Pros and cons of a two-pipe system. Two-pipe heating system: implementation features. Forced circulation heating system

According to statistics, over 70% of all residential buildings are heated by water heating. One of its varieties is a two-pipe heating system - this publication is devoted to it.

The article discusses the advantages and disadvantages, diagrams, drawings and recommendations for installing a two-pipe wiring with your own hands.

Article content

Differences between a two-pipe heating system and a one-pipe

Any heating system is a closed circuit through which the coolant circulates. However, unlike a single-pipe network, where water flows to all radiators in turn through the same pipe, a two-pipe system involves dividing the wiring into two lines - supply and return.

Two-pipe system heating a private house, in comparison with a single-pipe configuration, has the following advantages:

Minimal coolant losses. AT single pipe system the radiators are alternately connected to the supply line, as a result of which, passing through the battery, the coolant loses temperature and enters the next radiator partially cooled. With two-pipe configuration, each of the batteries is connected to the supply pipe by a separate outlet. You get the opportunity to install on each of the radiators, which will allow you to regulate the temperature in different rooms at home independently.
Low hydraulic losses. When setting up a system with forced circulation(required in buildings large area) a two-pipe system requires the installation of a less efficient circulation pump, which allows good savings.
Versatility. A two-pipe heating system can be used in a multi-apartment, one or two-story building.
Maintainability. On each branch of the supply pipeline, you can install stop valves, which makes it possible to cut off the coolant supply and repair damaged pipes or radiators without stopping the entire system.

Among the disadvantages of this configuration, we note a twofold increase in the length of the pipes used, however, this does not threaten a cardinal increase in financial costs, since the diameter of the pipes and fittings used is smaller than in the arrangement of a single-pipe system.

Classification of two-pipe heating

The two-pipe heating system of a private house, depending on the spatial arrangement, is classified into vertical and horizontal. More common is the horizontal configuration, which involves connecting radiators on a floor of a building to a single riser, while in vertical systems, radiators from different floors are connected to a riser.

The use of vertical systems is justified in a two-story building. Although this configuration is more expensive due to the need for more pipes, with vertical risers, the possibility of formation of air locks inside the radiators, which increases the reliability of the system as a whole.

Also, a two-pipe heating system is classified according to the direction of movement of the coolant, according to which it can be direct-flow or dead-end. In dead-end systems, the liquid circulates in different directions through the return and supply pipes, while in direct-flow systems, their movement coincides.

Depending on the method of transportation of the coolant, the systems are divided into:

with natural circulation;
with forced circulation.

Heating with natural circulation can be used in one-story buildings with area up to 150 squares. It does not provide for the installation of additional pumps - the coolant moves due to its own density. characteristic feature systems with natural circulation is laying pipes at an angle to horizontal plane. Their advantage is independence from the availability of electricity, the disadvantage is the inability to adjust the rate of water supply.

In a two-story building, a two-pipe heating system is always carried out with forced circulation. In terms of efficiency, this configuration is more efficient, since you get the opportunity to control the flow and speed of the coolant using a circulation pump, which is installed on the supply pipe leaving the boiler. In heating with forced circulation, pipes of relatively small diameters (up to 20 mm) are used, which are laid without a slope.

Which heating network layout to choose?

Depending on the location of the supply pipeline, two-pipe heating is classified into two varieties - with upper and lower wiring.

The scheme of a two-pipe heating system with an upper wiring involves the installation of an expansion tank and a distributing line at the highest point of the heating circuit, above the radiators. Such laying cannot be performed in a one-story building with flat roof, since the accommodation of communications will require an insulated attic or a specially designated room on the second floor of a two-story house.

A two-pipe heating system with a lower wiring differs from the upper one in that the distributing pipeline in it is located in the basement or in an underground niche, under the radiators. The extreme heating circuit is a return pipe, which is installed 20-30 cm lower than the supply line.

This is a more complex configuration that requires the connection of an upper air pipe, through which excess air will be removed from the radiators. With absence basement additional problems may arise due to the need to install the boiler below the level of the radiators.

Both the lower and upper circuits of a two-pipe heating system can be performed in a horizontal or vertical configuration. However, vertical networks, as a rule, are carried out with a lower wiring. With this installation, there is no need to install a powerful pump for forced circulation, because due to the difference between the temperatures in the return and supply pipes, a strong pressure drop is created, which increases the speed of the coolant. If, due to the peculiarities of the layout of the building, such laying is impossible, a highway with an upper wiring is equipped.

