Conclusion of a coaxial pipe through a roof. Features of the use of coaxial chimneys for boilers

When installing heating boilers (except for electric boilers), it is necessary to take care of proper smoke removal and oxygen supply, necessary to maintain the combustion of the coolant. A coaxial chimney for a gas boiler can be installed together with heating boilers with a closed combustion chamber. Often the necessary equipment is initially included in the boiler itself.

Heating boilers with a closed combustion chamber can be installed in any room, they do not require the installation of a classic system for extracting waste combustion products, it is enough to install a coaxial chimney for maintenance.

The definition of "coaxial" - means coaxially, that is, it is such a chimney that consists of two component pipes, located one in the other and brought out into the street. This is a single double-circuit design of two pipes of different diameters. Inside the pipes do not come into contact with each other, thanks to special jumpers, which give the pipeline increased rigidity.

This design combines two independent channels used for specific purposes:

• The pipe of small diameter is intended for removal of products of combustion of fuel;
• A larger diameter pipe serves to take air into the combustion chamber.

Thus, it turns out that the smoke is removed from the boiler, and the air enters the boiler without connecting with each other. . The advantage of such a system is that it is securely closed and the internal air of the room does not mix with the air and smoke inside the coaxial (coaxial) chimney.

Basically, horizontal coaxial chimneys are installed, although in rare cases vertical structures can also be found.

Special Benefits

When considering the main positive qualities of coaxial chimneys, it should be noted once again that such a design may not be connected to all types of heating boilers. For the highest quality operation of such a chimney, it should be borne in mind that it must be installed with heating boilers with a closed combustion chamber on forced draft. It is the built-in fan that allows the entire smoke exhaust system to work extremely efficiently. Such boilers can be both floor-standing and wall-mounted.

The most important advantage in favor of a coaxial chimney is the simplicity of the system and the installation of the heater in any required place.

Consider in detail all the undeniable advantages:

1. Horizontal chimney. There is no need to pierce the roof to remove combustion products. The pipe is brought out through the wall or window closest to the boiler.
2. The coaxial chimney system is not connected to the indoor air. During the operation of the boiler, oxygen in the room is not burned out, and carbon monoxide gases do not enter the interior of the rooms, as is the case with the operation of conventional gas boilers.
3. The air taken from the street enters the combustion chamber heated. This is possible due to the fact that it passes between the outer pipe and the inner one, through which hot, exhausted smoke is discharged outside. This allows you to increase the efficiency of the heating boiler.
4. The coaxial chimney is easy to install, the work does not require special knowledge and major redevelopment to equip the chimney. Thanks to such smoke removal, it is possible to install a heating boiler even in an apartment.
5. The coaxial chimney has an excellent degree of protection against possible fire. This is achieved by cooling the entire system with cool outdoor air, which enters through the channel between the pipes.
6. For such a chimney there is no need to arrange a separate equipped boiler room. Any of the boilers - wall or floor, can be installed in a convenient place chosen: in the kitchen, in the basement, in the annex, in the pantry.

Important installation requirements

Installation of a heating boiler with a closed combustion chamber requires the installation of an independent heating system. Such a system can be used in individual construction, in city apartments or industrial premises.

If a decision is made to use a coaxial chimney, certain rules and regulations for safety and installation should be followed. They will allow you to carry out the chimney as correctly and reliably as possible and protect the room from exhaust gases.

Rules for installing a coaxial chimney:

1. The maximum length of the vertical outlet pipe of the coaxial chimney should be around 3 meters. Sometimes longer chimneys are found. For example, it is possible to connect coaxial chimneys 4-5 meters long to Ferolli boilers (floor-mounted).
2. The outlet of the pipe to the street is carried out horizontally through the wall, near which the boiler is located in the room. The length of the horizontal section is not more than 1 meter.
3. In the case of forced draft installation with fans, there is no need for a vertical section of the system.
4. The chimney outlet is located at a height of two or more meters above the ground and at least 1.5 m relative to the location of the boiler (above it).
5. The chimney outlet should be at a distance of half a meter from any window (side or top), door or ventilation grill.
6. The outlet of the coaxial chimney pipe under the window is not recommended. But if necessary, the location of the window above the chimney should be more than 1 meter.
7. To drain condensate, when installing a coaxial chimney, it is necessary to provide a certain slope of the pipe.

