The two-pipe heating system is more complicated compared to one-tube, and the number of materials necessary for installation is noticeably larger. Nevertheless, it is the 2-pipe heating system that is more popular. From the title it follows that it uses two contours. One serves to deliver a hot heat carrier to radiators, and the second one removes the cooled heat carrier back. Such a device is applicable for any types of structures, if only their layout allowed the installation of this design.
The demand of the two-kinning heating system is explained by the presence a number of weighty advantages. First of all, it is preferable to single-mounted, because in the last heat carrier loses a noticeable part of the heat before entering radiators. In addition, the two-integral design is more versatile and suitable for houses of different floors.
Disadvantage of a two-pipe system It is considered a high price. However, many mistakenly believe that the presence of 2 contours suggests the use of a double amount of pipes, and the cost of such a system is twice as much as a single-tube. The fact is that for a single-tube design it is necessary to take pipes of large diameter. This ensures normal circulation of the coolant in the pipeline, and therefore the effective operation of such a design. The advantage of the same two-tube is that it takes a smaller diameter pipe for its installation, which are significantly cheaper. Accordingly, additional elements (splits, valves, etc.) are also used with a smaller diameter, which also reduces the cost of construction.
The budget of the installation of a two-pipe system will be out of a little big than for one-tube. On the other hand, the effectiveness of the first will be noticeably higher, which will become good compensation.
Example application
One of the places where two-pipe heating will be very appropriate, is garage. This is a work room, because there is no permanent heating. In addition, the two-pipe heating system with its own hands is quite a real undertaking. Installation in the garage of such a system is not necessary, however it will be absolutely not superfluous, because in the winter time it is very difficult to work here: the engine does not start, oil freezes, and it is uncomfortable to work with hands. The two-pipe heating system provides quite acceptable conditions for finding indoors.
Varieties of two-pipe systems for heating
There are several criteria by which such heating structures can be classified.
Open and closed
Closed systems Expose the use of an expansion tank with a membrane. They can operate at elevated pressure. Instead of conventional water in closed systems, coolants based on ethylene glycol can be used, which do not freeze at low temperatures (up to 40 ° C below zero). Motorists know such liquids called "antifreeze".
1. Heating boiler; 2. Security group; 3. Reset valve overpressure; 4. Radiator; 5. Pipe reversal; 6. Expansion tank; 7. valve; 8. Drain valve; 9. Circulating pump; 10. Manometer; 11. PUBLIC VALVE. However, it is necessary to remember that for heating devices there are special compositions of coolants, as well as special additives and additives. The use of conventional substances can lead to a breakdown of expensive heating boilers. Such cases can be regarded as non-warranty, because the repair will require significant costs.
Open system It is characteristic that the expansion tank must be installed strictly at the highest point of the device. It needs to provide a pipe for air and a tap pipeline, which merges excess water from the system. Also through it you can take warm water for household needs. However, this use of the tank requires the presence of an automatic fitting of the structure and eliminates the possibility of using additives and additives.
1. Heating boiler; 2. Circulation pump; 3. Heating devices; 4. Differential valve; 5. Shut-off valves; 6. Expansion tank. And yet the two-pipe system of the heating of a closed type is considered more secure, so modern boilers are most often constructed under it.
Horizontal and vertical
These species are characterized by the location of the main pipeline. It serves to connect all structural elements. Both horizontal and vertical systems have their own advantages and disadvantages. However, both of them demonstrate good heat transfer and hydraulic stability.
Two-pipe horizontal heating design meets in single-storey buildings, and vertical - In high-rise buildings. It is more complicated and, accordingly, more expensive. Here are used vertical risers to which heating elements are connected on each floor. The advantage of vertical systems is that in them, as a rule, air stoppers do not occur, as the air leaves the pipes up to the expansion tank. 
Systems with Forced and Natural Circulation
Such species differ in the fact that, firstly, there is an electric pump, which causes the coolant to move, and secondly, the circulation itself occurs by itself, obeying physical laws. The minus structures with the pump are that they depend on the availability of electricity. For small premises, there is no particular sense in the forced systems, except to heat the house will be faster. With large areas, such structures will be justified.
To choose the right type of circulation, you need to consider which type of pipe wiring Used: upper or lower.
