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, unlike 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

The open-type two-pipe system in city apartments did not take root 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 natural water circulation, pipes are laid with a mandatory slope; an expansion tank is installed at the top of the system. 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. Batteries installed in places where cold air accumulates (window openings, balcony doors) are supplied with branches coming from the main pipeline. Liquid enters the lower part of the pipeline, which is a bypass, and cools down during circulation. Such a system is suitable for large premises; in one-room or two-room apartments, installation of heating with an upper wiring is not recommended, since this is unprofitable for the owner from an economic and design point of view.

Installation of a heating circuit with an upper horizontal wiring is carried out according to the following scheme:

1. An angle fitting, necessary for connecting the pipe pointing upwards, is mounted to the boiler outlet.
2. With the help of tees and corners, a horizontal installation of the upper line is carried out: the tees are installed above the battery, the corners are on the sides.
3. 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.
4. On the lower branch, the outlet ends are connected to a common return line, on the section of which an injection pumping station (circulation pump) is installed.

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.

1. Installation work begins with a drain from the boiler nozzles using an angle fitting in a downward direction.
2. 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.
3. Connections of radiators with pipes are made using tees.
4. The expansion tank is located at the highest point of the supply pipe.
5. The end of the outlet pipe is connected to the circulation pump, the pump itself is located at the entrance to the heating tank.

Heating systems

Installation of a water heating system can be carried out in different ways. The central node is the installation that produces heat. It forms the temperature of the coolant, which, with the help of natural or forced circulation, is delivered to the heating devices along the laid pipelines. Conventionally, the transport network can be divided into two types. It can be assembled using one-pipe and two-pipe interchange. It is easier to mount a single-pipe line on your own, and the calculation of a two-pipe heating system must be carried out taking into account many technical parameters of various technical units.

To understand which system is better, a detailed analysis of the principle of operation of each option, as well as their operational advantages and disadvantages, will help. This will be discussed further.

Single pipe heating system

The single-pipe heating system began to be used initially, when the full-scale construction of small-sized five-story buildings was completed in the Soviet Union, and central heating was put into operation. The communal services were tasked with providing the people with warmth and making it as cheap as possible. Therefore, it was decided to save on everything, including the laying of utilities. That is why a single-pipe heating system was born, which allows heating both the residential and industrial sectors.

A serious economic effect when using a single-pipe system is formed due to the absence of coolant return risers. The vertical assembly of such a line does not require much labor, so it was it that was most often used until recently. No one considered heat losses in this case. No one thought about the effectiveness of the described assembly of the pipeline. However, many years of operation made it possible to identify all the shortcomings of a single-pipe line.

How does a single pipe line work?

The principle of operation of single-pipe piping is extremely clear. The coolant supply has one closed system consisting of a heating installation and heating devices. They are tied together with one circuit with one riser. It is he who connects all the technical nodes in sequential order. In order to ensure the transportation of the coolant, a hydraulic pump is often used, which pushes hot water through vertical risers laid in apartment buildings.

According to the implementation scheme, a single-pipe system is divided into two types:

• vertical.
• Horizontal.

Vertical is used to organize heating in multi-storey buildings. In this case, the batteries are connected from the upper floor to the lower one by means of a vertical riser. Horizontal strapping is best suited for a private home. In this case, all radiators are connected in series using a horizontal riser.

Negative aspects of using the described option

Single pipe heating system

Both vertical and horizontal strapping do not always work effectively. Serial connection of radiators does not allow you to control the temperature in a separate room. If, somewhere in the middle, with the help of a thermal valve, the coolant supply is slightly cut off, wanting to lower the heating temperature of a separate room, all subsequent heaters will become cold.

More than 10 batteries must not be connected to the vertical riser at the same time. Violation of this rule will lead to the fact that at the very top the coolant temperature will have maximum values ​​- approximately +105 degrees, and on the lower floor the batteries will not warm up above +45 degrees. In the winter season, when there are severe frosts outside the window, this is not enough, and people will freeze.

Another serious disadvantage is the need to use powerful pumping equipment. It is a powerful hydraulic pump that provides the necessary pressure inside the system, which allows single-pipe piping to work efficiently. Its inclusion in the system increases operating costs, but this is not the worst thing.

