Working principle and scope of two-way valve

In heating systems, where heaters and coolers are used in the piping nodes, a characteristic type of fittings is found — a two-way valve. The device quickly and accurately regulates the volume of water supply and withdrawal. It is in demand in heating, ventilation and air conditioning systems. Now two-way valves equipped with an electric drive, which are controlled by special sensors, are in great demand. These are reliable and easy-to-install devices, the design features and differences of which we will learn below.

Purpose and design

The classic equipment of the device is as follows:

• thermostatic valve;
• thermal head with remote sensor;
• thermal head valve;
• limiting sensor that takes into account the temperature;
• meter;
• circulation pump;
• water filter;
• check valve.

Two-way adjustment devices are used everywhere, but a lot depends on what material they are made of. Considering the design features, we immediately make a reservation that valves come with one or two seats. Using the second variety, the flows of the working medium are regulated and blocked, and significant pressure drops are allowed, which the valve with one seat cannot cope with. The armature itself looks like a separate part with a mechanical or electronic drive. It happens that an additional source of energy is not provided, so it is installed after the installation of the device.

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Advantages of a two-way valve:

• simple design;
• easy to install;
• for effective work does not require the involvement of a person;
• maintainable;
• reliable;
• serves for a long time;
• tight;
• characterized by low hydraulic resistance;
• available.

Paying attention to the design of the element, it will seem that it is similar to a standard valve, but the mechanisms differ significantly. For example, the main shut-off element of a valve is a stem or a ball. That is, a rod located in a horizontal or vertical position, or a ball rotated around its axis by 90 degrees, is responsible for limiting the flow of water. The device works according to a simple scheme — a special hole opens and liquid is transported through it. For these structural elements to function, an actuator is connected to the valve, which requires electricity or compressed air. The drive itself is combined with separate devices that take into account the pressure in the system, temperature and other characteristics.

Areas of use

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As noted above, this type of control valve is used in heating, ventilation and air conditioning systems. We will separately consider the features of its use in a circuit with a «warm floor».

If a boiler is installed in the house, then its task is to heat water and, as a rule, its temperature is quite high, suitable for radiators (from +75 to +95 degrees Celsius). For the «warm floor» system, such heating is not needed, since sanitary standards regulate a maximum of +35 degrees Celsius. This indicator is enough to comfortably walk on the floor. If the temperature is higher, this will not only cause inconvenience to the residents, but also adversely affect the finish of the floor. For example, linoleum or laminate is easily deformed.

«Warm floor» is mounted under the screed, in addition, different flooring materials are used. To do this, the coolant is heated to +50 degrees Celsius. When underfloor heating is directly connected to a boiler or central heating system, the resulting temperature is too high. To lower it at the entrance to the circuit, a mixing valve for underfloor heating is installed, with a two-way or three-way valve already provided. Based on the name, the purpose of such fittings is to mix hot and cold water circulating around the circuit. That is, the process of passing the liquid changes — for the radiator, the water remains hot, and already mixed, having a lower temperature, enters the warm floor.

What materials is it made from

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Cast iron, brass and steel products are now common. For example, iron and steel fittings are installed in piping systems with a high flow of water or steam. Brass valves are often found in ventilation systems. Their main advantage is their compact size, so the element is mounted even in small rooms with limited water consumption.

It is recommended to use a steel or cast iron control valve. Steel products are common, which are as strong as cast-iron counterparts, but much cheaper. When choosing a material, the characteristics of the pressure in the system and the dimensions of the valve itself are taken into account.

Types of control valves

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Reinforcement differs in several ways.

Depending on the design features, 2 types are distinguished:

• through passage — in them the branch pipes have the opposite location;
• corner — located at an angle of 90 degrees.

Notice how the valve is controlled.

There are 3 types of this parameter:

• pneumatic;
• hydraulic;
• electrically equipped.