Upper Wiring System It assumes the gasket of the main pipeline under the ceiling of the building. It provides high pressure of the coolant, so that it goes well through radiators, and therefore the use of the pump will be superfluous. Such devices look aesthetically, the pipes at the top can be hidden by decorative elements. However, this system needs to install a membrane tank, which entails additional costs. It is possible to install and open a tank, but it should be at the highest point of the system, that is, in the attic. In this case, the tank must be inspired. 
Lower layout Ensures the installation of the pipeline just below the windowsill. In this case, you can install an open expansion tank anywhere in the room slightly above the pipes and radiators. But without a pump in such a design it is not necessary. In addition, difficulties arise if the pipe must pass by the doorway. Then it is necessary to start it around the perimeter of the door or make 2 separate wings in the design circuit. 
Tupic and passing
In a dead-end system The coolant is hot and cooled go in different directions. In a passing system, constructed according to the scheme (loop) "Tichelman", both streams go in one direction. The difference between these species in the simplicity of balancing. If the passing when using radiators with an equal number of sections itself is already balanced, then in a dead-end on each radiator, you need to install a thermostatic valve or needle valve.
If the "Tielman" scheme uses radiators with an unequal amount of sections, it also requires the installation of valves or valves. But even in this case, this design is balanced easier. This is especially noticeable in extended heating systems. 
Selection of pipes in diameter
The selection of pipe cross sections should be performed based on the volume of the coolant, which should pass per unit of time. It, in turn, depends on the thermal power, which is required for heating the room.
In our calculations, we will proceed from the fact that the size of heat losses is known and there is a numerical value of the heat required for heating.
Start calculations from the final, that is, the long-range radiator system. To calculate the coolant consumption for the room, you will need a formula:
G \u003d 3600 × Q / (C × ΔT)Where:
- G - water consumption for room heating (kg / h);
- Q is the thermal power required for heating (kW);
- c - water heat capacity (4,187 kJ / kg × ° C);
- ΔT - the temperature difference between the hot and cooled coolant is taken equal to 20 ° C.
For example, it is known that the thermal capacity for heating the room is 3 kW. Then water consumption will be:
3600 × 3 / (4,187 × 20) \u003d 129 kg / h, that is, about 0.127 cubic meters. m of water per hour.
In order for water heating to be balanced as precisely as possible, it is necessary to determine the cross section of the pipes. To do this, use the formula:
S \u003d gv / (3600 × v)Where:
- S is the cross-sectional area of \u200b\u200bthe pipe (M2);
- Gv - volumetric water flow (m3 / h);
- v is the speed of water, is in the range of 0.3-0.7 m / s.
If natural circulation is used in the system, the speed of movement will be minimal - 0.3 m / s. But in the example under consideration, we take the average value of 0.5 m / s. According to the specified formula, we calculate the cross-sectional area, and on the basis of it - the inner diameter of the pipe. It will be 0.1 m. We select the polypropylene tube of the nearest larger diameter. This is a product with an inner diameter of 15 mm.
Then go to the next room, we calculate the flow rate of the coolant for it, we summarize with the flow rate for the descriptive room and determine the diameter of the pipe. And so to the boiler itself.
Installation of the system
When installing the design, specific rules should be followed:
- any two-pipe system includes 2 contours: the upper serves to supply the hot heat carrier to radiators, the lower - for the cooling cooled;
- the pipeline must have a small slope toward the final radiator;
- pipes of both contours must be parallel;
- the central riser must be insulated to prevent heat losses when serving coolant;
- in reversible two-pipe systems, several cranes must be provided, with which water drops from the device is possible. This may be needed during repair work;
- when designing the pipeline, it is necessary to provide a smallest possible number of angles;
- the expansion tank must be installed in the highest location of the system;
- diameters of pipes, cranes, Signs, connections must coincide;
- when mounting a pipeline from heavy steel pipes to support them, you need to install special fasteners. The maximum distance between them is 1.2 m.
How to make the correct connection of heating radiators, which will ensure maximum comfortable conditions in the apartment? Mounting two-pipe heating systems, it is necessary to adhere to this sequence:
- From the heating boiler is given to the central riser of the heating system.
- At the highest point, the central riser ends with an expansion tank.
- From it throughout the building, pipes are bred, which supply a hot heat carrier to radiators.
- To remove the cooled heat carrier from heating radiators at a two-pipe design, a parallel supply pipe is laid. It must be connected to the bottom of the heating boiler.
- For systems with coercive circulation of the coolant, an electrical pump should be provided. It can be installed at any convenient point. Most often it is mounted not far from the boiler, near the entry point or exit.
