Two-pipe wiring of the heating system: classification, types and types. Top and bottom wiring

The most popular, despite the presence of innovative technologies, remains the "classic" heating system. That is, hot water (or some other liquid coolant) in the boiler room and its further transfer through the system of laid pipelines to the premises for heat exchange. The type of heat generator can be different (gas boiler, electric, solid or liquid fuel, or even a furnace with a water circuit), but general principle work remains the same.

It is characterized by a sufficiently high efficiency, the ability to create the most comfortable microclimate, is simple and understandable in operation, and with proper design and installation, it can be very well adjusted.

But with all the external similarity of the applied water systems, they can differ quite significantly in design, use different principles for transporting the coolant through radiators installed in the premises. The subject of our discussion today is two pipe system heating a private house, which, with the existing shortcomings, can still be considered the best option.

If we describe the principle of operation of any "water" heating system, so to speak, in a nutshell, then it is as follows.

• In the boiler, due to one or another external energy source, water or another heat carrier is heated to a certain temperature level.
• Any system is a closed loop of pipes through which the coolant is transferred to heat exchange devices (radiators or convectors) and returned back to the boiler room. Thus, the water gives off heat to the premises, gradually cooling down at the same time.
• The cooled coolant enters the boiler room again, warms up - and so the cycle repeats further and further while the boiler is working. In a well-established autonomous system, by the way, the boiler does not heat up all the time - when the required level of heating in the premises is reached, its operation is suspended automatically, and the reverse switch-on will occur when the temperature drops to some predetermined threshold.

This principle of operation is the same for all such systems. The closure of the common circuit ensures constant circulation of water and heat transfer. But the closed circuit itself can be organized in different ways, which is the main difference between the systems.

The easiest way, of course, is to connect the supply and return pipe of the boiler (or collector, if we are talking about some selected section of the system) with one pipe, on which to place all the necessary heating radiators, as if “stringing” them on this loop closed loop. Exactly (in one form or another) set up a one-pipe system.

Indeed, it is very simple, but let's take a look at the circuit - and its main drawback will seem quite obvious.

Even those unfamiliar with the laws warmly technology, it should be completely clear to the reader that the coolant, successively passing from one heat exchange device to the next, significantly loses in temperature. This is understandable: what is a “return” for the previous radiator, for the next one it already becomes a supply. On a scale not even the most big system heating, this difference becomes very significant. That is, as you move away from the boiler room, the heating of the batteries is less and less.

In such a primitive form, as shown above, the one-pipe system, of course, is practically not used - it would be a completely mediocre performance. More often, more advanced schemes are used, which nevertheless make it possible to somehow regulate their work.

An example is the popular one-pipe system, known by the characteristic name "Leningradka". And although in it the temperature drops on the batteries are no longer so pronounced, it is impossible to completely get rid of it - all the same, a constant admixture of the cooled coolant on each of the radiators goes into the supply pipe.

Heating system "Leningradka" - advantages and disadvantages

Such a circuit organization scheme has gained wide popularity for its economy in terms of material consumption, ease of installation work. What it is, according to what principles it is created and debugged - read in a special publication of our portal.

There are, of course, many ways to minimize this negative phenomenon. So, for example, as you move away from the boiler room, the number of radiator sections is gradually increased, special thermostatic devices are installed, and pipe diameters vary in different parts of the circuit. Nevertheless, it is impossible to completely get rid of the "temperature gradient" from the radiator to the radiator. Still dependency follow heating appliances traced from the previous ones.

That's why a two-pipe heating system becomes optimal solution m. In it, such a phenomenon is excluded.

Each heat exchange device is necessarily connected with two pipes - one is supplied hot coolant, coming from the boiler room, cooled down, “sharing” its heat with the air in the room, is discharged along the other.

Please note that nowhere along the entire length of the supply pipe is the cooled coolant mixed with it. That you can talk that "temperature parity" is maintained at the inlet to any of the radiators. If there is a difference, then it is only due to the fact that slight temperature losses are possible due to heat transfer from the pipe body itself. But this point cannot be considered significant, especially since pipes with their hidden wiring are very often enclosed in thermal insulation.

In a word, the supply pipe turns into a kind of collector, from which distribution to heat exchange devices is already underway. And the second collector pipe is responsible for collecting and transporting the cooled coolant to the boiler room. And no significant dependence of the functioning of any of individual radiators from the work of others - can not be traced.

What kind Benefits characteristic of such a system?

• First of all, a uniform temperature distribution at the radiator inlets allows for very flexible control of the heating system as a whole. For each battery maybe be chosen its own thermal mode of operation, for example, by installing thermostatic regulators - depending on the type of heated room and its real need for heat supply. This does not affect the operation of other sections of the general circuit.

• Unlike a single-pipe system, there are minimal pressure losses in the circuit. This achieves a simplification of balancing all sections of the circuit, it becomes possible to use a less powerful, that is, less expensive and more economical circulation pump.
• There are no restrictions either on the length of the contours (within reasonable limits, of course), or on the number of storeys of the building, or on the complexity of wiring. That is, the system can be entered into a private house of any layout and area.
• If necessary, decommission any of the radiators - turn it off if there is no need to heat a particular room, or even dismantle it for carrying out certain preventive or repair work. This does not affect the overall performance of the system.

As you can see, the advantages already listed above are quite enough to understand all the benefits of installing a two-pipe heating system. But maybe she has some serious limitations ?

• Yes, of course, and to those in the first place can be attributed more high cost initial investment. The reason is banal, and lies already in the name itself - much more pipes will be required for such a system.
• The second drawback is inextricably linked with the first - since there are more pipes, it means that installation work is larger and more difficult during the creation of the system.

True, and here you can make a reservation. The fact is that the specifics of a two-pipe heating system often makes it possible to get by with pipes of small diameter. So the total costs, compared with single-pipe wiring with the same heat output indicators, may still differ not so frighteningly. And this - with a whole set of clear benefits!

Another disadvantage can be considered a more significant amount of coolant circulating through the pipes. This, of course, does not matter if ordinary water is used in this capacity. But in the case when the system is supposed to be filled with a special coolant-antifreeze, the difference can be felt. However, it is also not so important to neglect the advantages of a two-pipe system because of this.

What are two-pipe heating systems?

The principle of supplying the coolant to the radiators and its removal through two different pipes is common for the whole variety of such systems. But in other respects, they can be quite different.

Open and closed systems

As mentioned above, any system is a closed loop. But a prerequisite for its normal functioning is the presence of an expansion tank. This is explained simply - any liquid increases in volume when heated. Therefore, some kind of capacitance is needed, capable of "accepting" these fluctuations in volume.

An expansion tank is available in all systems. And the difference is whether it is open, vented, or sealed.

open system

Open-type heating systems once "ruled alone" - there were simply no other available options for the owner of the house. And even today, even with the possibility of other solutions, they are still very popular.

