Comfortable life in the house depends on the efficiency of the heating system. Home heating is associated with the use of open fire devices, which reduces the oxygen content in the atmosphere inside the house. Vicious circle? Not at all. The problem is solved by using coaxial chimneys for the removal of combustion products. What is it and how to build it yourself?
What is a coaxial chimney
An autonomous home heating system for any device requires the complete removal of combustion products. Traditional chimney systems are still used today. However, they are being replaced by new devices that solve several problems at the same time - coaxial chimneys.
Their appearance is associated with the solution of the problem of fuel combustion in the furnace, which occurs with the participation of oxygen from the heated room. If you do not renew concentration by airing, the room becomes stuffy and uncomfortable. The conclusion is obvious - isolate the fuel combustion device (boiler) and supply oxygen to the furnace from the outside. To do this, two-layer pipes were used, in which combustion products are removed internally, along the gap between the internal and external air from the street.
Coaxial chimney device
Advantages of coaxial chimneys
They are as follows:
- Increased efficiency of boiler equipment compared to traditional devices, obtained by supplying heated air with a normal oxygen content to the boiler furnace. This contributes to a more complete combustion of the fuel;
- there is no need for additional supply ventilation in the room;
- increased environmental friendliness obtained by efficient fuel combustion;
Flaws
These include the tendency of the inner pipe to freeze. This is made possible by the low flue gas temperature already at the furnace outlet. As a result, condensate is formed, which freezes when the outside temperature is below -15 degrees, which is not at all a wonder for Russia. The degree of freezing can completely block the channels for the movement of gases and air, which means an emergency.
Attention! It is impossible to allow complete freezing of the pipe, this causes the equipment of the boiler to fail.
As practice shows, such phenomena often arise from the desire to maximize the efficiency of the system by reducing the diameter of the internal chimney pipe, which leads to a decrease in gas temperature down to the “dew point”, increased condensation and, accordingly, to the formation of ice.
Kinds
Devices for removing combustion products of this type are divided according to several criteria.
Indoor and outdoor systems
Internal systems are located in mines specially arranged during the construction of the house. They are in no way in contact with the living space. In some cases, such devices are arranged in a standard brick chimney, but it should be noted that such chimneys are inconvenient for maintenance and repair.
Ways to install a chimney in a house
External chimney systems are arranged directly on the wall of the house from the outside. It is believed that they spoil the design of the house, so they are located with access to the patio. Such a scheme of the device is easy to install and convenient to maintain and repair.
Conclusion of the coaxial chimney through the wall of the building
Cold and insulated devices
As noted above, in the conditions of our harsh winters, the chimney freezes through. To avoid this effect, it is necessary to insulate the chimney. For this, several methods are used:
- Using an additional casing from a pipe of a larger diameter. In this case, the gap between the outer pipe and the casing is filled with insulation. For this, mineral wool is used;
- The outer pipe of the coaxial system is wrapped in a roll insulation. Wrap a protective aluminum foil jacket over this layer and secure it with clamps. The winding direction should be carried out in such a way that moisture does not flow inside the insulation layer, that is, it should be done from the bottom up.
Vertical or horizontal output
Initially, coaxial designs were developed as exclusively horizontal devices. But this is a theory, but in practice the location of the thermal unit becomes a decisive factor, which in some cases requires a combined design.
Vertical outlets are used only for boilers without forced draft.
Internal vertical and external combined coaxial chimney
Design and principle of operation
The coaxial piping kit includes a different number of parts, depending on the scheme of the chimney device.
The design of the coaxial chimney
The main ones are:
- adapter for connection to the combustion unit;
- elbow 90 degrees to change the direction of the pipeline;
- The pipe is coaxial straight. Structurally, it consists of two parts located one inside the other with longitudinal partitions between them;
- a coupling with a seal and a coupling clamp to strengthen the joint;
- air intake.
