Owners of private houses often face the choice of which type of home heating to give preference. There are only two types of heating systems traditionally used in everyday life: one-pipe and two-pipe. Each type has both advantages and disadvantages. The difference between both systems lies in the different way of delivering the coolant to the heating devices. Which heating structure for your own home is better, one-pipe or two-pipe - choose directly to the owner of the house, taking into account their own domestic needs, the estimated heated area and the availability of finances.
In the first version, heat is distributed throughout the house through one pipe, sequentially heating each room of the house. In the second case, the complex is equipped with two pipes. One is a direct supply of coolant to. Another pipe serves to drain the cooled liquid back to the boiler for subsequent heating. A correct assessment of your own financial capabilities, an accurate calculation of the optimal parameters of the coolant in each individual case, will help not only determine the type of heating system, but also correctly.
You can understand and figure out what is best for you, a one-pipe or two-pipe heating system, only after a thorough study of the technical nuances.
Single pipe heating system. General representations
A single-pipe heating system can work both with a pump and with natural circulation of the coolant. Considering the second type, you should delve a little into the existing laws of physics. It is based on the principle of expansion of a liquid when heated. During operation, the heating boiler heats the coolant, which, due to the temperature difference and the pressure created, rises through the riser to the highest point of the system. The movement of the coolant upwards is carried out along one pipe, reaching the expansion tank. Accumulating there, hot water fills all series-connected batteries through a descending pipe.
Accordingly, the connection points that are the first along the course of the coolant will receive maximum heat, while partially cooled liquid will already enter the radiators located further.
For large, multi-storey buildings, such a scheme is extremely inefficient, although in terms of installation and maintenance costs, a single-pipe system looks attractive. For private one-story houses, residential buildings with two floors, a similar principle of heat distribution is acceptable. Heating residential premises using a single-pipe scheme in a one-story house is quite effective. With a small heated area, the temperature in the radiators is almost the same. The use of the pump in longer systems also has a positive effect on the uniformity of heat distribution.
The quality of heating and the cost of installation in this case may depend on the type of connection. Diagonal connection of radiators gives greater heat transfer, but is used less often, due to the larger number of pipes needed to connect all heating devices in residential premises.
The scheme with the lower connection of radiators looks more economical due to the lower consumption of materials. From an aesthetic point of view, this type of connection looks preferable.
Advantages of a single-pipe heating system and its disadvantages
For owners of small residential buildings, a single-pipe heating system looks tempting, especially if you pay attention to its following advantages:
- has stable hydrodynamics;
- convenience and ease of design and installation;
- low costs for equipment and materials.
The indirect advantages of a single-pipe system include the safety of the supply of coolant, which diverges through the pipeline through natural circulation.
The most common problems that owners of a single-pipe heating system have to face include the following aspects:
- technical difficulties in eliminating miscalculations in the work made during the design;
- close relationship of all elements;
- high hydrodynamic resistance of the system;
- technological limitations associated with the impossibility of independent adjustment of the coolant flow.
Despite the listed disadvantages of this type of heating, a well-designed heating system will avoid many difficulties even at the installation stage. In view of the listed advantages and the economic component, single-pipe schemes have become quite widespread. Both a single-pipe and another type, a two-pipe heating system, have real advantages. What can you win and what can you lose by choosing one of the types for your home?
Technology for connecting and locating a single-pipe heating system
Single-pipe systems are divided into vertical and horizontal. In most cases, vertical wiring is used for multi-storey buildings. In this case, all radiators are connected in series from top to bottom. With horizontal wiring, the batteries are connected one after the other horizontally. The main disadvantage of both options is frequent air congestion due to air accumulation in the radiators. The proposed scheme makes it possible to get an idea of some wiring options.
Connection methods in this case are selected at the discretion of the owner. Heating radiators can be connected via side connection, diagonal or bottom connection. The figure shows similar connection options.