It should be noted here that the debate about the necessity and correctness of setting the pipe slope is a topic that is quite controversially interpreted and vigorously discussed on many construction forums and sites. At first glance, such a simple matter, it requires an intelligent approach and careful clarification of all the nuances. The main dispute arises over the side of the slope of the chimney. It is necessary to understand this issue in detail and note some of the nuances of installing a horizontal coaxial chimney.

Chimney slope

There are two different opinions about where the chimney slope should be installed.

In the first case, some experts are inclined to believe that it is best to make a slope from the boiler towards the street. This is quite logical, since with such a design of the system, the condensate formed during the cooling of the exhaust gas will flow out by gravity. This will prevent condensate from entering the boiler. But such a system can fully work only when there are no severe frosts on the street.

Otherwise, the condensate, not having time to drain through the pipe, simply freezes at the outlet. The resulting icicles interfere with the normal intake of air into the combustion chamber. Also, condensate can freeze not only at the outlet of a smaller pipe, but also inside the annular space of the chimney.

Here, condensate is formed due to the fact that the internal moist air, heated from a small channel, settles on a cold outer pipe. In the case when the slope is made towards the street, the condensate freezes before it leaves the pipe. Ice forms inside, the chimney ceases to function properly.

It is because of the constant freezing and ice formation during severe frosts that leading manufacturers of heating boilers recommend installing coaxial boilers with a slope towards the boiler. The issue of condensate getting into the furnace is solved very simply. To prevent this, a condensate collector is additionally installed.

Is there any point in warming

It should immediately be noted that the insulation of such a chimney does not solve the problem of freezing condensate. At first glance, it seems that you can simply insulate the outer pipe well, but even so, the prerequisites for the formation of ice inside the chimney remain. Cutting (shortening) the inner tube can help here. Naturally, all these measures are necessary only if the chimney slopes towards the street.

Attention! The instructions for the coaxial chimney indicate the maximum allowable pipe sizes. These parameters must be strictly observed - they are inextricably linked with fire safety requirements.

Installation

A coaxial chimney, unlike vertical traditional chimneys, is easy to install and does not require special skills, knowledge and devices. You must follow the instructions, be careful and adhere to safety standards. It should be noted that almost always a coaxial chimney is installed together with a heating boiler.

Installation steps:

• At the first stage, a place in the room under the boiler is determined. The floor boiler is installed on a small foot, wall models are fixed on the outer wall.
• The outlet of the chimney is marked on the same wall near which the boiler is located, at a height of more than 1.5 m above it. The diameter of the hole in the wall should be slightly larger than the outer dimension of the pipe.
• A special connecting element is installed through which the heating boiler is connected to the chimney. All turns and joints of pipes are fixed with fixing clamps.

Attention! When installing a coaxial chimney, it is strictly forbidden to use adhesive tapes, as well as sealants.

• The hole in the wall, that is, the place where the pipe passes, must be laid with non-combustible insulation.
• If forced ventilation is used in the boiler, then only a horizontal section of the chimney pipe is installed.

Attention! If it is necessary to turn the pipe, a swivel elbow is used. No more than two bends should be mounted on the entire chimney.

• The pipeline is attached to the wall with brackets: one for each joint.
• At the end (head) of the coaxial chimney, additional elements should not be installed: umbrellas, deflectors, etc.

In conclusion, it should be noted that the coaxial chimney is becoming quite popular in rooms with an autonomous heating system. Such chimneys are reliable, easy to install, have a long service life and are distinguished by modest price indicators.

The advantages of such a chimney

Mounting Features

Every person wants to be warm in his house. After all, the comfort of the whole family depends on this. Those who do not have centralized heating must take care of it themselves. In addition to installing the boiler and other components, you have to solve the issue with the chimney. Without it, the smoke from the combustion of fuel would go straight into the room. Previously, ordinary pipes were used for this. However, over time, a coaxial chimney was invented. What is this device? What is its advantage? These issues deserve special attention.

What is a coaxial chimney?

