-way valve for heating, a uniform flow of hot and cold heat carriers is carried out. For normal operation, no bypass installation is required, since the valve itself passes the required volume of liquid. The device is used where temperature control is required. First of all, in the heating system with radiators together with a solid fuel boiler. If in other cases the fluid adjustment is carried out using a hydraulic pump and bypass, then in this case the operation of the valve completely replaces these devices. It turns out that the boiler functions stably and constantly receives a certain amount of heat carrier.

Manufacturers

The four-way valve for heating is produced by companies such as Honeywell, ESBE, VALTEC and others.

The history of Honeywell began in 1885.

Today it is a manufacturer that is included in the list of 100 leading world companies compiled by Fortune magazine.

Honeywell Four Way Valve

Honeywell V5442A four-way valves are manufactured for systems where the heat carrier is water or liquids, with a percentage of glycol up to 50. They are designed to operate at temperatures from 2 to 110 ° C and at operating pressures up to 6 bar.

Honeywell manufactures valves with connection sizes of 20, 25, 32 mm. Therefore, the values ​​of the Kvs coefficient are from 4 to 16 m³/h. The series devices work together with electric drives. For systems with higher power, the ZR-FA flanged valve series is used.

The Honeywell 4-way valve is easy to install and there are many options.

The Swedish company ESBE has been setting new quality standards for valves and actuators used in various systems for more than 100 years.

All of its products are economical, reliable and easy to use in heating, cooling and water supply systems.

ESBE offers a 4-way heating valve with internal thread. The valve body is made of brass. Working pressure 10 atmospheres, temperature 110 degrees (short-term - 130 degrees). The four-way mixing valve is produced in sizes 1/2-2″, with a capacity of 2.5 -40 Kvs.

The VALTEC company appeared in 2002 in Italy and in a short time launched the production of products, which were developed on the basis of studying the pros and cons of products from various manufacturers.

Valtek offers mixing valves for various purposes, which are designed for long-term operation in the engineering system (water-heated floor, built-in wall, ceiling heating and cooling, hot water supply). The manufacturer's products can be found anywhere in Russia and the CIS countries.

It cannot be argued that a four-way valve for heating does not require financial investments. Installation of the device will be expensive, however, on the other hand, the efficiency of work and, as a result, profitability, justifies the money spent. There is only the main condition - the presence of a high-quality electrical network, since without it the valve drive will stop working.

Tags: ESBE Honeywell Valtec heating system installation economical heating

teplofan.ru

Characteristics of the three-way heating valve

A three-way valve for heating is especially necessary when the house needs to distribute hot water evenly in radiators, plumbing systems and underfloor heating systems.

Construction device

Outwardly, a three-way faucet looks like a triple tap, such a part is made of bronze or cast from brass, it has a plastic rotating handle with which you can adjust the water supply. Below it is a sensor that reacts to heat and a rod in which an element in the form of a cone is firmly installed.

The structure of the valve consists of:

• metal case;
• temperature sensing controller;
• element in the form of a cone;
• stock;
• seat;
• pressure mixing zone;
• sealing element.

Shut-off valves correct fluctuations in water temperature. The use of such a system not only provides comfort, but also allows you to significantly save money. This is due to the fact that due to the regulator there is a significantly lower fuel consumption for heating. And in the system of warm floors it is also an indispensable thing, it does not allow the floors to overheat, creating uncomfortable sensations, it provides smooth, imperceptible heating.

The principle of operation of the structure

The valve is usually installed in the heating system where the flow must be divided into 2 circuits. In the first flow with a constant temperature, and in the second, on the contrary - with a variable one. Typically, a constant temperature must be maintained where the flow must be in the required volume and quality. It will be monitored according to these indicators.

Variable temperature flow can be used where fluid quality is not required. In this case, attention is paid to the quantitative indicator, that is, the requirements for the volume of water.

2-way control valve

There are two-way valves, two of which can be combined with each other and you get a three-way valve. Only such a pair should work in reverse, because when one element closes, another opens.

Water flows through the hoses until it is heated to the set temperature level. The valve ensures the flow of water directly into operation from the boiler room at the desired temperature, previously set by the regulator.

If, nevertheless, the norms of the limiting temperature are violated, then the valve component will work, which presses on the stem. The rod will move, and the cone-shaped element will come out of the seat, thereby opening the channels. This process goes on until the temperature is the same as it was originally needed.

There is a three-way valve for heating with a ball part instead of a cone. Then the rod will rotate. There is another type of valve, there will be a sector instead of a ball. The sector simply blocks the water flow.