For the owner of the house, the economic feasibility of the equipment installed in the house and the effect obtained are always an important aspect. Do not underestimate the option with a single-pipe heating system. Today, in practice, quite effective measures are being taken to improve heating schemes of this type.
For instance: there is a technical solution that allows you to independently adjust the heating of individual radiators connected to the same line. For this purpose, bypasses are created in the system - a pipe segment that creates a bypass movement of the coolant from a straight pipe to the return, bypassing the circuit of a certain battery.
Valves and valves are placed on the bypasses, blocking the flow of the coolant. You can install thermostats on radiators that allow you to control the heating temperature in each radiator or throughout the system as a whole. A competent specialist will be able to calculate and install bypasses to achieve maximum efficiency. In the diagram you can see the principle of operation of bypasses.
Two-pipe heating system. Operating principle
Having become acquainted with the first type of heating system, a single-pipe, it's time to deal with the features and principle of operation of a two-pipe heating scheme. A thorough analysis of the technological and technical parameters of heating of this type allows consumers to make an independent choice - which heating is more efficient in a particular case, one-pipe or two-pipe.
The basic principle is the presence of two circuits along which the coolant diverges through the system. One pipe provides the coolant supply to the heating radiators. The second branch is designed so that the already cooled coolant, after passing through the radiator, returns back to the boiler. And so constantly, in a circle, while the heating is on. At first glance, the very presence of two pipelines in the scheme can repel consumers. The long length of highways, the complexity of wiring are factors that often scare owners of private houses away from a two-pipe heating system.
This is at first glance. Like single-pipe systems, two-pipe systems are divided into closed and open. The difference in this case lies in the design of the expansion tank.
Closed with a membrane expansion tank are the most practical, convenient and safe to use. The obvious benefits are confirmed by:
- even at the design stage, it is possible to equip heating devices with thermostats;
- parallel, independent connection of radiators;
- the technical possibility of adding heating devices after the installation is completed;
- ease of use of hidden gaskets;
- the ability to turn off individual radiators or branches;
- ease of adjustment of the system.
Based on the foregoing, one unambiguous conclusion can be drawn. A two-pipe heating system is much more flexible and more technologically advanced than a single-pipe one.
For comparison, the following diagram is presented:
The two-pipe system is very convenient for operation in a house in which it is planned to increase the living space, extension options are possible, both up and along the perimeter of the building. Already at the stage of work, technical errors made during the design can be easily eliminated. Such a scheme is more stable and reliable than a single-pipe one.
With all the obvious advantages, before choosing this type of heating, it is appropriate to recall the disadvantages of a two-pipe system.
It's important to know! The system is characterized by a higher complexity and cost of installation and rather cumbersome connection options.
If you have a competent specialist at hand, the necessary technical calculations have been carried out, then the listed disadvantages are easily compensated by the advantages of a two-pipe heating scheme.
As in the case of a single-pipe system, the two-pipe option involves the use of a vertical or horizontal arrangement of pipelines. Vertical system - radiators are connected to a vertical riser. This type is convenient for two-story private houses and cottages. Air congestion is not terrible for you. In the case of the horizontal version, the radiators in each room or room are connected to a pipeline located horizontally. Two-pipe horizontal heating schemes are mainly designed for heating one-story buildings and large residential buildings with the need for floor-by-floor adjustment. Arising air jams are easily eliminated by installing Mayevsky cranes on radiators.
The figure shows a vertical two-pipe heating system. Below you can see what a two-pipe horizontal type system looks like.
Traditionally, radiators can be connected using bottom and top wiring. Depending on the technical conditions and the project, the choice of wiring option depends on the owner of the house. The top wiring is more convenient. All highways can be hidden in the attic space. The system creates the circulation necessary for a good distribution of the coolant. The main disadvantage of a two-pipe heating scheme with an upper wiring option is the need to install a membrane tank outside the heated premises. The upper wiring does not allow the intake of technical water for domestic needs, as well as connecting the expansion tank to the tank for hot water used in everyday life. This scheme is not suitable for flat-roofed residential properties.