The main feature of such systems is the presence of a container installed at the highest point of the piping. A prerequisite is that the normal atmospheric pressure is maintained in the tank, that is, it does not close hermetically.

Let's go through the main elements of the system:

1 - boiler providing heating of the coolant circulating through the contours.

2 - riser (pipe) supply.

3 - open expansion tank.

4 - heat exchange devices installed in the premises (radiators or convectors).

5 - "return" line.

6 - a pump with an appropriate piping that circulates the coolant around the circuit.

What is an open expansion tank? It should be understood correctly - the name does not at all imply that it is really completely open, that is, it is not equipped with any cover. Of course, in order to protect the container from dust or debris, and in order to at least to some extent reduce the effect of liquid evaporation, as a rule, a lid is provided on it. But it does not in any way limit the direct contact of its volume with the atmosphere, that is, it is leaky.

An open-type expansion tank can be purchased ready-made, but very often home craftsmen make it on their own. For this, any container of the required capacity can be used (preferably from a material resistant to corrosion).

At the bottom of the tank there is a pipe for connecting it to the heating circuit. Branch pipes can be (optionally) provided for connection to the make-up system and to the overflow pipe - if the volume of expanded water goes beyond the established limits, the excess is discharged into the drain.

The determining condition is the location of the tank at the highest point of the system. This is due to two circumstances:

It is simply impossible to install a leaky tank below - otherwise, according to the law of communicating vessels, the coolant will pour out of it.

An open expansion tank in this position does an excellent job of air vent. All air bubbles or formed as a result of possible chemical reactions gases rise up and exit the tank to the atmosphere.

By the way, the location of the expansion tank shown in the diagram is not a dogma at all, although it is practiced most often. But other options are also possible:

a- most common option: the tank is located directly in the upper part of the vertical "accelerating" section of the supply line.

b- the connection to the expansion tank comes from the "return" line, for which a long vertical pipe is used. Sometimes such a placement is forced by the features of the system itself or even by the specifics of the structure. True, in this case, the functionality of the tank, as a gas vent, practically disappears. And you have to install additional devices on the circuit itself in its upper part and on heating radiators.

in – the tank is installed at the top of the remote supply outlet. In principle, this can be any section of the upper feed loop - the main thing is that the container should stand at the highest point.

G- let's say right away, an atypical location of the tank, similar to "a", but with a pumping unit in its immediate field.

Virtues open-type systems are the ease of installation, no need for additional complex nodes. The risk of dangerously high pressure in the system is completely eliminated.

But also shortcomings she has a lot:

• The highest point where such an expansion tank can be installed, in most cases in private housing construction, is in the attic. And this means that either the attic should be warm, or the tank itself will require high-quality thermal insulation. Otherwise, when extreme cold the water in it can freeze - and this is one step before a serious accident. In addition, you cannot dump accounts and a considerable unproductive heat leakage from the system.

On the Internet, you can find many examples when they try to install an open expansion tank indoors under the ceiling. The option is certainly possible, but not always. With the upper location of the supply pipe, the space under the ceiling may not be enough, because the volume of the tank is recommended to withstand at least 10% of the volume of the entire coolant in the heating system. Yes, and the interior of the room, such an addition, you see, will not decorate. It will be easier to purchase a closed membrane tank.

• The second obvious minus is the evaporation of the liquid, which, of course, can be minimized, but cannot be completely excluded. Even in the case of water, this will require additional hassle - controlling its level or using special automatic make-up devices. Otherwise, you can miss the moment, and the system will “air up”.

In addition, an open tank is incompatible with systems that use special antifreeze coolants. Firstly, it is wasteful, and secondly, the evaporation of many "non-freezing" is by no means harmless to the human body.

An open tank is not recommended for use even if an electrode heating boiler is installed in the system. Due to the peculiarities of the heating principle, the efficiency of the boiler directly depends on a balanced chemical composition coolant. Naturally, with constant evaporation, it will be extremely difficult to maintain the optimal composition.

One more nuance. Some heat exchangers, such as bimetal radiators heating, reveal their advantages only when quite high rates coolant pressure in the system. And in the case of open tank to achieve this is simply impossible, since the pressure is balanced by the external atmospheric pressure. This should also be kept in mind.

Closed heating system

AT general scheme such a heating system also included an expansion tank, but it already has a completely different design. To put it simply, it is a sealed container, divided into two parts by an elastic partition - a membrane. One part of the tank is filled with air, with the creation of a certain overpressure, the second part is connected through a branch pipe with the heating circuit. An example diagram is shown in the illustration below:

1 - metal body of the tank.

2 - branch pipe for connection to the heating circuit.

3 - a membrane that plays the role of an elastic partition between the two chambers of the tank.

4 - chamber filled with coolant.

5 - air chamber.

6 - nipple device for preliminary pumping of the air chamber.

The heating system is completely sealed. While it is not working, the pre-created pressure in the air chamber keeps the membrane in the down position. As the coolant heats up, according to the laws of thermodynamics, the pressure in the system rises, the liquid tries to expand in volume. The only possibility for this is precisely the expansion tank. Under the action of increasing pressure, the coolant begins to squeeze the membrane upward, thereby increasing the volume of the water chamber of the tank and, accordingly, reducing the volume of air. This also increases the pressure in the air chamber.

If everything is calculated correctly, and performance characteristics expansion tank correspond to the parameters of the system, then an approximate parity of pressure in the chambers occurs. When measuring the level of heating in the system, the membrane will simply take a slightly different position in one direction or another, and the equilibrium will not be disturbed. When the heating is completely turned off, as the coolant cools down, the membrane will again return to its original lower position.

Here is an example of the same simplified scheme that we used above, but only for a closed heating system:

The numbering of the main elements and nodes of the system has been retained, only two new items have been added.

7 - membrane expansion tank.

8 - "security group".

Everything is very simple and very effective. The tank, of course, will have to be bought - its independent production is hardly reasonable. (There is a nuance - some modern models heating boilers, especially wall-mounted ones, are already equipped with it, as they say “by default”). But these additional costs seem not burdensome, and in return there are many benefits.

• In principle, there are no restrictions at all on the installation location of the membrane expansion tank. Most often it is mounted on the return line near the boiler and the pumping unit, but this is not at all a mandatory rule.

• A closed heating system allows you to perform any kind of piping, unless, of course, it uses the principle of forced circulation (this will be discussed below).
• The owner is free to use any of the possible coolants.
• In the system, it is possible to maintain the optimum value of pressure (pressure) of water in the circuits.
• The coolant does not come into contact with air, that is, it is not saturated with it, which means that corrosion processes on metal parts contours will not become more active.