Types of three-way structures by type of drives

The actuator plays an important role in the operation of the valve.

Systems are classified according to the type of drive.

A common actuated valve system is that the actuator presses on the stem due to a pre-set temperature sensor. Such a standard drive can be replaced by any other.

The process is controlled by a temperature sensitive element, using a temperature sensor that can be removed for replacement. A three-way heating valve equipped with such a component does its job better than others.

Motorized 3-way valve

Electrically actuated valves have gained popularity in use. The meaning of the work lies in the fact that a special controller controls the drive. There are regulating electrical components that constantly measure flow data and give a signal to the controller, which in turn regulates the operation of the drive.

Valve with gas thermostat, equipped with servo drive. This system works without a controller and is controlled by a crane. It receives a warning from the thermostat. Usually composed of a spherical element or a sector element.

Classification according to the principle of operation

According to the principle of operation, the valve is divided into dividing and mixing.

The mixing valve mixes hot and cold streams together. This system is best suited for underfloor heating. How does temperature control work? You need to know the temperature data of the incoming streams, this will help to calculate the proportions and fulfill the necessary values.

The dividing valve has one inlet and 2 outlets. If you install the valve correctly, it will divide the flow into two.

Externally, these devices do not differ. But there are differences inside. The mixing heat-sensitive valve has a stem with a ball valve. It is usually in the middle and closes the exit.

The dividing system has two valves in the stem. The first valve presses on the seat and closes the channel, while the second opens another channel.

The principle of operation of the three-way valve

The mixing system can be manual or electric. Most often, a manual system is used. It looks like a faucet, which has a regulating component in the form of a ball and three branches into pipes.

The electrical system implies auto control, usually used in a private house for high-quality heating. And also it is quite possible to combine with the heating process of the underfloor heating system.

Valves with a thermostat must be selected taking into account the pipe diameter and pressure coefficient, otherwise the entire system may be disturbed.

Advantages of installing a three-way valve:

Installation of a three-way valve

• easy to install;
• no need to track work;
• easy to operate and easy to change;
• durability of use;
• damage can be repaired independently;
• the valve is absolutely impenetrable;
• low hydromechanical resistance;
• the water stream does not stagnate.

Mounting diagram

The valve is installed for the heating process according to the scheme with the first circuit of the circuit.

In the first circuit, the water passes, heating up to the desired temperature, usually 40-50 degrees Celsius. Then comes the launch of the stem, which opens the cold streams of water. For the system to work efficiently, a pump must be installed after the valve.

A variant is possible where the main role is played by the pump and the thermostat. After the first circle, the water heat flow will flow as needed and rotate throughout the system. The pump and valve will be subordinate to the controller.

Install the fittings so that the arrows of the manometer show the movement of water.

If it is necessary to weld during installation, care must be taken to ensure that the valve does not overheat. And you need to install it in an accessible place.

You can and even need to install a water filter, as some valves are of low quality. It is recommended to choose good filters and change as needed.

Selection rules

You should pay attention to the size of the temperature controller connectors, because they must fit the pipes of the system. Usually the diameter is 2–4 cm. If there is still no suitable size, an adapter can be used.

Pipe throughput indicators play a very important role in installation.

If it is decided that the valve will be installed for the operation of underfloor heating, then you need to make sure that the servo drive will probably be connected.

It is better to consult a specialist about buying a thermostatic valve. A mounting error can cause fluctuations in the temperature of the streams. And the most unpleasant moment can be a pipe break.

Selection of popular models

Esbe brand valve is one of the most popular. Reinforcement production has been established for decades in Switzerland. During its existence, the company has established itself as a reliable supplier of quality products.

Honeywell also produces faucets, they are convenient and easy to operate. They are relatively small in size and have a long service life.

Although Valtec products have recently appeared on the market, the company has already managed to establish itself as a dynamically developing company and has already concluded supply agreements with Russia and Italy. This product comes with a 7 year warranty at an affordable price.

The popular IMI Heimeier model is a safety valve with a separation type thermostat. It does an excellent job of distributing hot and cold streams. The part is cast in bronze and equipped with a cap. The stem is made of stainless steel, with a powerful seal in the form of a ring.

The model comes only with a flat seal or seal and triple development. If you need to connect with fittings, then they usually resort to welding or soldering. The seal is cone-shaped and external thread. If you need to connect with fittings, then the pipes are suitable from steel, copper or plastic.

conclusions

A three-way valve for heating is used in the water supply system in order to get it at the right temperature. Like a conventional faucet that adjusts the water warmer or colder.