Summary
The selected type of heating for a private house should provide all the inhabitants of the residential building with the necessary comfort. Save on heating is not worth it. By installing a heating system in your house that does not meet the parameters of a residential facility and domestic needs, you run the risk of spending a lot of money on refurbishment in the future.
Two-pipe or one-pipe heating system - the choice should always be justified, both from a technical point of view and from an economic one.
For each private household, the installation of a heating system is considered one of the fundamental issues. Modern construction technologies offer two options: a single-pipe or two-pipe system.
It is important not to sell cheap here, trying to reduce the cost of installation and purchase of materials. And only having understood the principle of operation of these systems, with their advantages and disadvantages, you can make the right choice.
The operation of a single-pipe heating system occurs according to fairly simple principles. There is only one closed pipeline through which the coolant circulates. Passing through the boiler, the carrier heats up, and passing through the radiators, it imparts this heat to them, after which, cooled, it again enters the boiler.
The riser in a single-pipe system is also one, and its location depends on the type of building. So, for one-story private houses, the horizontal scheme is best suited, while for multi-storey buildings - vertical.
Note! A hydraulic pump may be required to pump the coolant through vertical risers.
To improve the efficiency of a one-pipe system, some improvements can be made. For example, install bypasses - special elements, which are pipe sections connecting the direct and return pipes of the radiator.
This solution makes it possible to connect thermostats to the radiator that can control the temperature of each heating element, or completely disconnect them from the system. Another plus of bypasses is that they allow you to replace or repair individual heating elements without shutting down the entire system.
Mounting Features
In order for the heating system to give warmth to the owners of the house for many years, during the installation process it is worth adhering to the following sequence of actions:
- According to the developed project, the boiler is being installed.
- The pipeline is being installed. In places where the project provides for the installation of radiators and bypasses, tees are installed.
- If the system works according to the principle of natural circulation, it is necessary to provide a slope of 3-5 cm for each meter of length. For a circuit with forced circulation, a slope of 1 cm per meter of length will suffice.
- For systems with forced circulation, a circulation pump is installed. It should be borne in mind that the device is not designed for operation at high temperatures, so it would be better to install it near the return pipe inlet to the boiler. In addition, the pump must be connected to the electrical network.
- Installing an expansion tank. An open tank should be located at the highest point of the system, a closed one - in any convenient place (most often it is mounted near the boiler).
- Installation of heating radiators. They weigh a lot (especially when filled with water), so they are fixed with special brackets, which, as a rule, come with the kit. Installation is most often carried out under window openings.
- Additional devices are being installed - Mayevsky cranes, plugs, blocking devices.
- The final stage is testing the finished system, for which water or air is supplied under pressure. If the tests do not reveal problem areas, the system is ready for operation.
The heating system of a private house is an obligatory and integral part of housing in the Russian Federation, the territory of which is located mainly in the cold climate zone. Regardless of the type of heat generator (gas, electric, solid and liquid fuel boilers), heat sources (radiators, registers or batteries) are installed in the house, and the two-pipe heating system is by far the most popular and preferred due to its efficiency and high efficiency. Although the single-pipe circuit is simpler and cheaper to install, it is less efficient, since it does not have the ability to regulate heat transfer in each room and for each heating device, whether it be a battery, a radiator or a home-made pipe register.
Varieties of double-circuit wiring of the coolant
The main advantage that a two-pipe heating scheme provides is a very high heat transfer efficiency, so even double the cost of pipes, in comparison with a single-pipe network, is justified many times over. What explains this? The pipes in this scheme are used with a small diameter - the main source of heat is the radiator - and due to significant savings on materials, it turns out to cut the estimate. You also need to purchase much less fittings, valves and other fittings. The entire assembly of the system is easily done by hand. 
