Two-pipe heating system
There are only two types of heating systems: one-pipe and two-pipe. In private homes, they try to install the most efficient heating system. It is very important not to sell too cheap, trying to reduce the cost of buying and installing a heating system. Providing a house with heat is a lot of work, and so that the system does not have to be installed anew, it is better to understand thoroughly, and make "reasonable" savings. And in order to draw a conclusion about which of the systems is better, it is necessary to understand the principle of operation of each of them. Having studied the advantages and disadvantages of both systems, both from the technical side and from the material, it becomes clear how to make the best choice.
One-pipe heating system
It works according to the principle: along one main pipe (riser), the coolant rises to the upper floor of the house (in the case of a multi-storey building); all heating devices are connected in series to the downstream. In this case, all the upper floors will be heated more intensively than the lower ones. It is a very common practice in Soviet-built multi-storey buildings, when it is very hot on the upper floors and cold on the lower ones. Private houses most often have 2-3 floors, so one-pipe heating does not threaten with a large contrast of temperatures on different floors. In a one-story building, heating is almost uniform.Advantages of a one-pipe heating system: hydrodynamic stability, ease of design and installation, low costs of materials and funds, since it is required to install only one line for the coolant. The increased water pressure will ensure normal natural circulation. The use of antifreeze increases the efficiency of the system. And, although this is not the best example of a heating system, it has become very widespread in our country due to the high savings in material.
Disadvantages of a one-pipe heating system: complex thermal and hydraulic calculation of the network;
- it is difficult to eliminate errors in the calculations of heating devices;
- the interdependence of the work of all network elements;
- high hydrodynamic resistance;
- a limited number of heating devices on one riser;
- the inability to regulate the flow of the coolant into individual heating devices;
- high heat loss.
Improvement of one-pipe heating systems
A technical solution has been developed to regulate the operation of individual heating devices connected to one pipe. Special closing sections - bypasses - are connected to the network. The bypass is a jumper in the form of a pipe segment that connects the direct pipe of the heating radiator and the return pipe. It is equipped with taps or valves. The bypass makes it possible to connect automatic thermostats to the radiator. This allows you to regulate the temperature of each battery and, if necessary, shut off the supply of coolant to any individual heating device. Thanks to this, individual devices can be repaired and replaced without completely shutting down the entire heating system. Correct connection of the bypass makes it possible to redirect the flow of the coolant through the riser, bypassing the element being replaced or repaired. For a high-quality installation of such devices, it is better to invite a specialist. 
Vertical and horizontal riser diagram
According to the installation scheme, one-pipe heating is horizontal and vertical. A vertical riser is the connection of all heating devices in series from top to bottom. If the batteries are connected in series with each other throughout the floor, this is a horizontal riser. The disadvantage of both connections is the trapped air in radiators and pipes. 
The heating system with one main riser is equipped with heating devices with increased reliability characteristics. All devices in a one-pipe system are designed for high temperatures and must withstand high pressures.
Installation technology of one-pipe heating system
1. Installing the boiler at the selected location. It is better to use the services of a specialist from the service center if the boiler is under warranty.
2. Installation of the main pipeline. If an improved system is being installed, then the obligatory installation of tees at the points of connection of radiators and bypasses. For heating systems with natural circulation when installing pipes
create a slope of 3 - 5o per meter of length, for a system with forced circulation of the coolant - 1 cm per meter of length.
3. Installation of a circulation pump. The circulation pump is designed for temperatures up to 60 ° C, therefore it is installed in that part of the system where the lowest temperature is, that is, at the inlet of the return pipe to the boiler. The pump is running on the power supply.
4. Installation of the expansion tank. An open expansion tank is installed at the highest point of the system, a closed one - more often next to the boiler.
5. Installation of radiators. They make a markup of places for installing radiators, fix the latter with brackets. At the same time, they comply with the recommendations of the manufacturers of devices for observing the distances from walls, window sills, floors.