When purchasing such fittings, pay attention to technical characteristics, such as diameter, whether it is possible to install a servo drive, how much water supply can withstand.

Working in cooling mode, they lower the air temperature inside the building, and naturally increase it outside. It turns out that the air conditioner distills heat with the help of a coolant from the room to the street.

In the summer, you will find this process necessary, but in the winter, you will want to distill the heat back from the atmosphere into the room. Partially the problem is solved with the help of the reversing valve of the air conditioner, which allows to change the direction of the refrigerant flow (the principle of reversing the refrigeration cycle), and partly, with the help of the operation of the supply air heater.

Heating of outside air by the conditioner.

At not very low outside temperatures, the cool air of the atmosphere is able to boil the freon in the air conditioner and instruct it to transfer the absorbed heat to the room.

But at low winter temperatures of the atmosphere, the heat stored by freon may not be enough to heat the icy supply air - then an additional air heater mounted in the air conditioner supply unit comes into play.

Reversing the refrigeration cycle in the air conditioner.

In the process of reversing the refrigeration cycle, the roles of the condenser and evaporator change - the outdoor unit of the air conditioner now "boils" the freon, and the indoor unit condenses it and gives off the heat generated in this case to the air entering the room.

Both the condenser and remained in their places, but the route of the refrigerant has changed, and the engineers assigned the main role in this transformation of the refrigeration unit into a heat pump to the reversing (four-way) valve.

The principle of operation of the four-way valve of the air conditioner.

The schemes and principle of operation of the four-way valve in different versions are given below: 1 - compressor, 2 - control valve, 3 - piston, 4 - transition capillary tube, 5 - capillary tube, 6 - indoor unit of the air conditioner, 7 - outdoor unit of the air conditioner, 8 - winding of the four-way valve.

In cooling mode, the piston (3) moves to the left and connects the compressor (1) to the external air conditioner unit (7). The compressor inlet is connected to the indoor unit of the air conditioner (6).

Valve operation in heating mode.

In heating mode, the energized winding (8) shifts the control valve (2) to the right, allowing you to connect the right cavity of the piston (3) to the compressor inlet, changing the direction of the refrigerant circulation - the compressor inlet is connected to the external unit of the air conditioner 7.

Anyone who has ever tried to study various schemes of heating systems must have come across those where the supply and return pipelines miraculously come together. In the center of this node there is a certain element, to which pipes with a coolant of different temperatures are connected from four sides. This element is a four-way valve for heating, the purpose and operation of which will be discussed in this article.

About the principle of the valve

Like its more “modest” three-way counterpart, the four-way valve is made of high-quality brass, but instead of three connecting pipes it has as many as 4. Inside the body, a spindle with a cylindrical working part of a complex configuration rotates on the sealing sleeve.

In it, from two opposite sides, selections are made in the form of flats, so that in the middle the working part resembles a damper. It retains a cylindrical shape at the top and bottom so that sealing can be performed.

The spindle with the sleeve is pressed against the body by a cover with 4 screws, an adjusting handle is mounted on the outside of the shaft end or a servo drive is installed. How this whole mechanism looks like, the detailed diagram of the four-way valve shown below will help to visualize well:

The spindle rotates freely in the sleeve because it has no thread. But at the same time, the samples made in the working part can open the flow through two passes in pairs or allow three flows to mix in different proportions. How this happens is shown in the diagram:

For reference. There is another design of the four-way valve, where a push rod is used instead of a rotating spindle. But such elements cannot mix flows, but only redistribute. They have found their application in gas double-circuit boilers, switching the flow of hot water from the heating system to the DHW network.

The peculiarity of our functional element is that the coolant flow, connected to one of its nozzles, can never pass to the other outlet in a straight line. The flow will always turn into the right or left branch pipe, but will not fall into the opposite one. At a certain position of the spindle, the damper allows the coolant to pass immediately to the right and left, mixing with the flow coming from the opposite entrance. This is the principle of operation of the four-way valve in the heating system.

It should be noted that the valve can be controlled in two ways:

manually: the required distribution of flows is achieved by setting the rod to a certain position, guided by the scale opposite the handle. The method is rarely used, since the effective operation of the system requires periodic adjustment, it is impossible to constantly do it manually;

automatically: the valve spindle is rotated by a servomotor that receives commands from external sensors or a controller. This allows you to adhere to the specified water temperatures in the system when external conditions change.