Equipment in a private house of two-pipe heating is warmth, coziness, comfort and quality of the heating method used. The arrangement itself according to the two-pipe scheme is the supply of two pipes to each radiator: one is supplied with a hot coolant, the other is discharged. The supply is connected to all radiators in parallel, and a shut-off valve is cut in front of each heat source to regulate heat exchange, carry out preventive maintenance or repair the system without a general shutdown.
For the installation of piping in a two-pipe scheme, you will need to purchase the following materials:
- Heating boiler, expansion tank and circulation pump (if it is not already installed in the boiler);
- Heating radiators or batteries, safety valve, pressure gauge;
- Cleaning reagents, fittings (quantity and functionality is determined based on the project or scheme), air outlet devices (Maevsky taps, valves);
- Metal-plastic or PVC pipes.
And these tools:
- Impact type electric drill and screwdriver;
- Apparatus for welding and electrodes with a diameter of 3-4 mm;
- Keys - adjustable and gas, as well as a tape measure and a hammer;
- Plumb and spirit level.
A significant and fundamental difference between heating schemes in the vertical and horizontal planes lies in their wiring. Pipes enclose all batteries in one system, but according to different schemes.
Heating with wiring on top - varieties
Top-mounted home heating systems connect all radiators to a vertical riser that supplies heated coolant to the system. This is a reliable system in operation, since plugs from the air cannot appear in it, but installation and wiring are more expensive than a single-pipe circuit. Such a heating scheme is optimal for a low-rise building or cottage, since each floor can be connected to the boiler with a separate branch.
A two-pipe horizontal connection is relevant for a one-story house. Heat sources are connected to horizontally separated pipes, the connection risers of which are usually mounted in hallways, halls or corridors. 
Such a two-pipe heating system, the scheme of which is assembled according to a horizontal type, can have radial (collector) and serial types of radiator connection. With radiant wiring, the coolant is supplied separately to the radiators, and there is no need to regulate the heat supply in each individual heater, since the heat is distributed evenly throughout the system through pipes and batteries. The beam wiring scheme is effective in a one-story building.
The serial wiring solution is based on the total number of pipes, and if there are not many, then this type of connection can also be implemented. With horizontal wiring along the walls, it is difficult to ensure the original intentions of the designer - a large number of pipes will ruin everything. The only solution is to hide all the wiring under the floor or in the walls at the design stage of the house and heating. 
There are secrets in the installation and wiring of a two-pipe heating system according to the horizontal type of heating:
- This is a long and labor-intensive process;
- It is recommended to connect and adjust the entire circuit for each room before the onset of frost;
- The correct calculation is heat in the house. Therefore, if you are not sure of your capabilities, contact a specialized company.
The principle of operation of a two-pipe vertical system, according to which the heating of the house is organized, is based on the parallel connection of heating points (batteries or radiators). In such a scheme, the presence of an expansion tank is mandatory, as well as piping along the upper circuit. The hot coolant from the boiler rises through each pipe, falling into all points of the system. The expansion tank is mounted at the top of the heating circuit.
When organizing vertical double-circuit heating, the hot coolant rises under pressure, and then is distributed from top to bottom over heat sources. In the return line, which is laid lower than the lower part of the radiators, already cold coolant is supplied. Such a scheme promotes the movement of air through the pipes into the expansion tank and its automatic removal. 
Bottom wiring diagram
When installing a horizontal system, pipes are bred around the premises in compliance with a certain slope - 5-10 mm per 1 meter of pipe. The cooled coolant from the radiators on the return line enters the pipeline and into the boiler. The difference between this scheme is two main pipelines: one for supplying the coolant, the second for the return supply to the boiler. Hence the common name of the scheme - two-pipe. 
The water in the system is replenished either through a connected water supply, or manually - through the neck of the expansion tank. If it is possible to connect water from the water supply, then it is better to connect it to the return pipe so that cold and heated water mix immediately.
