The coaxial tube is vertical. The principle of operation of a coaxial boiler. Requirements for installing a coaxial boiler.

Increasingly, in the manufacture of a smoke removal system, coaxial chimney for gas boiler. On condition correct installation, coaxial tube copes immediately with two tasks at the same time: diverts the combustion products and ensures sufficient air flow for the operation of the heating equipment.

There are several types of chimneys, different material and design, as well as various technical characteristics.

Coaxial chimney - what is it

Coaxial chimney is a simple design. In fact, these are simply two pipes of different diameters inserted one into another, so that between the walls of the outer and inner contours there is a gap of several cm.

All pipes, regardless of the design and material used, can be divided into two groups:

Collective coaxial chimneys for gas boilers are manufactured exclusively in the factory, installed during the construction of the building. To increase the characteristics of traction, have an inner layer of thermal insulation.
Individual systems - chimneys intended for domestic use and connection to a single heating appliance. Basically, plastic chimneys are used for condensing boilers, which is due to their low cost. Two-channel pipes made of stainless steel are used much less often.

The effectiveness of the smoke removal system depends to a large extent on the correct choice of the pipe. First you need to find out how the chimney works, and what kind of boilers you can put on the coaxial pipe.

How coaxial chimney works

Coaxial tube is designed for simultaneous removal of combustion products and air intake from the street. The process of circulation of gases is carried out by two channels.

The principle of the chimney is as follows:

For effective operation of the pipe, it will be required: strictly comply with SNiP on coaxial chimneys, carry out a preliminary calculation of the system, and perform the correct assembly, including the installation of safety components: condensate collector, icing preventing icing, etc.

On which boilers can be put a coaxial pipe

Chimneys of coaxial type are designed for connection to condensing and turbine boilers with a closed combustion chamber, with forced or natural system smoke removal.

The pipe is optimally suited for parapet aggregates and convectors. It is possible to install a coaxial system on a boiler with an atmospheric burner if the pipes are made of stainless steel.

A simple design significantly increases the efficiency of work gas equipment. Almost all modern models are connected to two-channel systems. The installation of steel coaxial chimneys for single-circuit and double-circuit gas boilers is allowed, regardless of the principle of operation and design of the combustion chamber.

To determine if a two-channel chimney can be installed, the parameters specified by the manufacturer in the technical documentation should be followed. Usually, it contains detailed instructions and norms, as well as the requirements for installing a smoke removal system.

Some models of condensing turbine boilers have a separate system for removing combustion products, through two separate terminals. One for removing combustion products, the other for air intake. In such modifications, the connection of the coaxial tube is not advisable.

Types of coaxial smoke exhaust pipes

Choosing a coaxial pipe for gas equipment, it should be remembered that for boilers of some brands only suitable chimneys manufactured by the same company as the unit itself are suitable. , - all these companies manufacturers produce equipment with non-standard sizes of outlet nozzles. Therefore, the use of branded component parts is considered optimal for the production of smoke removal systems.

In all other cases, the choice basically comes down to the selection of a suitable pipe material. The design of the systems is made of aluminum, stainless steel and plastic. In domestic conditions, the most popular are plastic pipes and stainless steel products.

Two-channel plastic chimneys

Plastic chimneys are made of a special heat-resistant material that can withstand a maximum heating temperature of up to 205 ° C. The pipes are connected to the condensing equipment of gas type. Advantages of plastic:

Light weight.
Low cost.
Simple installation.

As a disadvantage can be identified relatively short life of coaxial chimneys made of plastic, as well as restrictions associated with the possibility of connection to conventional gas boilers. It is allowed to use the system only in conditions of low temperature gas removal.

Coaxial stainless steel pipes

The stainless steel used in making the chimney is acid resistant and can withstand more than plastic pipe temperature, up to 550 ° С. Manufacturers offer chimneys of two designs:

When choosing a coaxial pipe, first of all they follow the recommendations of the manufacturers of heating equipment specified in the technical documentation.

Normative requirements for installing a coaxial chimney

State regulations and rules for installing a coaxial chimney for a gas-fired boiler with a closed combustion chamber are set out in SNiP 2.04.08-87 and 2.04.05-91. Design, design and installation work are carried out in accordance with regulatory documents. Failure to comply with the recommendations leads to the failure of the Gas Service to put the heating system into operation.

The regulations regulate the distance from the coaxial chimney to the window, doorways, nearby buildings. Indicate the minimum requirements associated with the manufacture of firebreaks and other safety standards. In particular, the SNiP stipulates:

The location of the coaxial chimney on the façade facade is placed at least two meters from the ground level. The size of the hole in the wall should exceed the diameter of the coaxial tube by 1 cm, in the case of a brick, 5 cm for a wooden wall.
The use of coaxial chimneys in multi-storey residential buildings - the regulations allow the installation of pipes of this type, subject to the following conditions. The minimum distance to window and door openings located on one level is not less than 0.5 m. To the window located above the chimney, not less than 1 m.
The danger of poisoning by products of combustion, discharged through a coaxial pipe, in the case of a condensing boiler, is absent. Provided that the system is correctly installed, the effect of the flue gases on the inhabitants of the upper floors is insignificant. Violations during installation, lead to condensation on the windows of neighbors.
Fire and safety standards. The gap between the wooden wall and the coaxial chimney is 5 cm. The minimum clearance is due to the fact that the surface of the outer contour of the pipe practically does not heat up during operation. It is necessary to install non-combustible materials between the coaxial pipe and the wall of wood. Optimal use of basalt insulation.
The regulated distance from the coaxial chimney, relative to the windows and doors of neighboring houses and other buildings, is not less than 1.5 m. The site should not block walls, pillars, trees, etc. The removal of combustion products from the condensing boiler to a conventional chimney, instead of coaxial, is prohibited.
Coaxial chimney can be both horizontal and vertical. Installation of a collective smoke removal system is carried out only after obtaining permission from the gas service. It is not allowed to connect boilers with forced and natural removal of combustion products into one network.
Horizontal section - the laying of a two-channel chimney through an adjacent non-residential premise is allowed only if the length of the pipe does not exceed 3 meters. In turbocharged models, with the presence of the function of forced discharge of combustion products, it is allowed to increase the horizontal section to 5 m.
Restrictions on the withdrawal through the facade. It is necessary to carefully observe the prohibition on draining condensate to the ground. The pipe is installed under a slope to the boiler. If there is a steam trap, it is allowed to make a slope of the outlet pipe to the ground, for drainage of rainwater. With a collective connection, it will be necessary to agree on the utilization of the accumulated condensate, in the sanitary epidemiological inspectorate.
Mounting norms - a coaxial chimney must protrude from the wall for at least 30 cm. For turbocharged boilers with a chimney section of about 1 m, a tapering diaphragm - a unit compensating for the insufficient length of the chimney - must be installed. A diaphragm in a coaxial chimney is needed to limit the flow of air into a closed combustion chamber. Turbine boilers are designed to use a chimney 5 meters long. The diaphragm levels the difference.
Coaxial pipe maintenance - the system is serviced annually, at the beginning and at the end heating season. The accumulated condensate is removed, the joints are sealed and there is no burn-through in the structure.

Requirements for safe operation coaxial chimney systems can change, therefore, before buying and installing, you should get a specialist consultation.

Mounting options

Complete with a coaxial chimney, factory assembly, it is necessarily enclosed detailed instructions for installation. Following and careful implementation of these recommendations, affects the operation of the boiler and the efficiency of the smoke removal system. According to experts, the main cause of blowing the boiler, the appearance of frost or ice, is associated with errors in the calculations and when connecting the chimney.

Horizontal installation of coaxial tubes

Horizontal installation is performed taking into account the technical characteristics of the building. Initially, the place of exit of the pipe from the wall is selected. There are restrictions related to the distance to the nearest neighbor's window, when removing a horizontal coaxial chimney from the wall, which must be carefully observed.

In addition, the following parameters are calculated:

The height of the pipe - from the outlet pipe of the boiler to the opening in the wall, for floor gas boilers should be at least 1 m high. Do not directly pipe the pipe from the outlet pipe to the street. For wall gas boilers, a height of up to 0.5 m is allowed.
The number of rotary couplings in the section should not exceed 2 pcs.
The maximum length of the horizontal section is 3-5 m, depending on the boiler model. For the extension of the pipe, a coupling with heat-resistant rubber bands is used. It is forbidden to use silicones and sealants.

The peculiarity of using a two-channel chimney in the winter time is an increased production of condensate. The reason for the loss of moisture is that the system was originally designed for more favorable operating conditions. With increased condensate formation, it will be necessary to insulate the pipe.

Vertical installation of a two-pipe

Vertical installation of the chimney provides two ways of connecting:

How to install a coaxial chimney

Exist general rules and the norms that help to install the chimney pipe in such a way as to avoid further problems in operation. Recommendations separately specify:

Output of the system through the wall.
Connection to the boiler.
The possibility of extending the two-channel system.
Protection against icing and wind.

Flue outlet of coaxial type through the wall

Output coaxial system smoke removal through the wall, in fact quite simple. The difficulty is determining the optimal location for this task. Fire safety requirements for the location of the coaxial chimney are made. Some norms are described in JV 60.13330.2012.

The recommended angle of inclination of the horizontal section is 3 ° in the direction of the heater. If a steam trap is installed, it is allowed to slope to the other side.
The maximum length of a horizontal section of a coaxial pipe is from 3 to 5 m, depending on the technical parameters of the installed boiler. No more than two corners can be used throughout the chimney.
Node of passage through brick wall is made with a gap of 1 cm. The gap is not compacted by a non-combustible material and is closed with a special lining.
The node of the passage through the wooden wall expands by 5 cm, in comparison with the diameter of the pipe. Basal insulation is laid in the gap. Alternatively, a hole around the coaxial chimney in the wooden wall of the house can be sealed with a special fire-resistant mounting foam.
A tee with condensate collector and inspection channel for cleaning is installed.
The concentration of exhaust gases when connecting a coaxial chimney is small. But to ensure safety, it is recommended that the minimum distance of the coaxial chimney outlet above ground level is not lower than 2 meters from the ground. Thus, a minor danger of gas combustion products can be completely eliminated.