Coaxial means one object inside another. The chimney was so named because it also has one pipe built into another. Inside, they do not touch each other, but are connected by a jumper. This device is designed for gas boilers, convectors, radiators, and other devices with a closed combustion chamber. The coaxial chimney has 2 tasks:

1. provides a constant supply of air for combustion of gas in the chamber,
2. removes the combustion products.

coaxial chimney design

Its working principle is easy to understand. Air enters through the outer pipe, and harmful substances exit through the inner pipe. Usually this design is about 2 m, and it consists of the following parts:

• straight pipes - they form the channel of the chimney system itself;
• a collector for condensate - since water vapor accumulates in the pipe, it must not be allowed to enter the boiler;
• tee - used when connected to the boiler;
• knee bent 90% - this part helps to make turns in the chimney;
• cleaning - allows you to carry out routine maintenance;
• tip - protects from rain and wind.

This is the design of a standard chimney, but if its orientation is horizontal, then more often composition will be as follows:

• straight pipes,
• bent knee,
• side tip.

3 types of steel are used for the manufacture of coaxial chimneys:

1. stainless,
2. acid-resistant
3. galvanized.

In addition to these options, there are also combined designs, where parts from different steels are combined. Due to the fact that the device is made of high-quality material, it is not subject to destruction. These are the main points to be aware of when choosing a coaxial chimney.
But for it to work well, you should seriously approach the acquisition of equipment. Before buying, you will have to consider some points:

• make a detailed plan of the highway with exact dimensions,
• what type of fuel
• outside temperature,
• room isolation,
• boiler performance may affect the choice of pipe,
• product quality,
• wall thickness.

Given all this, it will be possible to select pipes of a suitable diameter, length, and so on.

The advantages of such a chimney

There are many arguments in favor of using a coaxial chimney.

• One of the most important advantages is that the oxygen necessary for burning the gas is taken from the street. Conventional boilers are fed with air from the room, so it becomes stuffy.
• Heat loss is also reduced. This is due to the fact that fresh air enters through the outer pipe, which is heated from the inner one. Therefore, this air is also warm. This design significantly reduces the heat loss of the heating line.
• Environmental friendliness of the process. Due to the fact that such a process has a high efficiency, the gas in the boiler burns completely. Because of this, there are no emissions that harm the atmosphere and humans.
• Prevents fire. Just as the outer tube heats up, the inner tube cools down. Therefore, if flammable objects come into contact with the chimney, there will not be a high temperature for ignition.
• People will not have to breathe smoke or carbon monoxide. It is unpleasant for everyone when a strong smell of smoke from the stove appears in the house. This negatively affects the human body. But, since this chimney supplies the oxygen necessary for combustion, all processes take place in a closed chamber. This means that nothing enters the room, and there is no need to breathe smoke or equip the hood.
• A large assortment. The choice of this equipment is very wide. Therefore, you can choose it for a system of any power.
• Compactness. Coaxial chimneys are small in size, so they do not take up much space from the area of ​​\u200b\u200bthe room.
• Mounting. Installation of this design is very easy.

So, from the points listed above, you can see how convenient it is to use a coaxial chimney.

Mounting Features

Speaking about the installation of this equipment, it should be remembered that there are 2 options - vertical and horizontal.

1. The vertical outlet of the pipe is used if it is not possible to mount it in the wall.
2. Horizontal installation is carried out on condition that the boiler has forced ventilation. According to the rules, the maximum length of a horizontally installed chimney should be no more than 3 m. But, before installing it, it is better to read the instructions from the manufacturer.

standard and coaxial chimney

Next, it is worth considering the basic principles of mounting this device.

• First you need to choose a place for the boiler and pipes. They must be installed at the same time. In relation to the boiler, the chimney must be 1–1.5 m higher. If there is a need, the pipe can be extended up to 3 m in height. And in relation to the ground, the structure is raised by 2 m. Also, it is necessary to maintain a distance of at least 0.5 m from windows, ventilation openings and doors. Windows located above the chimney should be at a distance of 1 m from each other. No obstacles, like walls, should be closer than 1.5 m.
• The next step is to verify the purchase. Make sure that all parts of the device are in place. Otherwise, in the middle of the installation process, you will have to run to the store for the missing element.
• Now you can start the work itself. First, a hole is drilled in the wall. Its diameter is measured by the chimney.
• The pipe is led into a hole, and then connected to the boiler using a clamp. When assembling all parts of the chimney, it is necessary to maintain an angle with respect to the ground. This is done so that condensate flows behind the building, and not into the boiler.
• The hole made is sealed with mounting foam around the chimney.
• For an aesthetic look, various nozzles are put on the joints. They can be attached with liquid nails or construction adhesive.
• If a pipe exit is made through the roof, then it is important to use insulating pipes and non-combustible insulation. Also, do not forget to leave an air gap between the ceiling and the chimney. The hole through which the pipe is led must be carefully sealed.
• The last step is to test run the system.