The principle of operation of a chimney of this design is that during the combustion of fuel, flue gases are formed that immediately rush into the pipe. The resulting low pressure zone is filled with outside air through the channel between the pipe walls. Warming along the way from the inner pipe, it enters the furnace and the heated oxygen actively reacts with the fuel. At the same time, the efficiency of the device increases significantly. The cooled outer wall is favorable for the fire safety of the device.
Materials and tools for chimney installation
The completeness of the chimney depends on the location of the thermal unit. The device consists of a number of standard units that allow the execution of chimneys of any configuration. The modules are modified, which makes it easy to complete the device with the necessary parts and simplifies installation work. When creating a coaxial chimney, the following nodes are used:
- straight pipes - the main element of the chimney;
- tees - performed at angles of 30, 90 and 45 degrees, designed to change direction during installation;
- couplings and bends angular - connection of pipes;
- condensate collectors - used in each vertical section, equipped with a water seal to prevent outside air from being sucked in, this reduces the draft in the chimney;
- inserts with inspection windows for repair and maintenance of the chimney;
- Inlet and outlet nozzles - come complete with heads, are used to remove furnace gases and take air from the atmosphere. The outlet nozzle is installed at a distance from the air intake to avoid mixing clean air with combustion products;
- adapter - devices for connecting the chimney to the heat generator;
- mounting fittings in the form of flanges, clamps and brackets;
The material for the manufacture of chimney elements can be:
- Steel sheet stainless.
- The sheet is galvanized.
- Heat resistant plastic.
- aluminum alloys.
The general requirement for them is resistance to temperatures not lower than 250-300 degrees.
When assembling the chimney, the simplest tool for installing fasteners, such as screwdrivers and wrenches, is used. To attach the brackets to the walls, you will need an electric drill and plastic inserts - dowels. A hole in a brick wall can be made with a bolt and a chisel.
Preparing for the installation of the chimney
Despite the seeming simplicity of the chimney assembly process, it must occur according to a certain algorithm:
- Purchase of a heat generator. It should be borne in mind that coaxial chimneys are used only with closed-type devices with forced draft. Their power is up to 30 kW.
- Determination of the installation site, fixing.
- Implementation of a draft design of the chimney, taking into account bends, rise and other features that depend on the architecture of the building.
- Acquisition of a set of standard parts that ensure the exact fulfillment of the requirements of the preliminary design.
Do-it-yourself installation of a coaxial chimney
Before proceeding with the assembly of the chimney, you need to clearly understand the main regulatory provisions:
Rules for the device for the removal of combustion products
When assembling the chimney, you must adhere to the following rules:
- The straight section crossing the wall should be installed with a slope of 3 degrees towards the street for unobstructed condensate drainage.
- The chimney channel along its entire length should not include more than two elbows.
- Inspection windows, transition devices and condensate collectors should be installed in easily accessible places for ease of use.
- The chimney must not lead below ground level. The distance to the nearest building must be at least 8 meters. When using a deflector at the end of the chimney, this distance can be reduced to two meters for a blank wall and up to five for a building with window openings.
- A horizontal chimney installed in the place of prevailing winds, opposite in direction to the smoke outlet, must be equipped with a visor - damper. It should be located no further than 40 cm from the smoke outlet.
- Coaxial chimneys located at a height of less than 1.8 meters must be equipped with a reflector grille to protect against hot smoke.
Installation of a horizontal coaxial chimney
Compliance with these rules will allow for the safe operation of the heating device with high-quality removal of combustion products.
Build Order
Installation of a horizontal coaxial chimney is carried out as follows:
- connecting the adapter from the heat generator to the chimney;
- installation on an elbow adapter to change the direction of the channel;
- Marking the place for making a hole in the wall for the corresponding diameter of the chimney pipe. Important! the joint of the pipeline elements should not be inside the wall;
- installation of decorative plugs at the intersection of the chimney with the wall;
- installation of a deflector at the end;
- installation of an inspection unit and a condensate collector.