Installation work is carried out in accordance with the instructions given by the manufacturer.

How to connect a two-channel chimney to the boiler

One common mistake when connecting a coaxial smoke removal system is the use of improvised tools, which is a gross violation of safety and operation. Norms require the use of a special adapter for connection. Do not install a self-made pipe from a piece of stainless steel pipe.

Immediately after the outlet pipe, mount the tee with a condensate collector, after which lift the pipe upwards by 0.5-1 m., Set the angle and remove the chimney through the wall. Before commissioning, check the quality of the thrust.

How to extend the coaxial tube

It is not always possible to install the boiler in such a way that the chimney is no more than 1 m. In some cases it will be necessary to increase the length of the pipe. There is a construction on the principle of "papa-mama". Pipes are mounted on condensate. For angles, rotary couplings are used at 45 ° and 90 °.

Sealing joints with silicone is prohibited. Adapters are equipped with sealing gums that withstand heating up to 250 ° C. During installation, it is required to minimize the number of turns and corners in order to provide the best traction. Over the entire length of the fixing clamps.

How to protect the coaxial system of gas evacuation from icing

Icicles on the headline indicate obvious irregularities during the installation works. As a rule, if the design calculations and subsequent installation are performed correctly, the probability of icing is absent.

You can additionally protect the chimney from frost formation as follows:

Anti-icing nozzle - a unit that helps to eliminate the problem of freezing the pipe, even with improper installation.
If there is no condensate trap in the pipe structure, the slope should be made towards the boiler, which will cause condensate to flow into the tee and a special collector. When, despite compliance with the deviations, the head is still formed frost - this indicates an incorrect calculation. If the steam trap is installed, it will be necessary to protect the brick from the gas combustion products by extending the pipe head 50-60 cm from the wall.

When using individual coaxial chimneys in low-rise residential construction, installation of an anti-icing nozzle is mandatory.

The maximum capacity of the boiler, permissible for connection to the coaxial chimney - 40 kW. Installing equipment with large performance parameters leads to insufficient traction, increased condensate production and icing.

How to protect a two-channel chimney from the wind

Blowout of the boiler, the presence of reverse traction is unacceptable. If you do not protect the system from wind and draft, combustion products will enter the room, which often leads to poisoning of residents with carbon monoxide.

Avoid reverse traction can be as follows:

Installation of wind protection and diaphragm.
The correct location of the pipe under the window, relative to the doorways and surrounding buildings.

The distance from the window, on the outside of the wall, is not less than 1 m. If the chimney is positioned closer, a draft will form when opening the window opening.

Pros and Cons of Coaxial Smoke Detectors

Certain advantages and disadvantages exist for each smoke removal system, without exception. Deciding how justified the use of coaxial pipe, you should pay attention to several important factors:

Cost of construction and installation.
Advantages and disadvantages.
Type of boiler.

Cost of a coaxial kit for a chimney

Compared to conventional, the coaxial chimney costs more. The standard meter set will cost about 3000 rubles. Each additional meter for elongation, as early as 1800-2000 rubles. Knee and sealing rubber in 1500 and 300 rubles. respectively.

In general, the assembly of the system, provided that the connection will be performed independently, will cost from 6 to 10 thousand rubles. Pleasure is not cheap. For some types of gas equipment, there is no alternative to installing a coaxial tube. For example, use a conventional chimney for a condensing heating boiler is prohibited.

Some, wanting to reduce the cost of the smoke removal system, use improvised means. On the Internet you can find videos and articles about how to use sewer pipes as a chimney for a condensing boiler, which is dangerous and leads to poisoning the residents of the house with carbon monoxide.

On safety it is better not to save and buy that chimney, which is recommended by the manufacturer of heating equipment.

Advantages of a chimney from coaxial pipes

The main advantage of the coaxial smoke removal system is that during the operation of the gas boiler, air taken from outside the premises is burned, and from the street. As a result, the ventilation requirements of the room and the total area of the room used for the boiler room are reduced.

Existing regulations allow installing the boiler in an unventilated room, since the need for ventilation of the boiler house is minimal. If to compare, then a boiler with a closed combustion chamber uses as much oxygen from the room during operation as is necessary for burning one of the plates of a gas cooker.

The main advantages of a coaxial pipe from a conventional chimney are as follows:

Speed of installation.
Possibility to use practically for any heating equipment.
If properly installed, good traction performance.
Possibility of application for apartment buildings.

Considering the merits of dual-channel designs, it is not surprising that such systems are widely used.

Disadvantages of two-channel pipes

Two-channel pipes have their drawbacks:

Coordination with Sanitary and Epidemiological Supervision is required. During operation, a large amount of toxic condensate is released. It is forbidden to pour it into the ground. Recycling is allowed in specially designated places.
In practice, if you install a two-channel design in a private house, then all possible claims will be reduced to the wishes of the owners of the house, from representatives of the gas service, to utilize the condensate in the right way. For collective systems, you will have to obtain permission from Sanitary and Epidemiological Supervision.
A large amount of condensate. How not to isolate a two-channel pipe, the amount of produced condensate will still be large. Even minor disturbances during installation lead to frost of the outlet opening, reduction of the thrust characteristics, and the like. When installing a coaxial chimney, it will be necessary to isolate the pipe from condensation.