It is very important, when installing a chimney, to adhere to safety precautions. Since the pipes can be sharp, it is safer to work with gloves. It is possible to strengthen and seal joints exclusively with refractory materials. By adhering to these installation and safety instructions, you will be able to make a quality smoke outlet.

However, there is a problem that can still be encountered - freezing of the chimney. If you ignore this possibility, then freezing can lead to damage to the heating unit. At the moment, experts believe that the problem is in the wrong heat engineering calculation. Since the efficiency of the heating apparatus depends on how hot the supply air is, the designers reduced the diameter of the pipe for the exit of the combustion product. This increased their efficiency. However, precisely because of this, more condensate appears in the inner pipe, which subsequently freezes. To avoid this problem, it is advised to choose the correct diameter and length of the pipe.

Gas boilers with coaxial chimney

Seeing the advantages of such a chimney, many want to use it. However, for this you need to choose the right boiler, because in order to use a coaxial chimney, you need a closed combustion chamber in the boiler. For this, gas-powered devices are suitable. But is it worth buying them? How are they different from conventional boilers?

exit of the coaxial chimney from the wall of the house

Nowadays, such equipment is in great demand. What is the advantage of a gas boiler with a closed combustion chamber?

• Today, in order to install the boiler, safety requires a specially designated place. It must be properly equipped and have forced ventilation. If the house does not have such a room, then it is necessary either to make an external chimney or re-plan the house. Both of these options are unprofitable from a financial point of view. Therefore, the solution to this problem will be a boiler with a closed combustion chamber and a coaxial chimney. Thus, it can be emphasized that this equipment will significantly save money.
• You can install such a boiler anywhere in the house, regardless of ventilation. The only important condition is the distance from the window. Therefore, such a room can be an attic, a kitchen, a basement, and so on. You can't say that about many boilers.
• Chimney installation. This is another argument in favor of a gas boiler with a closed combustion chamber. To install a coaxial chimney for it, you do not need to have special skills, but just follow the instructions.
• Another advantage of such a device is its high efficiency. This point is very important in terms of fuel economy. As already mentioned above, the hot air leaving the inner pipe heats the cold air, which is sent to the boiler through the outer pipe. Due to this, energy is not spent on heating the air entering the apparatus. All heat energy is used for heat carrier.
• This process should be considered from the reverse side. The outer pipe, taking heat from the inner, cools it. Thus, all equipment does not heat up to a dangerous temperature that can lead to a fire. Other boilers with a chimney do not have such fire ratings.
• Due to the high efficiency, gas equipment also has high environmental characteristics. After all, if all the gas inside is burned, through the constant presence of oxygen in the chamber, then no harmful substances are released into the atmosphere.
• Resident safety. This is another clear advantage. Since the combustion chamber is closed, neither gas nor smoke enters the room. In addition, the risk of fire is eliminated.

It is not surprising that today this equipment is in great demand in the market.

Conclusion

What conclusion can be drawn from the above information? The coaxial chimney is a very practical and useful invention. Unlike the usual one, it performs 2 functions at the same time - the removal of combustion products, and the introduction of the air necessary for combustion into the chamber. Of these advantages, one can especially highlight high efficiency, safety for people and the atmosphere, ease of installation. This is what every person today expects from a heating system. In addition, this chimney is compatible with the most popular type of gas boiler.

A modern autonomous heating system consists of many elements. Its composition may vary depending on the type of coolant or on the method of heating it. When heating the coolant in pipeline systems or in heat exchangers with an open fire, heating furnaces operating on various types of fuel can be used. Regardless of the material of combustion - the heating boiler must provide a system for removing combustion products, or a chimney. This design can also be built in different ways. So in the presence of a gas heating system, a coaxial chimney will be a good choice, for gas boilers they are:

1. wall (vertical);
2. horizontal (insertion through the wall).