Practical use

Wherever it is necessary to ensure high-quality control of the coolant, four-way valves can be used. Quality regulation is the control of the temperature of the coolant, and not its flow. It is possible to achieve the required temperature in the water heating system in only one way - by mixing hot and cooled water, obtaining a coolant with the required parameters at the outlet. The successful implementation of this process is just ensured by the device of a four-way valve. Here are a couple of examples of setting an element for such cases:

• in a radiator heating system with a solid fuel boiler as a heat source;
• in the underfloor heating circuit.

As you know, a solid fuel boiler in the heating mode needs to be protected from condensate, from which the walls of the furnace are corroded. The traditional scheme with a bypass and a three-way mixing valve that does not allow cold water from the system to enter the boiler tank can be improved. Instead of a bypass line and a mixing unit, a four-way valve is installed, as shown in the diagram:

A logical question arises: what is the use of such a scheme, where you have to put a second pump, and even a controller to control the servo? The fact is that here the operation of the four-way valve replaces not only the bypass, but also the hydraulic separator (hydraulic arrow), if there is a need for such. As a result, we get 2 separate circuits that exchange coolant with each other as needed. The boiler receives chilled water in doses, and the radiators receive a coolant with the optimum temperature.

Since the water circulating through the heating circuits of underfloor heating is heated to a maximum of 45 ° C, it is unacceptable to run the coolant directly from the boiler into them. In order to withstand this temperature, a mixing unit with a three-way thermostatic cock and bypass is usually placed in front of the distribution manifold. But if instead of this unit a four-way mixing valve is installed, then in the heating circuits you can use the return water coming from the radiators, which is shown in the diagram:

Conclusion

It cannot be said that the installation of a four-way valve is simple and does not require financial investments. On the contrary, the implementation of such schemes will result in tangible financial costs. On the other hand, they are not so great as to give up the advantages of such systems - work efficiency and, as a result, economy. An important condition is the availability of a reliable power supply, since without it the valve drive will stop working.

During the oil crisis of 1973, the demand for the installation of a large number of heat pumps increased dramatically. Most heat pumps are equipped with a four-way reversing solenoid valve, used either to switch the pump to summer mode (cooling) or to cool the external battery in winter mode (heating).
The subject of this section is to study the operation of the four-way solenoid reversal valve (V4V) installed on most classic air-to-air heat pumps and defrost systems using cycle reversal (see Fig. 60.14), in order to effectively control the directions of movement streams.
A) V4V operation

Let's study the diagram (see Fig. 52.1) of one of these valves, consisting of a large four-way main valve and a small three-way control valve mounted on the main valve body. At the moment, we are interested in the main four-way valve.


"T \ However, the compressor discharge (pos. 1) and suction (pos. 2) lines of the compressor are ALWAYS connected as shown in the diagram in fig.

Finally, 3 capillaries (pos. 7) are cut into the body of the main valve in the places shown in fig. 52.1, which are connected to the control solenoid valve

If the V4V is not installed on the machine, you will hear a distinct click when you apply voltage to the solenoid valve, but the spool will not move. Indeed, in order for the spool inside the main valve to move, it is absolutely necessary to provide a pressure difference in it. Why so, we will now see.

The discharge Pnag and suction Pvsac lines of the compressor are always connected to the main valve as shown in the diagram (Fig. 52.2). In this moment, we will simulate the operation of a three-way control solenoid valve using two manual valves: one closed (pos. 5) and the other open (pos. 6). In the center of the main valve, Рnag develops forces acting on both pistons in the same way: one pushes the spool to the left (pos. 1), the other to the right (pos. 2), as a result of which both of these efforts are mutually balanced. Recall that small holes are drilled in both pistons.
Therefore, Pnag can pass through the hole in the left piston, and in the cavity (pos. 3) behind the left piston, Pnag will also be installed, which pushes the spool to the right. Of course, at the same time Rnag also penetrates through the hole in the right piston into the cavity behind it (pos. 4). However, since the valve 6 is open, and the diameter of the capillary connecting the cavity (pos. 4) with the suction line is much larger than the diameter of the hole in the piston, the gas molecules that have passed through the hole will instantly be sucked into the suction line. Therefore, the pressure in the cavity behind the right piston (pos. 4) will be equal to the pressure Pbac in the suction line.

Thus, a more powerful force due to the action of Pnag will be directed from left to right and will force the spool to move to the right, communicating the non-pressurizing line with the left fitting (pos. 7), and the suction line with the right fitting (pos. 8).
If now Pnag is directed into the cavity behind the right piston (close valve 6), and Pvac into the cavity behind the left piston (open valve 5), then the predominant force will be directed from right to left and the spool will move to the left (see Fig. 52.3).
At the same time, he communicates the discharge line with the right fitting (pos. 8), and the suction line with the left fitting (pos. 7), that is, exactly the opposite compared to the previous version.