Typical errors during installation and operation

The main error still remains the independent connection of the pipe by a person who does not have special skills. The main recommendation of installation specialists is an invitation for the work of licensed workers who are able to perform calculations and mount the structure without disturbance.

As practice shows, certain violations occur more often than others:

Wrong calculation of the system - there is a direct temperature dependence on the output from the length of the pipe. Exceeding the limiting distances leads to cooling of the exhaust smoke so that it is not able to heat up the accumulating condensate. As a result, icicles are formed on the headband.
Non-compliance with fire regulations. The length of the horizontal section of the pipe outside the wooden building is increased to 60 cm. Fireproof gaps are mandatory.

As a separate point, we can distinguish the absence of protective assemblies and elements, which somewhat increase the cost of construction, but increase the effectiveness of the smoke removal system.

The mandatory component vertical system is a condensate drain kit, as well as a valve for increasing traction. Horizontal structures require wind protection, diaphragm, and an anti-icing module.

Correct calculation and skilled work, in accordance with the existing SNiP and JV, guarantees the efficient operation of the coaxial chimney throughout the life of the plant.

Calculation of the power and temperature of the warm water floor

Choice of air conditioner power

The issue of autonomous heating will be decided on an individual basis. Very popular gas boilers with a coaxial chimney in the form of excellent efficiency, fuel availability and affordable cost. The main advantage of such a system is the possibility of installation already after the house was built. In this article we will talk about how to install a coaxial boiler.

Installation of equipment can be entrusted to specialized firms that will perform works "on a turn-key basis". Thus, eliminating the owners from agreeing documentation with competent organizations and the nuances of installation.

However, if there is a desire to perform the installation work on its own, knowing the principle of gas equipment operation and following all the norms and rules (SNiP), it will be possible to cope with this process without special difficulties.

Single-circuit boiler, coaxial

Principle of operation of a coaxial boiler

The heat carrier, more often water, enters the heat exchanger, where it is heated to the desired temperature by the combustion of gas. The device has 2 igniters (primary and secondary, used to maintain the "sleeping" mode). The ignition can be manual or automatic.
Equipment is divided into single-circuit and two-circuit. In the first case, the models are only for connecting the heating system. Gas units with two circuits provide not only heat in the house, but also heat water for household and household needs.
The combustion chamber is isolated from external influences. Inflow air masses from the street and exit carbon dioxide (combustion products) is produced through a coaxial channel. Its design is a pipe in a pipe, it does not allow mixing of two different flows.

Basically, all units are equipped with control and safety systems. The automation consists of thermostats, indicators, relief and safety valves, sensors, fans, etc.

Types of coaxial heating boilers

The boilers differ not only in technical specifications, but also by the methods of installation. They are floor and wall. The latter is much lighter and does not take up much useful space.
With compact dimensions, accordingly, the power of the equipment decreases. Its installation is carried out for heating greenhouses, office and residential premises with a square to 150-250 sq.m.
The floor coaxial boiler, in view of the large combustion chamber, has a high coefficient of efficiency. Such models are suitable for heating and hot water buildings for industrial purposes and residential buildings of large areas.

Various metals and their alloys are used for the production of casings. The most popular are devices made of cast iron and steel. Such products are characterized by good indicators at an affordable cost.
High reliability, heat emission and long operating life differ copper and silumin boilers. However, their cost stops many consumers from acquiring.

Nuances of choice

For the selection of equipment is better to consult with experts, it is not superfluous to ask the opinion of neighbors or relatives who operate such devices.

Their disinterest will help to give a more objective assessment of the boiler, note the absence of a function or vice versa, emphasize a wide set, half of which can not be used.

As a rule, devices have a combined mode of operation - gas and electricity. When buying, give preference to non-volatile models, otherwise it will be hard not to switch on electricity. The equipment can be equipped with an uninterruptible power supply. The capacity of modern UPS is 200-350 kW / h.

In general, the plan will consist of the following items:

get permission to install in the gas service;
proceeding from the project, prepare a place for the installation of equipment and wiring for the chimney;
selection of the boiler in terms of capacity, size, brand, appearance and other parameters.

The consumption of natural or liquefied gas determines the capacity of the unit. As a rule, for every 10 sq.m. The area is consumed 1 kWh. It follows that for the construction of 100 sq.m. you need a device of at least 10 kW. Thus, a device with a minimum power of 10 kV / h consumes 1.12 cubic meters. natural gas or 0.86 kg / h of liquefied propane-butane.

Country of origin of coaxial gas boilers

As for the manufacturer, the leading places are occupied by the factories Sweden and Germany. Their products are characterized by reliability, quality and functionality. High positions support not less high cost.

Italian boilers have a stable quality without complaints. However, positive recommendations are given only to the devices assembled in this country. The Chinese assembly reduces all dignities to zero.