We make a two-pipe system with our own hands (video)

The choice of pipe diameter and the rules for installing a two-pipe network

When installing two-pipe heating, it is extremely important to choose correct diameter pipes, otherwise you can get uneven heating of radiators remote from the boiler. For most boilers for domestic use, the diameter of the supply and return pipes is 25 or 32 mm, which is suitable for a two-pipe configuration. If you have a boiler with 20 mm nozzles, it is better to stop at a single-pipe heating system.

The dimensional grid of polymer pipes on the market consists of diameters of 16, 20, 25 and 32 mm. Do-it-yourself installation of the system is necessary, taking into account the key rule: the first section of the distributing pipe must match the diameter of the boiler nozzles, and each subsequent pipe section after the branch tee to the radiator is one size smaller.

In practice, it looks like this - a diameter of 32 mm comes out of the boiler, a radiator is connected to it through a tee with a pipe of 16 mm, then after the tee the diameter of the supply line decreases to 25 mm, at the next outlet to the radiator of the 16 mm line after the tee the diameter decreases to 20 mm and so on. If the number of radiators is greater than the pipe sizes, it is necessary to divide the supply line into two arms.

When installing the system with your own hands, follow these recommendations:

the supply and return lines must be parallel to each other;
each outlet to the radiator must be equipped with a shut-off valve;
distribution tank, if installed in attic when installing a network with an upper wiring, it is necessary to insulate;
fastening pipes on the walls should be placed in increments of no more than 60 cm.

When equipping a system with forced circulation, it is important to choose the right power for the circulation pump. Concrete Choice is done based on the size of the building:

for houses with an area of up to 250 m 2, a pump with a capacity of 3.5 m 3 / h and a pressure of 0.4 MPa is sufficient;
250-350 m 2 - power from 4.5 m3 / h, head 0.6 MPa;
over 350 m 2 - power from 11 m 3 / hour, pressure from 0.8 MPa.

Despite the fact that do-it-yourself two-pipe heating is more difficult to install than a single-pipe network, such a system, due to its high reliability and efficiency, fully justifies itself during operation.

When designing a heating system, the question arises: “What kind of heating system will we make? One-pipe or two-pipe? In this article we will understand what these systems are and how they differ. To make things clear, let's start with definitions.

Definitions of one-pipe and two-pipe systems.

Single-pipe - (abbreviated as OSO) is a system in which all heating devices (radiators, convectors, and so on, we will abbreviate them as software) are connected to the boiler in series using one pipe.
Two-pipe - (abbreviated as DSO) is a system in which two pipes are supplied to each PO. According to one of them, the coolant is supplied from the boiler to the software (it is called the supply), and through the other, the cooled coolant is diverted back to the boiler (it is called the "return").

For the sake of completeness, we add two more definitions. According to these definitions, there is a division according to the principle of laying the supply line:

With upper wiring - the hot coolant is first supplied from the boiler to the highest point of the system, and from there the coolant is supplied to the software.
With lower wiring - the hot coolant is first discharged horizontally from the boiler, and then rises up the risers to the software.

Single pipe heating system.

As described above, in OCO all heating devices are connected in series. Passing through them, the coolant will cool down, so the “closer” the radiator is to the boiler, the hotter it will be. This fact must be taken into account when calculating the number of sections of heating radiators. The “farther” the radiator is from the boiler, the lower the coolant temperature will be in it and the large quantity sections will be needed for heating. Lower wiring is possible only for houses with one floor and forced circulation in the system. With two or more floors, an upper piping is already needed.

There are two types of OSS:

OSO, in which heating devices are installed on the "bypass" (bypass jumper).
Flow OCO - all devices are connected in series without jumpers.

The second type is unpopular due to the difficulty of regulating the temperature in radiators, which is caused by the fact that it is impossible to use special fittings (thermostatic valves). Since when closing or reducing the flow through one radiator, the flow through the entire riser decreases. The main advantage of OCO is the lower cost of components and easier installation. The most popular version of a single-pipe system is Leningradka.

What is "Leningrad".