The operation of such a scheme differs from the wiring along the top in that the coolant supply pipe cuts into the wiring from below, next to the return pipe, and the heated water and the boiler moves through the pipes and radiators from the bottom up - through the return pipes and radiators back to the boiler. If air locks form in the system, then the air is bled using special valves embedded in each heating device. 
A two-circuit system with a lower wiring can have one, two or more circuits, and can also be implemented using the organization of an associated or dead-end circuit. In their homes, the owners rarely use these schemes because of their high cost - air vents are required for each heating device. Also, heating systems made according to these schemes are equipped with a special expansion tank through which the air in the system circulates along with the coolant. Because of this feature of the scheme, it is necessary to bleed the accumulating air masses at least once every 5-7 days. But there is also a big advantage - heating, organized according to such a scheme, can be started even before the construction of the house is completed.
The difference between a two-circuit scheme and a one-circuit scheme lies in the name itself - when a two-pipe heating system is operating, two pipes are connected to each heater, and the hot coolant is supplied to the radiators through the upper heating pipe, and through the lower one it is discharged to the boiler already cooled down. The scheme for heating a private house in a two-circuit system consists of the following components, parts and elements:
- heating boiler;
- Balance;
- Radiators, registers or radiators;
- Shut-off valve and expansion tank;
- Cleaning filter;
- Pressure gauge and water pump;
- Valve.
The expansion vessel is mounted in the highest level of the heating circuit. If water is supplied to the house from an external source and is supplied to the pipeline under some pressure, then the expansion tank can be combined with a supply water supply tank. It is also necessary to observe the slope in the return water supply pipe and the supply - it should be no more than 10 mm per 2 meters of pipe length - too small a slope will not ensure proper movement of the coolant, and the radiators will warm up for a long time. Also, a small slope will contribute to the creation of air congestion. But if the slope is more than acceptable, then the air will also remain in the system, not having time to get to the outlet points. 
If an autonomous double-circuit heating circuit is organized in the house with wiring along the upper circuit, then its installation itself can be carried out using different design solutions, depending on where, how and at what height the expansion tank is mounted. The best option can be considered if the expansion tank is located in a heated room, and it can be freely approached. The upper pipe of the horizontal circuit should run as high as possible - preferably under the ceiling, but in such a way that the expansion tank can also be mounted in the house, and not in the attic. 
The highest efficiency for a two-circuit scheme can only be if the supply pipe is as long as possible. Even with different sizes of pipes and other elements of the system, the efficiency and efficiency of the system will always be high, since the upper connection point of the heat carrier supply pipe is located at the beginning of the heating main.
Also, the efficiency of the system can be significantly increased by including a circulation pump in the circuit. A standard pump with a power of 65-110 watts consumes little electricity, and even with non-stop operation it does not need additional maintenance or preventive maintenance. The presence of a circulation pump increases the speed of movement of the coolant, which means heating the premises. But the installation of heating in a two-pipe scheme with an upper circuit makes the inclusion of a pump in the circuit superfluous and optional.
You can decide which heating system is better, one-pipe or two-pipe, after analyzing the design features, the pros and cons of each option. In any case, it is necessary to make a verdict at the design stage of construction. is a rather complex structure. It is difficult, and sometimes impossible, to redo it after finishing work. Consider the difference between two different approaches to arranging the heating of 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 return water supply line. Batteries are connected in series, assembly is carried out in a short time and does not require complex preliminary calculations.
How does a single pipe line work?
In such designs, the coolant is supplied to the top point and flows down, 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 through a closed circuit.
Given the low height of the house and a limited number of heat consumers, water circulation is sufficiently efficient.
Vertical and horizontal layouts
The construction of a single-pipe line is carried out in vertical and horizontal orientation. Vertical wiring is installed in buildings with two or more floors. The coolant is supplied to the radiators, starting from the top one. A horizontal heating main is most often used for arranging single-level buildings - houses, summer cottages, warehouses, offices and other commercial facilities.