Any hydraulic pump cannot provide uniform pressure within the system, so water hammer often occurs, contributing to leakage. Accidents force you to constantly replenish the system with water. And this also leads to additional costs.

And the last negative point in the operation of a single-pipe piping. For its normal functioning, it is necessary to install a special expander tank. When heating a private house, it is placed in the attic, and a technical room is set up there to service this unit. In an apartment building, this problem is solved differently. Stable temperature balancing is ensured by installing jumpers on each floor. And also by increasing the number of radiator sections, with the help of which the lower floors are heated.

Positive points

Heating system of a private house

Despite such a large number of disadvantages of a single-pipe system, it has its own positive operational and technical characteristics. They are quite capable of compensating for all the listed shortcomings:

• Firstly, with the advent of new technologies, it was possible to eliminate the problem of uneven heating of rooms. This is done by installing modern radiators, equipped with automatic thermostats, thermostatic valves or radiator regulators. Their use is especially important when heating a private house.
• Secondly, the use of bypasses and valves, with which balancing is carried out, as well as convenient ball valves and reliable shutter equipment, makes it possible to repair one heater without shutting down the entire system as a whole.
• Thirdly, the assembly of a single-pipe system still takes 2 times less material than the installation of a two-pipe system. The absence of unnecessary pipes, jumpers and complex battery connections allows not only saving on the purchase of additional elements and installation of the line itself, but also laying a pipeline that looks more aesthetically pleasing.

Two-pipe heating system

The principle of operation of a two-pipe heating system is somewhat different from that described above. In this case, the coolant rises up the riser and is supplied to each heating battery. And then, along the return line, it returns back to the pipeline, which transports it to the heating boiler.

With this scheme, the radiator is served by two pipes - supply and return, therefore the system is called two-pipe.

What are the benefits of such a layout?

Two-pipe line

What can you expect by choosing this option for organizing the heating of a private and residential apartment building?

• Such a system allows you to organize uniform heating of each radiator. In any battery, no matter what floor it is on, hot water enters with the same temperature. If desired, a thermostat can be installed on the radiator, and then the weather in the house can be independently adjusted. The use of a thermostat in a single room does not affect the heat transfer of radiators installed in other apartments.
• In a two-pipe piping, when the coolant circulates, there are no large pressure losses. Therefore, a powerful hydraulic pump is not needed for the normal functioning of the system. Water is able to circulate due to the gravitational force, that is, by gravity. And if the water pressure is weak, it is enough to install a low-power pumping unit, more economical and easy to maintain.
• With the help of shut-off equipment, bypasses and valves, it is easy to organize such schemes that will allow you to repair, if necessary, one heater without turning off all the heating in the house.
• Another additional bonus of a two-pipe piping is the ability to use the associated and dead-end movement of hot water.

What is a passing scheme? This is when the supply and return water flows in the same direction. In a dead-end circuit, water in the supply and return circulates in opposite directions. When passing along, provided that radiators of the same power are used, an ideal hydraulic balancing is established. Therefore, there is no need to additionally use presetting valves.

If the heating devices have different capacities, you will have to calculate the heat loss of each, carry out the calculation and link the radiators using thermostatic valves. It is very difficult to do this on your own without knowledge and skills.

Note! Associated hydraulic gravity flow is used where long pipelines are installed. For short systems, a dead-end scheme for the movement of the coolant is used.

Classification of a two-pipe heating system

Types of systems

The classification of the two-pipe piping is made according to the location of the pipeline and the method of arranging the distribution system.

According to the location of the pipeline, it is divided into vertical and horizontal. With a vertical circuit, all batteries are connected to a vertical riser. This option is most often used in apartment buildings. The main advantage of this connection is the absence of air pockets.

For a private house of a large area, experts recommend choosing a horizontal two-pipe wiring and installing a Mayevsky crane in each radiator immediately. It is needed to bleed air, and an example of its correct installation has been described in detail more than once in previous articles.

According to the wiring method, a two-pipe system can be with lower and upper trim. In this case, the hot water supply riser is placed in the basement or basement. The return line is located here, but is installed below the feed. All radiators are at the top. An upper air line is connected to the common circuit, which allows excess air to be removed from the system.