A few words about shortcomings, since there are very few of them:

• If the boiler is not initially equipped with an expansion tank, you will have to purchase it yourself. However, with an open tank, the situation is about the same.
• A closed system must be completely sealed, the coolant does not come into contact with air, but gas formation processes in the boiler, pipes and radiators cannot be completely excluded. And exit like in open system, not for gases. That is, you will have to install gas vents at the highest points of the system and on radiators.
• The tightness of the system requires control. Situations vary, and sometimes failure of any level of protection can lead to a dangerous increase in pressure in the circuits. This is fraught with leaks at the connections, and even an explosive situation.

In order to combat these negative features, a closed system necessarily provides for the installation the so-called "security group".

1 - control and measuring device. This is either just a pressure gauge showing the level of coolant pressure in the system, or even combined instrument, which also shows the heating temperature at the same time.

2 - automatic air vent, which independently bleeds accumulated gases.

3 - safety valve, with a preset level of operation. That is, if the pressure reaches a possible "ceiling", the valve will release excess liquid, preventing the creation of a dangerous situation.

Very often, a security group is installed directly in the boiler room - it's easier to track the readings of the pressure gauge. Often heating boilers already have in their design a similar safety knot . True, this does not relieve the owner of the need to install air vent valves and at the top of the heating system.

The selection of the desired model of the expansion tank is subject to certain rules and is carried out on the basis of calculations. This will certainly be discussed in a series of publications dedicated specifically to the calculationsall the main elements of a two-pipe heating system.

Differences in the principle of organizing the circulation of the coolant.

For normal heat transfer, the coolant should not be static - it constantly moves along the heating circuit. And this necessary circulation can be achieved in different ways.

Two-pipe system with natural circulation of the coolant.

Not so long ago, such a system in private homes was considered almost the only possible one - it was very difficult to purchase pumping equipment. Nothing, as they say, was completely dispensed with. Many do not refuse it to this day - for its reliability and complete energy independence.

The movement of the coolant flow in this system is due to the influence of natural gravitational forces arising from the difference in density of the heated and cooled coolant. In addition, the special arrangement of the individual elements of the heating circuit also contributes to this.

The diagram below will make it easier to understand the principle:

Let's look at the top of the diagram first. The numbers on it indicate the following:

1 - heating boiler.

2 - supply pipe, and, in particular, its vertical so-called accelerating section of large diameter, usually installed directly from the boiler.

3 - heat exchange device - radiator. The diagram conventionally shows the lowest radiator in the system. It must be located in excess of the boiler. This height difference is shown by the letter h.

4 - "return" pipe.

When the coolant is heated in the boiler, the density of the liquid changes - hot water always has a density (Рgor), which is less than that of a cooled one (Rokhl). Naturally, this already gives the flow an upward direction, along the accelerating section. From the top point, all pipes are laid with a slight downward slope (depending on the diameter - from 5 to 10 mm per meter of pipe length). This is the second factor promoting natural flow.

And finally, look at the bottom of the diagram. We will discard the upper “red” section - we will leave only the “return” from the last radiator to the boiler. There is already no difference in density here - the water gave up its heat on the last battery, and with approximately the same temperature level flows towards the boiler room. But that same excess in height, which was mentioned above, does its job. Before us is nothing but ordinary communicating vessels. It is clear that any hydraulic system with a liquid of equal density and temperature will tend to equilibrium. That is, in this case - to the equality of levels in both "vessels". It turns out that such an arrangement, even if there is no slope (and it is still usually set even in this area), creates a directed flow of the coolant towards the boiler. The more significant this excess h”, the greater the naturally generated pressure. True, this height, even in the largest system, should not exceed 3 meters.

The consolidated action of all these interrelated factors creates a stable circulation in the heating circuit.

Advantages systems with natural circulation of the coolant are as follows:

• Reliability and reliability - no complex mechanisms or components are expected, and the durability of the entire system, in principle, depends solely on the condition of the circuit pipes and radiators.
• Complete independence from power supply. Naturally, no costs for the consumed electricity are expected either.
• The absence of pumping equipment is also the silent operation of the system.
• A system with natural circulation has a very useful quality of self-regulation. What does this mean? Suppose the temperature in the rooms of the house is close to optimal. The heat transfer on the radiators is not so intense, the coolant cools down less, therefore, the difference in density becomes less noticeable. This leads to a "calming down" of the flow. It got cold. The water in the batteries cools more strongly, the difference in the density of the hot and cooled coolant grows, and therefore the intensity of its circulation spontaneously increases. Thus, the system, as it were, constantly strives for the optimal temperature balance. This property greatly simplifies the adjustment of the system, so that it is often not necessary to install additional thermostatic devices in the premises.
• If there is a desire, then any system with natural circulation can be easily equipped with a pumping unit.

All this is wonderful, but also very serious shortcomings such a system is decent.

• Considerable difficulties are expected with the installation of circuits. Firstly, pipes of a fairly large diameter must be used, which makes the entire structure heavier and more expensive. And in different sections, the dimensions of the pipes must vary correctly. Secondly, the slope of the pipes must be observed, and sometimes this becomes a considerable problem due to the characteristics of the premises. Thirdly, the system will work correctly only when the coolant is supplied from the top to the radiators, that is, you will have to forget about the hidden piping.

• There are restrictions on the distance of radiators from the boiler room, when viewed in terms of. Otherwise, the hydraulic resistance of pipelines and fittings may exceed the created natural pressure of the coolant, and circulation will freeze in remote areas.
• Low pressure indicators in the pipes almost completely make it impossible to use modern thermostatic devices for precise temperature control on radiators. Underfloor heating system natural circulation impossible in principle.
• The system is rather inert. In order for it to work in “normal mode”, the boiler will need to operate initially on high power, otherwise the circulation will not work.
• The energy efficiency of such a system is not the best. Part of the generated energy is spent precisely on creating conditions for circulation. This thoroughly makes it undesirable to use natural circulation circuits if an electric boiler is installed - the losses will be too expensive.

But, nevertheless, a system with natural circulation is quite viable, and is used quite often. It was said above that it is not designed for large houses. It should be correctly understood that what is meant here is the "sprawl" of the building in terms of - the distance of the radiators from the boiler in the horizontal projection cannot be more than 25, maximum - 30 meters. Yes, and try to observe the slope at such a considerable distance!

But for a compact house, even two floors, the system is quite suitable. Practice has proven that natural circulation, without the use of any pumping equipment, will cope with the height of the accelerating section up to 10 meters. And this, you see, is a lot. Let's say, if you "give" to the floor 3 meters in height, and taking into account the location of the boiler room below the level of the radiators (for example, in the basement or basement), then for two-story house there are enough opportunities even with a margin.

An example of an open two-pipe heating system with natural circulation for a two-story house is shown in the illustration below:

The boiler is located at the lowest point of the heating system (pos.1). As already mentioned, it should be below the radiators of the first floor by an amount h. In the immediate vicinity of the boiler, a water pipe (item 2) is cut into the “return” line, which provides primary filling system or its make-up as needed - with the gradual evaporation of the coolant.