According to legend, this system got its name from the city where it was first applied. But of course, it is impossible to confirm this reliably, and I don’t really want to. So, "Leningradka" is a one-pipe heating system in which the software is installed on the "bypass". This allows you to regulate the temperature of individual radiators or convectors or turn them off altogether, if necessary. All the advantages and disadvantages of a single-pipe system are inherent in Leningrad, therefore, for distant radiators, it is necessary to increase the number of sections. Possible various options pipe layouts:

Horizontal - the pipe lies in a horizontal plane and radiators are already installed on it.
Vertical - the pipe runs vertically through the floors and radiators are connected to it.

OSO of the "Leningradka" type is best used for small private houses, where the number of floors does not exceed two. For large cottages with extended heating systems, such a "Leningrad" will not work.

An example of the implementation of "Leningradka"

Two-pipe heating system.

The main advantage of DSO is that the coolant comes to all software equally hot. This allows not to increase the number of sections on the "distant" radiators. That is, the most efficient use of heating devices occurs. The presence of two separate pipes for supply and return makes the installation of such a system more expensive. For such systems, both top and bottom piping and horizontal or vertical piping are possible.

In addition, DSO may differ in the direction of the coolant flow:

Dead-end systems - water in the supply and return pipes flows in different directions.
Flow systems - water in the supply and return pipes flows in the same direction.

Drawing from the book "Heating and water supply country house» Smirnova L.N.
You can use a two-pipe system for houses of any size, but it is most suitable for large cottages. Its use will allow you to change the flow rate of individual radiators, without affecting all the others. That is, it will be possible to apply various room thermostats, which will create comfortable conditions for all residents.

Summary of the article.

The question of choosing the type of heating system depends on several factors:

your budget
area of your house.
Features internal device at home. For example, the number of floors
The number of heating devices.

Most often for small country houses(no more than 2 floors), a one-pipe system is better suited, and for large cottages (with a number of floors of 2 or more floors and a large length of pipelines), a two-pipe heating system will be more efficient. Specific features of the implementation of a particular system are best discussed with a professional designer.

When abandoning inefficient centralized heating in favor of an individual system, it can be difficult for the landlord to decide which is better: a single-pipe or two-pipe heating system. Let's find out which type of system is better to choose for installation, what is the difference between these connection schemes and how significant it is.

Advantages and disadvantages of one-pipe and two-pipe heating systems

The main difference between the two heating schemes is that the two-pipe connection system is more efficient in operation due to the parallel arrangement of two pipes, one of which supplies the heated coolant to the radiator, and the other drains the cooled liquid.

The scheme of a single-pipe system is a series-type wiring, in connection with which the first connected radiator receives the maximum amount of thermal energy, and each subsequent one heats up less and less.

However, efficiency is an important, but not the only criterion that you need to rely on when deciding to choose one or another scheme. Consider all the pros and cons of both options.

Advantages:

ease of design and installation;
savings in materials due to the installation of only one line;
natural circulation of the coolant, possible due to high pressure.

Flaws:

complex calculation of thermal and hydraulic parameters of the network;
the difficulty of eliminating errors made in the design;
all elements of the network are interdependent; if one section of the network fails, the entire circuit stops working;
the number of radiators on one riser is limited;
regulation of the flow of coolant into a separate battery is not possible;
high coefficient of heat loss.

Two-pipe heating system

Advantages:

the ability to install a thermostat on each radiator;
independence of the network elements;
the possibility of inserting additional batteries into an already assembled line;
ease of elimination of errors made at the design stage;
to increase the volume of coolant in heating devices, it is not necessary to add additional sections;
no restrictions on the length of the contour along the length;
the coolant with the desired temperature is supplied throughout the entire ring of the pipeline, regardless of the heating parameters.

Flaws:

complex connection scheme compared to single-pipe;
higher consumption of materials;
installation requires a lot of time and labor.

Thus, a two-pipe heating system is more preferable in all respects. Why do the owners of apartments and houses refuse it in favor of a one-pipe scheme? Most likely, this is due to the high cost of the installation and the high consumption of materials necessary for laying two highways at once. However, one should take into account the fact that a two-pipe system involves the use of pipes of a smaller diameter, which are cheaper, so the total cost of arranging a two-pipe option will not be much more than a single-pipe one.

The owners of apartments in new buildings are lucky: in new houses, in contrast to residential buildings of Soviet development, a more efficient two-pipe heating system is increasingly being used.