Upon completion of the assembly, it is necessary to check the compliance of the assembled device with all the rules that were outlined above. It should be remembered! The use of sealing gels and sealants in coaxial chimneys is prohibited.
Installing a coaxial chimney vertically, as a rule, is a forced measure, due to the impossibility of horizontal execution without violating the installation rules. The design feature is that such outlets of combustion products cannot be installed in a straight line from the furnace due to the formation of a large amount of condensate. With this design, it will fall directly into the furnace, which is highly undesirable. Therefore, from the furnace you need to make a knee for the horizontal component. Next, a second elbow and a condensate collector are installed. After that, the chimney is mounted vertically. The intersection with the ceiling and roofing pie is performed using insulator cups. On the roof, the pipe is equipped with a sealing umbrella to prevent leaks.
Attention! The vertical coaxial chimney is not used for closed boilers with forced draft.
Operation features
First of all, attention should be paid to the noticeably higher efficiency of furnaces with such devices for removing combustion products. The efficiency increases due to the optimal mode of fuel combustion.
With normal heating of the dwelling, the air in it does not deteriorate, remaining clean, since oxygen from the outside air is used for combustion. There is no need for the mandatory organization of supply ventilation, although it is usually created anyway, it will not be superfluous.
Coaxial chimneys are distinguished by long-term operation, because there is no overheating of the pipes, which are constantly cooled by the flow of air.
Repair and service
The device practically does not require special maintenance. At the beginning of the heating season, you need to inspect all fasteners and ties, tighten loose connections.
A regular maintenance measure is the periodic draining of condensate from the storage tank. Moreover, the frequency of such an operation is determined by the weather that affects its formation.
The need to clean the wall of the inner pipe is determined by visual inspection through the inspection window before the start of the heating season. The procedure is performed with a special ruff equipped with hard bristles. Chemical agents are used to soften soot and soot.
Coaxial chimneys should be recognized as the most perfect for saving heating costs, which are reduced by 15–20%. This improves the living conditions in the house.
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:
- Lead through the wall (the easiest option)
- Outlet to the central chimney type LAS
- 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.
Coaxial chimneys for wall-mounted gas boilers have recently been widely used for modern heating equipment. This is an excellent solution for a private house in the absence of a chimney in it, as well as for apartment buildings that have a common riser for smoke removal.
Simplicity of design and aesthetic appearance make coaxial chimney indispensable for the correct operation of a gas wall-mounted double-circuit or single-circuit boiler. Let's take a closer look at its features, principle of operation, requirements for installation and installation of this design.
Coaxial chimney for a gas boiler: what is it and where is it used
Coaxial chimney is used for heating with forced draft. The boiler itself must be turbocharged, i.e. have a built-in fan for ejection of combustion products. The very concept of "coaxial" means coaxial, i.e. chimney "pipe in pipe". Air flows into the boiler through the outer pipe, and exhaust gases into the atmosphere through the inner pipe.
The diameter of these chimneys is usually 60/100. Its inner tube is 60 mm, and the outer tube is 100 mm. For condensing boilers chimney diameter: 80/125 mm. The material of execution is steel, painted with white heat-resistant enamel. We look at the standard equipment according to the photo scheme.
There is also such a thing as an insulated coaxial chimney. This is the same coaxial chimney, only its outer pipe is made not of metal, but of plastic. Or the second option: when the inner pipe is slightly longer than the outer one. This is done specifically so that condensation does not form on the outer pipe. This type of chimney is a little more expensive, but not much.
A coaxial chimney can be made up of several elements:
– coaxial pipes (extensions) of different lengths from 0.25 m to 2 meters;
- coaxial knee (corner) at 90 or 45 degrees;
- coaxial tee;
- a pipe tip, sometimes an umbrella;
- clamps and gaskets.