6. Connect the radiators according to the selected scheme, installing Mayevsky taps (for airing out the radiators), overlapping taps, plugs.
7. The system is pressurized (air or water is supplied to the system under pressure to check the connection quality of all system elements). Only after that, the coolant is poured into the heating system and a test run of the system is carried out, the adjustment elements are adjusted. 
Two-pipe heating system
In a two-pipe heating system, the heated coolant circulates from the heater to the radiators and vice versa. This system is distinguished by the presence of two pipeline branches. One branch is used to transport and distribute the hot coolant, and along the second, the cooled liquid from the radiator returns to the boiler.Two-pipe heating systems, like single-pipe ones, are divided into open and closed depending on the type of expansion tank. In modern two-pipe closed heating systems, membrane-type expansion tanks are used. The systems are officially recognized as the most environmentally friendly and safe.
According to the method of connecting elements in a two-pipe heating system, they are distinguished: vertical and horizontal systems.
In a vertical system all radiators are connected to a vertical riser. Such a system allows each floor to be connected separately to the riser in a multi-storey building. With this connection, there are no air pockets during operation. But the cost of this connection is slightly higher. 
Two-pipe horizontal the heating system is mainly used in single-storey houses with a large area. In this system, the heating devices are connected to a horizontal pipeline. Risers for wiring the connection of heating elements are best installed on the staircase or in the corridor. Air locks are vented by Mayevsky's taps. 
Horizontal heating system is with bottom and top wiring... If the wiring is lower, then the "hot" pipeline runs in the lower part of the building: under the floor, in the basement. In this case, the return line is laid even lower. To improve the circulation of the coolant, the boiler is deepened so that all the radiators are above it. The return line is located even lower. The upper air line, which must be included in the circuit, serves to remove air from the network. If the routing is top, then the "hot" piping runs along the top of the building. The place for laying the pipeline is usually an insulated attic. With good insulation of pipes, heat loss is minimal. With a flat roof, this design is unacceptable.
Advantages of a two-pipe heating system:
- even at the design stage, it is envisaged to install automatic thermostats for heating radiators and, therefore, the possibility of regulating the temperature in each room;
- pipes in the premises are routed according to a special collector system, which ensures the independence of the operation of the circuit devices;
- in other words, the circuit elements in a two-pipe system are connected in parallel, in contrast to a single-pipe system, where the connection is sequential;
- batteries can be embedded in this system even after assembling the main line, which is impossible with a one-pipe system;
- the two-pipe heating system can be easily extended vertically and horizontally (if you have to finish building the house, then the heating system does not need to be changed). 
For this system, it is not necessary to increase the number of sections in radiators in order to increase the volume of coolants. Errors made at the design stage are easily eliminated. The system is less vulnerable to defrosting.
Disadvantages of a two-pipe heating system:
- a more complex connection diagram;
- higher project cost (much more pipes are required);
- more laborious installation.
But these disadvantages are very well compensated for in winter, when the maximum accumulation of heat occurs in the house.
Installation of a two-pipe heating system
I. Installation of a heating system with an upper horizontal wiring
1. An angle fitting is mounted to the branch pipe leaving the boiler, which turns the pipe upward.
2. Using tees and angles, mount the top line. Moreover, the tees are attached above the batteries.
3. When the upper line is installed, the tees are connected to the upper branch pipe of the battery, a shut-off valve is installed at the junction point.
4. Then the lower branch of the outlet pipeline is mounted. It goes around the perimeter of the house and collects all the pipes coming from the lowest point of the batteries. Usually this branch is mounted at the basement level.
5. Install the free end of the outlet pipe in the receiving branch pipe of the boiler; if necessary, install a circulation pump in front of the inlet.
In a similar way, a closed system with a constant pressure maintained by a pressure pump and an open heating system with an open expansion tank at the highest point are installed.
