Two-pipe heating system with vertical risers. Which heating system to choose: one-pipe or two-pipe. Horizontal wiring system

Most of the heating systems of multi-apartment and private houses are built according to this scheme. What are its advantages and are there any disadvantages?

Can a do-it-yourself two-pipe heating system be installed?

The difference between a two-pipe heating system and a single-pipe

Let's first decide what kind of animal it is - a two-pipe heating system. That she uses exactly two pipes is easy to guess from the name; but where do they lead and why are they needed?

The fact is that in order to heat the heater with any coolant, its circulation is needed. It can be achieved in one of two ways:

One-pipe scheme (the so-called barrack type)
Double heating.

In the first case, the entire heating system is one large ring. It can be opened by heating devices, or, which is much more reasonable, they can be placed in parallel with the pipe; the main thing is that a separate supply and return pipeline does not pass through the heated room.

Rather, in this case, these functions are combined by the same pipe.

What do we gain and what do we lose in this case?

Advantage: minimal material costs.
Disadvantage: a large variation in the temperature of the coolant between the radiators at the beginning and at the end of the ring.

The second scheme - two-pipe heating - is a little more complicated and costly. Through the entire room (in the case of a multi-storey building - at least on one of its floors or in the basement) there are two pipelines - supply and return.

According to the first, the hot coolant (most often ordinary industrial water) is sent to the heaters in order to give them heat, according to the second, it returns.

Each heater (or a riser with several heaters) is placed in the gap between the supply and return.

There are two main consequences of such a connection scheme:

Disadvantage: much more pipe consumption for two pipelines instead of one.
Advantage: the ability to supply a coolant of approximately the same temperature to ALL heating devices.

Tip: for each heater in the case of a large room, it is imperative to install a control throttle.

This will allow you to even out the temperature more precisely, making it so that the flow of water from the supply to the return line on the nearby radiators will not "land" those more distant from the boiler or elevator.

Features of two-pipe heating systems in apartment buildings

In the case of apartment buildings, of course, no one puts chokes on individual risers and regulates the flow of water all the time; equalization of the temperature of the coolant at different distances from the elevator is achieved in a different way: the supply and return pipelines running through the basement (the so-called heating bed) has a much larger diameter than the heating risers.

Alas, in new houses built after the collapse of the Soviet Union and the disappearance of strict state control over construction organizations, it began to be practiced to use pipes of approximately the same diameter on risers and logs, as well as thin-walled pipes installed for welding valves and other nice signs of a new social order.

The consequence of such savings is cold radiators in apartments located at the maximum distance from the elevator unit; by a funny coincidence, these apartments are usually corner and have a common wall with the street. Pretty cold wall.

However, we digress from the topic. The two-pipe heating system in an apartment building has one more feature: for its normal functioning, water must circulate through the risers, rising and falling up and down. If something interferes with it, the riser with all the batteries remains cold.

What to do if the house heating system is running, but the radiators are at room temperature?

Make sure the valves on the riser are open.
If all the flags and lambs are in the “open” position, close one of the paired risers (of course, we are talking about a house with where both beds are in the basement) and open the reset located next to it.
If the water flows with normal pressure, there are no obstacles to the normal circulation of the riser, except for air at its upper points. Tip: Drain plenty of water until, after a long snort of the air-water mixture, a powerful and stable jet of hot water comes out. Perhaps in this case you will not need to go up to the top floor and bleed air there - circulation will be restored after launch.
If the water does not flow, try bypassing the riser in the opposite direction: perhaps a piece of scale or slag is stuck somewhere. It can be carried away by countercurrent.
If all attempts have not had an effect and the riser does not go to the discharge, most likely it will be necessary to search for a room in which repairs were made and heating appliances were changed. Here you can expect any trick: a removed and muffled radiator without a jumper, a completely cut riser with plugs at both ends, a throttle blocked for general reasons - again in the absence of a jumper ... Human stupidity truly gives an idea of infinity.

Top filling system features

Another way in which the installation of a two-pipe heating system is carried out is the so-called top filling. What is the difference? Only that the supply pipeline migrates to the attic or upper floor. A vertical pipe connects the feed filling to the elevator.

Circulation from top to bottom; the path of water from supply to return at the same height of the building is half as long; all the air is not in the jumpers of the risers in the apartments, but in a special expansion tank at the top of the supply pipeline.

The launch of such a heating system is immeasurably easier: after all, for the full operation of all heating risers, you do not need to get into every room on the top floor and bleed air there.

It is more problematic to turn off the risers if repairs are needed: after all, you need to go down to the basement and go up to the attic. Shut-off valves are located here and there.