The very concept of "coaxial" involves the placement of one cylinder inside another cylinder. Thus, a coaxial chimney system for gas boilers is one pipe that is placed inside another pipe. Thus, the system will have two circuits created from a pipe of larger and smaller diameters. So that the distance between the large and small pipes remains the same throughout their entire length, they are fixed with jumpers that prevent the walls of the pipelines from touching.

Purpose of coaxial chimney system

The main area of ​​use of coaxial chimneys are heating systems with gas heating boilers equipped with closed fireboxes for fuel combustion. It can be represented by a gas boiler, convector or radiator. The two circuits of the coaxial chimney perform different functions:

• The first circuit is responsible for the removal of gas combustion products from the boiler furnace.
• The second circuit is responsible for the influx of fresh air into the furnace, which is necessary for efficient combustion.

In order to ensure efficient draft and uniform combustion of gas, boilers with closed combustion chambers must be equipped with coaxial chimney systems with a length of not exceeding 2 meters. Otherwise, turbulences will form along the pipe, which will prevent the free removal of combustion products and the flow of fresh air.

Rules for the placement of coaxial chimney systems

The short length of coaxial flue systems dictates a strict framework for their placement. The most common installation method is direct penetration through the wall to the street. More rarely, during installation, the passage of coaxial chimney systems through ceilings or through the roof is observed. The coaxial chimney pipeline works most efficiently if it has a strictly horizontal arrangement. In the event that the gas heating boiler is located in an inconvenient place for such a conclusion, it is possible to draw a conclusion through the roof using the vertical sections of the structure.

The structure of the coaxial chimney

The standard design of a coaxial chimney for gas boilers consists of the following main parts:

Straight pipes - they form the channel of the chimney system

Connecting elements (tee or swivel section) are designed to connect straight sections and connect the chimney directly to the gas boiler. The cleaning section is designed for regular routine maintenance,

A place for collecting water condensate - the products of gas combustion carry water vapor, which, as it cools, can accumulate on the walls. To prevent it from entering the combustion chamber, such a section is formed.

The upper outer section of the chimney is designed to protect the internal contours of the chimney coaxial chimney system from the effects of atmospheric conditions: snow or rain, as well as to protect against wind.

What materials are coaxial chimneys most often made of?

Industrial production of elements of coaxial chimneys for gas heating boilers is carried out from many materials:

Pipes made of stainless steel. This is perhaps the most long-lived material, but such equipment has an increased price.

Galvanized steel pipes - such devices are sold cheaper, but they are more susceptible to corrosion.

In addition, various sections of the chimney, as well as external and internal pipelines, can be made from a wide variety of materials, up to high-strength polymers.

What does the installation of a coaxial chimney give?

The most important advantage of placing a coaxial chimney for a gas heating boiler is the fact that fresh air is taken in to constantly maintain combustion in the furnace from outside the room. In this case, you will not experience discomfort due to the burning of oxygen in the room, you will not encounter excessive dryness of the air. The use of coaxial chimneys will avoid frequent ventilation of the room in which the gas boiler is located. This is especially important in cold weather, because when you ventilate through windows, you cool the air in the rooms, and for reheating, an increased consumption of heat carriers and energy is required.

In addition, the air entering the coaxial chimney circuit when moving from the street to the combustion chamber is heated, which facilitates the combustion reaction and increases the efficiency of your gas boiler. With a constant influx of fresh air heated to room temperature, the gas in the furnace of your boiler is completely burned, significantly increasing the efficiency of the entire heating system.

It is worth noting that the complete combustion of fuel also increases the environmental friendliness of the heating system - you do not pollute the surrounding air with unburned elements.

Also, the combustion products, when passing through the emission circuit, give up part of their heat to the fresh air coming from outside. This reduces the risk of fires inside the pipe in areas with accumulation of unburned particles. The coaxial pipe has an outer surface temperature much lower than a classic chimney, which reduces the fire requirements for its installation. Thus, coaxial pipes (with appropriate insulation, of course) can be carried through wooden walls or ceilings, which is impossible for a conventional steel chimney. The gas heating system with a coaxial chimney creates a completely closed fuel combustion circuit, in which oxygen for continuous combustion is taken from the outdoor air and combustion products are removed there. This creates a comfortable atmosphere in the room where the gas heating boiler is located. This is important, since gas water heaters are often located in habitable areas, such as kitchens.