The piping layout assumes a horizontal arrangement of the riser with its serial 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 single-pipe collector several meters high compares favorably with a complex system of two lines.
- Small budget. The cost calculation shows that the construction requires a minimum number of pipes, fittings and fittings.
- If consumers are installed on the 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 highway. This allows you to replace radiators, insert devices, and other improvements without a long stop 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 per line. It is not advisable to set them more than 10, since at the lower levels the temperature will be below the permissible level.
- The need to install a pump. This event requires additional financial investments. The power plant can cause water hammer and damage to 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 warming measures.
Two-pipe heating system
This design has a more complex device, but also differs in efficiency and functionality.
Invested funds are compensated by comfort for people, ease of maintenance and modernization.
Principle of operation and scheme of work
They are two risers and radiators located between them, underfloor heating and other heat consumers. The supply is carried out along one line, the cooled liquid returns to the boiler along the return branch. That is why such structures are called two-pipe.
Classification: bottom and top 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 space 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 strapping, the systems are divided into upper and lower, regardless of where the radiators are installed.
With the upper option, the entire interchange is arranged in the attic or technical floor of the building. At the same time, an expansion tank is installed, which is carefully insulated. After the boiler, a pump is installed that supplies the coolant to the upper level.
In the case of the 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 completely blocked if the room is not used for a long time.
- The ability to remove individual devices for repair or replacement without turning off the heat supply to the remaining batteries. For this, ball valves are used, with the help of which the flow of water is blocked at the inlet and outlet of the radiator.
- There is no need to install a centrifugal pump. Water rises from the boiler upward due to the difference in temperature at the inlet and outlet.
- The choice of a passing or dead-end design option. This makes it possible to balance the distribution of heat without constant adjustments and adjustments.
Design flaws are:
- Use in the construction of more pipes and components. This leads to the complexity of construction, an increase in financial and time costs.
- An increase in cost if the trunk 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 this is an additional cost and complexity with the service.
What's better?
What to choose: one- or two-pipe design, the master decides individually. Each of them has its own positive and negative properties associated with the features of design, construction, routine maintenance and improvements.
For a small house up to three stories high, a single riser option can be the ideal solution when high-quality results are 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 is much more difficult.
How to convert a one-pipe into two?
The two-pipe system is much more efficient in many respects. makes the process of its construction simple and inexpensive. Alteration will not be difficult, but it will require sacrificing the repairs carried out, since you will have to install and gradually increase the return riser and attach batteries to it.
Another option is to install bypasses on the consumers closest to the boiler in order to reduce their temperature and increase the flow of coolants to the final radiators.
If you have experience in this area, please share it. You will provide a valuable service to craftsmen who have not yet made a choice in favor of one or another option for heating their homes.
When developing a heating system for our home, we certainly think about the scheme for laying pipes and connecting radiators. Most often, when creating projects, common schemes are used with two pipes laid through heated rooms. A two-pipe heating system is more difficult to install, but it has many undeniable advantages - this is what we will talk about in our review. We will also look at:
- Structural features of two-pipe heating systems;
- Their main disadvantages;
- Varieties of two-pipe systems.
At the very end, we will talk about the most effective ways to connect batteries to heating systems.
Features of two-pipe heating systems
A two-pipe heating system is the most common scheme for laying heating pipes and connecting radiators. It provides for the use of two pipes - one is used to supply hot coolant, and the second it is diverted to the heating boiler. This scheme is highly efficient and ensures uniform distribution of heat throughout all heated rooms.
Single-pipe heating systems, unlike two-pipe ones, have a number of disadvantages:
The difference in the operation of single-pipe and two-pipe heating systems is well illustrated by this picture.
