Increasingly, in the manufacture of a smoke exhaust system, a coaxial chimney is used to gas boiler. If installed correctly, the coaxial pipe copes with two tasks at once: it removes combustion products and provides sufficient air flow for the operation of heating equipment.

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

Coaxial chimney - what is it

The coaxial chimney is simple design. Basically it's just two pipes different diameters, inserted one into the other, so that between the walls of the outer and internal contour there was a gap of several cm.

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

• Collective coaxial chimneys for gas boilers are manufactured exclusively in the factory and installed during the construction of the building. To increase traction characteristics, they have an internal layer of thermal insulation.
• Individual systems – chimneys designed for household use and connections to one heating device. Plastic chimneys are mainly used for condensing boilers, due to their low cost. Double-channel stainless steel pipes are used much less frequently.

The effectiveness of a smoke exhaust system largely depends on the correct choice of pipe. First you need to learn about how a chimney works, as well as on which boilers you can install a coaxial pipe.

The principle of operation of a coaxial chimney

The coaxial pipe is designed for simultaneous removal of combustion products and air intake from the street. The gas circulation process is carried out through two channels.

The principle of operation of the chimney is as follows:

For efficient operation of the pipe, you will need to: strictly observe SNiP for coaxial chimneys, carry out a preliminary calculation of the system, and also carry out correct assembly, including the installation of safety components: condensate collector, anti-icing nozzle, etc.

On which boilers can a coaxial pipe be installed?

Coaxial type chimneys are designed for connection to condensing and turbocharged boilers that have a closed combustion chamber, with forced or natural system smoke removal

The pipe is optimally suited for parapet units 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.

Simple design significantly increases operating efficiency gas equipment. Almost everything modern models connect to two-channel systems. The installation of steel coaxial chimneys for single-circuit and double-circuit gas boilers is permitted, regardless of the operating principle and design of the combustion chamber.

To determine whether it is possible to install a two-channel chimney, you should be guided by the parameters specified by the manufacturer in the technical documentation. Typically, it contains detailed instructions and standards, as well as requirements for installing a smoke exhaust system.

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

Types of coaxial smoke exhaust pipes

When choosing a coaxial pipe for gas equipment, you should remember that for some brands of boilers only branded chimneys manufactured by the same company as the unit itself are suitable. , – all these manufacturing companies manufacture equipment with non-standard sizes outlet pipes. Therefore, the use of branded components is considered optimal for the manufacture of a smoke exhaust system.

In all other cases, the choice mainly comes down to selection suitable material pipes. The design of the systems is made of aluminum, of stainless steel and plastic. In domestic conditions, plastic pipes and stainless steel products remain the most in demand.

Double-channel plastic chimneys

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

1. Light weight.
2. Low cost.
3. Easy installation.

The disadvantages include the relatively short service life of coaxial chimneys made of plastic, as well as limitations associated with the ability to connect to conventional gas boilers. The system may only be used in low-temperature gas exhaust conditions.

Stainless steel coaxial pipes

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

When choosing a coaxial pipe, they are primarily guided by the recommendations of heating equipment manufacturers specified in the technical documentation.

Regulatory requirements for installing a coaxial chimney

State standards and rules for installing a coaxial chimney for a gas heating boiler with a closed combustion chamber are set out in. Design, calculation and installation work is carried out in accordance with regulatory documents. Failure to comply with the recommendations leads to a refusal by the Gas Service to commission the heating system.

The standards regulate the distance from the coaxial chimney to the window, doorways, nearby buildings. Indicated minimum requirements, related to the production of fireproof cuts and other safety standards. In particular, SNiP stipulates:

• The location of the coaxial chimney on the facade - the head is placed no lower than two meters from the ground level. The size of the hole in the wall should exceed the diameter of the coaxial pipe by 1 cm, in the case of a brick wall, by 5 cm for a wooden wall.
• The use of coaxial chimneys in multi-storey buildings residential buildings– standards allow the installation of pipes of this type, subject to the following conditions. The minimum distance to window and door openings located on the same level is at least 0.5 m. To a window located above the chimney is at least 1 m.
  Danger of poisoning from combustion products discharged through the coaxial pipe, if used condensing boiler, absent. Provided that the system is installed correctly, the influence of discharged flue gases for residents of the upper floors is insignificant. Violations during the installation process lead to condensation on neighbors' windows.
• Fire regulations and safety requirements. The size of the gap between wooden wall and a coaxial chimney 5 cm. Minimum clearance This is due to the fact that during operation the surface of the outer contour of the pipe practically does not heat up. It is necessary to install non-combustible materials between the coaxial pipe and the wooden wall. It is optimal to use basalt insulation.
  The regulated distance from the coaxial chimney, relative to the windows and doors of neighboring houses and other buildings, is at least 1.5 m. The area should not be blocked by walls, tree poles, etc. Discharge of combustion products from a condensing boiler into a conventional chimney, instead of a coaxial one, is prohibited.
• A coaxial chimney can be either horizontal or vertical. Installation of a collective smoke exhaust 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 to the same network.
• Horizontal section - laying a two-channel chimney through an adjacent non-residential premises allowed only if the pipe length does not exceed 3 meters. In turbocharged models, with the presence of a function for forced removal of combustion products, it is allowed to increase the horizontal section to 5 m.
• Restrictions on output through the facade. The prohibition against draining condensate onto the ground must be carefully observed. The pipe is installed at an angle to the boiler. If there is a condensate drain, it is possible to slope the outlet pipe towards the ground to drain rainwater. When connecting collectively, you will need to coordinate the disposal of accumulated condensate with the sanitary and epidemiological authorities.
• Installation standards - the coaxial chimney must protrude from the wall at a distance of at least 30 cm. For turbocharged boilers, with a chimney section of about 1 m, a narrowing diaphragm must be installed - a unit that compensates for the insufficient length of the chimney. A diaphragm in a coaxial chimney is needed to limit the flow of air into a closed combustion chamber. Turbocharged boilers are designed to use a chimney 5 m long. The diaphragm eliminates the difference.
• Coaxial pipe maintenance - the system is serviced annually, at the beginning and end heating season. The accumulated condensate is removed, the tightness of the joints and the absence of burnout in the structure are checked.

Requirements regarding the safe operation of coaxial chimney systems may change, therefore, before purchasing and installing, you should consult a specialist.

Mounting options

Complete with a coaxial chimney, factory assembled, required detailed instructions on installation. Following and carefully implementing these recommendations is reflected in the operation of the boiler and the efficiency of the smoke exhaust system. According to experts, main reason blowing out of the boiler, the appearance of frost or ice, is associated with errors in calculations and when connecting the chimney.

Horizontal installation of coaxial pipes

Horizontal installation is carried out taking into account technical characteristics building. Initially, the location where the pipe exits 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.

Additionally, the following parameters are calculated:

• The height of the pipe is from the boiler outlet to the passage hole in the wall; for floor-standing gas boilers, the height must be at least 1 m. Direct pipe outlet from the outlet to the street is not allowed. For wall-mounted gas boilers, the height can be reduced to 0.5 m.
• The number of rotary couplings on the site should not exceed 2 pieces.
• The maximum length of the horizontal section is 3-5 m, depending on the boiler model. Used to extend the pipe coupling with heat-resistant sealing rubber bands. The use of silicones and sealants is prohibited.

Features of using a two-channel chimney in winter time– increased production of condensate. The reason for moisture loss is that the system was originally designed for more favorable conditions operation. If the formation of condensate increases, the pipe will need to be insulated.

Vertical installation of a two-channel pipe

Vertical installation of the chimney provides two connection methods:

How to properly install a coaxial chimney pipe

Exist general rules and standards that help install the chimney pipe in such a way as to avoid further operational problems. The recommendations specifically stipulate:

1. System output through the wall.
2. Connection to the boiler.
3. Possibility of extending the two-channel system.
4. Protection against icing and wind.

Coaxial type chimney outlet through the wall

Installing a coaxial smoke exhaust system through a wall is actually quite simple. The difficulty lies in the definition optimal location, to complete this task. Demands are being made fire safety to the location of the coaxial chimney. Some standards are described in SP 60.13330.

• The recommended tilt angle of the horizontal section is 3° towards the heater. If a condensate drain is installed, it is possible to slope in the other direction.
• The maximum length of the horizontal section of the coaxial pipe is from 3 to 5 m, depending on the technical parameters of the installed boiler. No more than two corners may be used along the entire length of the chimney.
• Node of passage through brick wall is done with a gap of 1 cm. The gap is not sealed with non-flammable material and is closed with a special lining.
• The passage through a wooden wall expands by 5 cm compared to the diameter of the pipe. Basalt insulation is placed into the resulting gap. Alternatively, seal the hole around the coaxial chimney in wooden wall at home, you can use special fireproof polyurethane foam.
• A tee with a condensate collector and an inspection channel for cleaning is installed.
• The concentration of exhaust gases when connecting a coaxial chimney is low. But for safety reasons, it is recommended that minimum distance the exit of the coaxial chimney above ground level was no lower than 2 meters from the ground. Thus, the minor danger of gas combustion products can be completely eliminated.