Wide range of

The selection of a coaxial chimney is possible for almost any gas heating system, regardless of its power: pipes of various diameters, made from a variety of materials, are on sale. Installation of such a system is relatively simple and can be easily performed even by an untrained specialist.

Installation of a coaxial chimney

Please note that improper construction or installation of a coaxial chimney system can negate all its advantages. For proper installation, follow the step-by-step instructions:

1. Make sure you have all the necessary materials and tools. To do this, you will need a set of coaxial pipes and fittings, wall linings to form seals, and an outdoor tip.
2. Before proceeding with the installation, make a markup, calculate the path of the chimney, remove unnecessary items, make a hole of the appropriate diameter in the wall. When designing the installation, make sure that there are no flammable objects near the pipe.
3. The best choice would be the simultaneous installation of a gas heating boiler and its corresponding coaxial chimney.
4. The exit point of the chimney should be located about a meter and a half above the level of the gas combustion chamber. To achieve the optimal location, the chimney system can be extended, but installing more than two elbows in it will lead to the formation of turbulences with a sharp decrease in its efficiency.
5. The coaxial pipe is connected to the outlet pipe of the combustion chamber of the gas boiler using a clamp. It is fixed with two screws.
6. After that, we assemble the chimney system in accordance with the designed configuration.
7. Between themselves, the knees of the chimney are also fixed by means of clamps.
8. At the outlet section of the chimney, we form a slight downward slope, so that the condensed moisture is removed by gravity from the system.
9. A protective vane can be put on the upper outer part of the coaxial chimney.

We insulate the coaxial chimney

At low negative temperatures outside, some sections of the coaxial chimney may well freeze through, which adversely affects its efficient operation. In order to avoid negative moments - such areas must be insulated. It would seem that this is a reasonable solution, but the “pipe in pipe” design itself negates any insulation.” Instead, the best solution would be to reduce the cross section of the chimney system. In the event that frost is observed on the chimney head, try to make the inner pipe of the system shorter. In this case, freezing of condensate can be avoided. In extreme cases, it is practiced to install two separate steel pipes, one of which takes in air and the other removes combustion products.

Coaxial chimney for a gas boiler video

The chimney is one of the most important parts of the boiler, on which its correct operation depends. Incorrect selection of parameters and / or installation of the chimney can lead to breakage of an expensive wall-mounted or floor-standing gas boiler. Chimneys for boilers (here we will talk about boilers) are of two main types:

• separate
• coaxial

Coaxial chimneys.

Such chimneys are the most popular for wall-mounted boilers. They combine 2 pipes - one for removing exhaust gases, and the other for air flow to the boiler. It is possible to use such a "pipe" only if the boiler has a closed combustion chamber. Their length is limited to four or five meters. With a longer length, the boiler will not have enough air and it will turn off or not work optimally.

Various ways to install a coaxial chimney.

These recommendations were taken by me from the Baxi Eco Four boiler passport. For all other boilers, there may be some nuances and before installation, you must read the instructions. All possible installation options are shown in the figure below.

All possible installation options

The figure shows that there are 3 different options for coaxial chimneys:

1. Lead through the wall (the easiest option)
2. Outlet to the central chimney type LAS
3. Vertical chimney with roof outlet

The rest of the drawings are for separate chimneys, and we'll talk about them a little later.

During installation, it must be taken into account that various bends (most often at 90° and 45°) reduce the possible length of the coaxial smoke extraction system. This is due to the fact that they create additional resistance to exhaust gases:

The first outlet, which is at the outlet of the boiler, is not taken into account. For a better understanding, let's use the figure again:

Length of various coaxial chimney options

It is clear from the figure that if you need maximum length, then the number of corners must be reduced to a minimum. Now consider the LAS system, everything is absolutely the same there:

LAS chimney system

Such a system is quite exotic, but has every right to exist. I think it will be especially convenient for apartment buildings heated with natural gas.