Connecting the heating radiator is not such a complex process if you approach this question scrupulously.
The heating system is divided into two types: single-tube and two-pipe. Obviously, it is most profitable to install a more workable that will not only cope with its functions, but also serves you not one year. In order not to stay "in fools" and not mistaken with the choice of the heating system.
You need to figure out which of the heating systems is suitable for you better and why.
Thus, you will know which of the systems is better from the technical side and how to pick it up, given your budget.
High water pressure provides a natural cycle, and antifreeze makes the system more economical.
Disadvantages of a single-tube system - Very complex thermal and hydraulic network calculation, since, having permissible in the calculations of devices, it is very difficult to eliminate it.
Also, it is a very high hydrodynamic resistance and an involuntary number of heating devices on the same highway.
The receipt of the coolant goes immediately into everything and is not subject to separate adjustment.
In addition, very high heat loss.
In order to adjust the operation of individual devices connected to one riser, the bypass (closing areas) are connected to the network - this is a jumper in the form of a piece of pipe connected by the straight and reverse pipes of the radiator, with cranes and valves.
For the possibility of regulating the temperature of each separately, the bypass allows you to connect autotothermorts to the radiator.
In addition, it also makes it possible, in the event of a breakdown, replace or repair individual devices, without turning off the entire heating system.
One-tube heating is divided into vertical and horizontal:
- vertical - This is the connection of all batteries successively from top to bottom.
- horizontal - This is a consistent connection of all heating devices on all floors.
Due to the accumulation of air in batteries and pipes, so-called traffic jams occur, which is the disadvantage of both systems.
Installation of a single-tube system
Connecting- is made according to the scheme, using cranes for losing radiators, which overlap the cranes and plugs.
Pressing system-after which the coolant is poured into the battery and the system adjustment directly is configured.
Two-pipe heating system
Advantage of two-pipe heating system - This is the installation of autotroid matters, which gives the full possibility of adjusting the temperature in separate rooms.
This will take the independence of the operation of the chain devices, which the special collector system provides.
The difference between the two-pipe from the one-tube system is that the first can be connected to additional batteries after connecting the main, as well as the possibility of prolonging in vertical and horizontal directions.
Unlike a single-tube, here you can also easily correct permissible errors.
Disadvantages of this system Minimal, if you have a sufficient amount of material tools and have the ability to call the wizard.
Installation of the heating system with lower horizontal pipeline wiring
This system allows you to have an open tank at a convenient warm place. Also, it is possible to combine expansion and consumables allow you to enjoy hot water directly from the heating itself.
In systems with forced circulation to reduce the flow of pipes, the discharge and feeding risers are located at the level of the first.
There are several ways to water heating. There is a two-pipe, one-pipe placement scheme and two types of pipeline: the bottom and top. Consider the design with two pipes and layout at the bottom.
Characteristic
The most common is the two-pipe organization of heating, despite some advantages of single-tube structures. No matter how difficult is such a highway with two pipes (separately for water supply and returning it), most preferred it.
Such systems are in multi-storey and apartment buildings.
Device
The elements of the two-power heating with the bottom insertion of the pipes are as follows:
- boiler and pump;
- auto aircraft, thermostatic and safety valves, valves;
- batteries and expansion tank;
- filters, control devices, temperature and pressure sensors;
- you can use bypass, but optionally.
Advantages and disadvantages
The two-pipe connection scheme under consideration, when used, detects many advantages. First, the uniformity of the propagation of heat throughout the highway and the individual flow of the coolant into radiators.
Therefore, it is possible to adjust the heating instruments separately: turn on / off (you only need to block the riser), change the pressure.
In different rooms you can set different temperatures.
Secondly, such systems do not require disconnection or drain of the entire coolant when breakdown of one heating device. Thirdly, the system can be installed after the construction of the lower floor and do not wait until the whole house is ready. In addition, the pipeline has a smaller diameter than in the system with one pipe.
There are some drawbacks:
- more materials required than for a single-tube highway;
- a small pressure in the feeding creates the need to frequently drop the air, connecting the additional valves.
Comparison with other types
In the lower rush, the feed line is laid below, next to the return, because the coolant is sent downward upwards. Both types of wiring can be designed with one or more contours, dead-end and passing water flow in the feed pipe and return.
Natural circulation systems with eyeliner are used very rarely, as they require a large number of risers, and the meaning of such pipes of the pipes is to reduce their number to a minimum. Taking into account this, such structures most often have forced circulation.