From the boiler, a large-diameter booster pipe is laid upwards. It is laid to an open expansion tank installed in the vodka room (pos. 3). In this case, the tank is made of large volume and is located approximately in the center of the building. The fact is that in the shown scheme, it performs another interesting function - it becomes like a collector, from which feed risers diverge in different directions. Radiators (pos. 4) of both the second and first floors are connected to these drains, from which, in turn, “return” pipes descend, closing on the return manifold leading to the boiler. Valves (pos. 5) are installed on each of the radiators, which allow both to block this area (for example, for maintenance and repair work), and quite accurately regulate the heat transfer of the battery.

It has already been mentioned above that it is very important correct selection pipe diameters for each section of the system. This ideally requires special calculations, although many experienced craftsmen without problems, they select the desired diameters, based on the practice of many years of work.

In this diagram, the diameters are indicated by the letters of the Latin alphabet. Pipe sections with the diameters shown are limited to the tie-in points of branches (tees) or radiators.

a- DN 65 mm

b- DN 50 mm

c- DN 32 mm

d- DN 25 mm

e - DN 20 mm

(DU - nominal diameter of the pipe).

Forced circulation heating system

With this system, detailed explanations are probably not required. The circulation of the coolant in it is ensured by the installation of a pumping unit (one or even several, if the system is highly branched and requires different pressure values ​​in its individual sections).

Installation of pumping equipment immediately gives a lot of important benefits :

• Restrictions for heating systems, caused by both the number of storeys of the building and its size, disappear. It all depends on the parameters of the installed pump.
• It becomes possible to use pipes with a much smaller diameter for mounting contours - and this is both easier to assemble and cheaper. There are no requirements for the obligatory observance of the slope of the pipes.
• Forced circulation allows a smooth commissioning of the system, without "peak" heating at the beginning of operation. Yes, and during operation, the value of the temperature of the coolant in the circuit can be maintained in a very wide range. That is, even at low heating levels, the circulation will not stop, which is quite likely in a system with a natural fluid flow. This opens up wide opportunities for fine adjustment of both the entire system as a whole and its individual sections.
• Based on the foregoing, there is no big difference in temperatures at the “return” and boiler supply pipes. And this leads to less wear of heat exchangers, prolongs the "active life" of the equipment.
• The system does not impose any restrictions either on the method of laying pipes or on the connected heat exchange devices. That is, it is quite possible to use hidden gaskets, any radiators or convectors, "warm floors" or thermal curtains.
• More stable pressure indicators of the coolant in the supply pipes allow the use of any modern thermostatic heating controllers on radiators or convectors.

There are also limitations which also needs to be kept in mind.

• Building a system, especially if it's different branching and diversity used heat exchange devices will require careful calculations for each of the sections. It is necessary to achieve complete "harmony" of the work of all circuits. This is usually achieved by installing a hydraulic switch.

What is a hydraulic arrow in a heating system?

The heating system is a complex "organism" that requires consistency in the work of all its sections. To achieve such "harmony" allows a simple, but very efficient device- which is described in detail in a separate publication of our portal.

However, it is difficult to call this a disadvantage, since any heating system must be created based on preliminary calculations.

• The main drawback is the pronounced energy dependence. That is, in case of interruptions in the power supply network, the system is paralyzed. If in the settlement where construction is being carried out, such phenomena happen quite often, you will have to think about purchasing an uninterruptible power supply.

Very often they resort to another method. The system is made "hybrid", that is, with the ability to work both with forced circulation of the coolant and with natural circulation. In this case, the pump is tied according to a special scheme using a bypass jumper. The owner has the opportunity, if necessary, to switch the direction of flow using taps - through the pump or directly through the "return" pipe.

In some pumping units even an automatic valve is provided that will independently open the passage through the straight section if the pump stops for any reason.

Useful information on circulation pumps.

In order for the heating system to work correctly and as efficiently as possible, the choice optimal model pump should be approached wisely. More about the device, about the variety of models, about calculating the required characteristics - in a special article on our portal.

Differences in two-pipe systems according to wiring diagrams

Possible differences in vertical wiring

Let's start with the vertical. If the house is planned on several levels, then either a riser system or floor wiring can be used.

• The riser system was clearly demonstrated in the diagram above. True, it shows the top feed from an open-type expansion tank. But these are particulars. Even if circulation is provided by pumping equipment, this does not change anything in principle. On the contrary, it becomes possible to apply a scheme with a lower coolant supply to the risers, which in this case become like vertical collectors.

With a small number of storeys (just for a private house, where there are rarely more than two floors), such a system shows high efficiency. The circuits extending upwards from the main collector (laid, for example, in the basement or along the floor of the first floor) do not differ in great length and branching, that is, their hydraulic calculation, and adjustment on heaters will also be easy.

It makes sense to resort to such schemes when the premises on the first and second (and more) floors are located symmetrically, that is, the radiators will be installed exactly one above the other. Otherwise, it doesn't make much sense.

A clear disadvantage is that for each group of risers you will have to punch a passage in the interfloor ceiling. These are unnecessary worries, including those for insulation, waterproofing and decorative trim, and weakening the structure. And one more obvious "minus" - vertical risers are almost impossible to place discreetly. For many owners, this factor is crucial.

• So this is how it is done very often. A vertical pair of risers (supply and "return") - only one. Getting it out of your sight is no easy task. But on each of the floors, its own horizontal piping for heating radiators is carried out.

Differences in horizontal wiring by floor

Now - about horizontal wiring diagrams for one-story construction, or within one single floor.

• First of all, the scheme may differ in the location of the supply pipe.

It can be located on top (usually under the ceiling), and in this case, the coolant is supplied to the heating radiators only from above.

Unfortunately, this approach may be the only possible one when equipping a heating system with natural circulation of the coolant. As we have seen before, the overall "direction" of the fluid flow must be from top → down. That is, it will not work to place the supply below the radiator - full circulation through it may not happen. Alas, such are the costs of this system.

No words, such an arrangement of the pipe thoroughly spoils the overall interior, since disguising it in the ceiling area is not an easy task, and there is also nowhere to go from the vertical section laid directly from it to the radiator.

In this regard, it is much more profitable bottom feed scheme, for which there are no restrictions if a circulation pump is installed in the circuit. To place such a wiring covertly - it will not be difficult. For example, it can be hidden under a decorative floor covering, and sometimes even pipes are completely filled with a screed.

In a word, it is this principle of the location of the supply and return pipes that seems to be optimal.

• Very serious differences can be in the organization of the direction of the circulation flow of the coolant.

The diagram below shows a diagram in which, on conditional three floors, three possible options for laying circuits to heating radiators are shown.

• Let's start with the conditional "first floor". Here, a dead-end wiring scheme is used, or, as it is also called differently, with a counter flow of coolant. With this approach, all heat exchange devices are divided into branches - their number may vary (two are shown in the example). In each of these branches, the supply pipe is laid to the final radiator (dead end), and the flow of the cooled coolant moves towards it through the "return" pipe.