Now consider a vertical chimney for a gas boiler. Let's look at the picture again:

Vertical coaxial chimney for gas boiler

The figure does not show a condensate collector, which must be installed. Otherwise, the burner will flood with condensate and the boiler will turn off.

Separate chimneys.

Separate chimneys are used if it is necessary to increase the length of the chimney. For some boilers, the length of separate chimneys can be up to 30 meters. The maximum length and diameter of separate chimneys may vary depending on the manufacturer. If the boiler was originally designed to install a coaxial chimney, then a special separator must be installed to switch to a separate chimney. At the end of the pipe, you can again connect using a gadget called a terminal. This gadget will reduce the maximum possible length.

Separator for coaxial chimney

Various ways to install a separate chimney.

For corners in a separate smoke exhaust system, the same rule remains as for a coaxial one:

• The 90° bend shortens the chimney by 0.5 meters.
• The 45° bend shortens the chimney by 0.25 meters.
• The first 90° bend is not taken into account.

In addition, the fence and exhaust pipes should not be on opposite sides of the building, and the total length of the supply pipe should not exceed 10 meters.

Separate chimney length
Vertical split chimney

Removal of condensate from the chimney.

During operation of the boiler, condensation is inevitable in the chimney. This condensate must be removed from the chimney, for this you can do the following:

• Install the condensate collector. In this case, the slope of the chimney pipes must be made towards the collector in the ratio of 1 cm per 1 meter of pipe
• Without installation of a condensate collector. In this case, the slope of the pipes is made away from the boiler so that the condensate itself flows out of the chimney under the action of gravity. The slope of the pipes must be at least 1 cm per 1 meter.
• For condensing gas boilers, it is necessary to provide a special condensate drain to the sewer or a special container. 1 kW of power of such a boiler produces 1 liter of condensate per day.

Summary of the article.

The simplest and cheapest chimney is coaxial, but its length is limited to 5 meters. And if you need a longer length, then you should consider using a separate smoke exhaust system. Also, we must not forget about the collection and removal of condensate from the chimney. Let's stop at this for now, if you have any questions, write them in the comments.

Living in country houses is impossible without the arrangement of the heating system, and gas heating is considered the most economical. But for gas, as well as for another type of fuel, both the influx of oxygen and the removal of combustion products are necessary. And the coaxial chimney system is recognized as the best: it can simultaneously cope with both the removal and the inflow of the gases necessary for combustion.

What are coaxial chimneys

Coaxial means internally combined, or in another way, one in the other. A coaxial chimney is a structure of two pipes, which are reinforced with jumpers that do not allow them to come into contact with each other. This arrangement of the chimney system is best suited for gas heating boilers, but it can also be used in other heating systems where the combustion chamber does not have open access.

A coaxial chimney can simultaneously supply air to a closed combustion chamber, and remove the resulting carbon dioxide to the street.

Device

Since this system needs not only an influx of oxygen, but also an autonomous removal of condensate and combustion products, it consists of several components:

• Double straight pipes for the removal of carbon dioxide;
• A small container for collecting the resulting condensate: in no case should it fall into the combustion boiler;
• Connecting triple design is used to collect all parts;
• Bent at 90 0 elbow designed for turning the chimney pipe;
• Cleaning systems: with its help, repair or maintenance work is carried out;
• Tip - it is designed to protect the system from precipitation.

Advantages and disadvantages

What are the positive characteristics of a coaxial chimney system?

• The intake of air necessary for combustion comes from the street, which does not create a stuffy environment;
• Minimum heat loss, since the air is supplied through the external pipeline, and it warms up from the internal structure;
• Meets all environmental requirements: a gas boiler has a high percentage of efficiency, and all fuel burns completely, so components harmful to nature and humans are practically not emitted into the atmosphere;
• Meets all fire safety requirements: both pipes compensate for heating and cooling, and therefore, even if they come into contact with flammable objects, ignition cannot occur;
• The compact design allows you to install in any, even a small room;
• Installation does not provide for violation of the integrity of the roof of the house.

There are very few disadvantages of such a chimney system, these include high cost and low aesthetic perception: if installed in the basement, it can slightly reduce the harmony of the room.

Kinds

The coaxial chimney system is of horizontal and vertical type, each of them can be installed under certain conditions.