Manufacturers of coaxial chimneys for gas boilers
When buying a wall-mounted gas boiler, you will be offered to immediately buy a coaxial pipe for it. In a normal, standard situation, a coaxial kit for a horizontal smoke exhaust system is sold, which includes: a 90 degree elbow, a 750 mm extension with an outdoor tip, a crimp collar, gaskets and decorative inserts.
If you have a slightly different case, then all other parts and elements can be purchased separately. These elements are universal for almost any manufacturer of wall-mounted gas boilers.
The first element is an exception; it is either the first elbow or the first pipe from the boiler. The fact is that each manufacturer of boilers has its own characteristics of the seat. This applies to branded (native) coaxial chimneys.
But there are times when pipes are not available for a certain brand of boiler or they are very expensive. For example, a branded coaxial kit for a German boiler costs about 70 euros. In such cases, you can consider buying its counterpart.
Analogues of manufacturers of coaxial chimneys
These kits have universal seats, and the holes for mounting the starting elbow (outlet) match those of most manufacturers of gas boilers on the Russian market.
Coaxial chimney "Royal Thermo"
Coaxial chimneys of the company " Royal Thermo» suitable for , Vaillant or Navien. When buying Royal pipes, carefully look at the packaging; on it, at the end, for each brand of boiler, its own article is affixed: “Bx” - Baxi, “V” - Vaillant, “N” - Navien.
Another manufacturer on the market of coaxial pipes and elements for them is the company " Grosseto».
Their chimneys are universal and suitable for boilers of the brands Ariston, Vaillant, Wolf, Baxi, Ferroli, as well as Korean and Korea Star.
The main advantage of universal analogues of coaxial chimneys is their low price. It differs from branded kits by two or even three times.
Installation and installation requirements for a coaxial (coaxial) chimney
The coaxial chimney can be installed in three versions:
— horizontally with an output to the street;
- horizontally with an output to the mine (apartment heating);
- vertically with an output to an existing chimney.
The most common way to output a coaxial chimney is the horizontal variant with an output to the street.
Coaxial chimney to the wall
From the diagram above, we see:
1 - coaxial pipe with a tip;
2 - knee coaxial;
4 - coaxial pipe (extension);
For the correct installation of a coaxial chimney, there are a number of requirements
1. The total length of the chimney should not exceed 4 meters.
2. Only two turns are allowed, no more than two knees.
3. The minimum distance from the pipe to the section of the ceiling and walls made of non-combustible material should be 0.5 meters.
4. The horizontal section of the pipe should be made with a slight downward slope towards the street.
These must be done so that the resulting condensate does not flow into the boiler, but goes outside.
Separate chimney systems for gas boilers
Another popular way to remove combustion products from turbocharged gas wall-mounted boilers is a separate smoke exhaust system. What is it?
There are cases when, for one reason or another, it is impossible to remove a coaxial chimney. For this, a system was developed, consisting of two separate pipes: one for the emission of gases, the other for air suction into the boiler. See installation diagram.
Separate chimney for the boiler
As a rule, the diameter of such pipes is 80 mm. Execution material — steel. In some cases, the air suction pipe is replaced with a flexible aluminum corrugation, which stretches up to 3 meters.
In order to install a separate chimney on a gas boiler, you need to buy a special adapter - a channel separator. It is installed on top of the mounted boiler and converts the pipe-in-pipe outlet into a separate one, on which the pipes are then mounted.
Some manufacturers, for example, the same Navien, took care of consumers in advance, and produce wall-mounted gas boilers with an already installed system for separate pipes. This is a purely Korean version of the boilers, designated under the article "K". A boiler with such a system will have the name "Navien Deluxe-24 K", where 24 is its power in kW.
Installation of a boiler with a separate chimney system
Pipes can be displayed in 3 versions:
- both pipes in one wall;
- both pipes in different walls;
- one pipe into the wall, the second - into the existing chimney.
Which of the methods of smoke removal is suitable for your home should be decided by the design organization. According to the specifications, they draw up an individual project for each house.