Roof and floors - meaning
In the upper section, the supply line is higher than the level of the radiator. It is mounted in the attic, in the ceiling overlap. The heated water comes upstairs, then - through the feed risers evenly spreads across the batteries. Radiators must be above the return. To eliminate air accumulation, the compensating tank is mounted in the highest point (in the attic). Therefore, it is not suitable for houses with a flat roof without a attic.
The wiring from below has two pipes - feeding and reducing, - the heating batteries must be higher than them. It is very convenient to remove air traffic jams by cranes of Maevsky. The feeding line is in the basement, in the base, under the floor. The feed pipe must be higher than the return. An additional slope of the highway towards the boiler minimizes air traffic jams.
Both wiring are most effective when the vertical configuration is mounted on various floors or levels.
Principle of operation
The main characteristic of the two-pipe system is the presence of an individual water supply line to each radiator. In this scheme, each of the batteries is equipped with two separate pipes: supplying water and discharge. To batteries, the coolant flows upwards. The cooled water is returned to reverse risers in the return highway, and on it in the boiler.
In a multi-storey room, it is appropriate to put a two-pipe construction with a vertical arrangement of the highway and lower wiring. In this case, the temperature difference between the coolant in the feed pipe and the return creates a strong pressure, increasing as the floor increases. Pressure helps water to advance through the pipeline.
In the lower connection of the pipes, the boiler must be in the recess, as the batteries and heating devices should be higher to ensure the uniform shipping of water to them.
The air that accumulates is removed by the cranes of Maevsky or slutters, they are mounted on all heating devices. Automatic discharges are also used, which are fixed on risers or special air lines.
Views
The two-pipe heating system may be the following types:
- horizontal and vertical;
- direct-time - the coolant flows in one direction on both pipes;
- tupic - hot and cooled water moves in different directions;
- with the circulation of forced or natural: for the first you need a pump, for the second - the slope of the pipes towards the boiler.
The horizontal scheme can be with impasses, with a passing water movement, with a collector. It is suitable for single-storey buildings with a significant length when the batteries are appropriate to connect to a horizontally located trunk tube. This system is also convenient for buildings without simpleness, in panel-frame houses, where the risers are conveniently placed on the staircase or corridor.
According to experts, the most effective was the vertical scheme with forced water current. For her, a pump is needed, which is located on the return on the boiler. On it, the expansion tank is also mounted. Due to the pipe pump, it may be less than in the design with a natural movement: water with it is guaranteed to move throughout the line.
All heating devices are connected to the vertically located riser. This is the optimal option for high-rise buildings. Each floor is connected to the cutting pipe separately. The advantage is the lack of air traffic jams.
Installation
Conditionally, you can allocate several stages of work. First, the type of heating is determined. If the house is supplied to the house, then the most ideal option will be the installation of two boilers: one is gas, the second is a spare, solid fuel or electricity.
Stages
Briefly, installation consists of such items:
- from the boiler is displayed up the feed pipe and connects with a compensatory tank;
- from the tank to bring the pipe of the upper highway, which goes to all radiators;
- bypass is installed (if it is provided) and the pump;
- the reverse line is carried out in parallel feed, it is connected to the radiators and cut into the boiler.
For a two-pipe system, a boiler is first installed, for which a mini-boiler is created. In most cases, this is a basement (ideally a separate room). The basic requirement is good ventilation. The boiler must have free access and are located at some distance from the walls.
The floor and walls around it are faced with refractory material, and the chimney is excreted into the street. If necessary, a circulation pump is installed, a collector for distribution, regulating, measuring instruments near the boiler.
They are mounted last. They are located under the windows and fixed by the brackets. The recommended height from the floor is 10-12 cm, from the walls - 2-5 cm, from the windowsides - 10 cm. The inlet and the release of the battery is fixed by shut-off and control devices.
It is advisable to set the thermal sensors - with their help you can track the temperature indicators and adjust them.
If the gas heating boiler, then the presence of the relevant documentation and the presence of a representative of the gas farm during the first launch.
The expansion tank is located at or above the peak point of the highway. If there is an autonomous water supply, it can be integrated with a consumable tank. The bias of the feed and return pipes should be no more than 10 cm on 20 or more routing meters.
If the pipeline turned out to be at the entrance door - it is appropriate to divide it into two knees. Then the layout is created from the site of the upper point of the system. The lower highway of the two-pipe design should be symmetrically and parallel to the top.