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

How to connect a two-channel chimney to a boiler

One of the common mistakes when connecting a coaxial smoke removal system is the use of improvised means, which is a gross violation of safety and operational regulations. The standards require the use of a special adapter for connection. It is prohibited to install a self-made pipe from a piece of stainless pipe.

Immediately after the outlet pipe, install a tee with a condensate collector, after which the pipe is raised up 0.5-1 m, an angle is set and the chimney is brought out through the wall. Before commissioning, check the quality of traction.

How to lengthen a coaxial pipe

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. The structure is assembled according to the “father-mother” principle. Pipes are installed over condensate. For corners, 45° and 90° rotary couplings are used.

It is prohibited to seal joints with silicone. The adapters are equipped with rubber seals that can withstand heating up to 250°C. During installation, it is necessary to reduce the number of turns and angles as much as possible to ensure better traction. Mounting clamps are installed along the entire length.

How to protect a coaxial gas exhaust system from icing

Icicles on the head indicate obvious violations during installation work. As a general rule, if the design calculations and subsequent installation are carried out correctly, there is no risk of icing.

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

• An anti-icing nozzle is a unit that helps eliminate the problem of pipe freezing, even if installed incorrectly.
• If the pipe design does not have a condensate drain, the slope should be made towards the boiler, which will lead to condensate draining into the tee and a special collection tank. When, despite observing the slopes, frost still forms on the head, this indicates incorrect calculations. If a condensate drain is installed, you will need to protect the brick from 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 boiler power allowed for connection to a coaxial chimney is 40 kW. Installing equipment with high performance parameters leads to insufficient draft, increased condensate production and icing.

How to protect a two-channel chimney from the wind

Blowing out the boiler, availability reverse thrust unacceptable. If you do not protect the system from wind and draft, combustion products will enter the room, which often leads to carbon monoxide poisoning of residents.

You can avoid backdraft as follows:

• Installation of wind protection and diaphragm.
• Correct placement of the pipe under the window, relative to doorways and surrounding buildings.

Distance from window, at outside walls, at least 1 m. If the chimney is placed closer, then when the window opening is opened, a draft will form.

Pros and cons of coaxial smoke removal systems

Every smoke exhaust system, without exception, has certain advantages and disadvantages. When deciding whether the use of a coaxial pipe is justified, you should pay attention to several important factors:

1. Cost of design and installation.
2. Advantages and disadvantages.
3. Boiler type.

Cost of a coaxial chimney kit

Compared to a conventional chimney, a coaxial chimney is more expensive. A standard meter set will cost approximately 3,000 rubles. Each additional meter for extension costs another 1800-2000 rubles. Knee and sealing rubber at 1500 and 300 rubles. respectively.

In general, assembling the system, provided that the connection is carried out 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 pipe. For example, it is prohibited to use a conventional chimney for a condensing heating boiler.

Some, wanting to reduce the cost of the smoke exhaust 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 carbon monoxide poisoning of the residents of the house.

It is better not to skimp on safety and buy the chimney pipe that the heating equipment manufacturer recommends installing.

Advantages of a chimney made of coaxial pipes

The main advantage of a coaxial smoke exhaust system is that during the operation of a gas boiler, air taken not from the room, but from the street, is burned. As a result, the requirements for room ventilation and the total area of ​​the room used for the boiler room are reduced.

Existing standards allow the boiler to be installed in an unventilated room, since the need for ventilation in the boiler room is minimal. If we compare, a boiler with a closed combustion chamber uses the same amount of oxygen from the room during operation as is necessary to burn one burner of a gas stove.

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

• Installation speed.
• Can be used for almost any heating equipment.
• Provided that it is installed correctly, good performance traction characteristics.
• Possibility of application for apartment buildings.

Given the advantages of two-channel designs, it is not surprising that such systems have become widespread.

Disadvantages of two-channel pipes

Double-channel pipes have their disadvantages:

• Coordination with sanitary and epidemiological supervision is required. During operation it is released a large number of toxic condensate. It is prohibited to pour it into the ground. Disposal is allowed in specially designated areas.
  In practice, if you install a two-channel design in a private house, then all possible complaints will be reduced to the wishes of the owners of the house, from representatives of the gas service, to dispose of condensate in the correct way. For collective systems, you will have to obtain permission from the sanitary and epidemiological inspectorate.
• Large amount of condensation. How not to isolate two-channel pipe, the amount of condensate produced will still be large. Even minor violations during installation lead to icing of the outlet, decreased traction characteristics, etc. When installing a coaxial chimney, you will need to insulate the pipe from condensation.