When installing the upper trim, the entire distributing line is mounted in the insulated attic of the building. An expansion tank is also installed there. This scheme cannot be used with a flat roof.

Disadvantages of a two-pipe system

Dual circuit system

Comparing the two battery strapping schemes, it is easy to conclude which is better. Two-pipe in any case is much more efficient. But she has one major drawback. It will take twice as many pipes to assemble it. In addition, they come with a large number of fasteners, valves and fittings, so the installation of a two-pipe system is much more expensive.

Until recently, when steel pipes and labor-intensive welding processes were used to assemble a two-pipe piping, the amount was outrageous. With the advent of metal-plastic and hot soldering technology, laying a two-pipe line has become accessible to almost everyone.

Generalization on the topic

We hope you have concluded for yourself which heating battery piping system is better - single-pipe or two-pipe. For a private house of a small area and a multi-storey building, the height of which does not exceed 5 floors, single-pipe piping can be an ideal option. In all other cases, it is worth using a two-pipe scheme.

Almost all heating systems currently available in any buildings and structures can be attributed to one of the two classes mentioned in the title of this article.

To answer the question of what is better single-pipe or two-pipe heating system, you can only carefully understand the advantages and disadvantages of each of the options considered.

Characteristics of a one-pipe home heating system

Which heating system is more efficient, one-pipe or two-pipe? It is impossible to answer this question unambiguously.

Single-pipe CO has all the basic elements inherent in any heating system. The main ones are:

• A heating boiler operating on any type of fuel that is most available at the location of the heated building. It can be a gas boiler, solid fuel or designed to run on liquid fuel. The type of fuel used by the boiler has no effect on the heating scheme;
• Pipes through which the coolant circulates;
• Shut-off equipment for various purposes (gate valves, valves);
• Heating appliances and thermometers;
• Air bleed valves. Placed on radiators (Maevsky cranes) and at the top point of CO;
• Drain cock (at the bottom point of CO);
• Expansion tank of open or closed type.

Benefits of using single pipe systems

The difference between a single-pipe heating system and a two-pipe one is that the first one is by far the simplest and most effective way to heat buildings up to 150 m2.

The installation of a circulation pump and the use of modern technical solutions make it possible to guarantee the required temperature parameters in heated rooms. Therefore, answering the question, what to choose a one-pipe or two-pipe heating system, among the indisputable advantages of the first system, it should be noted:

Mounting versatility. Such a system can be installed in a building of any configuration, and a closed circuit guarantees the movement of the coolant along the entire perimeter of the heated premises.
Unlike two-pipe, one-pipe CO can be mounted in such a way that space heating starts from the coldest side of the building (northern), regardless of the boiler installation location, or from the most significant rooms (nursery, bedroom, etc.).

The installation of the system requires a minimum number of pipes and shut-off and control equipment, a complete installation of CO is carried out in much less time than CO with two pipes. All this allows you to get serious savings in the funds allocated for the payment of construction work.

The system allows the installation of pipes directly on the floor or under it, which allows you to implement any design solutions in the premises.

The scheme provides for serial and parallel connection of heating devices, which allows you to control the temperature in them and adjust it;

Subject to certain requirements during installation, the system can be made in a non-volatile version. In the event that the pump stops due to a power failure, the coolant supply line switches to a parallel line. In this case, CO, from the variant with forced (PC) circulation, switches to natural circulation (EC).

Disadvantages inherent in the specified variant of CO

Two-pipe or one-pipe heating system of a private house? When evaluating the pros and cons, it should be borne in mind that the main disadvantage of a single-pipe CO is the fact that the heaters are connected in series. And this, during operation, excludes the possibility of effective temperature control in one of them, without affecting the other radiators.

A factor influencing the choice of whether a two-pipe or one-pipe heating system of a private house will be installed at your facility, one should not forget about such a disadvantage of the latter as increased pressure in the system compared to the two-pipe version. This can be achieved by increasing the power of the circulation pump installed in the system, which entails an increase in operating costs and increases the likelihood of leakage, and also requires more frequent addition of coolant to the system.

The system requires vertical filling. And this automatically determines the location of the expansion tank in the attic and, accordingly, the solution of the issue with its insulation.