All technological nodes need to be equipped with cranes, and the feeding pipe is preferably insulated. The distribution tank is also desirable to post in a warmed room. It should not be straight corners, sharp fractures that will subsequently create resistance and air traffic jams. Finally, you must not forget about pipe supports - they must be made of steel and crash for every 1.2 meters.
In apartments and private houses an integral part of comfort is to ensure heat. Preferably use water heating. Water heating happens with a single-tube and two-pipe contour. In the first case, water passing through a closed loop, heavily cools. Each subsequent radiator gets a colder liquid. The two-pipe system eliminates this drawback.
The two-pipe heating system is effective for a private house. These designs have become more popular. The complexity of the installation and a slightly greater consumption of materials pays off with obvious advantages.
Pluses of two-pipe heating:
- Each radiator receives the same heated coolant, increasing the air temperature in the room.
- The ability to adjust the heat of each battery by installing the thermostat.
- When breakdown with one of the systems, you can repair without stopping heating. To do this, you need to hind the locking elements.
- For installation, you can use small diameter pipes, significantly saving money.
- Installation indoors of any area.
A distinctive feature of the system is to connect to each radiator 2 pipes. Through the first heat enters the battery, the second outputs the cooled liquid from the device. This design allows you to effectively damn the room.
The layout of the pipes of the two-pipe heating system
The two-pipe layout diagram is 2 species vertical and horizontal. In the first case, heating elements are located vertically along one riser, which is typical for apartment buildings. In most cases, the coolant is supplied up, the removal of signed down.
With a horizontal version, the batteries are located on the same line. Such a wiring is inherent in single-storey buildings.
Two-pipe design can be in the open and. Any heating includes an expansion tank. When heated, the pressure in the pipes increases, and the compensation system allows you to save the required working level. The device is placed at the highest point, usually in the attic of houses. With an open layout, the liquid in the tank comes into contact with air. Part of it evaporates, so such a system requires constant control. In the closed type, the design is equipped with a membrane, and does not require constant attention.
Advantage of the scheme:
- A more aesthetic look of the room, the pipes are hidden under the battery and are not striking;
- For passage to radiators, one hole is required;
- Thermal loss is reduced.
All heating systems can be made with natural and forced circulation. The choice of design affects the upper or lower water supply. For the bottom feed, it is necessary to establish forced water circulation. Pipes from the boiler to radiators are laid by floor, just below the batteries. All over the perimeter of the room passes 2 pipes: distribution and return. To each radiator they are connected 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 system of the heating of a private house
In private homes, you can install both the bottom and the upper hand. For the upper layout, the use of natural water circulation is preferable. Distribution with a hot coolant pulls from the boiler to the ceiling, then stacked around the perimeter of the building.
Design Description:
- From the top pipe vertically lowered outlets to radiators;
- In terms of the floor lay the opposite;
- Connect both pipes to radiators;
- For physical circulation, the tilt angle must be in 3-5ᵒ, while the compensation tank is installed at the highest point of the circuit.
The heating system of natural circulation begins to work when water is heated. The coolant becomes easier and rushes up, reaching the highest point of the scheme, then the pipes are descended into radiators, cooling 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 of 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 the boiler in the basement. The disadvantage of the upper scheme is an external aesthetic appearance, in addition, part of the heat goes up. You can compensate for the lack of combining one-tube and two-pipe heating. For example, a single-tube to make a warm floor on the 2nd floor, to 1 hold a two-pipe layout.
Accurate calculation of the two-pipe heating system
Before starting work, it is necessary to make a heating scheme, decide on the material, make a hydraulic calculation. It is necessary to calculate the pressure drop in the rear area or to calculate the diameter of the pipe.
The calculation is based on the following factors:
- The inner surface of the pipes and its roughness;
- Diameter of the section;
- The number of flexural pipes;
- Pressure drop between feeding and reverse;
- The number of radiators and their cross section;
- Shut-off elements.
When calculating, formulas and aksonometric table are used. You can use a special program on software. Behind the main object take the most loaded ring or contour. As a result of calculations, the optimal speed should be from 0.3 to 0.7 m / s.
For greater speed, heating will be noise, with a smaller - there will be strong temperature scatter.
After the calculations performed, the pipes of an effective diameter, the required number of radiators, boiler, fittings, a split, an expansion tank, a pump for circulation, if there is such a need.