Vertical. For this system, it is necessary to equip a drain on the roof of the house, and a condensate collection tank is also very necessary, but usually all the necessary set of components is already included in the chimney supply.

Horizontal. This is the most popular coaxial chimney system, because its installation is very simple: you need a hole in the wall and that's it. In addition, there is no need to equip a place for a chimney on the roof, and the collected condensate can be discharged directly, that is, there is no need to equip an additional container: it simply flows down the pipe to the street if the pipe is installed with a slight slope.

Placement of coaxial chimney systems

1. Experts recommend determining the location of the chimney system only after installing the gas combustion boiler itself.
2. Place pipes from window and door openings at a distance of at least 50 cm. To ensure the best traction, the first component pipe must be at least 1 meter long. It is fixed at the place of the boiler outlet on the branch pipe with a metal clamp.
3. If the boiler is equipped with natural exhaust, then the chimney elbow must be installed above this structure. If a fan is installed, installation can be carried out at any height.
4. Then you need to equip a hole for the pipes to exit to the street, if the house is made of wood, then you will need to install a thermal insulation layer: this will prevent a possible fire in the tree.
5. So that the resulting condensate can go through the drainage system to the street, the pipes are mounted with a downward slope.

Mounting

Fire authorities require for the arrangement of the heating system the presence of a separate room, in which ventilation is carried out and there is all the necessary equipment. This leads to unnecessary costs, you need to either rebuild an already finished house, or equip a separate chimney system.

But all this can be avoided if you purchase a gas boiler of a closed combustion type and equip a special coaxial chimney system, which will save the owner of the house money on arranging a separate smoke exhaust.

And only for these reasons, the installation of the boiler is allowed in any suitable room, even where there is no ventilation system: in the attic, in the kitchen, in the basement of the house. It is impossible to say the same about boilers with an open type of combustion.

The rules for mounting connections must be observed: they must end before the system exits the wall hole. The pipe itself must protrude from the wall by at least 20 cm, and a greater distance is allowed.

To ensure that the reverse thrust cannot be returned to the boiler, a special valve is equipped on it, which will prevent this phenomenon.

The connection of all parts of the chimney is carried out using clamps and, in some cases, insulation. Building foam can be used to achieve better sealing.

Tip: use as few vertical parts as possible: this way the efficiency of the chimney will be higher.

There are regulatory rules for self-installation of a coaxial chimney:

• For installation of the system, it is recommended to use only parts of the kit;
• Do not use self-made parts, but purchase the missing parts only at the manufacturer's service centers;
• After installing the chimney system, it must be tested for leaks;
• Docking of joints should be carried out in free, and not in wall space.

Step-by-step instruction

1. First determine the location of the gas boiler;
2. Installation of gas equipment is carried out simultaneously with the installation of a coaxial chimney system;
3. The chimney itself should be located 1.5 meters above the gas boiler itself;
4. Fulfill the fire safety requirement: arrange the chimney pipes so that there is at least 50 cm between the window, the vent and the door;
5. Make a hole for the pipe outlet in the wall in accordance with the diameter;
6. Connect the pipes to the boiler outlet with a metal clamp. Do not forget about the slope to the ground to drain condensate;
7. After installing the pipe, the hole is sealed;
8. You can try the system in test mode.

How to lengthen a coaxial chimney for a gas boiler

If gas enclosed equipment is used to heat an apartment building, it may be necessary to extend the chimney system.

For installation you will need:

• Propylene elbows;
• Additional flue pipe no more than 5 meters long;
• Adaptive device for tight connection;
• Pads for fastening to an external wall;
• Flanges and clamps.

All additional extension parts must be purchased from the chimney system manufacturer's dealers, as parts from other brands may not be compatible with equipment already purchased.

Estimated cost

The cost of a coaxial chimney largely depends on the configuration. For example, the basic kit may differ in cost depending on the diameter of the pipes. The most sought-after kit can cost from 4 thousand rubles to 13.5: which chimney pipes you need to purchase. Additional knees can cost from 1.5 to 3 thousand, a condensate collector - about 3 thousand.

If you want to buy a protective grill for the exit of the chimney, then its cost is about 3 thousand rubles.

As can be seen from our review, the coaxial chimney system is a new word in the construction of chimneys, it is completely autonomous and easy to use.