If such a system is mounted in a two-story building, then another problem arises. The temperature of the water entering the first floor may differ from that which is initially supplied to the second floor by almost 50%. To avoid this, it is required to install additional jumpers on each floor, and the number of sections of heating devices on the first floor should significantly exceed that which is mounted on the second.

Which heating system is more efficient, one-pipe or two-pipe? We have already considered the first one. Let's consider the second.

Such a system a priori implies the presence of 2 pipelines placed along the perimeter of the heated room. Radiators cut between them, which dampen pressure drops and create hydraulic jumpers. However, the problems created by this can be leveled out due to the correct configuration of the CO.

• Two-pipe systems can be vertical and horizontal, depending on the location of the supply and return (parallel to the ceilings or perpendicular to them). However, it should be understood that the circuit mounted in apartment buildings is essentially a horizontal two-pipe CO.

  A two-pipe vertical one will turn out when the radiators are installed not in the breaks of the risers (as in the case described above), but between the supply and return.

• Associated and dead-end SO. The first variety includes systems in which hot water, passing through the radiator, moves in the same direction along the return line. If the direction of movement of the coolant changes after the heater, the system is classified as a dead end.

  The required option is selected taking into account the presence of doorways on the CO pipe laying line, which are quite difficult to get around, it is easier to return the water in the direction in which it came.

• With bottom and top filling.
• With natural (EC) and forced (PC) circulation.

Advantages and disadvantages of the system

Schemes of one-pipe and two-pipe heating systems are compared according to their inherent advantages and disadvantages. The advantages of the second system can be called:

1. Receipt in all heating devices of a coolant with the same temperature, which allows you to set your own value of the required temperature for a specific room;
2. Less pressure loss in the lines, which allows the use of a lower power pump (savings in operation costs);
3. The system allows installation in buildings of any area and number of storeys;
4. The presence of shut-off valves allows you to perform preventive maintenance and repair without stopping the entire CO.

All existing heating systems can be divided into two groups:

• single-pipe;
• two-pipe.

To answer the question: which heating system is better single-pipe or two-pipe, it is necessary to understand by what principle each of them works.

This will clearly indicate the advantages and disadvantages of each of them, and will also help you make the most optimal choice, both technically and in terms of the necessary funds, in order to understand a one-pipe or two-pipe heating system is more suitable.

Videos on types of heating systems can be easily found on the World Wide Web.

Advantages of a one-pipe heating system

• fewer materials and means;
• hydrodynamic stability;
• lower complexity of design and installation;
• no special infrastructure requirements.

But with all these advantages, we can say with full confidence that a single-pipe system is far from the best scheme by which heating can be implemented. Still, the main reason why the single-pipe system has become widespread in our country is the undeniable savings in material.

Single-pipe heating system: principle of operation

Such a system has one riser (main pipe). Through it, heated water (or any other coolant) rises to the upper floors of the building (if it is a multi-storey building).

All heating devices (heat transfer units - batteries or radiators) are connected in series to the downstream line.

Modernization of single-pipe heating systems

A technical solution that makes it possible to regulate the operation of each individual heater has been developed.

It consists in connecting special closing sections (bypasses), which make it possible to embed automatic radiator thermostats in heating. What other benefits are possible with the installation of bypasses? We will talk about this in detail later.

The main advantage of such a modernization is that in this case it becomes possible to regulate the heating temperature of each battery or radiator. In addition, you can completely shut off the coolant supply to the device.

Due to this, such a heater is repaired or replaced without shutting down the entire system.

Bypass is a bypass pipe equipped with valves or taps. With the correct connection of such fittings to the system, it will allow you to redirect the flow of water through the riser, bypassing the repaired or replaced heater.

It is not difficult to understand that the task of installing such devices into the system with your own hands is hardly possible to solve, even if detailed instructions are available. In this case, one cannot do without the participation of a specialist.

A heating system with one main riser should be equipped with heating devices that have improved characteristics in terms of reliability. Any devices in a one-pipe system must withstand increased pressure and high temperature.

Vertical and horizontal riser layout

According to the implementation scheme itself, single-column heating can be of two types:

• vertical;
• horizontal.