The main disadvantage of a two-pipe heating system with top wiring is the installation of an expansion tank outside a warm room on the ceiling. The heating system with top wiring also does not allow taking hot water for technical needs, as well as combining the expansion tank with the supply tank of the water supply system at home.
II. Installation of a heating system with lower horizontal piping
The system with bottom piping replaced the two-pipe heating system with top piping. This made it possible to place an open-type expansion tank in a warm room and in an easily accessible place. Also, some saving of pipes became possible, the combination of an expansion tank and a supply tank of the water supply system at home. The compatibility of the two tanks eliminated the need to control the coolant level, made it possible, if necessary, to use hot water directly from the heating system.
In such a scheme, the discharge line remains at the same level, and the supply line is lowered to the level of the discharge line. This improves aesthetics and reduces pipe consumption. But it works only in systems with forced circulation.
Installation sequence:
1. Mount downward-facing corner fittings on the boiler nozzles.
2. At floor level, two pipe lines are installed along the walls. One line is connected to the supply outlet of the boiler, and the second - to the receiving one.
3. Tees are installed under each battery to connect the batteries to the pipeline.
4. An expansion tank is installed at the top of the supply pipe.
5. As with the top piping, the free end of the discharge pipe is connected to the circulation pump and the pump to the inlet of the heating tank.
Maintenance of a two-pipe heating system
For high-quality maintenance of the heating system, it is necessary to implement a whole range of measures, including adjusting, balancing and adjusting the two-pipe heating system. To adjust and balance the system, special pipes are used, located at the highest and lowest point of the heat pipe. Air is released through the upper branch pipe, and water is supplied or drained through the lower branch pipe. With the help of special taps, excess air in the batteries is vented. To regulate the pressure in the system, a special container is used, into which air is pumped using a conventional pump. Special regulators, reducing the pressure in a specific battery, adjust the two-pipe heating system. The consequence of the redistribution of the pressure is the equalization of temperatures between the first and last batteries.
Several heating systems are known today. They are conventionally divided into two types: one-pipe and two-pipe. Determining the best heating system requires a good understanding of how they work. With this, it will be easy to make the choice of the most suitable heating system, taking into account all the positive and negative qualities. In addition to technical characteristics, when selecting, you must also take into account your financial capabilities. Still, is a one-pipe or two-pipe heating system better and more efficient?
All the details that are installed in each system are present here. The most important are:
Positive and negative properties of a one-pipe system
It consists of one horizontal collector and several heating batteries connected to the collector with two connections. Part of the coolant moving along the main pipe enters the radiator. Here, heat is released, the room is heated and the fluid is returned back to the collector. Liquid gets into the next battery at a slightly lower temperature. This continues until the last radiator is filled with coolant.
The main distinguishing feature of a one-pipe system is the absence of two pipelines: return and supply. This is the main advantage.
No need to lay two lines. You will need a lot fewer pipes, and installation will be easier. No need to punch through walls and make additional fixings. It would seem that the cost of such a scheme is much lower. Unfortunately, this is not always the case.
Modern fittings allow automatic adjustment of the heat transfer of each individual battery. To do this, it is necessary to install special thermostats with a large flow area.
However, they will not help get rid of the main disadvantage associated with the cooling of the coolant after it enters the next battery. Because of this, the heat transfer of the radiator, included in the common circuit, decreases. To keep warm, it is necessary to increase the capacity of the battery by building up additional sections. Such work increases the cost of the heating system. 
If you make the connection of the device and the line from pipes of the same diameter, the flow will split into two parts. But this is unacceptable, since the coolant will begin to cool quickly when it enters the first radiator. In order for the battery to fill at least a third of the coolant flow, it is necessary to increase the overall collector size by about 2 times.
What if the collector is installed in a large two-story house, the area of which exceeds 100 m2? For the normal passage of the coolant, pipes with a diameter of 32 mm must be laid along the entire circle. To mount such a system, large financial investments are required.