Types of two-pipe systems

Two-pipe systems are divided into types depending on:

type of circuit (open and closed);
method and direction of water flow (flow and dead ends);
method of moving the coolant (with natural and forced circulation).

Systems with open and closed circuits

Two-pipe system open type did not take root in city apartments due to the peculiarity associated with the upper piping, which involves the use of an expansion tank. This device makes it possible to control and replenish the heating system with water, but there is not always a place in the apartment for mounting such a volumetric device.

Flow and dead ends

In a flow system, the direction of water flow in the supply and discharge pipes does not change. With a dead-end scheme, the coolant in the supply and return pipes moves in opposite directions. Bypasses are installed in such a network, and radiators are located in closed areas, which makes it possible to turn off any of them without disturbing the heating.

With natural and forced circulation

For the natural circulation of water, pipes are laid with a mandatory slope, in top point system is installed expansion tank. Forced circulation is carried out by a pump installed in the return pipe. Such a system requires air vent valves or Mayevsky taps.

Components of a two-pipe individual heating system

The two-pipe scheme of the individual heating network of the apartment includes the following elements:

heating boiler;
thermostatic valves for radiators;
automatic air valve;
balancing device;
pipes and fittings;
radiators;
valves and taps;
expansion tank;
filter;
temperature gauge;
circulation pump (if necessary);
safety valves.

Installation of a two-pipe heating system with top and bottom wiring

The two-pipe system has varieties according to the installation scheme. The most commonly used top and bottom wiring types.

Top wiring

Laying the upper wiring involves installation work to fix the heating system under the ceiling of the room. To batteries installed in places where cold air accumulates (windows, balcony doors), branches coming from the main pipeline are supplied. AT lower part pipeline, which is a branch, liquid enters, which has time to cool down in the circulation process. Such a system is suitable for large rooms, in one-room or two-room apartments installation of heating with top wiring is not recommended, as it is unprofitable for the owner from an economic and design point of view.

Installation of the heating circuit from the top horizontal wiring perform according to the following scheme:

An angle fitting, necessary for connecting the pipe pointing upwards, is mounted to the boiler outlet.
With the help of tees and corners, horizontal installation is carried out top line: tees are installed above the battery, corners are on the sides.
The final stage of the installation of the upper horizontal is the installation of tees with pipes on the battery, supplemented by a shut-off valve.
On the lower branch, the outlet ends are connected to a common return line, on the section of which an injection pump is installed. pumping station(circulation pump).

Bottom wiring

In a network with a lower wiring, outlet channels and supply heat pipes are installed. The superiority of the lower mounting scheme is expressed as follows:

Heating pipes are located in the lower, inconspicuous part of the room, which gives more opportunities for the implementation of various design projects.
Minimum consumption of pipes: all installation work is carried out practically at the same level. The wiring point and radiator pipes are located at a short distance from each other.
Due to the simplicity of the scheme, the installation of such a system will be possible even for a non-professional.

Important! The lower wiring is installed only if the circulation of the coolant is forced, otherwise the water will not move through the heating pipes. This scheme is applicable only in city apartments or one-story buildings.

One of the disadvantages of the circuit is the complexity of adjustment and balancing, but the ease of installation and reliability in operation covers these shortcomings.

Installation work begins with a drain from the boiler nozzles using an angle fitting in a downward direction.
Wiring is carried out at floor level along the wall using two pipes of the same diameter. One of them connects the boiler pipe to the battery inlet, the other is connected to the receiving pipeline.
Connections of radiators with pipes are made using tees.
The expansion tank is located at the highest point of the supply pipe.
FROM circulation pump the end of the outlet pipe is connected, the pump itself is located at the entrance to the heating tank.

The water heating system can be one-pipe and two-pipe. Two-pipe is called so because two pipes are needed for operation - one from the boiler is supplied with hot coolant to the radiators, the other is cooled down from the heating elements and fed back into the boiler. Boilers of any type on any fuel can work with such a system. Both forced and natural circulation can be implemented. Two-pipe systems are installed in both one-story and two- or multi-story buildings.

Advantages and disadvantages

The main disadvantage of this method of organizing heating follows from the method of organizing the circulation of the coolant: a double number of pipes compared to the main competitor - a single-pipe system. Despite this situation, the cost of purchasing materials is slightly higher, and all due to the fact that with a 2-pipe system smaller diameters of both pipes and, accordingly, fittings are used, and they cost much less. So as a result, the cost of materials is higher, but not significantly. What is really more is the work, and accordingly it takes twice as much time.