If the heating devices are connected from the upper floor to the lower one, this is a vertical riser. If the batteries are connected in series to each other in all rooms of the floor of the building, this is a horizontal riser.

Disadvantages of a single-pipe heating system

• complexity of thermal and hydraulic calculation of the network;
• the difficulty of eliminating errors in the calculations of heating devices;
• the interdependence of the characteristics of the operation of all devices in the network;
• increased hydrodynamic resistance;
• limiting the number of heating devices on one riser;
• inability to regulate batteries and radiators with regulators (pictured below)

Important!
If more than ten heating devices are connected to a vertical riser (for example, eleven), then the water temperature on the first radiator in the network will be about 105 ° C, and on the last - 45 ° C.

Single-column heating in individual construction

If heating with one main riser is installed in a one-story building, then it will be possible to get rid of at least one significant drawback of such a scheme - uneven heating.

If such heating is implemented in a multi-storey building, then the upper floors will be heated much more intensively than the lower floors. This will lead to a situation where it is cold on the first floors of the house, and hot on the upper floors.

A private house (mansion, cottage) is rarely more than two or three stories high. Therefore, the installation of heating, the scheme of which was described above, does not threaten that the temperature on the upper floors will be much higher than on the lower floors.

Two-pipe heating system: advantages and disadvantages

Advantages of a two-pipe collector system

• It becomes possible to install automatic thermostats for batteries or heating radiators. In this case, such devices are provided at the design stage of the system;
• Pipes according to this scheme are bred through the premises through a special collector system. If one of the elements in the system fails or starts to work unstably, this does not affect the operation of other devices in the circuit;
• In other words, with a two-pipe system, the elements of the heat circuit are connected in parallel, in contrast to the serial connection - with a single-pipe system.

The main disadvantages of a two-pipe heating system

• heating becomes more complex according to the connection scheme;
• the price of the project requires more funds;
• circuit wiring is more labor intensive.

Where are two-pipe heating systems used:

• in individual housing construction;
• in the projects of the so-called "elite" housing;
• high-rise buildings (with overhead wiring)

Important!
When designing buildings with more than 9-10 storeys, it is better to use either a single-pipe system with a horizontal floor distribution, or a two-pipe system with an upper vertical wiring.
This will provide better circulation.

Advantages of two-pipe collector heating

• reduced hydrodynamic resistance;
• the possibility of independent temperature control in each room.

Before starting, the collector heating system requires careful preliminary adjustment. For the correct installation, installation and operation of a two-pipe system, it is necessary to have the appropriate infrastructure.

Variants of wiring diagrams for a two-pipe system

Top wiring

The overhead system is suitable for natural circulation (without pumps) (). It has a lower hydrodynamic resistance. In this case, the upper supply main pipe is partially cooled. Due to this, an additional circulation pressure of the coolant is formed.

Bottom wiring

In a system with bottom wiring, both the supply and discharge pipes are located side by side.

There are such modifications of the lower wiring:

So, one-pipe heating system or two-pipe? In each case, it is necessary to have preliminary calculations and a project (see), on the basis of which both heating devices and the main pipes themselves will be selected (see). The final decision is yours.

A two-pipe system is the most popular scheme for a water heating complex. The scheme favorably differs in maneuverability and ease of regulation from a single-pipe system, it is more economical in the amount of material compared to a manifold configuration. The publication material gives an overview of the device and the principle of operation, varieties of the two-pipe configuration of the heating complex.

The device of a two-pipe heating system

In water heating, pipelines are one of the main elements; they serve to supply the heated liquid heat carrier to heating devices and return the water that has given off heat to the heat source. In the case of autonomous heating, the source of heat is an individual boiler, in the case of centralized heating, the main pipelines.

To ensure the circulation of the coolant between the radiators and the heat source in water heating, 3 main schemes are used:

1. Single pipe;
2. Two-pipe;
3. Collector (beam).

In addition, these schemes are sometimes combined with each other. The disadvantage of a single-pipe circuit is the complexity of controlling and adjusting the temperature in individual rooms and on heating devices. The collector system requires the largest amount of material for installation compared to other types of system.