- More limited contour length;
- Uneven distribution of heat over heated rooms - the very last rooms suffer;
- It is difficult to heat multi-storey buildings;
- Increased hydrodynamic resistance in the heating system;
- Lack of separate adjustment of the heating temperature in different rooms;
- Difficulties in repair - you can not remove a faulty battery without stopping the entire system.
Some of the above problems are partially solved using the Leningradka scheme, but this is not a full-fledged way out of the situation.
A two-pipe heating system provides for the laying of two parallel pipes to which radiators are connected. The coolant from the supply pipe enters the heating devices, after which it is sent to the return pipe (return). Despite the more impressive financial and labor costs, the finished system is more functional in operation and easy to repair.
Two-pipe heating is actively used for heating rooms and buildings for various purposes. These include one-story private houses and cottages, multi-storey apartment buildings, as well as industrial and administrative buildings. In other words, the scope of its application is distinguished by its breadth.
Advantages and disadvantages of two-pipe heating systems
Two-pipe heating is distinguished by its versatility. It works equally well in both small buildings and high-rise buildings, including high-rise residential buildings. Let's look at the main advantages of two-pipe systems:
When using two-pipe heating, even the most distant batteries in the house will be able to provide heat at an acceptable level.
- The increased length of one line (circuit) is relevant when heating elongated buildings, for example, hospital or hotel buildings;
- Uniform supply of heat to the premises - unlike single-pipe systems, it will be warm even in the rooms farthest from the boiler;
- Two-pipe heating makes it easy to organize separate temperature control in separate rooms and premises - for this, thermostatic heads are placed on each battery;
- The possibility of dismantling batteries and convectors without stopping the entire heating system is an important advantage that manifests itself in large buildings;
- Two-pipe heating is the best suited for heating large buildings - for a more even distribution of heat, certain piping schemes and connection of heating devices are used.
Unfortunately, there are some downsides:
- High costs for the purchase of equipment - compared to single-pipe heating systems, two-pipe systems require an increased number of pipes;
- Difficulty in installation - an increase in the number of nodes and the need for optimal distribution of the coolant over the heated premises affects.
However, the pros completely outweigh the above cons.
Varieties of two-pipe heating systems
We have already familiarized ourselves with the advantages and disadvantages of two-pipe heating systems, as well as their distinctive features. It remains to talk about their varieties.
Forced or natural circulation
The natural circulation of the coolant provides for the absence of a circulation pump. Heated water circulates through the pipes independently, obeying the forces of gravity. True, this requires pipes of increased diameter - two-pipe heating with thin plastic pipes will not be able to provide independent circulation, which is associated with a large hydrostatic pressure in the system. Heating with natural circulation is simple and cheap, but you need to remember about the limited length of the circuit - it is not recommended to make it longer than 30 meters.
The scheme of a two-pipe heating system with forced circulation involves the use of a circulation pump. It is installed next to the heating boiler and provides a quick run of the coolant through the pipes. Due to this, the warm-up time is reduced, the length of the heating circuit is increased, and the distribution of thermal energy is noticeably improved. A two-pipe heating scheme with forced circulation allows you to heat buildings of any number of storeys - you just need to choose a productive pump.
Disadvantages of two-pipe heating systems with circulation pumps:
- Rise in the cost of installation - a good pump is expensive, while buying a cheap one does not make sense due to its reduced service life;
- Possible noises - cheap pumps sooner or later begin to vibrate, the sounds from their work are carried through the pipes even to the farthest rooms. The higher the speed of rotation of the pump shaft, the stronger the noise;
- Energy dependence of the heating system - when the power is turned off, the circulation of the coolant stops.
For the correct operation of a two-pipe heating system with a circulation pump, it is necessary to provide a backup power supply, otherwise the heating boiler may break down.
It should be noted that cheap circulation pumps are noisy even at the very beginning of operation. The increased noise level is most noticeable in heating with metal pipes. And if any section of the pipe gets into resonance, the sound will only increase.