This disadvantage is compensated by the fact that a thermostatic head can be installed on each radiator, with the help of which the system is easily balanced in automatic mode, which cannot be done in a one-pipe system. On such a device, you set the desired temperature of the coolant and it is maintained constantly with a small error ( exact value error depends on the brand). In a single-pipe system, it is possible to realize the ability to regulate the temperature of each radiator individually, but this requires a bypass with a needle or three-way valve, which complicates and increases the cost of the system, negating the gain in cash for the purchase of materials and time for installation.

Another disadvantage of a two-tube is the impossibility of repairing radiators without stopping the system. This is inconvenient and this property can be bypassed if placed next to each heater on supply and return Ball Valves. By blocking them, you can remove and repair the radiator or heated towel rail. The system will continue to function indefinitely.

But such an organization has heating important advantage: unlike a single pipe, in a system with two lines, each heating element receives water of the same temperature - immediately from the boiler. Although it tends to take the path of least resistance and will not spread beyond the first radiator, installing thermostatic heads or flow control valves solves the problem.

There is another advantage - lower pressure losses and easier implementation of gravity heating or the use of smaller pumps for systems with forced circulation.

Classification of 2 pipe systems

Heating systems of any type are divided into open and closed. In the closed ones, a membrane-type expansion tank is installed, which makes it possible for the system to function when high blood pressure. Such a system makes it possible to use not only water as a coolant, but also ethylene glycol-based compounds, which have a lower freezing point (up to -40 ° C) and are also called antifreezes. For normal operation of equipment in heating systems, special formulations designed for this purpose and not general purpose, and even more so, not automobile. The same applies to the additives and additives used: only specialized ones. It is especially tough to adhere to this rule when using expensive modern boilers with automatic control- repair in case of malfunctions will not be guaranteed, even if the breakdown is not directly related to the coolant.

AT open system at the top point, an open-type expansion tank is built in. A pipe is usually connected to it to remove air from the system, and a pipeline is also organized to drain excess water in the system. Sometimes from the expansion tank they can take warm water for household needs, but in this case it is necessary to make the system recharge automatically, and also not to use additives and additives.

Vertical and horizontal two-pipe system

There are two types of organization of a two-pipe system - vertical and horizontal. Vertical is most often used in high-rise buildings. It requires more pipes, but the possibility of connecting radiators on each floor is easily realized. The main advantage of such a system is the automatic air outlet (it tends to rise and exits there or through expansion tank or through a drain valve).

The horizontal two-pipe system is used more often in one-story or, at most, in two-storey houses. To bleed air from the system, Mayevsky taps are installed on the radiators.

Two-pipe horizontal heating scheme for a two-story private house (click on the picture to enlarge)

Top and bottom wiring

According to the method of distributing the supply, a system with an upper and lower supply is distinguished. With the upper wiring, the pipe goes under the ceiling, and from it the supply pipes go down to the radiators. The return line runs along the floor. This method is good in that you can easily make a system with natural circulation - the difference in height creates a flow of sufficient force to ensure a good circulation rate, you just need to observe the slope with a sufficient angle. But such a system is becoming less and less popular due to aesthetic considerations. Although, if at the top under the hanging or stretch ceiling, then only pipes to the devices will remain in sight, and they, in fact, can be monolithic into the wall. Upper and lower wiring are also used in vertical two-pipe systems. The difference is shown in the figure.

With lower wiring, the supply pipe goes lower, but higher than the return. The supply tube can be placed in the basement or semi-basement (the return line is even lower), between the rough and finish floor, etc. The coolant can be supplied / removed to the radiators by passing the pipes through the holes in the floor. With this arrangement, the connection is the most hidden and aesthetic. But here you need to select the location of the boiler: it does not matter in its position relative to the radiators - the pump will “push through”, but in systems with natural circulation, the radiators must be above the level of the boiler, for which the boiler is buried.

The two-pipe heating system of a two-story private house is illustrated in the video. It has two wings, the temperature in each of which is regulated by valves, the lower type of wiring. System with forced circulation, because the boiler hangs on the wall.