To create water circulation in a private one-story house, you need to equip the one-pipe heating system with an accelerating vertical collector, the height of which must exceed 2 meters. It is installed after the boiler. There is only one exception, this is a pumping system equipped with a wall-mounted boiler, which is suspended at the desired height. The pump and all additional elements also increase the cost of one-pipe heating.
Individual construction and one-pipe heating
The installation of such a heating, which has a single main riser in a one-story building, eliminates the serious disadvantage of this scheme, uneven heating. If something similar is done in a multi-storey building, the heating of the upper floors will be noticeably stronger than the heating of the lower floors. As a result, an unpleasant situation will arise: it is very hot upstairs, and cold downstairs. A private cottage usually has 2 floors, so the installation of such a heating scheme will evenly heat the whole house. It won't be cold anywhere.
Two-pipe heating system
The operation of such a system is somewhat different from the above-described scheme. The coolant moves along the riser, entering each device through the branch pipes. Then, through the return pipe, it returns to the main pipeline, and from there it is transported to the heating boiler.
To ensure the operability of such a scheme, two pipes are supplied to the radiator: through one, the main supply of the coolant is carried out, and through the other, it is returned to the common line. That is why they began to call it two-pipe.
The pipes are installed along the entire perimeter of the heated building. Radiators are installed between pipes to absorb pressure surges and form hydraulic bridges. Such work creates additional complications, but they can be reduced by creating the correct scheme. 
Two-pipe systems are divided into types:
Main advantages
What are the positive qualities of such systems? Installation of such a heating system makes it possible to achieve uniform heating of each battery. The temperature in the building will be the same on all floors.
If you attach a special thermostat to the radiator, you can adjust the desired temperature in the building yourself. These devices have no effect on the heat dissipation of the battery.
Double-pipe piping makes it possible to maintain the pressure value during the movement of the coolant. It does not require the installation of an additional high power hydraulic pump. The circulation of water occurs due to gravitational force, in other words, by gravity. With a poor head, you can use a low-power pumping unit that does not require special maintenance and is quite economical.
If you use shut-off equipment, various valves and boypasses, then it will be possible to mount such systems in which it becomes possible to repair only one radiator without turning off the heating of the whole house.
Another advantage of two-pipe piping is the possibility of using any direction of hot water.
The principle of operation of the passing scheme
In this case, the movement of water along the return and main pipes occurs along the same path. In a dead-end scheme - in different directions. When the water in the system has a passing direction, and the radiators have the same power, excellent hydraulic balancing is obtained. This eliminates the use of battery preset valves.
With different power radiators, it becomes necessary to calculate the heat loss of each individual radiator. To normalize the operation of heating devices, it will be necessary to install thermostatic valves. It is difficult to do it yourself without specific knowledge.
Hydraulic gravity is used when installing a long-distance pipeline. In short systems, a dead-end circuit for the circulation of the coolant is created.
How is the maintenance of the two-pipe system
For the service to be of high quality and professional, it is necessary to perform a whole range of operations:
- adjustment;
- balancing;
- customization.
To adjust and balance the system, special branch pipes are used. They are installed at the very top of the system and at its lowest point. Air is discharged after opening the upper pipe, and the lower outlet is used to drain the water.
Excess air accumulated in the batteries is vented using special taps.
To adjust the pressure of the system, a special container is installed. Air is pumped into it with a conventional pump.
Using special regulators that help reduce the water pressure in a particular radiator, a two-pipe heating system is adjusted. After the redistribution of the pressure, the temperature in all radiators is equalized.
How can you make a two-pipe from a one-pipe
Since the main difference between these systems is the decoupling of streams, it is quite easy to perform this rework. It is necessary to lay another pipeline parallel to the existing pipeline. Its diameter should be one size smaller. Next to the last device, the end of the old collector is cut off and tightly closed. The remaining section is connected directly in front of the boiler to a new pipeline.