Equipment from Czech Republic quite unpretentious. However, their weak point is electronics, which is especially important to bear in mind, because the instability of the voltage supply in the electricity networks is typical for our country. The output can be the installation of a stabilizer.
Budgetary options include boilers of domestic, Korean and Chinese production. This category can be called a "lucky chance", that is, you can buy a cheap boiler that will surprisingly last for many years or, more often than not, a breakdown will occur in the midst of the first heating season.

Requirements for installing a coaxial boiler

When choosing the location for gas coaxial equipment, it is necessary that it meets the following requirements:

availability ventilation system and a gas analyzer;

the wall during the installation of the overhead heat generator is insulated with non-combustible material;
installation of floor models is carried out on a concrete base or metal sheet;
have other gas appliances and electrical equipment is closer than 30 cm to the main boiler is prohibited.

If the above rules and regulations are observed, you can count not only on the effective operation of the system, but also on the safety of all members of the family.

Attention: when installing a boiler with an open firebox, the requirements are more stringent!

Coaxial chimney

Boilers with a closed combustion chamber are installed much more often than other types of heating equipment. Their main advantage lies in the possibility of installation in rooms that are not equipped with special stationary hoods. To operate the heat generator requires a coaxial channel, which is output through a window or a technological hole in the wall.
Equipment of this design can be mounted in attics, kitchens and basement floors. Here, only one condition is necessary - the presence of a window or the possibility of drilling a wall for the outlet of the chimney.
The structure is two pipes different sections, inserted into each other. On the inner tube of the combustion products. The distance obtained by the difference in diameters is used to take fresh air masses.

The features and advantages of a coaxial chimney include:

the inflow of air with the simultaneous withdrawal of combustion products provides protection against the supply of carbon monoxide to the room;
a special design does not allow to heat the outer shell of the pipes, and therefore do not transfer heat to the walls, which is not safe for wooden buildings;
this system increases the efficiency of the entire heating system of the whole house, by partially warming up the street air.

Channels are purchased separately from the boiler, a large selection provides the opportunity to pick up products not only of the required diameter, but also the preferred material (polymers, ceramics, galvanized steel, etc.). Sometimes pipes come in a complete set to the gas device.

Installation of coaxial boilers

Installation of the equipment is performed no closer than 60 cm from the window opening, such norms are stipulated by the fact that the exiting carbon monoxide does not return back. In the absence of such conditions, use the maximum possible distance.

Floor boiler.A flat base is required for this unit. Between the back wall of the shell and the building wall, a technological gap is left to maintain the device. After placing the unit in the intended location, assemble the coaxial system. Then on the wall, mark the point of its exit with a minimum distance from the floor of 1.5 m.
Wall-mounted boiler.Installation of this type of device is carried out on a load-bearing or fortified wall. Estimate, at what altitude its maintenance will be convenient, the optimal parameter is 1-1.6 m. At this level, mark the points under the bar (it is included in the kit). Check the horizontal level of the building level.

Install the boiler on the mounting strip. Next, you need to build a chimney, and determine where you want to drill a hole under the pipe. Here it should be taken into account that with a horizontal channel outlet the slope should be at least 3 degrees. This will greatly facilitate the flow of condensate.

Hole for chimney

Pushing or removing the equipment, using a perforator with a special nozzle, drill a hole of the desired diameter. The pipe must pass through freely. The crown is selected depending on the material from which the walls are built (wood, brick, concrete blocks).
Experiencing the interior and exterior is not worth it. On sale there are special decorative overhead parts.

Assembly of coaxial tubes

Each specific case determines the direction of the channel. It can be inclined, vertical and horizontal arrangement.

Advice: the horizontal travel of the system is only possible if there is forced ventilation!

Vertical direction is often used when there is no way to make a channel exit through a wall. In this case, it is necessary to calculate the channel path through the roof, so that the pipe does not rest against lags or other structural details of the roof.

For the chimney, use the factory fittings and accessories. With their help, assembly and installation will be better and more reliable. Avoid numerous bends and turns.
The simplest form of the channel will work more efficiently. When extending the channel, but not more than 3 m, special clamps are used.

Advice: use of sealant and any other improvised materials is prohibited.

Assembling the entire system

The final assembly of all elements of the system begins with the installation of gas equipment in place. The boiler is connected to the gas supply. For this, a special rubber hose is used. The tightness of joints is checked by wetting them with a soap solution.
The adapter connects the pipe to the equipment. Next is a vertical extension, a connecting clamp, and then a knee for horizontal channel rotation. You can immediately use the knee after the adapter.
A pipe of the required length is connected to the knee, followed by a start-off channel. The distance must be calculated in such a way that this element protrudes to the street for at least 30 cm.
In the case of a horizontal tap, a condenser collector must be present. It is mounted at the bottom of the structure.
Now it remains to make connection of the socket of the boiler to the water supply system.

Before work, they are contacted by the authorized bodies to obtain permission for the installation and operation of heating equipment. The ease of mounting the boiler itself and the coaxial chimney should not be misleading. Only by adhering to the attached instructions and observing the requirements of SNIP it is possible to speak about the quality of heating of premises and the safety of all residents.