Stages of work on the installation of two-pipe heating with their own hands
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 boilers on liquid and solid fuel, a separate niche is required. When installing radiators, it is necessary to take into account the bias of the pipeline in 1-2% relative to the entire length of the pipe.
Work plan:
- Installing the boiler.
- From the heat generator, the main pipe with hot water, running through all radiators, is output.
- In parallel, the second highway is held with reverse.
- With a compulsory version of heating, a circular pump is cut.
- Install radiators. Batteries suspend on special brackets. All radiators should be placed at the same level. For convenience of operation, they are equipped with locking cranes at the input and output points. Batteries are connected in several ways: lateral, diagonal, lower connections. The most effective side and diagonal design.
- Finish the heating system by mounting pipes of accompanying nodes, installation of the expansion barrel and additional elements.
The highway should not contain straight and sharp corners, as the resistance will increase. Cranes and valves must match the size of the pipes. When designing with an upper wiring, the expansion tank is placed on a warmed attic. After completing all installation work, the system is connected.
To do this, overlap all the cranes, and necessarily slowly fill the feed loop.
Next, open the valve of the first battery, and with the help of air to the outlet of a smooth jet. The element is closed, and open the exhaust crane of the radiator. These manipulations must be carried out with each radiator. All detected defects eliminate.
Two-pipe heating of a private house with their own hands (video)
Installing a two-pipe system with your own hands will take more time, ultimately will provide efficient and practical heating, and will save on assembly work. It is important to choose the best option for the house, and make the competent calculation of the parameters of the system. Skillful hands and following instructions will be converted to the house by making it cozy and warm.
Examples of heating wiring in a private house (photo)
The water heating system can be a single-tube and two-pipe. Two-pipe is called so because you need two pipes for work - a hot heat carrier is supplied to the radiators from one of the boiler, on the other from the heating elements, the cooled and is supplied again to the boiler. With such a system, boilers of any type on any fuel can work. It can be implemented both forced and natural circulation. Two-pipe systems are installed and in one-storey, and in two or many storey buildings.
Advantages and disadvantages
From the method of organizing the circulation of the coolant, the main minus of such a method of organizing heating is subject to a double number of pipes compared to the main competitor - a single-tube system. Despite such a position, the cost of acquiring materials is slightly slightly, and all due to the fact that under the 2-pipe system, smaller diameters and pipes are used, and, accordingly, fittings, and they are much less. So as a result, the costs of materials are larger, but slightly. What is really more, so it works, and accordingly it is required twice again.
This disadvantage is compensated by the fact that each radiator can be put in a thermostatic head, with which the system is easily balanced in automatic mode, which cannot be made in a single-tube system. On such a device, put the desired temperature of the coolant and it is constantly supported with a small error (the exact value of the error depends on the brand). In a single-pipe system, you can implement the ability to adjust the temperature of each radiator separately, but for this you need a bypass with a needle or three-way crane, which complicates and increases the cost of the system, reducing notes in cash on the purchase of materials and time to install.
Another disadvantage of the two-tube is the impossibility of repairing radiators without stopping the system. It is inconvenient and this property can be circumvented, if you put the ball valves near each heating device near each heating device. Bring them, you can remove and repair the radiator or heated towel rail. The system will function as much as possible.
But there is an important advantage in such an organization of heating: unlike one-tube, in a system with two highways for each heating element, water of one temperature comes from the boiler immediately. Although it strives to go along the path of least resistance and then the first radiator does not apply, the installation of thermostatic heads or cranes for regulating the flow intensity solves the problem.
There is another advantage - less pressure loss and easier realization of self-heating or the use of lower power pumps for systems with forced circulation.
Classification 2 pipe systems
Heating systems of any type are divided into open and closed. In the closed, the expansion tank of the membrane type is set, which makes it possible to function by the system at elevated pressure. Such a system makes it possible to use not only water as a coolant, but also compositions based on ethylene glycol, which have a reduced freezing temperature (up to -40 ° C) and are called antifreeze. For the normal operation of the equipment in heating systems, special compositions designed for these purposes should be used, and not general purpose, and even more so, not automotive. The same applies to the additives used and additives: only specialized. Especially hard to adhere to this rule when using expensive modern boilers with automatic control - the repair during malfunctions will not be warranty, even if the breakage is not connected directly with the coolant.