Of course, the use of two manual valves for the reversibility of the working cycle cannot be envisaged. Therefore, now we will begin to study the three-way control electrovalve, the most suitable for automating the process of reversing the cycle.
We have seen that the movement of the spool is possible only if there is a difference between the values ​​of Pnag and Pbac. Therefore, the control solenoid valve will be very small and remain the same for all main valve diameters.
The central inlet of this valve is a common outlet and is connected to the suction cavity (see Fig. 52.4).
If voltage is not applied to the winding, the right input is closed, and the left one is connected to the suction cavity. Conversely, when voltage is applied to the winding, the right input is in communication with the suction cavity, and the left one is closed.

Let us now study the simplest refrigeration circuit equipped with a four-way valve V4V (see Fig. 52.5).
The electromagnet winding of the control solenoid valve is not energized and its left input communicates the cavity of the main valve, behind the left piston of the spool, with the suction line (recall that the diameter of the hole in the piston is much smaller than the diameter of the capillary connecting the suction line with the main valve). Therefore, in the cavity of the main valve, to the left of the left piston of the spool, Pvsac is installed.
Since Pnag is set to the right of the spool, under the influence of the pressure difference, the spool moves sharply to the left inside the main valve.
Having reached the left stop, the piston needle (pos. A) closes the hole in the capillary connecting the left cavity with the Pvac cavity, thereby preventing the passage of gas, since this is no longer necessary. Indeed, the presence of a constant leak between the cavities Pnag and Pbac can only have a detrimental effect on the operation of the compressor.

Note that the pressure in the left cavity of the main valve again reaches the value of Pnag, but since Pnag has also been established in the right cavity, the spool will no longer be able to change its position.
Now let's remember properly the location of the condenser and evaporator, as well as the direction of flow in the capillary expansion device.
Before you continue reading, try to imagine what will happen if voltage is applied to the solenoid valve coil.

When power is supplied to the solenoid valve winding, the right cavity of the main valve communicates with the suction line and the spool moves sharply to the right. Having reached the stop, the piston needle interrupts the outflow of gas into the suction line, blocking the opening of the capillary connecting the right cavity of the main valve with the suction cavity.
As a result of the displacement of the spool, the discharge line is now directed towards the former evaporator, which has become a condenser. Likewise, the former condenser has become an evaporator and the suction line is now connected to it. Note that the refrigerant in this case moves through the capillary in the opposite direction (see Fig. 52.6).
To avoid naming errors for heat exchangers that alternate between evaporator and condenser, it is best to refer to them as external coil (outdoor heat exchanger) and indoor coil (indoor heat exchanger).

B) Danger of water hammer
During normal operation, the capacitor is filled with liquid. However, we have seen that at the moment of cycle reversal, the condenser almost instantly becomes an evaporator. That is, at this moment there is a danger of a large amount of liquid entering the compressor, even if the expansion valve is completely closed.
To avoid this hazard, it is generally necessary to install a liquid separator in the compressor suction line.
The liquid separator is designed in such a way that in the event of a build-up of liquid at the outlet of the main valve, mainly during cycle reversal, it does not allow it to enter the compressor. The liquid remains at the bottom of the separator, while pressure is taken into the suction line at its highest point, which completely eliminates the risk of liquid entering the compressor.

However, we have seen that the oil (and hence the liquid) must be constantly returned to the compressor through the suction line. To give the oil this opportunity, a calibrated hole (sometimes a capillary) is provided in the lower part of the suction pipe ...

When liquid (oil or refrigerant) lingers at the bottom of the liquid separator, it is sucked through the calibrated orifice, slowly and gradually returning to the compressor in quantities that are insufficient to lead to undesirable consequences.
C) Possible malfunctions
One of the most difficult valve failures V4 V is associated with a situation where the spool is stuck in an intermediate position (see Fig. 52.8).
At this moment, all four channels communicate with each other, which leads to more or less complete, depending on the position of the spool during jamming, gas bypass from the discharge line to the suction cavity, which is accompanied by the appearance of all signs of a malfunction such as "too weak compressor": - capacity, drop in condensing pressure, increase in evaporating pressure (see section 22 "Compressor too weak").
Such jamming can occur accidentally and is due to the design of the main valve itself. Indeed, since the spool is free to move inside the valve, it can move and, instead of being at one of the stops, remain in an intermediate position as a result of vibrations or mechanical shocks (for example, after transportation).