The latest solution for modern technologies heating is a coaxial chimney. It allows to significantly reduce the chimney volume, moreover, in the process of work, air from the room is not used at all, which is undoubtedly an important advantage. A chimney of this type is suitable for boilers with built-in smoke exhaust (forced draft). It is much shorter and more compact than an ordinary traditional pipe. Its European quality is combined with an excellent price.

Principle of operation of the coaxial chimney

The smoke exhaust system integrated in the boiler system allows the external pipe to produce from the outside air intake simultaneously with the removal of the internal flue gases. Since the draft of air is practically ensured, the outer tube has a small diameter and length corresponding to the layout of the installation. The exhaust air containing the admixture of combustion products is discharged from the boiler through the inner pipe. It is also shorter than traditional, and the boiler, therefore, does not take up much space. Coaxial chimney is made of modern reliable acid-resistant materials, therefore inner tube does not react with harmful impurities, that is, it is not subject to destruction.

The structure of such a chimney is such that, when leaving, the flue gases do not enter the air duct. All this must be taken into account when designing a coaxial chimney, installation norms and fire safety including. Another important condition for its reliable functioning is the tightness of the connection of the external air duct and branch pipe.

Down-link installation

Heating systems operating on gas fuel differ somewhat from coal and woodburning stoves. Therefore, if a coaxial chimney is installed, the installation rates are also different.

In the case of chimneys of this type, the combustion products can be vented to the atmosphere through the outer wall of the room. In this case, in particular, there is no need for a vertical channel device from the system, by which combustion products will be forced to be removed. In this case, the hole smoke channel on the facade of the house is placed in accordance with the instructions for installing gas equipment from the manufacturer, but subject to the following conditions:

at a distance of not less than 2 meters from the ground level;
the minimum distance to doors, windows and open ventilation grilles (holes) horizontally should be 0.5 meters;
the minimum distance to the top of the doors, windows and open ventilation grilles (openings) should also be 0.5 meters;
the vertical distance from the windows located above the opening of the smoke channel - from 1 meter;
in the region of 1.5 meters from the coaxial pipe there should be no barriers, say, walls, pillars, etc.

The chimney, if there is no condensate collector, should be installed at an angle to the ground, preventing the condensate from draining back. Optimal bias is 6-12 °.

If the smoke channel is placed under a balcony, canopy or roof eaves, then it must extend outside the circle with a radius of R. It is equal to the width of the part of the building projecting above the chimney.
The smoke channel must not go through the outer wall into the passageways (arches), underground passages, tunnels, etc.

When leaving the wall, the length of the horizontal section of the channel is no more than 3 meters. However, in this matter, manufacturers allow different interpretations. For example, according to the instructions, the Ferroli coaxial chimney has a maximum permissible pipe length of 4 m (60/100) or 5 m (80/125), and the Navien coaxial chimney is 3 m. From this, it can be concluded that, first of all, it is necessary to carefully study the instructions of the gas equipment that is to be installed, since for some boilers some of the main parameters may not coincide.
(below are documents SNIP, and installation rules for chimneys of some manufacturers)

Coaxial chimneys of the best producers guarantee reliability and quality

Coaxial chimney Ariston
Ariston fumes manufactured in Italy are suitable for most modern boilers. Sealing gaskets and wall lining are also supplied with them.

Coaxial chimney Baxi
The chimney in its construction should have a length of up to 5 m. If it is directed to the street, it is given a slope at a rate of 1 cm per meter of its length. For the conditions of the Russian climate, warmer versions are more suitable with the following changes introduced into the design:

lengthened the head,
the design of the air intake channel is especially protected,
is made of a composite material.

Such a system makes it possible to prevent icing of the chimney and cause the boiler to stop in emergency mode if the outside temperature drops to -50 ° C.

Co-axial chimney Protherm
These products are very easy to install and contribute to an increase in the efficiency of the corresponding Protherm boilers. In addition to them, the company also offers extensions for chimneys, adapters designed for separate smoke removal and more.

Coaxial chimney Vaillant
This company is considered one of the leaders in the European market. Its products are quite in demand in recent years. When choosing chimneys it is especially important that its cross-section corresponds to the cross-section of the Vaillant boiler connection. During installation, it is necessary to ensure a minimum distance of 100 mm between the chimney and flammable components.

Coaxial chimney Viessmann
In addition to a coaxial tap (diameter 60/100, 90 °), the kit usually includes: a coaxial tube equipped with a tip (diameter 60/100, length 0.75 m) and wall lining. Its special design does not allow the pipe to be fixed in the winter.

Regulatory documents and installation rules

23-May-2014 Alexey

The use of modern boiler equipment is impossible without a system for the withdrawal of combustion products. It is necessary for efficient operation of the boiler using any type of fuel.

But the installation of the classic smoke channel is carried out during the erection of the house and is not possible in the already constructed building. In this case, the ideal solution is to install a coaxial chimney. In this article we will consider what this design is and how to perform its installation.