The dead-end scheme is very popular, as it requires a minimum number of pipes and is not so difficult to install. But it also has some very serious shortcomings. So, within even one small dead-end branch with several radiators, it is necessary to use pipes of various diameters (with a gradual decrease in diameter to a dead-end battery). Besides, in without fail this dedicated circuit is to be balanced with the help of special valves in order to prevent the flow from closing through the radiator closest to the collector.

• The "second floor" shows a diagram with a passing movement of the coolant. It has another name - Tichelman's loop. For such wiring, pipes of the same diameter are used. It is claimed that this arrangement provides an equal value of pressure at the inlet to each of the radiators, which greatly simplifies the balancing of this circuit. It becomes possible to very accurately set the temperature regimes on each battery. True, the consumption of pipes during the installation of such a scheme, of course, increases.

True, many experienced craftsmen are not at all delighted with the advantages of a system with a passing movement of the coolant. Moreover, theoretical layouts are given that some of the advantages are seriously exaggerated, and the calculations show a far from so cloudless picture.

What is the conclusion from this comparison? The following tips are given:

At small sizes contour around the perimeter (if it does not exceed 30 ÷ 35 meters), the Tichelman loop will indeed become the optimal solution. That is, its advantages will be shown only on a closed loop that is very limited in total length.

It is quite suitable for large circuit sizes, but only if a very “budget” system is planned, for which there is no possibility of acquiring thermostatic devices for precise temperature control in each of the rooms. Indeed, the pressure spread at the points of entry into the batteries is small. But here the hydraulic resistance will already be very significant, pipes of increased diameter will be required, that is, there is no longer any advantage over the dead-end system in this regard. On the contrary, the complexity of installation and high flow pipes makes associated wiring seriously losing.

If the perimeter of the building (floor) exceeds 35 meters, then it will be much more profitable to split the system into several (two or more) dead-end branches. Yes, you will need to make a hydraulic calculation for each of them. But this will be justified by lower costs and lower heat losses during the transportation of the coolant. Well, for adjustment, in any case, one cannot do without thermostatic valves.

• On the conditional "third floor" - a collector or beam wiring diagram. From the common collector node (which they usually try to place closer to the geometric center of the floor), a separate “dead-end line” is laid to each of the radiators - a supply and “return” pipe.

Such a scheme allows the use of pipes of a minimum diameter, however, their consumption can be very significant. In the illustration, the wiring is shown along the walls, but in practice, the laying of individual circuits is more often carried out along the shortest distance, using hidden wiring under the floor surface.

The adjustment accuracy of each individual radiator reaches a maximum here. True, the complexity of installation with the need for subsequent finishing and the high consumption of materials still limit the widespread use of this approach to system wiring.

The first steps in the calculations - determining the total power of the heating system and the required heat transfer of radiators

Any heating system is a very complex "organism", and each of its elements must function in close connection with others. Such a "unison" is provided by accurate calculations of each of the sections.

It is simply impossible to consider all the subtleties of the calculations on the scale of one publication. It probably makes sense to collect a whole series of articles on the design of a particular section or node of two-pipe systems various varieties. And it will be in the nearest plans of the editors.

But you still need to start somewhere. And this beginning will be a preliminary calculation total power heating systems and the necessary heat transfer of radiators for each of the rooms.

On the what is the calculation?

Why are these two parameters above put together? Everything is explained simply.

It would be more correct to start planning a heating system with an estimate of the amount of heat that needs to be supplied to each of the premises of a house under construction or an existing one. This will allow you to immediately outline the number and characteristics of heat exchange devices, that is, virtually arrange radiators in rooms.

The total amount of heat energy required on a house scale (that is, the sum of all values ​​​​calculated for individual rooms) will show the required power of the boiler equipment.

Having a preliminary plan for the arrangement of radiators, you can decide on the choice of the preferred scheme of the heating system, with the features of piping in the premises. This forms the basis for hydraulic calculations, determining pipe diameters, coolant flow rates, pump characteristics, performance collector nodes etc . And so on until the very end. But the beginning, as you can see, comes precisely from the needs of each of the premises.

There is quite common the practice is to take the necessary thermal power for space heating equal to 100 W / 1 m² of area. Alas, this approach does not differ in accuracy, since it does not at all take into account the forecast of possible heat losses that will require compensation from the heating system. Therefore, we propose a different, much more detailed algorithm, which takes into account many nuances.

There is no need to be scared in advance - with our online calculator, you will not have any difficulties in performing the calculation.

Moreover, the calculator will help the reader to evaluate in advance the advantages of a particular scheme for connecting radiators to pipes, placing them on the wall. And if you plan to purchase and install collapsible batteries, then you can immediately calculate and required amount sections.

We get acquainted with the calculator, and below will be given a number of explanations for working with it.

There are several ways to heat a room with water. There is a two-pipe, one-pipe layout and two types of pipes: lower and upper. Consider a design with two pipes and wiring at the bottom.

Characteristic

The most common is precisely the two-pipe organization of heating, despite some advantages of single-pipe structures. No matter how complicated such a main line with two pipes (separately for supplying water and returning it) is, most people prefer it.

Such systems are in high-rise and apartment buildings.

Device

The elements of dual-main heating with a lower pipe insert are as follows:

• boiler and pump;
• air vent, thermostatic and safety valves, valves;
• batteries and expansion tank;
• filters, control devices, temperature and pressure sensors;
• bypasses can be used, but not required.

Advantages and disadvantages

The considered two-pipe connection scheme, when used, reveals many advantages. Firstly, the uniformity of heat distribution throughout the line and the individual supply of coolant to the radiators.

Therefore, it is possible to regulate the heating devices separately: turn on / off (you only need to close the riser), change the pressure.

AT different rooms You can set different temperatures.

Secondly, such systems do not require shutting down or draining the entire coolant in the event of a breakdown of one heater. Thirdly, the system can be installed after the construction of the lower floor and not wait until the whole house is ready. In addition, the pipeline has a smaller diameter than in a single pipe system.

There are also some disadvantages:

• more materials are required than for a single-pipe line;
• low pressure in the supply riser makes it necessary to bleed air frequently by connecting additional valves.

Comparison with other types

In the lower tie-in, the supply line is laid from below, next to the return line, therefore the coolant is directed from the bottom up along the supply risers. Both types of wiring can be designed with one or more circuits, dead-end and associated water flow in the supply pipe and return.

Natural circulation systems with a downpipe are very rarely used, since they require a large number of risers, and the point of such a tie-in of pipes is to minimize their number. With this in mind, such designs most often have forced circulation.

Roof and floors - meaning

In the upper connection, the supply line is above the level of the radiator. It is mounted in the attic, in ceiling. The heated water comes up, then - through the supply risers it evenly spreads over the batteries. Radiators must be above the return. To exclude air accumulation, a compensating tank is mounted at the topmost point (in the attic). Therefore, it is not suitable for houses with a flat roof without an attic.