In the open system at the top point, an open-type expansion tank is embedded. It is usually connected to a pipe for removing air from the system, and also organize a pipeline for draining excess water in the system. Sometimes from the expansion tanks can take warm water for household needs, but in this case you need to make the system to make automatic, 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 applies most often in high-rise buildings. It requires more pipes, but it is easily implemented by connecting radiators on each floor. The main advantage of such a system is an automatic air output (it seeks up and comes out there or through the expansion tank or through the buckthor).
The horizontal two-pipe system is used more often in one-storey or, maximum, in double-storey houses. For airbagging from the system on radiators, Maevsky cranes are installed.
Two-pipe horizontal heating scheme of a two-story private house (click on the picture to zoom in scale)
Top and Lower Wiring
According to the method of laying the feed, the system is distinguished from the upper and lower feed. At the top wiring, the pipe goes under the ceiling, and it is lowered from it to the feed pipe radiators. The reverse goes along the floor. This method is good in that it is easy to make a system with natural circulation - the height difference creates a stream of sufficient force to ensure good circulation speed, it is only necessary to observe a slope with a sufficient angle. But such a system is becoming less popular due to aesthetic considerations. Although, if at the top under the suspension or stretch ceiling, then only the pipes will remain to the instruments, and they actually can be deposited into the wall. Top and lower layout are used in vertical two-pipe systems. The difference is demonstrated in the picture.
At the bottom wiring, the feed pipe goes to lower, but higher than the return on. The supply tube can be positioned in the basement or semi-basement room (the return is even lower), between the draft and finishing floors, etc. You can bring / allocate the coolant to radiators by passing the pipes through the holes in the floor. With this location, the connection is obtained the most hidden and aesthetic. But here you need to select the location of the boiler: In its position relative to the radiators, it does not matter - the pump "sells", but in systems with natural circulation, radiators should be above the boiler level, for which the boiler is plugged.
The two-pipe system of heating of the 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 layout. The system with forced circulation, because the boiler hangs on the wall.
Tepique and passing two-pipe systems
A deadlock is called such a system in which the movement of the supply of heat carrier and the inversion is multidirectional. There is a system with a passing movement. It is called still loop / scheme "Tichelman." The last option is easier than balanced and configured, especially during extended networks. If radiators with the same number of sections are installed in the system with the associated movement of the coolant, it is automatically balanced, while the impressive thermostatic valve or needle valve is needed on each radiator.
Even if the radiators and valves / valves are installed with the "Tielman" scheme, the radiators and valves / valves should be put, then the chance is to balance such a scheme much higher than the dead-end, especially if it is quite extended.
To balancing a two-pipe system with a multidirectional movement of the coolant, the valve on the first radiator is required to be screwed very much. And there may be a situation at which it will be necessary to close so that the heat carrier will not flow there. It turns out then you need to choose: it will not warm the first battery on the network, or the latter, because it will not be possible to align heat transfer in that case.
Heating systems for two wings
Nevertheless, more often use the system with a dead-end scheme. And all because long the line of the return and collect it more difficult. If your heating circuit is not very large, it is quite possible to adjust the heat transfer on each radiator and when a dead-end connection. If the contour is large, and I don't want to do the loop "Tichelman", you can divide one large heating circuit into two wings of smaller size. There is a condition - for this there should be a technical possibility of such a network construction. At the same time, in each contour after separation, it is necessary to put the valves that will be adjusted by the intensity of the coolant flow in each of the contours. Without such valves, balance or is very difficult, or impossible.
Different types of coolant circulation are demonstrated in video, it also provides useful tips on the 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 of connecting radiators are implemented: diagonal (cross), unilateral and lower. The best option is a diagonal connection. In this case, the heat transfer from the heating device may be in the region of 95-98% of the nominal thermal power of the device.
Despite the different meaning of heat loss with each of the types of connection, they are all used, just in different situations. The lower connection, although the most unproductive, is more common if the pipes are laid under the floor. In this case, it is realized the easiest. You can connect radiators with a hidden gasket and on other schemes, but then large areas of pipes remain, or it will be necessary to hide them in the wall.
The side connection is practiced if necessary with the number of sections not more than 15. In this case, there are almost no heat losses, but with the number of radiator sections, more than 15 requires a diagonal connection, otherwise the circulation and heat transfer will be insufficient.
RESULTS
Despite the fact that the organization of two-pipe schemes uses more materials, they become more popular due to a more reliable scheme. In addition, such a system is easier to compensate.