However, the above two-pipe heating systems are still more typical for apartment buildings. What about private traders?

It’s worth starting with the fact that in private houses the 2-pipe heating system used can be radiant and sequential according to the type of connection of heating devices.

Radiation: from the collector to each heater there is its own supply and its own return.
Sequential: from a common pair of pipelines, radiators are powered by all heating devices.

The advantages of the first connection scheme boil down mainly to the fact that with such a connection, balancing of the two-pipe heating system is not required - there is no need to adjust the patency of the chokes for radiators located closer to the boiler. The temperature will be the same everywhere anyway (of course, with at least approximately the same length of the rays).

Its main drawback is the largest pipe consumption among all possible schemes. In addition, it will be simply unrealistic to stretch the piping to most of the radiators along the walls, retaining any decent appearance: they will have to be hidden under the screed during construction.

You can, of course, drag it through the basement, but remember: in private houses there are often simply no basements of sufficient height with free access there. In addition, it is somehow convenient to use the beam scheme only when building a one-story house.

What do we have in the second case?

Of course, we have left the main drawback of single-pipe heating. The temperature of the coolant in all heating devices can theoretically be the same. The key word is theoretical.

Setting up the heating system

In order for everything to work exactly the way we want, we need to set up a two-pipe heating system.

The setup procedure itself is extremely simple: you need to turn the throttles on the radiators, starting from those closest to the boiler, reducing the flow of water through them. The goal is to make sure that a decrease in the flow of water through nearby heaters increases the flow of water in distant ones.

The algorithm is simple: we slightly tighten the valve and measure the temperature on the distant heater. With a thermometer or by touch - in this case it doesn’t matter: the human hand perfectly feels the difference of five degrees, and we don’t need more accuracy.

Alas, it is impossible to give a more accurate recipe, except for “pressing and measuring”: it is an unrealistic task to calculate the exact permeability for each throttle at each coolant temperature, and then also adjust it to achieve the desired numbers.

Two points to consider when adjusting a two-pipe heating system:

It takes a long time simply because after each change in the dynamics of the coolant, the temperature distribution stabilizes for a long time.
Adjustment of the heating of a two-pipe system should be carried out BEFORE the onset of cold weather. This will prevent you from defrosting your home heating system if you miss the setting.

Tip: with a small amount of coolant, you can use non-freezing coolants - the same antifreeze or oil. This is more expensive, but you can leave the house without heating in winter, without fear for pipes and batteries.

Horizontal wiring system

With the horizontal arrangement of the supply and return pipelines, recently from its patrimony - private and low-rise buildings - it began to penetrate into multi-storey new buildings.

Apparently, this is most due to the fact that studio apartments began to gain popularity: with a large area of \u200b\u200bthe room without internal partitions, it is simply unprofitable to pull risers through the ceilings, as a 2-pipe vertical heating system implies; much easier to do horizontal wiring.

A two-pipe horizontal heating system in a typical modern house looks like this: risers from the basement pass along the porch. On each floor, tie-ins are made into the risers, which supply the coolant to the apartment through the valves and drain the waste water into the return pipeline.

Everything else is exactly like in a private house: two pipes, batteries and chokes on each of them. By the way, a horizontal heating system - two-pipe or one-pipe - is easier to repair: to dismantle and replace a pipe section, it is not necessary to violate the integrity of the ceiling; this, of course, should be written down in the merits of such a scheme.

The horizontal two-pipe heating system has one feature that follows from its design and leaves its mark on the start of heating. In order for the heater to transfer maximum heat from the coolant to the room air, it must be completely filled.

And this means that each such heating device, being in a typical case above the supply and return pipelines, must be equipped with a Mayevsky crane or any other vent in the upper part.

Tip: Mayevsky taps are very compact and aesthetic, but they are not the most convenient device for removing air from a radiator.

Where aesthetics are unimportant (for example, when heating appliances are closed with decorative grilles), it will be more convenient to install a tap with a spout up or a ball valve.

We will not add this feature to the list of shortcomings: bypassing the batteries in one apartment once a year is not a big deal.

As you might guess, a two-pipe horizontal heating system is not only a solution strictly for one-story buildings or for apartment buildings with studio apartments. For example, a two-story house with separate rooms can also be heated in the same way; you just have to make the wiring identical on both floors and bring the pipelines from the boiler to both systems.

Of course, balancing such a heating system will have to take a little more time; but this is a one-time event, and it is not difficult to experience it once in a few years.

Finally - a few definitions and just useful tips.

In the direction of water flow in pipelines, a 2-pipe heating system can be dead-end and direct-flow.