The wiring from the bottom has two pipes - supply and discharge - radiators must be above them. It is very convenient for removing air congestion with Mayevsky cranes. The supply line is located in the basement, in the basement, under the floor. The supply pipeline must be higher than the return. The additional slope of the line towards the boiler minimizes air pockets.

Both wirings are most effective in a vertical configuration with the batteries mounted on different floors or levels.

Principle of operation

The main characteristic of a two-pipe system is the presence of an individual water supply line to each radiator. In this circuit, each of the batteries is equipped with two separate pipes: water inlet and outlet. The coolant flows to the batteries from the bottom up. The cooled water returns through the return risers to the return line, and through it to the boiler.

In a multi-storey building, it is appropriate to install a two-pipe structure with a vertical arrangement of the main line and a lower wiring. In this case, the temperature difference between the coolant in the supply pipe and the return pipe creates a strong pressure that increases as the floor rises. Pressure helps water move through the pipeline.

In the considered lower pipe connection, the boiler must be in a recess, since the radiators and heaters must be higher to ensure uniform delivery of water to them.

The air that accumulates is removed by Mayevsky taps or drains, they are mounted on all heating appliances. Automatic vents are also used, which are fixed on risers or special air vent lines.

Kinds

A two-pipe heating system can be of the following types:

• horizontal and vertical;
• direct-flow - the coolant flows in one direction through both pipes;
• dead end - hot and cooled water moves in different directions;
• with forced or natural circulation: the first requires a pump, the second requires a pipe slope towards the boiler.

The horizontal scheme can be with dead ends, with the associated movement of water, with a collector. She is suitable for one-story buildings with a considerable length, when it is advisable to connect the batteries to a horizontally located main pipe. Such a system is also convenient for buildings without piers, in panel-frame houses, where it is convenient to place risers on stairwell or corridor.

According to experts, the vertical scheme with forced water flow has become the most effective. It needs a pump, which is located on the return line in front of the boiler. An expansion tank is also mounted on it. Due to the pump, the pipes can be smaller than in the design with natural movement: water with its help is guaranteed to move along the entire line.

All heaters are connected to a vertical riser. This is best option for high rise buildings. Each floor is connected to the riser pipe separately. The advantage is that there are no air pockets.

Mounting

Conventionally, several stages of work can be distinguished. First, the type of heating is determined. If gas is supplied to the house, then the most ideal option there will be the installation of two boilers: one - gas, the second - spare, solid fuel or electricity.

Stages

Briefly, the installation consists of the following items:

• the supply pipe is brought up from the boiler and connected to the compensatory tank;
• a pipe of the upper line is taken out of the tank, which goes to all radiators;
• a bypass (if provided) and a pump are installed;
• a return line is drawn parallel to the supply line, it is also connected to radiators and cut into the boiler.

For a two-pipe system, the boiler is installed first, for which a mini-boiler room is created. In most cases, this is a basement (ideally, a separate room). The main requirement is good ventilation. The boiler must have free access and be located at some distance from the walls.

The floor and walls around it are lined with refractory material, and the chimney is led out into the street. If necessary, a circulation pump, a manifold for distribution, regulating, measuring instruments near the boiler.

They are installed last. They are located under the windows and are fixed with brackets. The recommended height from the floor is 10-12 cm, from the walls - 2-5 cm, from the window sills - 10 cm. The inlet and outlet of the battery is fixed by locking and regulating devices.

It is advisable to install temperature sensors - with their help, you can monitor the temperature and regulate them.

If the heating boiler is gas, then you must have the appropriate documentation and the presence of a representative gas facilities at first start.

The expansion tank is located at or above the peak point of the line. If there is an autonomous water supply, then it can be integrated with a supply tank. The slope of the supply and return pipes should be no more than 10 cm per 20 linear meters or more.

If the pipeline is at the front door, it is appropriate to divide it into two knees. Then the wiring is created from the place of the highest point of the system. The lower line of a two-pipe design should be symmetrical and parallel to the upper one.

All technological units must be equipped with taps, and it is desirable to insulate the supply pipe. The distribution tank is also desirable to be placed in an insulated room. In this case, there should be no right angles, sharp fractures, which will subsequently create resistance and air congestion. Finally, we must not forget about the pipe supports - they must be made of steel and crash every 1.2 meters.

In an autonomous heating system, a situation is often observed when radiators remote from the boiler give off less heat than those installed closer. The problem may lie not only in the long length of the highway, but also in an incorrectly drawn up scheme with a single circuit. Is it possible to make several of them and what are heating circuits, their description and balancing?

Heating circuit balancing problems

The simplest example of a competent distribution of a coolant among several consumers is the heating of a multi-storey building. If a single-circuit scheme had been used during its creation, some consumers would have been left without heat. Therefore, the building has several heating circuits. The same principle can be applied to an autonomous system of a private house or cottage.

But first you need to figure out what a heating circuit is. Imagine that a branching occurs in a certain section of the pipeline, and part of the coolant is sent through a separate circuit to another room. In this case, the length of each of the contours can be different, since the rooms in the house have unequal areas. As a result, water with varying degrees of cooling enters the common return pipe. But a big problem is the uneven distribution of heat in the house. To eliminate this, balancing the heating circuits is necessary.

This set of measures aimed at uniform distribution of the coolant, depending on the length of each branch heating system. This can be foreseen at the design stage:

• If the system has two heating circuits- their length should be approximately equal. To do this, make the division of pipelines according to the areas of each room;
• Installation of distribution manifolds. Their advantage lies in the possibility of using special elements, which automatically limit the flow of coolant. The determining indicator is the length of the heating circuit;
• The use of special devices, regulating the volume of hot water depending on the set values.

The result of the measures taken to balance the heating circuits should be a uniform temperature in all rooms of the house.

The calculation of balancing the heating circuits must be done at the design stage. It is not always possible to make modifications to an existing system.

Adjustment of a water heat-insulated floor

Most often, the problem of thermal control is encountered when designing a water-heated floor system. That is why in its scheme a collector is necessarily provided, which is responsible for this closed heating circuit.

Separate circuits are connected to each inlet and outlet branch pipe. Not always their length can be the same. Therefore, the design provides control mechanisms:

• flow meter- installed on the return pipe of the collector. It performs the function of adjusting the quantitative indicator of water depending on the length of the heating circuit;
• Temperature controllers- limit the flow of water according to the temperature indicator.

For the initially correct distribution of the coolant over a closed heating circuit, it is enough to make a simple calculation. The main indicator is the volume of each branch. The sum of these values ​​will correspond to 100%. To calculate, you need to divide the volume of each circuit and calculate the coefficient of limitation of water inflow into it.

When balancing a water heated floor with a large area, it is recommended to take into account the number of turns in each circuit. They create additional hydraulic resistance.