It prescribes the design of the gas boiler (floor-mounted, wall-mounted), its maximum power, as well as which pipes should be installed: separate or you need to buy a coaxial chimney for a gas boiler.
The only thing they can't decide for you is the brand of the boiler. No one can force you to buy a model from a certain manufacturer. Here, the choice is yours alone. Let's watch the video.
Everyone knows that the performance of heating systems that use the principle of fuel combustion is impossible without oxygen, which supports combustion and proper removal of exhaust gases. Today, to create autonomous heating systems, various gas equipment is in great demand. It is compact and safe, easy to use, perfectly automated and does not require constant intervention of the owner in the work process.
The device and purpose of the coaxial chimney
This device looks more like a motorcycle exhaust pipe. In fact, this is a specially designed design, a pipe in a pipe with different diameters, which are inserted one inside the other and rigidly fixed to each other. Combustion products are discharged through the inner tube, and the air necessary for fuel combustion enters the combustion chamber through the space between the inner and outer tubes. A coaxial chimney for a gas boiler solves two main tasks at once: exhaust gases and air supply to the device.
Such chimneys are made of pipes of circular cross section, and the inner one is most often made of aluminum alloy, and the outer one is made of steel, with a thickness of 1; 1.5 or 2 mm. The ratio of the inner and outer diameter for wall and floor heaters is 60 to 100 mm. For condensing boilers, chimneys are used, with a diameter ratio of 80 to 125 mm.
There are two types of coaxial chimneys: horizontal and vertical. The easiest to install, and accordingly, the most common smoke exhaust system of this type is a horizontal chimney. A vertical coaxial chimney is quite difficult to install and therefore is used if horizontal installation is not possible or if there is more than 4 m from the heater to the street wall.
Advantages and disadvantages
As mentioned above, this type of smoke exhaust system is used only for gas equipment with a closed combustion chamber, namely:
- Double-circuit heating boilers for wall and floor arrangement with a closed combustion chamber.
- Gas water heaters.
- Generators and convectors.
The main advantages of such an air intake and smoke exhaust system are:
- Safety. In such a chimney system, heat exchange occurs between outdoor air and exhaust gases, as a result of which the temperature of the combustion products decreases.
- Heating the air coming from the street by contacting it through the pipe wall significantly increases the efficiency of the boiler.
- The coaxial chimney draws outside air, and not from the room, so that no vacuum is created, which prevents the normal operation of the boiler and the natural circulation of air in the room.
- Easy installation and a large number of accessories.
- Significant savings in interior space.
- Oxygen from the room is not used.
The most attractive for the use of chimneys of this type are apartment buildings, since the emission of carbon monoxide and fuel combustion products is not carried out into the ventilation shaft, but directly into the atmosphere.
Such chimneys also have disadvantages, namely: rather expensive insulation to prevent freezing of the chimney cap. The possibility of freezing of the pipe head is quite high. This happens because the temperature of the outgoing gases is too low and is not able to melt the ice formed during the exit of moist air. The consequences of icing can be quite serious: repairs to burners, combustion chambers and turbocharging.
Mounting diagrams and installation requirements
As mentioned above, there are two main installation schemes for a coaxial chimney: vertical and horizontal. During installation, one should adhere to certain rules for installing a coaxial chimney, regulated by SNiP 2.04.08–87; SNiP 2.04.05–91.3, as well as a set of "Safety Rules in the gas industry".
The total length of the coaxial chimney cannot exceed 4 m.
With vertical installation, the chimney passes through the ceiling and roof. In order to install the system in a vertical position, a special adapter is used. 
It should be noted that such an adapter is not a universal device and each manufacturer produces this device strictly for its equipment. To achieve the required length of the chimney, special extensions are used.
To ensure tightness during the passage of the chimney through the roof and protect it from precipitation, a device called a terminal is used.
When installing a vertical smoke exhaust system, one should be guided by the rules that regulate its height, depending on the location in relation to the ridge of the pitched roof. 