An associated water circulation pattern is formed. The outgoing heating medium must be routed through a new pipeline. For this purpose, the inlet pipes of all radiators must be reconnected. That is, disconnect from the old collector and connect to the new one, according to the diagram: 
The rework process can present additional difficulties. For example, there will be no room for laying a second line, or it is very difficult to break through the floor.
That is why, before embarking on such a reconstruction, you need to think over all the details of future work. It may be possible to adjust the one-pipe system without making any alterations.
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All heating systems today are divided into two main types: one-pipe and two-pipe heating systems. Each type has its own characteristics and features, but two-pipe heating systems have become the most popular. Sometimes people ask themselves a question, one-pipe or two-pipe heating system - which one to choose?
One-pipe heating system
Such a heating system is a closed circuit that is interrupted by the boiler. The installation of such a system involves the installation of a pipeline throughout all rooms in the house. Radiators are connected to the pipes, and a coolant is launched into the system (most often distilled water plays its role), which provides heat transfer to each room. The principle of operation of such a heating system is based on the difference in water temperatures at the beginning of the cycle and during the reverse movement, that is, the water that has passed through the entire circuit returns to the boiler cooled down.Most often, this design uses the natural circulation of the coolant. For this, the heated water first rises to the maximum possible height, after which it gradually descends through the pipes, cooling in the process of movement.
- thermostatic valves;
- radiator regulators;
- balancing valves;
- Ball Valves.
Characteristics of a one-pipe heating system
The most important advantage of a one-pipe heating system with natural circulation is that there is no need for electricity. Instead, a significant drawback appears, which is expressed in a rather large diameter of the pipes and the need to create a constant slope of the pipeline.Advantages of one-pipe heating over two-pipe:
- Pipes can be connected to "warm floors" or heating radiators.
- Such a system can be installed in any room, regardless of the layout.
- The closed circuit allows the entire building to be heated as a single piece.
- Such a system is significantly less expensive because it requires much less materials.
In multi-storey buildings, a vertical one-pipe heating system is most often used, and a horizontal one is better suited for compact one-story houses. In this case, all heating elements are located at the same height, which gives rise to the following problem: the water that has cooled down in one radiator comes to the next already cold. Such a system is much cheaper, but it also has significant drawbacks.
Radiators in such a system are not controlled: a horizontal heating system does not imply free regulation of each heater. If necessary, bypasses can be built into such a system, which make it possible to let the coolant bypassing a separate radiator, but such a device will make the system more expensive. Turning off the radiator leads to the fact that the room begins to be heated due to the heat coming from the pipes or riser.
In addition, for the efficient use of this system, it is recommended to use heating elements of different sizes. To equalize heat dissipation, the radiator installed first should be quite small, and the latter should be much larger.
Two-pipe heating system
Despite the presence of a number of modifications, a two-pipe heating system works according to the same principle. The heated liquid rises along the riser, from where it enters the radiators. But if one pipeline circuit goes to the radiators, then the cooled liquid is removed using the second circuit. This is the point. Water enters such a system directly from the water supply system. For the system to function properly, it needs an expansion tank, which can be simple or complicated.
In the simple room there is a container to which two pipes are connected. One of them is a riser designed to supply water, and the second pipe allows you to eliminate excess liquid (read: ""). In a complex structure, four pipes are installed, two of which are responsible for the circulation of the liquid, and the other two monitor the water level in the system and the tank itself.
Two-pipe heating systems work perfectly in conjunction with a pump. Circulation can be carried out both with a passing flow and a dead-end method. In the latter case, the heated and cooled liquid move in the opposite direction. Both circulation circuits are of the same length, so all radiators provide equal heat dissipation.
A two-pipe heating system bypasses a single-pipe heating system in a number of parameters:
- The ability to accurately control the uniformity of heat supply in different rooms.
- The system is well suited for heating single-storey buildings.
- The riser locking systems can be located in the basement, thus saving on the usable building area.
- There are practically no heat losses in this system.