Collector heating system

It is much more difficult to organize a uniform distribution of the coolant in a circuit consisting of two heating circuits. Until recently, conventional tee distributors were used for this. However, they could not provide desired result- a larger volume of water passed along the path of least hydraulic resistance. The result was a significant temperature difference in the rooms.

Having found out what a circuit in heating is on the example of warm water floors, the same model was transferred to the entire system of the house. Only in this case it became possible to make separate highways for each room or group of rooms. Most often used, which, compared with the classical one, has the following advantages:

• The ability to adjust the flow rate of the coolant in each branch using flow meters. Thus, the balancing of individual heating circuits is carried out without changing the parameters of the entire system;
• If necessary, you can completely exclude heat supply to the premises. This may be necessary to save ongoing heating costs;
• The absence of a large influence of the length of the circuit in heating on the temperature regime of operation. The main thing is to install control equipment.

The disadvantage of this scheme is the large length of highways. On average, to create collector heating, 30-40% more consumables will be required than for the classic version. This increases the total amount of coolant, which increases the required power of the heating boiler.

It is not advisable to install collector heating for one-story houses area up to 120 m².

balancing valve

But what to do if initially there is a ready-made heating system, and the mechanisms described above for adjusting the circuits are absent? Then in similar closed circuits heating, you can install a balancing valve.

The closest analogue of a balancing valve is a conventional shut-off valve. But only in contrast to it, the valve mechanism provides for the possibility of automatic or manual adjustment of the flow of coolant into a specific heating circuit. For large systems choose automatic models. If it is possible to carry out manual periodic adjustment, you can install a mechanical analogue.

The principle of its operation is to limit the flow of coolant into a separate line. For this purpose, a rod is provided in the design that performs a locking function.

When choosing a particular model, you need to pay attention to the following parameters of this equipment:

• The value of the pressure of the working medium - maximum and nominal;
• Pressure difference in the return and supply pipes. This is important, since the excess coolant is redirected to the return line;
• The value of the flow rate of water in pipes;
• Rated operating temperature of the system.

These features can be taken from preliminary calculation heating, or get them empirically by simple calculations. The cost of a balancing valve directly depends on its functionality, nozzle diameter and material of manufacture. Stainless steel models operating in automatic mode have proven themselves well.

Having learned what heating circuits are and how to balance them, you can optimize the performance of the entire system. But at the same time, it is important to monitor the pressure readings in each of them so that excessive hydraulic pressure is not created.

To date, there are the most different ways organization of systems, among which heating on two wings with a pump has gained great popularity. Its device is made according to the principle of effective maintenance with minimal heat loss. The two-pipe heating system has become especially in demand in single-storey, multi-storey and private houses, the connection of which allows you to achieve all necessary conditions for a comfortable stay.

What is a two-pipe heating system

Two-pipe heating has been used more and more often in recent years, and this despite the fact that the installation of a single-pipe version is usually much cheaper. This model provides the ability to adjust the temperature in each room of a residential building according to own will, because a special control valve is provided for this. As for the one-pipe scheme, unlike the two-pipe one, its coolant, when circulating, sequentially passes absolutely all radiators.

As for the model of two pipes, here a pipe is separately supplied to each radiator, designed to inject the coolant. And the return pipeline is collected from each battery into a separate circuit, the function of which is to deliver the cooled carrier back to the flow or wall-mounted boiler. This circuit (natural / forced circulation) is called the return flow, and it has become especially popular in apartment buildings when it becomes necessary to heat all floors with a single boiler.

Advantages

Double-circuit heating, despite the higher installation cost compared to some other analogues, is suitable for objects of any configuration and number of storeys - this is a very important advantage. In addition, the coolant that enters all heating devices has an identical temperature, which makes it possible to evenly heat all rooms.

The remaining advantages of a two-pipe heating system are the possibility of installing special thermostats on radiators and the fact that a breakdown of one of the devices will in no way affect the operation of others. In addition, by installing valves on each battery, you can reduce water consumption, which is a big plus for family budget.

disadvantages

The above system has one significant disadvantage, which is that all its components and their installation are much more expensive than the organization of a single-pipe model. It turns out that not all tenants can afford it. Other disadvantages of a two-pipe heating system are the complexity of installation and the large number of pipes and special connecting elements.

Scheme of a two-pipe heating system

As mentioned above, a similar method of organizing a heating system differs from other options in a more complex architecture. Scheme double-circuit heating is a pair of closed circuits. One of them is used to supply the heated coolant to the batteries, the other is to send the spent, i.e., cooled liquid back for heating. The use of this method on a particular object depends to a greater extent on the power of the boiler.

Dead end heating system

In this embodiment, the direction of supply of heated water and return is multidirectional. A two-pipe dead-end heating system involves the installation of batteries, each of which has an identical number of sections. To balance the system with such a movement of heated water, the valve installed on the first radiator must be screwed with great force in order to close.

Associated heating system

This circuit is also called the Tichelman loop. An associated two-pipe heating system or just a ride is easier to balance and adjust, especially if the line is very long. With this method of organizing the heating system, each battery requires the installation of a needle valve or a device such as a thermostatic valve.

Horizontal heating system

There is also such a type of scheme as a two-pipe horizontal heating system, which is widely used in one- and two-story houses. It is also used in houses with a basement, where you can easily place the necessary communication networks and devices. When using this wiring, the installation of the supply pipeline can be done under the radiators or on the same level with them. But this scheme has a drawback, which is the frequent formation of air pockets. In order to get rid of them, the installation of Mayevsky cranes on each device is required.

Vertical heating system

Scheme of this type more often used in houses with 2-3 or more floors. But its organization requires the presence of a large number of pipes. It should be noted that a vertical two-pipe heating system has such a significant advantage as the ability to automatically remove air that exits through a drain valve or expansion tank. If the latter is installed in the attic, then this room must be insulated. In general, with this scheme, the temperature distribution over the heating devices is carried out evenly.

Two-pipe heating system with bottom wiring

If you decide to choose this scheme, then keep in mind that it can be collector or with radiators mounted in parallel. Scheme of a two-pipe heating system with a lower wiring of the first type: two pipelines depart from the collector to each battery, which are supply and discharge. This model with the wiring of the lower type has the following advantages:

• installation stop valves carried out in one room;
• high level efficiency;
• the possibility of installation in an unfinished object;
• overlapping and adjustment is carried out easily and simply;
• the ability to turn off the top floor if no one lives there.

Two-pipe heating system with top wiring

A closed two-pipe heating system with an upper wiring is used to a greater extent due to the fact that it is devoid of air locks and has high speed water circulation. Before making a calculation, set a filter, find a photo with detailed description scheme, it is necessary to compare the costs of this option with the benefits and take into account the following disadvantages:

• unaesthetic appearance of the premises due to open communications;
• high consumption of pipes and necessary materials;
• the appearance of problems associated with the placement of the tank;
• rooms located on the second floor warm up somewhat better;
• the impossibility of location in rooms with large footage;
• additional costs associated with decorative trim, which should hide the pipes.