Purpose and types of coaxial systems

Let's start by getting acquainted with the name. The word coaxial is treated as a double channel. In a constructive plan, this chimney is a two-circuit chimney. In it, the smaller diameter pipe is located in the larger one. At the same time, they do not touch each other, but are joined together by means of special jumpers.

In general, it is a system that outputs combustion products and air from the street for the most complete combustion of fuel inside the boiler. About 90% of modern heating units are equipped with a closed combustion chamber, having a pipe for removing smoke within 3 m in length.

Having decided to use a coaxial chimney it is important to know that it is installed in a horizontal position. The outlet is through one of the outer walls.

On the market are the following:

And stainless steel
Galvanizing

Depending on the method of installation, they are divided into:

Internal
External

Having decided to equip a coaxial chimney, the installation standards must be studied in advance, this will help to perform all the work correctly and ensure trouble-free operation of the equipment in the future.

Installation rules

Whatever the design of the chimney is not simple, its installation must be carried out in accordance with the requirements normative documents. When installing coaxial chimneys, the following rules must be adhered to:

The outlet is made 1.5 m above the gas boiler and not less than 1 m above ground level
If it is necessary to extend the pipe, its length should not exceed 3 m, while the use of sealants and other similar materials is prohibited
Horizontal installation is carried out with an angle of inclination of 3 degrees
It is forbidden to use more than 2 knees
Between the chimney and the nearest opening in the wall, a distance of 60 cm

Only by meeting all the above requirements can you be sure of quality work system.

Benefits of use

Why do most consumers today choose exactly these designs? The answer to this question can be its positive qualities. The main advantage of a coaxial chimney is the possibility of air intake from the outside.

This allows you to maintain a good indoor climate without additional investment in ventilation systems.

Another plus in favor of this design is the heating of air during the sampling, which completely excludes heat losses and significantly increases the efficiency of the boiler. The latter contributes to the complete combustion of gas, which makes the unit work environmentally friendly.

Watch the video, the work of the system:

The design features allow to avoid heating the outer surface of the pipe. This makes it possible to minimize the risk of fire from facing materials located at the junction of the pipe and the wall.

Add to this:

Wide choice of diameters
Easy installation
Compact size

If we compare the possibilities of a conventional design and a coaxial one, we can once again be convinced of its superiority. The only drawback is the high cost and expensive maintenance.

How does the installation begin?

Installing a coaxial chimney will not take long if you make an action plan. Beforehand make sure that the complete set of the unit corresponds to the declared by the manufacturer and take care of purchasing the necessary tools.

The section of the chimney must correspond to the diameter of the boiler outlet pipe. You can determine this by passport.

Build without errors

The first step in installing the chimney will be to prepare a hole in the wall. Its diameter should correspond to the pipe that is led out.

Then connect the chimney with the outlet mouth of the boiler, using a clamp for fixation. The assembled structure is bolted on both sides. Next proceed to assemble the chimney itself. Its parts are connected with each other by means of clamps, in order to ensure their reliability. On top of them put on decorative lining. Their function is to preserve the design of the room.

Whichever simple installation and installation of the coaxial chimney seems to be necessary, certain knowledge is needed to carry it out. After all, in case of incorrect calculations of the output system of combustion products, smoke and carbon monoxide can enter the room.

Installation of an external chimney

Installation of this design can be carried out in two versions:

Outdoor
Inner

The first is used in case the building is already built. Before mounting, the location for the location of the system and for the entrance of the chimney is determined.

On the outer wall, note where the exit will be located. When implementing it, you should adhere to fire safety rules. After the hole of the required diameter is ready to start the installation of the chimney.

For this purpose, all internal works: connection of the pipe to the boiler using a sectional single-circuit bend and a double-circuit tee. The latter is necessary for fixing the system in an upright position. Further, the chimney is strengthened by brackets on the wall surface.

Installation internal system begins with the correct selection of the diameter of the pipe. Usually its diameter is indicated in the product passport. The main thing is that it coincides in size with the outlet of the boiler.

The connection between the unit and the chimney is performed using a tee. Thus fastening of links is carried out by a chain (bottom should come in the top). This design allows smoke to escape unhindered.

Two-circuit pipes are connected with the use of a transition node. The joints are sealed using clamps.

If the nozzle is located on the side of the boiler, horizontal assembly is carried out for the chimney outlet. When the outlet is from above, the chimney is removed in an upright position using brackets.

Checking the working capacity of the structure

After all the stages of installation have been successfully completed, it is necessary to check:

Reliability of fixing the connecting parts of the chimney
Correct location of smoke extraction pipe (it should be slightly inclined)
No obstructions in the place of exit of the structure to the outside

Only after making sure of correct installation Equipment hole in the wall is covered with decorative pads. Their fastening is carried out on building glue or liquid nails. A hole around the chimney is recommended to stop, this will avoid entering the room with cold air and accumulating condensate.

It is important

The coaxial exhaust system is a design that not only improves the characteristics of the heating boilers, but also increases the efficiency of their operation.

Its installation can be done independently, with the necessary skills and knowledge. If you are not sure of your own abilities, then you better entrust this work to professionals.

After all, competent installation of a condensate drain is only possible for a specialist. Therefore, you should not take risks.