The two-pipe scheme is the "golden mean", is the most popular, especially in the construction of autonomous heating systems. The popularity of this type of system is due to the convenience of regulation due to the hydraulic content of the circuit.

The basic principle of a two-pipe system is based on the parallel connection of heaters to two independent pipelines. One of them serves to supply hot coolant to heating devices (radiators, convectors, registers, etc.), the second one - to return the cooled coolant to the boiler - for heating.

The forward and return pipelines act as collectors, the water pressure varies slightly along the length. This allows you to maintain approximately the same pressure at all points of the heating system.

Equivalent pressure in all heating devices makes it easy to adjust the temperature on individual devices, in rooms. Installation of thermostatic fittings, thermal heads, temperature sensors makes it possible to fully automate the process of temperature control.

Maintaining the same hydraulic characteristics is also carried out by changing the diameter of the pipes along the length - in the dead-end branches of the system. The flow area decreases gradually from the first to the last radiator - such a configuration of a two-pipe circuit is called a dead end. In addition to it, there is another type of scheme - a passing (or Tichelman's loop).

Types of two-pipe heating system

The dead-end two-pipe system is more popular than the Tichelman loop. Its construction usually requires a smaller amount of material.

As mentioned above, the basic principle of the dead-end system is a gradual decrease in the diameters of the direct and return pipelines along the length of the branch, from the first to the last heater.

Temperature control is carried out by control valves. It should be noted that when installing any type of water heating system, shut-off and control valves should be installed on each heating element. This is necessary to turn off the radiator or other heating device for maintenance (flushing) or repair. When any device in the two-pipe network is turned off, the system continues to work - this is a significant advantage of the described scheme.

The adjustment algorithm is as follows. On the first radiator, the control valves close as much as possible, leaving a small coolant flow. On each subsequent device, the valve (or tap) is opened a little more. Such a stepwise adjustment allows you to equalize the pressure along the length of the circuit and adjust the required coolant flow rates (and, accordingly, the temperature).

A small disadvantage of the dead-end construction of a two-pipe circuit is that with a significant opening of the control valves on the first or second radiator, they can work in bypass mode. This situation is rare and is usually caused by the wrong choice of pipeline diameters.

More hydraulically advantageous is the passing scheme, also known as the Tichelmann loop. Here, the direct and return pipelines have the same diameter, they are connected to radiators from different directions. This allows you to practically equalize the pressure of the coolant in all heating devices without serious adjustment by control devices - valves or taps.

The installation of the line according to the Tichelmann scheme requires more pipeline than the assembly of a dead-end branch. The use of one or another scheme is usually justified by the construction parameters of the heated building - the size and relative position of the premises.

A two-pipe system allows you to mount more radiators on one line than a single-pipe counterpart. Moreover, the Tichelman loop can work qualitatively with a larger number of heating elements than a dead-end configuration due to its hydraulic structure.

The two main varieties of the two-pipe system - dead-end and associated - serve as the basic elements. The general arrangement of the entire heating complex has the following design solutions:

1. Connection of system branches to vertical risers with more than 1 floor;
2. Insertion of system branches into horizontal sunbeds placed in the lower or upper part of the building;
3. Connection of dead-end branches or associated Tichelman circuits to distribution manifolds;
4. Construction of a two-pipe system with natural circulation.

A prerequisite for connecting dead-end or associated branches to risers and sunbeds is the installation of balancing valves at the point of connection. They are necessary for the general hydraulic adjustment of the entire heating system.

It should be noted that the two-pipe scheme is used mainly in closed-type systems with forced circulation. The construction of an open system with natural circulation most often requires balancing - the installation of shut-off and control valves.

For the presented scheme, the obligatory technical solution will be to install a tap and limit the supply to the first radiator, otherwise the coolant will pass along the shortest path. In this case, subsequent radiators will receive insufficient heat.

Installing a tap or valve with a certain hydraulic resistance can introduce an imbalance in the gravitational movement of the coolant. Therefore, the best solution for organizing natural circulation is a single-pipe scheme, which is usually performed in this case without bypasses.

The two-pipe scheme of the heating system is the most popular configuration of water radiator heating of premises. Due to its advantages - maneuverability, ease of balancing, independence of devices - it rightfully occupies a leading position in the design solutions of heating complexes.