A two-pipe dead-end heating system is a system in which the coolant moves through the supply and return pipelines in opposite directions.
In a direct-flow two-pipe heating system, the direction of the current in both pipelines is the same.

In private houses, two-pipe heating systems can be used with both forced and natural circulation.

Forced circulation of the coolant is provided by a circulation pump; this quiet and low-power device is supplied, in particular, in the same housing with many electric boilers.
Natural circulation is used in small heating systems; the principle of its operation is based on the fact that hot water has a lower density and rushes up.

A two-pipe closed heating system, that is, a system with constant pressure and without both water intake and heat carrier inflow from the outside, is the most popular solution for private houses with electric boilers.

In order to transfer heat to distant rooms from a solid fuel boiler or stove, an open one and two-pipe system is quite suitable.

The project of a two-pipe heating system may include radiators of any type, registers and convectors as heating devices; underfloor heating implies a different connection method.

In order to install the heating of a two-pipe system, it is certainly better to involve specialists in the work. However, the abundance of materials on this topic on the Internet and the ease of assembling modern plumbing and heating systems using fittings and machines for makes it possible for an amateur to do this work - there would be a desire.

If you are installing a two-pipe heating system for a two-story house, when balancing the system, it is worth considering the peculiarity of the communicating floors in terms of heat distribution: all other things being equal, it will always be warmer on the second floor.

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 heat at home is a lot of work, and in order not to have to reinstall the system, it is better to understand it 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 side, it becomes clear how to make the best choice.

Single pipe heating system

It works according to the principle: through one main pipe (riser), the coolant rises to the top floor of the house (in the case of a multi-storey building); all heating devices are connected in series to the descending line. In this case, all the upper floors will be heated more intensively than the lower ones. A well-known practice in Soviet-era high-rise 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 single-pipe heating does not threaten with a large temperature contrast 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 only one line for the coolant is required. 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 among us due to the high material savings.

Disadvantages of a single-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 elements of the network;
- high hydrodynamic resistance;
- a limited number of heating devices on one riser;
- the inability to regulate the flow of coolant into individual heating devices;
- high heat losses.

Improvement of single-pipe heating systems
A technical solution has been developed that makes it possible 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 coolant supply to any individual heating device. Thanks to this, it is possible to repair and replace individual devices without completely shutting down the entire heating system. Proper connection of the bypass makes it possible to redirect the coolant flow through the riser, bypassing the replaced or repaired element. For high-quality installation of such devices, it is better to invite a specialist.

Vertical and horizontal riser layout
According to the installation scheme, single-pipe heating can be horizontal and vertical. A vertical riser is the connection of all heaters in series from top to bottom. If the batteries are connected in series to each other throughout the floor, this is a horizontal riser. The disadvantage of both connections is the air locks that occur in heating radiators and pipes due to accumulating air.

The heating system with one main riser is equipped with heating devices with improved characteristics in terms of reliability. All single pipe system devices are designed for high temperature and must withstand high pressure.

Installation technology of a single-pipe heating system
1. Installation of the boiler in the selected location. It is better to use the services of a specialist from a service center if the boiler is under warranty.
2. Installation of the main pipeline. If an improved system is being installed, then the mandatory installation of tees at the connection points of radiators and bypasses. For heating system 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 powered by 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 near the boiler.
5. Installation of radiators. They make markings for installing radiators, fix the latter with brackets. At the same time, they comply with the recommendations of instrument manufacturers on observing distances from walls, window sills, and floors.
6. The radiators are connected according to the selected scheme, installing Mayevsky taps (for airing the radiators), blocking taps, plugs.
7. Pressure testing of the system is carried out (air or water is supplied to the system under pressure to check the quality of connection of all elements of the system). Only after that, the coolant is poured into the heating system and a test run of the system is performed, 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 back. Such a system is distinguished by the presence of two branches of the pipeline. On one branch, the hot coolant is transported and distributed, on 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, there are: vertical and horizontal systems.

In a vertical system All radiators are connected to a vertical riser. Such a system allows you to connect each floor 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 somewhat higher.

Two-pipe horizontal the heating system is mainly used in one-story houses with a large area. In this system, heaters are connected to a horizontal pipeline. Risers for wiring connecting heating elements are best installed on the stairwell or in the corridor. Air congestion is bled by Mayevsky cranes.