The horizontal closed two-pipe system can be equipped with top and bottom piping. The use of the lower wiring allows you to add new heating devices to the system gradually, as new floors are built (more: ""). The vertical system is well suited for houses with variable number of storeys. In any case, a two-pipe heating system will cost more than a one-pipe heating system, but its use will provide much greater comfort and convenience.
One-pipe or two-pipe heating system: advantages and disadvantages
In one-pipe systems, there are no return risers. In this case, the movement of the coolant is provided by natural circulation or a pump. The cooled liquid enters the lower part of the system, and along the way it mixes with the coolant from the supply riser. The closed circuit ensures constant fluid circulation in the system. Passing through the pipeline, the water cools down, therefore, the surface area of the heater located farther from the boiler must be larger in order to increase heat transfer.
One-pipe heating systems can be built according to two schemes: flow-through and mixed (read: ""). In the flow-through circuit, there are no by-pass routes at all, therefore, if one heating element fails, the entire system must be turned off. This option is currently practically not used, since it is extremely irrational. Nevertheless, one-pipe systems are inexpensive due to the minimum of materials and easy installation. When installing such systems, an upper wiring is required.
Installation of heating systems
One-pipe and two-pipe heating systems are installed in different ways, and the installation of a suitable system will depend on the parameters chosen, and any specialist can calculate the cost of the installation. If natural circulation is chosen for the installation, then it will be advisable to install the upper wiring, and if there is a pump and there are no problems with the power supply, the lower one can be used.In addition, the methods of installing heating systems can be classified according to:
- type of wiring;
- the number of risers;
- type of pipe connection.
The main classification of heating installation methods is still based on the chosen scheme. One-pipe and two-pipe heating systems have a lot in common, but the difference between them is too great to put them in one row. The advantages of one-pipe heating lie on the surface: low cost and ease of use. But this system also has enough drawbacks, and the most important of them is that if the house is too large (more than 100 sq.m.) or if there is a second floor, a one-pipe scheme will simply not justify itself. In such cases, it will be much more profitable to opt for a two-pipe heating system.
The latter option also makes it possible to choose the appropriate method for installing radiators:
- consistently;
- parallel;
- diagonally;
- from the side.
The classification of installation methods can be carried out by the location of the risers:
- heating with horizontal wiring;
- heating with vertical wiring;
- heating without risers.
The one-pipe system is cheaper and simpler. The two-pipe system is more convenient and reliable. Regardless of whether a one-pipe or two-pipe heating system is installed in the house, the premises will still be heated. The final choice depends on the homeowner, but still a two-pipe system has many advantages, and its performance suggests that using such a scheme in your home will be more profitable and convenient.
The video shows a one-pipe and two-pipe heating system for comparison:
All existing heating systems can be conditionally divided into two groups:
- one-pipe;
- two-pipe.
To answer the question: which heating system is better than one-pipe or two-pipe, it is necessary to understand on what principle each of them works.
This will clearly indicate the advantages and disadvantages of each of them, and will also help to make the most optimal choice, both technically and in terms of the necessary means, in order to understand a one-pipe or two-pipe heating system is more suitable.
Videos about the types of heating systems can be easily found on the World Wide Web.
Advantages of a one-pipe heating system
- fewer materials and funds;
- hydrodynamic stability;
- less laboriousness of design and installation;
- no special requirements for infrastructure.
But with all these advantages, we can say with complete confidence that a one-pipe system is far from the best scheme according to which heating can be realized. Still, the main reason why the one-pipe system has become widespread in our country is the indisputable saving of material.
One-pipe heating system: how it works
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 (units for heat transfer - batteries or radiators) are connected in series to the downstream.
Modernization of one-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 integrate automatic radiator thermostats into the heating. What other benefits are possible with bypass installations? Let's talk about this in more detail later.
The main advantage of such 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.
Thanks to this, such a heater is repaired or replaced without shutting down the entire system.