The electric driving device is a low-power electric motor or retracting solenoids. Of course, there are products with manual control, but they are more difficult to operate, as they do not allow you to set the exact parameters. The devices are powered by an electrical network that has an alternating current of 220 V or a direct current of 24 V.

Certain pass-through nodes operate offline, without power supply. Such fittings are controlled and regulated by means of a membrane and an opposing spring. A stroke is used as feedback, along which the coolant moves — it also directs the membrane in the right direction.

What does a two-way valve do:

• consumption is regulated, resources (water) are distributed and saved;
• more economical heat consumption;
• equipment and networks receive protection against pressure drops;
• if used correctly, the valve prolongs the life of the connected equipment and the network itself.

The devices are fastened with flanges, threaded or welded. One of the subspecies of the threaded connection is the pin mount, in which the valve is screwed into another device. When the installation is welded, special nozzles are used.

Separately, we highlight the valve with remote control, which is the easiest to operate. Such devices are supplemented by electric drives or remote controls. It is the consoles that receive all the current characteristics and parameters of the system. Remotely decreases, increases pressure or overlaps certain branches of the heating system.

Wiring diagram

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For water heated floors, the valve is most often installed in parallel. For its implementation, 2 or 3 heating circuits with a circulating coolant should be used. The supply and pressure of water is regulated by one or more valves installed in parallel. When mixing the heat carrier in parallel, it is necessary to disconnect the underfloor heating lines in advance.

As a rule, adjusting taps are adjusted independently, manually, where the required volume of water to be passed is set.

Important! If a parallel circuit is used, it is recommended to replace the bypass with a bypass valve. This is done in order to reduce the operating load and save electricity supplied to the pump.

The scheme has a minus — the coolant entering the circuit will be the same temperature as the water leaving the return circuit to the boiler. Because of this, hot water is unevenly distributed along the circuits.

Installation Features

The procedure itself boils down to the fact that the valve is connected to the necessary pipelines. In order for the fittings to work for a long time and without problems, the connection should be correctly implemented, taking into account all the tips and recommendations. If there is a lack of experience, it is recommended to contact specialists. Otherwise, the heating system will not be as efficient and economical as it should be.

Before proceeding with the installation work, pay attention to the two-way valve — there is an external or internal thread on its body, onto which the union nut (or fitting) of the pipeline is screwed. For a reliable connection, experts advise wrapping the thread with a sealant, which is suitable for FUM tape.

Fittings are supplied with special gaskets that ensure the proper level of tightness. If there are none, then they will have to be purchased separately, of the appropriate thickness and diameter. The main task is to ensure a tight connection, without distortions on the thread, which will prevent possible leaks. No special tools or devices are required.

Note! Two-way valves do not function in the simplest conditions, namely, under the influence of high temperature. Because of this, threaded connections can lose their tightness, so the connection procedure must be carried out responsibly.

Expert advice:

1. During installation, make sure that there is no force in the piping.
2. Before mounting the element on the water supply, the latter should be thoroughly cleaned, removing all impurities. They adversely affect the condition of the sealing materials, due to which the tightness of the valve is violated.
3. Over time, it may be necessary to repair or dismantle the device, so it is necessary to leave enough free space around it.
4. It is important to carry out careful installation. If a flange connection is used, it is recommended that the corresponding screws be tightened alternately so that internal stress does not occur. With the threaded installation method, adjusting links are used, which will allow the valve to be dismantled in the future.
5. If you need to blow or flush the entire pipeline system, the valve is removed, and an adapter is put in its place.

Installation is a complex process and largely depends on the chosen scheme. To avoid mistakes, we recommend ordering a valve installation service from specialists.

Conclusion

The mixing valve for heating with a thermostat is the main element of a warm floor, which directly affects the flow of hot and cold water, thereby maintaining the required temperature. In mixing units, a large role is given to a two-way valve, which allows you to accurately adjust the operating mode of the heated floor. It is important to choose a suitable valve model, taking into account many features.