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 radiators are above it. Below is the return line. The upper air line, which is necessarily included in the circuit, serves to remove air from the network. If the wiring is top, then the “hot” pipeline runs along the top of the building. The place for laying the pipeline is usually an insulated attic. With good pipe insulation, 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 planned to install automatic temperature controllers for heating radiators and, therefore, the possibility of controlling the temperature in each room;
- pipes in the premises are routed through 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 inserted into this system even after the main line is assembled, which is impossible with a single-pipe system;
- a two-pipe heating system is easy to extend in the vertical and horizontal direction (if you have to complete the construction of 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 the 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:
- more complex connection scheme;
- higher project cost (much more pipes are required);
- more labor-intensive installation.
But these shortcomings are very well compensated in winter, when the maximum heat accumulation occurs in the house.

Installation of a two-pipe heating system
I. Installation of a heating system with upper horizontal wiring
1. An angle fitting is mounted to the branch pipe leaving the boiler, which turns the pipe upwards.
2. Using tees and angles, mount the top line. Moreover, the tees are mounted above the batteries.
3. When the upper line is mounted, the tees are connected to the upper pipe of the battery, a shut-off valve is installed at the junction.
4. Then the lower branch of the discharge pipeline is mounted. She bypasses 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. The free end of the outlet pipe is mounted in the receiving pipe of the boiler, if necessary, a circulation pump is installed 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 mounted.

The main inconvenience of a two-pipe heating system with an upper wiring is the installation of an expansion tank outside a warm room on the ceiling. The heating system with the upper wiring also does not allow the selection of hot water for technical needs, as well as combining the expansion tank with the supply tank of the house's water supply system.

II. Installation of a heating system with lower horizontal piping
The bottom piping system replaced the two-pipe heating system with the top piping. This made it possible to place an open-type expansion tank in a warm room and an easily accessible place. It also became possible to save some pipes, combining the expansion tank and the supply tank of the house's water supply system. The compatibility of the two tanks eliminated the need to control the level of the coolant, made it possible, if necessary, to use hot water directly from the heating system.
In such a scheme, the outlet line remains at the same level, and the supply line drops to the level of the outlet line. This improves aesthetics and reduces pipe consumption. But it works only in systems with forced circulation.

Installation sequence:
1. Downward-facing elbow fittings are mounted on the boiler nozzles.
2. At floor level, two lines of pipes are mounted along the walls. One line is connected to the supply outlet of the boiler, and the second to the receiving outlet.
3. T-pieces are installed under each battery, connecting the batteries to the pipeline.
4. An expansion tank is installed at the top of the supply pipe.
5. As in the case of the upper wiring, the free end of the outlet pipe is connected to the circulation pump, and the pump is connected 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 adjustment, balancing and tuning of a two-pipe heating system. To adjust and balance the system, special pipes are used, located at the highest and lowest points of the heat pipe. Air is discharged through the upper pipe, and water is supplied or drained through the lower pipe. With the help of special taps, excess air in the batteries is bled. 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 particular battery, adjust the two-pipe heating system. The consequence of pressure redistribution is the equalization of temperatures between the first and last batteries.

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

Advantages and disadvantages

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

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

Another disadvantage of a two-tube is the impossibility of repairing radiators without stopping the system. This is inconvenient and this property can be circumvented by placing ball valves near each heater on the supply and return. By blocking them, you can remove and repair the radiator or heated towel rail. The system will continue to function indefinitely.

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

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

Classification of 2 pipe systems

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

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

Vertical and horizontal two-pipe system

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

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

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

Top and bottom wiring

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

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

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

Dead-end and associated two-pipe systems

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

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

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

Heating systems for two wings

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

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

Connecting heating radiators with a two-pipe system

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

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

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

Results

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

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

Definitions of one-pipe and two-pipe systems.

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

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

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

Single pipe heating system.

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

There are two types of OSS:

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

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

What is "Leningrad".

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

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

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

An example of the implementation of "Leningradka"

Two-pipe heating system.

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

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

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

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

Summary of the article.

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

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

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

In apartments and private houses, an integral part of comfort is the provision of heat. Mostly use water heating. Water heating comes with a single-pipe and two-pipe circuit. In the first case, the water, passing through a closed circuit, cools down greatly. Each subsequent radiator receives a colder fluid. The two-pipe system eliminates this disadvantage.

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

Advantages of two-pipe heating:

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

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

Layout of pipes of a two-pipe heating system

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

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

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

Circuit advantage:

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

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

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

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

Design description:

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

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

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

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

Accurate calculation of a two-pipe heating system

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

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

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

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

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

After the calculations, they acquire pipes of effective diameter, the required number of radiators, a boiler, fittings, squeegees, an expansion tank, a circulation pump, if such a need exists.

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

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

Work plan:

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

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

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

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

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

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