Dead-end and associated two-pipe systems

A dead-end system is such a system in which the movement of the coolant supply and return flow is multidirectional. There is a system with passing traffic. It is also called the Tichelman loop / scheme. The latter option is easier to balance and configure, especially with long networks. If radiators with the same number of sections are installed in a system with a passing movement of the coolant, it is automatically balanced, while with a dead-end circuit, a thermostatic valve or a needle valve will be required on each radiator.

Even if radiators of different numbers of sections and valves / valves are installed with the Tichelman scheme, it is still necessary to install, then the chance to balance such a scheme is much higher than a dead-end one, especially if it is quite long.

To balance a two-pipe system with multidirectional movement of the coolant, the valve on the first radiator must be screwed very tightly. And a situation may arise in which it will need to be closed so much that the coolant will not flow there. It turns out that then you need to choose: the first battery in the network will not heat, or the last one, because in this case it will not be possible to equalize the heat transfer.

Heating systems for two wings

And yet, a system with a dead-end scheme is more often used. And all because the return line is longer and it is more difficult to assemble it. If your heating circuit is not very large, it is quite possible to adjust the heat transfer on each radiator and with a dead-end connection. If the circuit turns out to be large, but you don’t want to make the Tichelman loop, you can divide one large heating circuit into two wings smaller. There is a condition - for this there must be technical possibility such networking. In this case, after separation, valves must be installed in each circuit, which will regulate the intensity of the coolant flow in each of the circuits. Without such valves, it is either very difficult or impossible to balance the system.

Different types of coolant circulation are demonstrated in the video, it also gives helpful tips on installation and selection of equipment for heating systems.

Connecting heating radiators with a two-pipe system

In a two-pipe system, any of the ways to connect radiators is implemented: diagonal (cross), one-sided and bottom. Most the best option — diagonal connection. In this case, the heat transfer from the heater can be in the region of 95-98% of the rated heat output of the device.

In spite of different meanings heat loss for each type of connection, they are all used, just in different situations. Bottom connection, although the most unproductive, is more common if the pipes are laid under the floor. In this case, it is the easiest to implement. It is possible to connect radiators with hidden laying according to other schemes, but then either large sections of pipes remain in sight, or they will need to be hidden in the wall.

Lateral connection is practiced, if necessary, with the number of sections not exceeding 15. In this case, there is almost no heat loss, but if the number of radiator sections is more than 15, a diagonal connection is already required, otherwise circulation and heat transfer will be insufficient.

Results

Despite the fact that more materials are used to organize two-pipe circuits, they are becoming more popular due to more reliable scheme. In addition, such a system is easier to compensate.

In apartments and private houses, an integral part of comfort is the provision of heat. Mostly use water heating. Water heating Available in single and double pipe configurations. In the first case, water passing through closed loop, cools down a lot. Each subsequent radiator receives a colder liquid. The two-pipe system eliminates this disadvantage.

A two-pipe heating system is effective for a private house. These designs have become more popular. The complexity of installation and a slightly higher consumption of materials pay off with clear advantages.

Advantages of two-pipe heating:

Each radiator receives an equally heated coolant, increasing the air temperature in the room.
Possibility to regulate the heat of each battery by setting a thermostat.
If one of the systems breaks down, repairs can be carried out without stopping the heating. To do this, it is necessary to install locking elements.
For installation, you can use pipes of small diameter, significantly saving money.
Installation in a room of any size.

A distinctive feature of the system is the connection to each radiator 2 pipes. Through the first, heat enters the battery, the second removes the cooled liquid from the device. This design allows you to efficiently heat the room.

Layout of pipes of a two-pipe heating system

The two-pipe wiring diagram is of 2 types - vertical and horizontal. In the first case, the heating elements are located vertically along one riser, which is typical for apartment buildings. In most cases, the coolant is fed upwards, the outlet descends by gravity.

At horizontal version, the batteries are arranged in one line. Such wiring is inherent in single-story buildings.

The two-pipe design can be open and. Any heating includes an expansion tank as part of the elements. When heated, the pressure in the pipes increases, and the compensation system allows you to maintain the required operating level. The device is located at the highest point, usually in the attics of houses. With open wiring, the liquid in the tank comes into contact with air. Part of it evaporates, so such a system requires constant monitoring. AT closed type, the design is equipped with a membrane, and does not require constant attention.

Circuit advantage:

A more aesthetic appearance of the room, the pipes are hidden under the radiators and are not conspicuous;
To pass to the radiators, one hole is required;
Reduced heat loss.