Typical errors during installation and operation

The main mistake still remains independent connection pipes by a person who does not have special skills. The main recommendation of installation specialists is to invite licensed workers to carry out the work, capable of performing calculations and installing the structure without violations.

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

• Incorrect calculation of the system - there is a direct dependence of the outlet temperature on the length of the pipe. Exceeding the maximum distances leads to cooling of the escaping smoke so much that it is not able to heat the accumulating condensate. As a result, icicles form on the head.
• Non-compliance fire safety standards. The length of the horizontal section of the pipe outside the wooden building increases to 60 cm. Fire clearances must be made.

As a separate point, we can highlight the absence of protective units and elements, which slightly increase the cost of the structure, but increase the efficiency of the smoke exhaust system.

Required components vertical system is a kit for draining condensate, as well as a valve to increase draft. Horizontal structures require wind protection, a diaphragm, and an anti-icing module.

Correct calculation and qualified performance of work, in accordance with existing SNiP and SP, guarantees effective work coaxial chimney throughout its entire service life.

Warmth creates coziness and comfort in the house. And nowadays there are many ways to heat your home. In multi-storey buildings, heating is central, but owners of private houses prefer various boilers that directly require a smoke exhaust duct. Through it, smoke will go out into the street, and not into the living room. Standard pipes are being replaced by more advanced and compact ones.

A coaxial chimney is latest system with an increased level of security. It is designed for many gas boilers. The baxi coaxial chimney is especially popular. Let's take a closer look at what it is coaxial system smoke removal, with its design, installation standards.

What is a coaxial chimney duct?

This question is asked by many owners of heating boilers. A coaxial chimney is a design that is assembled according to the “pipe-in-pipe” principle and is used in heat heaters, such as: gas boilers, convectors, radiators with buried combustion chambers. The uniqueness of such chimney channels is that this structure is assembled from several parts, which are inserted into each other and held together due to the fact that inside of this device there are specialized jumpers. They prevent parts from touching and sliding.

The advantage of these chimney channel models is that the cold air flows that are needed for draft penetrate through outer pipe from the street, not from the premises. Also, coaxial type chimney ducts solve several of the most important issues in heating at once:

• safety during operation of the chimney is increased due to the flow of cold air through the outer pipe, which cools the inner one;
• supplies oxygen, which is simply necessary for combustion and removal of fumes;
• efficiency increases heating devices by warming cold air flow about a heated exhaust pipe;
• good efficiency increases the environmental friendliness of heat generators and improves afterburning of gas fuel;
• the entire work process is carried out outside the room, which increases comfort when heating with a gas boiler;

Read also about it on our portal.

• they reduce the consumption of combustible material and increase the efficiency of the heating system as a whole due to complete combustion;
• with low weight and affordable price they are highly fire resistant and steel High Quality. The coaxial chimney for a baxi gas boiler is especially known for these qualities;
• they have a special drain for condensate;
• the risk of fire is reduced to zero, since due to constant circulation the air temperature in the chimney is reduced to a safe temperature.

Equipment with such a chimney is environmentally friendly, as they do not allow the remains of unburnt particles to fly out into the street and enter the atmosphere.

Advice! They are great for homes, as they provide comfort and safety to owners, even wooden houses due to their device.

For the current heating situation topical issue is the arrangement of the selected type of equipment. An important point is the chimney for a gas boiler in a private house or apartment. Today there is whole line products suitable for this purpose, so it is important not to make a mistake in choosing. To do this, you need to take into account specific conditions and comply with established requirements.

Types of coaxial chimneys

They are divided into two types: insulated and non-insulated. The first of them is most adapted to winter conditions and is successfully used throughout Russia.

They are divided into three types according to installation:

• vertical coaxial chimney. Can be used if it is not possible to remove the chimney through the wall;
• horizontal coaxial chimney. It is installed when installing forced ventilation of the boiler. The maximum length of the horizontal section is limited. It should be no more than three meters, but still manufacturers set their own restrictions. Before designing a structure, it is necessary to study the characteristics of the device being installed;
• inclined coaxial chimney. The rarest installation option and used only when the other two options cannot be used.

For each boiler, the direction of the chimney is individual.

Installation Requirements

A coaxial chimney, the installation requirements for which are indicated in the passport for each device, are individual, but there are also general ones. Among them:

• To installation work should be carefully prepared. First you need to choose the right section. You need to carefully study the passport for the boiler and the instructions from the manufacturer, which should indicate information about the required length of the chimney;

Advice! If it is not indicated, then you should focus on the generally accepted framework. In the very best options The length of the smoke exhaust duct must be at least five meters.