The bypass is a bypass pipe fitted with valves or taps. With the correct connection of such fittings to the system, it will allow 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, you cannot do without the participation of a specialist.
A heating system with one main riser must be completed with heating devices that have increased characteristics in terms of reliability. Any devices in a one-pipe system must withstand increased pressure and high temperature.
Vertical and horizontal riser diagram
According to the implementation scheme itself, single-column heating is 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 with each other throughout all rooms of a building floor, this is a horizontal riser.
Disadvantages of a one-pipe heating system
- the complexity of the 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;
- impossibility of regulating batteries and radiators with regulators (pictured below)
Important!
If more than ten heating devices (for example, eleven) are connected to a vertical riser, 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 mounted 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 ground floors of the house and hot on the upper floors.
A private house (mansion, cottage) is rarely more than two or three floors 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 the two-pipe manifold system
- It becomes possible to install automatic thermostats for radiators or radiators. In this case, such devices are provided at the system design stage;
- Pipes according to this scheme are routed through the premises through a special collector system. If one of the elements in the system breaks down or starts to work unstably, this does not affect the operation of the other devices in the circuit in any way;
- In other words, with a two-pipe system, the elements of the thermal circuit have a parallel connection, as opposed to a serial one - with a one-pipe system.
The main disadvantages of a two-pipe heating system
- heating becomes more complex according to the connection diagram;
- the price of the project requires more funds;
- installation of the circuit is more time consuming.
Where are two-pipe heating systems used:
- for individual housing construction;
- in projects of the so-called "elite" housing;
- high-rise buildings (with top wiring)
Important!
When designing buildings with more than 9-10 storeys, it is better to use either a one-pipe system with a horizontal floor wiring, 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 ability to independently adjust the temperature in each room.
The collector heating system requires careful preliminary adjustment before starting. Adequate infrastructure is required for the correct installation, installation and operation of a two-pipe system.
Wiring options for a two-pipe system
Top routing
The top-wired system is suitable for natural circulation (without the use of pumps) (). It has a lower flow resistance. In this case, the upper supply pipe is partially cooled. Due to this, additional pressure is generated for the circulation of the coolant.
Bottom wiring
In a bottom-wired system, the supply and return pipes are 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 (see) will be selected. The final decision is only yours.
You can decide which heating system is better, one-pipe or two-pipe, after analyzing the design features, pros and cons of each option. In any case, a verdict must be made at the construction design stage. is a rather complex structure. It is difficult, and sometimes impossible, to remodel it after finishing work. Consider the difference between two different approaches to the arrangement of heating buildings using boilers, batteries and piping.
This option is used in cases where it is necessary to carry out communications quickly and at minimal cost.
It is used in residential, private and industrial construction. A feature of this solution is the absence of a water return line. The batteries are connected in series, the assembly is carried out in a short time and does not require complex preliminary calculations.
How does a one-pipe line work
In such structures, the coolant is supplied to the upper point and flows downward, successively passing through the heating elements. When arranging a multi-storey building, it is practiced to install an intermediate pump that creates the necessary pressure in the supply pipe to push hot water in a closed loop.
Given a low house height and a limited number of heat consumers, water circulation is sufficiently efficient.
Vertical and horizontal schemes
The construction of a one-pipe line is carried out in a vertical and horizontal orientation. Vertical distribution is installed in buildings with two or more floors. The coolant is supplied to the radiators, starting from the topmost one. The horizontal heating main is most often used for the arrangement of single-level buildings - houses, summer cottages, warehouses, offices and other commercial facilities.
The layout of the pipeline assumes a horizontal arrangement of the riser with its sequential supply to the batteries.
Advantages and disadvantages
The single-pipe design of the heating main has the following advantages:
- Installation is carried out quickly, which is important given the modern requirements of the pace of construction. In addition, the appearance of a one-pipe collector with a height of several meters is superior in comparison with a complex system of two lines.