If the V4V valve has not yet been installed and therefore it is possible to hold it by hand, the installer MUST check the position of the spool by looking inside the valve through the 3 lower holes (see fig. 52.9).

In this way, he will be able to ensure the normal position of the spool very easily, because after the valve is soldered, it will be too late to look inside!
If the spool is not positioned correctly (fig. 52.9, right), it can be brought into the desired state by tapping one end of the valve on a block of wood or a piece of rubber (see fig. 52.10).
Never knock the valve against a metal part, as this risks damaging the tip of the valve or completely destroying it.
With this very simple trick, you can, for example, set the V4V valve spool to the cooling position (discharge line in communication with the outdoor heat exchanger) when replacing a defective V4V with a new one in a reversible air conditioner (if this happens in the heat of summer).

The cause of the spool jamming in the intermediate position can also be numerous defects in the design of the main valve or auxiliary solenoid valve.
For example, if the main valve body has been impacted and deformed in the barrel, this deformation will prevent the spool from moving freely.
One or more capillaries connecting the cavities of the main valve with the low-pressure part of the circuit may become clogged or bent, which will lead to a decrease in their flow area and will not allow for a sufficiently rapid release of pressure in the cavities behind the spool pistons, thereby disrupting its normal operation (recall also times that the diameter of these capillaries must be substantially larger than the diameter of the holes drilled in each of the pistons).
Signs of excessive burnout on the valve body and poor appearance of the solder joints are an objective indication of the skill of the torch brazing fitter. Indeed, during soldering, it is imperative to protect the main valve body from heat by wrapping it with a wet rag or moistened asbestos paper, since the pistons and spool are equipped with sealing nylon (fluoroplastic) rings, which at the same time improve the sliding of the spool inside the valve. During soldering, if the temperature of the nylon exceeds 100°C, it loses its sealing ability and anti-friction characteristics, the gasket is irreparably damaged, which greatly increases the likelihood of the spool jamming at the first attempt to switch the valve.
Recall that the rapid movement of the spool when the cycle is reversed occurs under the action of the difference between Pnag and Pvac. Therefore, movement of the spool becomes impossible if this difference AP is too small (usually its minimum allowable value is about 1 bar). Thus, if the control solenoid valve is activated when the differential AP is insufficient (for example, when starting the compressor), the spool will not be able to move freely and there is a danger of it getting stuck in the intermediate position.
Seizing of the spool can also occur due to malfunctions in the operation of the control solenoid valve, for example, due to insufficient supply voltage or improper installation of the solenoid mechanism. Note that dents on the core of the electromagnet (due to impacts) or its deformation (during disassembly or as a result of a fall) do not allow normal sliding of the core sleeve, which can also lead to valve sticking.
It is not superfluous to recall that the condition of the refrigeration circuit must be absolutely perfect. Indeed, if in a conventional refrigeration circuit the presence of copper particles, traces of solder or flux is highly undesirable, then for a circuit with a four-way valve, even more so. They can jam it or clog the piston holes and capillary passages in the V4V valve. Therefore, before proceeding with the dismantling or assembly of such a circuit, try to think through the maximum precautions that you must observe.
Finally, we emphasize that the V4V valve is strongly recommended to be mounted in a horizontal position to avoid even a slight drop of the spool due to its own weight, as this can cause permanent leakage through the upper piston needle when the spool is in the top position. Possible causes of spool jamming are shown in fig. 52.11.
Now the question arises. What to do if the spool is stuck?

Before requiring the V4V valve to operate normally, the repairer must first ensure that the conditions for this operation on the circuit side. For example, a lack of refrigerant in the circuit, causing a drop in both Рnag and Рвсаc, can lead to a weak drop in DR, insufficient for a free and complete transfer of the spool.
If the appearance of the V4V (no dents, bumps or overheating) seems to be satisfactory and there is confidence that there are no electrical faults (very often such faults are attributed to the V4V valve, while it is only an electrical defect), the repairman should ask the following question:

Which heat exchanger (internal or external) should the compressor discharge line be connected to and in what position (right or left) should the spool be in a given operating mode of the unit (heating or cooling) and a given design (heating or cooling with a de-energized control solenoid valve)?

When the repairman has confidently determined the required normal position of the spool (right or left), he can try to put it in place, lightly but sharply, tapping on the main valve body from the side where the spool should be with a mallet or wooden hammer (if there is no mallet, never use an ordinary hammer or sledgehammer without first placing a wooden spacer on the valve, otherwise you risk seriously damaging the valve body, see Fig. 52.12).
In the example in fig. 52.12 hitting the mallet from the right causes the spool to move to the right (unfortunately, the developers usually do not leave space around the main valve for hitting!).