Most often, a vertical coaxial chimney is mounted in private homes. But there is another option for a vertical smoke exhaust system - a collective one, which is designed for apartment buildings. A common coaxial chimney in an apartment building makes the use of individual gas heaters completely safe.
The horizontal outlet of exhaust gases is most often used for wall-mounted heating equipment. The horizontal scheme implies the output of the chimney through the outer wall to the street.
During installation, the slope of the chimney of 2-3° should be taken into account to prevent condensate from entering the boiler.
Two types of fixtures are used to pass through the wall: basic or horizontal. The only difference between these kits is the adapter for connecting to the heating device. If, when passing through a wall, it is necessary to go around a beam, reinforcement, etc., then special bends and elbows are used.
Self-assembly
Installing a coaxial chimney with your own hands is quite simple and any home craftsman with basic skills in using power tools can do this work. 
To perform the work, you will need a kit that includes: a pipe with a flange, a clamp, an adapter for connecting to a boiler unit and a coaxial elbow. If necessary, you should purchase a special extension of the coaxial chimney.
- Make a hole in the outer wall at the desired location. It should be noted that the chimney outlet should not be located closer than 0.6 m to the window.
- Connect the adapter to the boiler.
- To it, using a crimp collar, connect directly the chimney. If you want to bring the structure to the wall, then use the knee. Secure everything with zip ties.
- Lead the pipe through the hole, providing a slope towards the outlet of 2-3 °.
- Seal the gaps with mounting foam or mineral wool.
- Close the pipe outlet with a decorative overlay.
It should be noted that with each turn of the chimney by 90 °, the maximum length of the coaxial chimney decreases by 0.5 m.
Coaxial - this word means the presence of one object in another. The coaxial chimney for wall-mounted gas boilers is built according to the "pipe in pipe" system. . The chimney is a double-circuit design, in which a pipe with a smaller diameter is located in a pipe with a larger cross section. Inside the pipes are interconnected only with the help of jumpers that do not allow them to come into contact.
Coaxial chimneys are used for heat generators with closed combustion chambers. Such heat generators can be not only gas boilers, but also convectors, radiators and others.
The coaxial chimney for a gas boiler performs 2 functions at once: it removes the products of combustion to the outside and provides an influx of fresh air, which is necessary to maintain the process of gas combustion in the chamber.
As a rule, for boilers that have a closed combustion chamber, the length of the chimney does not exceed two meters. It is worth noting that often the chimney is laid simply through the wall to the street. Very rarely, but you can find a vertical coaxial chimney brought out into the street through the ceiling and roof.
Advice! When installing a coaxial chimney, you should try to ensure that the pipes have only a horizontal orientation.
If the place in the wall where the chimney is supposed to be brought out is located next to the window, then it is better to bring the chimney out just above the roof. In this case, you will definitely have to collect a vertical section of the chimney.
The standard set of coaxial chimney for wall-mounted boilers contains the following components:
- straight pipes;
- tee;
- cleaning;
- condensate collector;
- upper tip of the chimney;
- knee (turning angle is 90 °).
Straight pipes are a direct chimney shaper. The elbow is intended for connection between the horizontal part of the chimney and the vertical part, as well as for connecting the horizontal chimney with a gas boiler.
If the chimney has only a horizontal orientation, then the kit includes the following elements:
- a set of straight pipes;
- knee (turn angle 90°);
- side chimney cap.
At the moment, the industry offers coaxial chimneys for gas boilers in the following range:
- chimneys made of stainless acid-resistant steel;
- chimneys for gas boilers made of stainless steel;
- coaxial chimneys for gas boilers made of galvanized steel.
In addition, it is worth considering that there are chimneys that have various combinations, that is, the outer and inner pipes can be made of different steel.
Advantages of coaxial chimneys
The first and main advantage of coaxial chimneys is that the air to support the combustion process is taken not from the room, but from outside. A conventional stove takes oxygen from the room where it is installed, so it often has to be ventilated to get rid of the lack of fresh air.