- Small budget. The cost estimate shows that the construction requires a minimum number of pipes, fittings and fittings.
- If consumers are installed on a bypass, then it becomes possible to regulate the heat balance separately in each room.
- The use of modern locking devices makes it possible to modernize and improve the line. This allows replacing radiators, inserting devices, and other improvements without a long shutdown of the system and draining water from it.
This design also has its drawbacks:
- The sequential arrangement of the batteries does not exclude the possibility of adjusting the heating temperature in them separately. This entails cooling all other radiators.
- Limited number of batteries on one line. It is impractical to put more than 10 of them, since at the lower levels the temperature will be below the permissible level.
- The need to install a pump. This event requires additional cash investments. The power plant can cause water hammer and damage to the lines.
- In a private house, you will need to install an expansion tank with a valve to bleed air. And this requires a place and carrying out insulation measures.
Two-pipe heating system
This design has a more complex structure, but also differs in efficiency and functionality.
The invested funds are compensated by the comfort for people, ease of maintenance and modernization.
Principle of operation and scheme of work
They are two risers and radiators located between them, warm floor and other heat consumers. The supply is carried out along one line, along the return line, the cooled liquid returns to the boiler. That is why such structures are called two-pipe.
Classification: lower and upper wiring
There are two types of systems according to the location of the highways. The choice is made based on the features of the structure and the possibility of allocating areas for additional equipment. Two-pipe communications are classified into vertical for high-rise buildings and horizontal for one-story buildings.
According to the location of the piping, the systems are divided into upper and lower, regardless of where the radiators are installed.
In the case of the upper version, the entire interchange is settled in the attic or on the technical floor of the building. At the same time, the expansion tank is being installed, which is carefully insulated. After the boiler, a pump is mounted that supplies the coolant to the upper level.
In the case of a lower wiring, the hot riser is located above the return. The heating boiler is installed in the basement or on the ground floor with a recess below the floor. An upper air line is connected to the pipeline to bleed air from the radiators.
Advantages and disadvantages
The main advantages of the two-pipe design are as follows:
- Simultaneous transfer of the coolant to consumers allows you to adjust the temperature individually in each room. If necessary, the radiators are closed completely if the room is not used for a long time.
- The ability to remove individual devices for repair or replacement without shutting off the heat supply to the remaining batteries. For this, ball valves are used, with the help of which the flow of water at the inlet and outlet of the radiator is shut off.
- No need to install a centrifugal pump. Water rises up from the boiler due to the temperature difference at the inlet and outlet.
- The choice of a passing or dead-end design option. This makes it possible to balance the heat distribution without making constant adjustments and adjustments.
The design flaws are as follows:
- The use of more pipes and components in the construction. This leads to the complication of construction, increased costs of finance and time.
- Increase in cost if the line is made of steel or aluminum. The use of reinforced polypropylene pipes significantly reduces the construction budget.
- Not everyone likes the abundance of communications in the interior. They can be hidden in walls or boxes. And these are additional costs and difficulties with maintenance.
What's better?
What to choose: one- or two-pipe construction, it is up to the master to decide individually. Each of them has its own positive negative properties associated with the design, construction, maintenance and improvements.
For a small house with a height of up to three floors, the option with one riser can be an ideal solution when a high-quality result is achieved with minimal investment. But, it should be remembered that in such cases, the process of installing additional equipment and replacing radiators that have served their purpose becomes much more difficult.
How to remake a one-pipe in two?
The two-pipe system is significantly more efficient in many respects. makes the process of its construction simple and inexpensive. The alteration will not be difficult, but it will require sacrificing the repairs carried out, since you will have to install and gradually build up the return riser and connect the batteries to it.
Another option is to install bypasses for consumers closest to the boiler in order to reduce their temperature and increase the flow of coolants to the final radiators.
If you have any experience in this field please share it. You will render a valuable service to craftsmen who have not yet made a choice in favor of one or another option for heating their homes.