All heating systems can be made with natural and forced circulation. The choice of design is influenced by the top or bottom water supply. For the bottom supply, it is necessary to install forced water circulation. Pipes from the boiler to the radiators are laid at floor level, just below the batteries. Around the entire perimeter of the room, 2 pipes are passed: distribution and return. They are connected to each radiator using fittings and tees. Such a system can be constructed from metal-plastic or polypropylene pipes on their own, without resorting to the services of specialists.

Option with top wiring in a two-pipe heating system of a private house

In private houses, you can install both lower and upper distribution. For top wiring, the use of natural water circulation is preferable. Distribution with hot coolant is pulled from the boiler to the ceiling, then laid along the perimeter of the building.

Design description:

Branches are vertically lowered from the upper pipe to the radiators;
The reverse stroke is laid at the level of the floor;
Connect both pipes to radiators;
For physical circulation, the angle of inclination of the pipe should be 3-5ᵒ, while the expansion tank is installed at the highest point of the circuit.

The heating system of natural circulation starts to work when the water is heated. The coolant becomes lighter and rushes up, reaching highest point circuits, then descends through the pipes into the radiators, cooling down and becoming heavier, goes back to the boiler.

The lower the room temperature, the faster the circulation of water in the batteries.

The maximum effect from the top distribution can be obtained in a 2-storey building. Natural circulation will be stimulated by the difference in the height of the batteries on the 2nd floor and the installation of a boiler in the basement. The disadvantage of the upper scheme is the external aesthetic appearance, in addition, part of the heat goes up. You can compensate for the disadvantage by combining one-pipe and two-pipe heating. For example, make a single-pipe warm floor on the 2nd floor, on the 1st conduct a two-pipe wiring.

Accurate calculation of a two-pipe heating system

Before starting work, it is necessary to draw up a heating scheme, decide on the material, and make a hydraulic calculation. It is necessary to calculate the pressure drop on back section or to calculate the pipe diameter.

The calculation is carried out taking into account the following factors:

The inner surface of the pipes and its roughness;
Section diameter;
Number of pipe bends;
Pressure drop between supply and return;
The number of radiators and their cross section;
Locking elements.

When carrying out the calculation, formulas and an axonometric table are used. You can use a special software program. The most loaded ring or contour is taken as the main object. As a result of calculations, the optimal speed of movement should be from 0.3 to 0.7 m/s.

At a higher speed, the heating will make noise, at a lower speed, there will be a strong temperature variation.

After the calculations, they acquire pipes of effective diameter, required amount radiators, boiler, fittings, shackles, expansion tank, circulation pump, if necessary.

Do-it-yourself steps for installing two-pipe heating

Installation of the heating system begins with the installation of the boiler. The heat generator on gas and electricity is located in any room. For liquid and solid fuel boilers, a separate niche is required. When installing radiators, it is necessary to take into account the pipeline slope of 1-2% in relation to the entire length of the pipe.

Work plan:

Boiler installation.
The main pipe is discharged from the heat generator with hot water passing through all radiators.
Parallel to the first, a second line with a reverse course is carried out.
With a forced heating option, a circular pump is inserted.
Install radiators. Batteries are hung on special brackets. All radiators must be at the same level. For ease of use, they are equipped with shut-off valves at the entry and exit points. Batteries are connected in several ways: lateral, diagonal, bottom connection. The most effective side and diagonal design.
The heating system is completed by installing pipes of related units, installing an expansion tank and additional elements.

The main line should not contain straight and sharp corners, as resistance will increase. Taps and valves must match the dimensions of the pipes. With a design with top wiring, the expansion tank is placed in an insulated attic. After completion of all installation work, it is time to connect the system.

To do this, close all the taps, and be sure to slowly fill the supply circuit.

Next, the valve of the first battery is opened, and with the help the air is bled until an even jet exits. The element is closed and the radiator outlet cock is opened. These manipulations must be carried out with each radiator. All found defects are eliminated.

Do-it-yourself two-pipe heating of a private house (video)

Do-it-yourself installation of a two-pipe system will take more time, ultimately provide efficient and practical heating, and save on installation work. It is important to choose the right best option for the home, and make a competent calculation of the system parameters. Skillful hands and following the instructions will transform the house, making it cozy and warm.