Indeed, the discharge pipe of the compressor must be very hot (beware of burns, as in some cases its temperature can reach 100°C). The suction pipe is usually cold. Therefore, if the spool is moved to the right, nozzle 1 should have a temperature close to the temperature of the discharge pipe, or, if the spool is moved to the left, close to the temperature of the suction pipe.
We have seen that a small amount of gases from the pressure line (hence very hot) pass for a short period of time, when the spool is overturned, through two capillaries, one of which connects the cavity of the main valve on the side where the spool is located, with one of inputs of the solenoid valve, and the other connects the output of the control solenoid valve to the suction line of the compressor. Further, the passage of gases stops, since the needle of the piston, which has reached the stop, closes the opening of the capillary and prevents gases from entering it. Therefore, the normal temperature of the capillaries (which can be touched with your fingertips), as well as the temperature of the body of the control solenoid valve, should be almost the same as the temperature of the body of the main valve.
If groping gives other results, there is nothing left but to try to understand them.

Let's say that during the next maintenance, the repairman finds a small increase in suction pressure and a small drop in discharge pressure. Since the lower left fitting is hot, it infers that the spool is on the right. Feeling the capillaries, he notices that the right capillary, as well as the capillary connecting the outlet of the solenoid valve with the suction line, have an elevated temperature.
Based on this, he can conclude that there is a constant leak between the discharge and suction cavities and, therefore, the needle of the right piston does not provide tightness (see Fig. 52.14).
He decides to increase the discharge pressure (for example, by covering part of the condenser with cardboard) in order to increase the pressure difference and thereby try to press the spool to the right stop. He then moves the spool to the left to verify that the V4V valve is working properly, and then returns the spool to its original position (increasing the discharge pressure if the pressure difference is insufficient, and checking the response of the V4V to the operation of the control solenoid valve).
Thus, on the basis of these experiments, he can draw the appropriate conclusions (in the event that the leakage rate continues to be significant, it will be necessary to provide for the replacement of the main valve).

B Discharge pressure is very low and suction pressure is abnormally high. Since all four fittings of the V4V valve are quite hot, the repairman concludes that the spool is stuck in the intermediate position.
Feeling the capillaries shows the repairman that all 3 capillaries are hot, therefore the cause of the malfunction lies in the control valve, in which both flow sections were open at the same time.

In this case, you should completely check all components of the control valve (mechanical installation of the solenoid, electrical circuits, supply voltage, current consumption, condition of the solenoid core)
and repeatedly try, turning the valve on and off, to return it to working condition, removing possible foreign particles from under one or both of its seats (if the defect persists, the control valve will need to be replaced).
With regard to the control valve solenoid coil (and any solenoid valve coils in general), some beginner repairers would like guidance on how to tell if a coil is working or not. Indeed, in order for the coil to excite a magnetic field, it is not enough to apply voltage to it, since a wire break may occur inside the coil.
Some installers install the tip of a screwdriver on the fixing screw of the coil in order to assess the strength of the magnetic field (however, this is not always possible), others remove the coil and monitor the core of the electromagnet, listening to the characteristic knock that accompanies its movement, still others, having removed the coil, insert it into the hole for the core of the screwdriver to make sure that it is retracted by the force of the magnetic field.
Let's take this opportunity to make a little clarification...

As an example, consider a classical solenoid valve coil with nom-^| nal supply voltage 220 V.
As a rule, the developer allows a long-term increase in voltage relative to the nominal value by no more than 10% (that is, about 240 volts), without the risk of excessive overheating of the winding, and normal operation of the coil is guaranteed with a long-term voltage drop of no more than 15% (that is, there are 190 volts). These allowable deviation limits of the supply voltage of the electromagnet are easily explained. If the supply voltage is too high, the winding will become very hot and may burn out. Conversely, at low voltage, the magnetic field is too weak and will not allow the core, together with the valve stem, to be drawn into the coil (see section 55. "Various electrical problems").
If the supply voltage provided for our coil is 220 V, and the rated power is 10 W, we can assume that it will consume the current I \u003d P / U, that is, 1 \u003d 10 / 220 \u003d 0.045 Ar (or 45 mA).
Voltage applied I = 0.08 A A,
High risk of coil burnout
In fact, the coil will draw a current of about 0.08 A (80 mA), since for alternating current P \u003d U x I x coscp, and for electromagnet coils, coscp is usually close to 0.5.
If the core is removed from the energized coil, the current consumption will increase to 0.233 A (that is, almost 3 times more than the nominal value). Since the heat released during the passage of current is proportional to the square of the current strength, it means that the coil will heat up 9 times more than under nominal conditions, which greatly increases the risk of its combustion.
If a metal screwdriver is inserted into an energized coil, the magnetic field will draw it in and the current consumption will drop slightly (in this example, to 0.16 A, that is, twice the nominal value, see Fig. 52.16).
Remember that you should never dismantle an electromagnet coil that is energized, as it can burn out very quickly.
A good way to determine the integrity of the winding and check the presence of supply voltage is to use a clamp meter (transformer clamp), which opens and moves up to the coil to detect the magnetic field created by it during normal operation.