The principle of operation of the coaxial chimney is slightly different (see). The combustion product enters the inner pipe, but fresh air flows through the outer pipe.
This design solves several problems at once that are typical for conventional heaters and chimneys:
- The air that enters from the outside comes already hot, since it is heated by the inner pipe due to the passage of highly heated combustion products through it. This significantly reduces heat losses, and, as a result, increases the efficiency of the entire heating system.
- Higher efficiency leads to the fact that natural gas is burned completely. This contributes to the fact that particles of unburned fuel are not emitted into the atmosphere, this increases the environmental friendliness of the boiler.
- Equally important is the fact that the inner pipe, transferring part of its heat to the outer one, becomes not so hot. it reduces the risk of fire at the point of contact between the pipe and flammable parts of the room (wallpaper, wood paneling, etc.).
- All heating processes, from the moment the clean air enters to the moment the combustion products are removed, take place in a closed space - the combustion chamber. it makes it more comfortable for the person, since there is no need to take care of additional ventilation of the room into which smoke and carbon monoxide could enter, that is, maximum safety is ensured;
- The presence of a large range of pipe sizes - both external and internal, contributes to the fact that it is possible to choose a coaxial chimney for a gas boiler of any power.
- Small size, which is largely saves indoor space.
The advantages include the most simple installation. If a lot of difficulties arise during the installation of a conventional chimney pipe, then the installation of a coaxial chimney can be done independently. You can also talk about the relative ease of operation and maintenance of such a heating system.
Installation of coaxial chimneys
All the advantages that distinguish a coaxial chimney for a gas boiler, including safety and environmental friendliness, can be reduced to zero. This situation occurs when an incorrect installation of the coaxial chimney was performed.
Advice! Before you start installing a coaxial chimney, you should make sure that you have all the necessary elements of the chimney itself, as well as tools and other materials.
In order to carry out the installation of the chimney, it is required:
- coaxial pipe or several pipes;
- flue pipe;
- connecting adapter;
- lining on the walls - 2 pieces;
- flange for pads;
- connecting clamp;
- pipe tip.
The chimney is attached to the branch pipe of the heating installation and goes outside the room. If there are any obstructions, it is best to remove them before removing the chimney. In addition, if possible, flammable substances and objects should be removed from the pipe at a safe distance.
In any case, the installation begins with the choice of location. It is easier to do this when you have already decided on the choice of a place for installation for the boiler itself. It is better to mount gas boilers with a coaxial chimney together. The best option would be if the distance from the chimney to the boiler is approximately 1–1.5 m. If necessary, the length of the chimney can be increased, but so that there are no more than 2 elbows in total, and the maximum length is 3m.
The smoke channel opening should be located in compliance with certain rules:
- distance from the ground - at least 2 meters;
- minimum distance from the door and windows - at least 50 cm
Further, as already noted, you need to remove everything superfluous from the chosen place to a safe distance. After that, you can begin installation by starting to drill a hole of the desired diameter, which can vary from 11 before 12.5 cm.
Next, the pipe is connected to the outlet neck of the heating installation using a clamp, which is clamped with bolts on both sides. After that, the installation of the chimney of the required configuration is carried out. All connections are made with clamps. The chimney leaving the room should have a slight slope so that moisture (condensate) can easily be removed by itself.
After the chimney is installed, decorative overlays are installed, which perform only an aesthetic function.
Insulation of coaxial chimneys
Sometimes there is such a problem that coaxial chimneys for gas boilers freeze.
A simple solution seems to be just warming it (see). However, this does not help. It is for this reason that the insulation of coaxial chimneys is not practiced. The only way out of this situation is to reduce the size of the chimney itself.
If the tip freezes due to the fact that condensate enters the air intake pipe from the pipe with combustion products, then the length of the inner pipe must be reduced relative to the outer one.
The best option would be to install 2 separate pipes, the insulation of which has a much greater effect than the insulation of a coaxial chimney.