Everybody knows that working capacity heating systems, in which the principle of fuel combustion is used, is impossible without oxygen supporting combustion and proper exhaust gas removal. Today, for the creation of autonomous heating systems, various gas equipment uses the widest demand. It is compact and safe, easy to use, highly automated and does not require the owner to constantly intervene in the work process.

Design 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 that are inserted one inside the other and rigidly fixed to each other. On the inner tube are derived combustion products, and through the space between the inner and outer tube from the combustion chamber comes the necessary air for combustion of fuel. The coaxial chimney for the gas boiler solves at once two main tasks: the exhaust of exhaust gases and the supply to the air device.

Such chimneys are made of round tubes, the inner most often made of aluminum alloy, and the outer one made of steel, thickness 1; 1.5 or 2 mm. The ratio of internal and external diameter for wall and floor heating devices is 60 to 100 mm. Condensing boiler units use chimneys with a diameter ratio of 80 to 125 mm.

There are two types of coaxial chimneys: horizontal and vertical. The most simple installation and, accordingly, a widespread smoke removal system of this type is a horizontal chimney. The vertical coaxial chimney is sufficiently complex in the installation and is therefore used if horizontal installation is not possible or from a heater to a street wall of more than 4 m.

Advantages and disadvantages

As already mentioned above, this type of smoke removal system is used only for gas equipment with a closed combustion chamber, namely:

Two-circuit heating boilers wall and floor with a closed combustion chamber.
Gas water heating columns.
Generators and convectors.

The main advantages of such an air intake and smoke removal system are:

Security. In such a smoke extraction system, there is a heat exchange between the outdoor air and the exhaust gases, as a result of which the temperature of the combustion products decreases.
Heating of air coming from the street by contacting it through the pipe wall significantly increases the efficiency of the boiler.
By a coaxial chimney, the intake of outdoor air is taken, and not from the room, so that there is no vacuum which prevents the boiler from operating normally and natural circulation air in the room.
Simple installation and a large number of accessories.
Significant savings in the internal space.
Do not use oxygen from the room.

The most attractive for using chimneys of this type are apartment buildings, since the emission of carbon monoxide and fuel combustion products is not produced in the ventilation shaft, but directly into the atmosphere.

Disadvantages of such chimneys, too, is, namely: quite expensive insulation to prevent the freezing of the head of the chimney. The possibility of freezing the head of the pipe is quite high. This is due to the fact that the temperature of the outgoing gases is too low and is not able to melt the ice that formed when the moist air exits. The consequences of icing can be quite serious: repair of burners, combustion chambers and turbocharging.

Schemes of installation and installation requirements

As already mentioned above, there are two main schemes for installing a coaxial chimney: vertical and horizontal. At installation it is necessary to adhere to the certain rules of installation of a coaxial flue, regulated SNiP 2.04.08-87; SNiP 2.04.05-91.3, as well as a set of "Safety rules in the gas economy."

The total length of the coaxial chimney can not be more than 4 m. If a longer length of the chimney system is required, a coaxial chimney of a larger size should be used.

With vertical installation, the chimney passes through the ceiling and roof. To install the system in a vertical position, a special adapter is used.

It should be noted that such an adapter - the device is not universal and each manufacturer produces this device strictly for its equipment. To achieve the required length of the chimney, special extensions are used.

To ensure the integrity of the passage of the chimney through the roof and protect it from rain, a device called a terminal is used.

When installing a vertical smoke removal system, one should follow the rules that regulate its height, depending on the location in relation to the pit of the pitched roof.

Most often a vertical coaxial chimney is installed in private houses. But there is another version of the vertical smoke removal system - collective, which is designed for apartment buildings. Common coaxial chimney in apartment house makes use of individual gas heating devices completely safe.

Horizontal discharge of exhaust gases, most often used for wall heating equipment. The horizontal scheme implies the outlet of the chimney through the outer wall to the street.

For installation, take into account the slope of the chimney at 2-3 °, to prevent condensate from entering the boiler.

For passage through the wall, two types of devices are used: basic or horizontal. The only difference between these sets is the connection adapter for heating device. If the passage through the wall should be bent beam, reinforcement, etc., then use special bends and bends.

Self-assembly

Install a coaxial chimney with their own hands is simple enough and this job will be able to any home master with the presence of elementary skills of using power tools.

To perform the work you will need a kit, which includes: a flanged pipe, a clamp, an adapter for connection to the boiler and a coaxial bend. If necessary, purchase a special extension coaxial chimney.

In the required place, make a hole in the outer wall. Please note that the chimney outlet should not be located to the window, closer than 0.6 m.
Connect the adapter to the boiler.
To it, with the help of a crimp clip, connect the chimney directly. If you want to connect the structure to the wall, then use the knee. Fix all with crimp clips.
Pull the pipe through the hole, providing a slope towards the outlet of 2-3 °.
Fix the slots with mounting foam or mineral wool.
Close the outlet of the pipe with a decorative cover.

It should be noted that with each turn of the chimney by 90 ° decreases and maximum length coaxial chimney at 0.5 m.