If the coil is energized, the ammeter needle deviates
Transformer clamps, reacting according to their purpose to a change in the magnetic flux near the coil, allow, in the event of a malfunction, to register a sufficiently high current strength on the ammeter (which, however, means absolutely nothing), which quickly gives confidence in the health of the electrical circuits of the electromagnet.

Note that the use of open transformer current clamps is permissible for any windings powered by alternating current (electromagnets, transformers, motors ...), at a time when the winding under test is not in close proximity to another source of magnetic radiation.

Exercise #1

The repairman must replace the V4 V valve in the dead of winter on the installation shown in fig. 52.18.

After draining the refrigerant from the installation and removing the faulty V4V, the repairman asks the following question:

Bearing in mind that the outdoor and indoor temperatures are low, the heat pump must be operated in heating mode for the air-conditioned space.

Before installing a new V4V, in which position should the spool be: on the right, on the left, or does its position matter?

As a hint, here is a diagram engraved on the solenoid valve body.

Solution of exercise No. 1

After the repair is completed, the heat pump should be in heating mode. This means that the internal heat exchanger will be used as a condenser (see fig. 52.22).

An examination of the pipelines shows us that the V4V spool must be on the left.
Therefore, before installing a new valve, the installer must ensure that the spool is actually on the left. He can do this by looking inside the main valve through the three lower connecting fittings.
If necessary, move the spool to the left, either by tapping the left end of the main valve on a wooden surface, or by lightly hitting the left end with a mallet.
Rice. 52.22.
Only then can the V4V valve be installed in the circuit (paying attention to prevent excessive overheating of the main valve body when soldering).
Now consider the designations on the diagram, which is sometimes applied to the surface of the solenoid valve (see Fig. 52.23).
Unfortunately, such schemes are not always available, although their presence is very useful for the repair and maintenance of V4V.
So, the spool has been moved by the repairman to the left, while it is better that at the time of start-up there is no voltage on the solenoid valve. This precaution will avoid an attempt to reverse the cycle at the time of compressor start,
when the difference between AP between pH is very small.

It must be borne in mind that any attempt to reverse the cycle with a low differential AP is fraught with the risk of jamming the spool in an intermediate position. In our example, to eliminate such a danger, it is enough to disconnect the solenoid valve winding from the mains when starting the heat pump. This will make it completely impossible to attempt cycle reversal with a low AP drop (e.g. due to incorrect wiring)
Therefore, the precautions listed should allow the repairer to avoid possible malfunctions of the V4V unit when replacing it.

Let's study the diagram (see Fig. 52.1) of one of these valves, consisting of a large four-way main valve and a small three-way control valve mounted on the main valve body. At the moment, we are interested in the main four-way valve.
First, note that of the four ports on the main valve, three are next to each other (with the compressor suction line always connected to the middle of these three fittings), and the fourth port is on the other side of the valve (the compressor discharge line is connected to it).
Note also that on some V4V models the suction port may be offset from the center of the valve.
"T\ However, the discharge (pos. 1) and suction (pos. 2) lines of the compressor-^^ sor are ALWAYS connected as indicated in the diagram in Fig. 52.1.
Inside the main valve, communication between the various channels is provided by a movable spool (item 3) sliding along with two pistons (item 4). Each piston is drilled with a small hole (item 5) and, in addition, each piston is equipped with a needle (item 6).
Finally, 3 capillaries (pos. 7) are cut into the body of the main valve in the places shown in fig. 52.1, which are connected to the control solenoid valve.
Rice. 52.1.
ness, if you do not perfectly study the principle of operation of the valve.
Each element presented by us plays a role in the operation of V4V. That is, if at least one of these elements fails, it can be the cause of a very difficult to detect fault.
Consider now how the main valve works...