Connecting heating radiators with a two-pipe system

Installation work related to the installation of double-circuit heating includes several stages. So, the connection diagram for radiators with a two-pipe system looks like in the following way:

1. At the first stage, the boiler is installed, for which a specially designated place is prepared, for example, basement.
2. Further, the installed equipment is connected to an expansion tank mounted in the attic.
3. Then, a pipe is drawn from the collector to each radiator battery to move the coolant.
4. At the next stage, pipes for heated water are again drawn from each radiator, which will give them their heat.
5. All return pipes form a single circuit, which is further connected to the boiler.

If a circulation pump is used in such a circuit system, then it is installed directly in the return circuit. The fact is that the design of the pumps consists of various cuffs and gaskets, which are made of rubber, which do not withstand high temperatures. This completes all installation work.

Video

Among the many ways of distributing heat mains around the house, the two-pipe heating system is the most common. It is practical, reliable in operation and uncomplicated in execution, especially if modern materials are used for mounting radiators and highways. If desired, an ordinary user will be able to assemble such a heating system with his own hands, without involving installers, whose performance often does not shine with quality.

General presentation and scope

Unlike single-pipe wiring, a 2-pipe heating system is aimed at supplying coolant of the same temperature to all heating devices. 2 separate pipelines are supplied to the radiators, one by one the hot coolant moves from the boiler to the batteries, and the cooled water returns back through the other. The scheme of a two-pipe heating system provides that the heaters are connected to both branches.

As a rule, the movement of water in two-pipe heating systems is carried out using a circulation pump. This allows you to make a pipeline network of any complexity and branching in order to provide heating for the most remote premises. But if necessary, the circuit is also made gravity-flowing, without the use of a pump. Large diameter pipes are used open way with a slope of at least 10 mm per 1 m of pipeline length. The two-pipe heating system of a private house has the following advantages:

• reliability in operation;
• efficiency due to the supply of water with the same temperature to the heating devices;
• versatility, which makes it possible to lay heat supply branches in an open and closed way;
• ease of balancing;
• possibility of automatic regulation by thermostatic valves;
• relative ease of installation work.

Due to the versatility of the scheme, the scope where it is possible to use two-pipe heating is very wide. These are civil buildings of any purpose and number of floors, as well as production shops and administrative buildings.

About pipe laying methods

When organizing the heating of private houses, a dead-end scheme of a two-pipe heating system is most often used. A group of radiators is connected to 2 lines in turn - from the first to the last device.

The required water flow in each radiator is ensured by pre-balancing and automatic regulation by means of radiator valves with thermal heads.

In addition to the dead-end scheme, other types of wiring are widely used:

• passing (Tichelman's loop);
• collector wiring diagram.

With associated wiring, there are no first and last radiators; this horizontal two-pipe heating system is a ring that supplies a group of heating devices with a coolant.

The battery, the first in a row on the supply line, is the last on the return pipeline. That is, the coolant in the supply and return flows only forward, and not towards each other (along the way). Due to the fact that the water in the loop travels the same distance, the two-pipe horizontal heating system with passing movement is initially hydraulically balanced.

The strength of the collector heating system with lower wiring lies in the two-pipe connection of each heater to one distribution unit - the collector. These are used in the organization of water floor heating. The laying of individual branches to each battery is carried out in a hidden way in a screed or under a wooden flooring. Regulation and balancing is carried out in one place - on the manifold, equipped with special valves and flow meters (rotameters).

In accordance with modern requirements for interior design in houses, heating with bottom wiring is most often used, which makes it possible to hide pipes in walls and floors or lead them openly over baseboards. A two-pipe heating system with an upper wiring, when the supply line is located under the ceiling or in the attic, is in demand when organizing gravity networks. Then the heated coolant rises to the ceiling directly from the boiler, and then diverges along the horizontal pipe through the batteries.

According to the working pressure in the network, the schemes are divided into 2 types:

1. Open. At the top of the system, an expansion tank is installed that communicates with the atmosphere. The pressure at this point is zero, and near the boiler it is equal to the height of the water column from the top to the bottom of the heating network.
2. Closed type heating systems. Here, the coolant is given overpressure in the amount of 1-1.2 bar, and there is no contact with the atmosphere. The closed expansion tank of the membrane type is located at the lowest point, next to the heat source.

The wiring of two-pipe systems are horizontal and vertical. With a vertical scheme, both highways turn into risers, lowering interfloor ceilings at the installation sites of heating devices. It is characteristic that the coolant is still supplied to the risers by horizontal collectors laid in the lower or upper part of the house.

Selection rules

There are some general recommendations regarding the selection of a suitable heating system:

• with an unreliable power supply at home, when the circulation pump is often turned off, there is no alternative to a two-pipe dead-end circuit with an upper wiring;
• in buildings of a small area (up to 100 m²), a dead-end or associated two-pipe heating system with a lower wiring will be appropriate;
• installation of vertical risers is done in multi-storey buildings, where the layouts of each floor are repeated and the radiators are in the same places;
• in cottages and wooden houses large area with high requirements for the interior, it is customary to arrange a collector system with laying branches under the floors.

It is impossible to foresee all possible options, there are too many of them. To choose the best one, the homeowner is advised to draw a diagram of the arrangement of batteries, power them on paper in various ways, and then perform a calculation of the cost of materials.

Before undertaking the installation of a two-pipe heating system, it is necessary to select pipes of a suitable diameter.

For stub network small house, where forced circulation of the coolant is planned, this is not difficult to do: a pipe with a diameter of 20 mm is accepted on the main line, and 16 mm for connections to radiators. In a two-story house with an area of ​​up to 150 m², the required flow rate will be provided by pipes with a diameter of 25 mm, the connections remain the same.

With a collector scheme, the connections are made with pipes of 16 mm, and the laying of lines to the collector is carried out from pipelines of 25-32 mm, depending on the floor area. In other cases, it is recommended to contact design specialists for calculation, they will help you choose the optimal scheme and dimensions of all branches.

To install home heating with your own hands, you should pick up pipes from suitable material from the list:

1. Metal-plastic pipelines. When assembling on compression fittings, no special tools are required, only wrenches. More reliable press connections are made with tongs.
2. Cross-linked polyethylene. This material is also connected by compression and press fittings, and Rehau pipes - by expanding and tightening the locking ring.
3. Polypropylene. Most cheap option, but requiring some skills in welding joints and the presence of a welding machine.
4. The corrugated stainless pipe is joined by clamp fittings.

Pipelines made of steel and copper are not considered, since not everyone can make heating out of them, skill and experience are required here. The system is assembled starting from the boiler, followed by the connection of radiators and valves.

Upon completion, the network is checked for tightness using a pressure test pump.