You should also pay attention to the method of laying pipes - in two-pipe heating systems with natural circulation, a slope is provided, which ensures the normal movement of the coolant. In circuits with forced circulation, no slopes are needed. For the same reason, pipes can be bent as many times as you like, bypassing obstacles - in circuits with natural movement of the coolant, the pipes should be as straight as possible so as not to create excessive hydrodynamic resistance.
Open and closed schemes
An open-type two-pipe heating scheme involves the use of a traditional expansion tank, which is mounted at the highest point of the circuit. The pressure here is minimal, the coolant is in contact with the atmosphere. In case of excessive expansion, the water goes into a special branch pipe that extends from the tank. The undoubted advantage of open circuits is the ease of air removal - it exits through the expansion tank on its own. Only now, together with the departure of air, the evaporation of the coolant is observed, so its level must be constantly monitored.
With insufficient water in open two-pipe heating systems, water gurgling is heard in the radiators.
Closed heating systems include sealed expansion tanks of membrane type. The coolant circulates here in a closed space, so it has nowhere to evaporate. If necessary, antifreeze ethylene glycol can be poured here. In order to prevent airing of the circuit, air vents are placed in it - automatic or manual.
In closed heating systems, a circulation pump is required, while in open ones, its presence is not mandatory.
Vertical and horizontal two-pipe heating systems
A two-pipe horizontal heating system is relevant in one-story houses. Two pipes are laid across the premises, parallel to which radiators are connected. If a household or building includes 2-3 floors, then a separate horizontal circuit is created on each floor, connected to vertical risers. Such a connection scheme ensures uniform distribution of the coolant over all floors and rooms.
Vertical systems are most often mounted in apartment buildings. Two vertical pipes are mounted here from the upper to the lower floor. Hot coolant is supplied through one, and through the other it goes back to the boiler room. Radiators are connected to both pipes. Most often, the scheme looks like this, that separate risers serve all the radiators in the kitchens, others - in the bedrooms, halls and other rooms.
Also, mixed systems are laid in buildings, which include both vertical and horizontal sections.
Top and bottom wiring
There are two-pipe heating systems with upper and lower piping. The upper wiring implies that the coolant first rises to the highest point of the circuit, and from there it is distributed over separate vertical sections. Two-pipe heating with bottom wiring provides that both pipes pass below (near the floor or under it), and branches go up from them, to radiators and individual radiator cascades.
The upper wiring is focused on the creation of two-pipe heating systems with independent movement of the coolant. The pipe from the boiler rises to the upper point of the system, from where the horizontal section begins - it is made at a slope. A similar slope is made in the return pipe so that the coolant flows independently towards the boiler, obeying the pressure in the circuit and gravity.
The second scheme (bottom) is optimal where you need to hide all the pipes. In this case, a two-pipe heating system with a lower polypropylene wiring is hidden in the floors or behind the ceilings, only radiators and convectors are visible in the rooms.
Connecting radiators
We introduced you to the main varieties of two-pipe heating systems. Now you know that the coolant is supplied here through one pipe and removed through the other. This ensures uniform heat distribution even in the largest buildings. Let's see how best we can connect the radiators. There are three possible connection schemes:
- Lateral connection - the supply and return pipes approach the heater from the side. Accordingly, the areas located on only one edge will be as warm as possible;
- Bottom connection - the supply and return pipes go to the lower edges of radiators and convectors. Heat losses in such a scheme will be maximum, since the coolant tends to pass through the internal volume "through", along the most direct section;
- Diagonal - the most optimal connection scheme, providing uniform heat distribution throughout the internal volume of radiators. For example, the supply pipe goes to the upper left inlet, and the outlet pipe goes to the lower right (or vice versa). In this case, the coolant will heat the entire area of \u200b\u200bheaters as evenly as possible.
The choice of a suitable scheme depends on the design of the heating system and the number of sections in the radiators. When creating two-pipe heating, we recommend making a choice in favor of a diagonal and lateral connection.
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