• in order for the draft in the chimney to be better, it should be installed slightly higher than the roof ridge;
• They must be installed very carefully and carefully secured. If the smoke exhaust duct is installed incorrectly, leakage or smoke may enter the heated room;
• outlet channel at correct installation the chimney must be larger in diameter than the outlet from the boiler;

Advice! Before installation, it is necessary to check the data with technical passport for the smoke exhaust duct in the field - diameter. This will help avoid mistakes.

• The heating device must be installed one and a half meters lower than the outlet pipe of the smoke exhaust duct, and the pipe entry must have an angle of at least three degrees. This arrangement ensures unimpeded drainage of condensate.
• The chimney inlet must be located at a height of no less than a meter and a half from the floor. This will protect it from contamination.

Advice! If a false smoke exhaust system is being installed, its length should not be more than three meters. This will allow the smoke to escape freely.

Required Fasteners

The list of elements required for assembling a coaxial smoke exhaust duct will depend on where the smoke outlet pipe will be installed: from the side or from the top. For the first case, horizontal assembly of the structure will be required, but in the second option, the removal of the chimney duct will be much easier. To bring the outlet into a vertical position, you will need brackets of various modifications and clamps to secure the joints.

Important! It is strictly prohibited to use sealant and homemade adapters for fastening, as this is unsafe and can lead to incorrect functioning of the system.

At making the right choice installation of elements will not require much time, and the system will serve for a long time.

Features of Baxi chimneys for boilers

Baxi is one of the most famous companies producing heating systems. It produces chimneys from high quality polypropylene.

The coaxial chimney for the Baxi gas boiler has the following characteristics: reliability and lightness. They are manufactured by the manufacturer in two types of diameters: 100/60 millimeters and 125/80, while the size of the chimney protrusion is 350 millimeters. This type is suitable not only for the southern, but also for the northern regions of Russia. They prevent the formation of internal ice at low temperatures. Baxi chimneys have an elongated head and a protective design, which allows them to operate without interruption at fifty degrees Celsius below zero.

Video: tips for installing a coaxial chimney

Coaxial chimneys are a new step in the creation of modern heating systems for private houses. They are environmentally friendly, safe and comfortable, and easy to install. When choosing, you should take into account that some of them are not designed to work at low temperatures, so residents of the northern regions are best to pay attention to heating system from Baxi. Providing heat to your home will become easier with the advent of such a system.

Updated:

2016-08-15

It's no secret that one of the main components of comfort in a home is warmth in it. A coaxial chimney will serve as a faithful assistant for solving this problem in private homes. This boiler smoke removal device is an effective replacement for outdated traditional pipes.

The design of a coaxial chimney (hereinafter referred to as KD) involves a design of a pair of pipes arranged according to the matryoshka principle. The pipe contours are connected by jumpers. The design itself is designed to work with heat generators closed type. An example of this is geyser. The inner pipe ensures the removal of combustion products, while the outer pipe serves to supply air from the outside. This allows you to forget about constant ventilation of the room. The price justifies the money, because boilers with pressure blowers, especially from the well-known company Baxi, are much more efficient than traditional ones, and at the same time their maximum length does not exceed 2 m in length. Most often, the CD is taken outside through a hole in the wall. Much less common is a vertical coaxial chimney that goes onto the roof.

In addition, there are a number of problems that can be successfully resolved by installing a coaxial chimney:

• The compactness of the device allows you to save a lot of space;
• an impressive selection of CD models for systems of various capacities, the price of which may surprise no less than their quality;
• ecology and economy: thanks to high efficiency, the system not only ensures complete combustion of fuel, but also reduces heat losses(due to heating of the air entering through the outer pipe with hot smoke in the inner one);
• the risk of fire of surfaces in contact with the coaxial chimney is significantly reduced (due to constant cooling of the inner pipe);
• after installing a coaxial chimney, ensuring additional ventilation no premises are required, the design eliminates the possibility of carbon monoxide poisoning of residents, whether systems from Baxi or from other manufacturers.

Where does the installation of coaxial chimneys begin?

Before installing a coaxial chimney, you first need to choose the type of system - vertical or horizontal (including inclined). The price here is approximately the same, but it should be noted that the latter option requires the installation of forced ventilation with the device. In addition, the horizontal section of the device should not exceed 3 m in length. Vertical CD is recommended if smoke will enter nearby nearby windows or onto a narrow street. Always follow the diagram and instructions from the manufacturer (Baxi, Ochag, etc.) for a specific system, which describes the installation rules in detail.

For example, the ratio of the size of the boiler to the diameter of the outlet pipe matters; they must be equal to avoid overheating of the channel. And to ensure that combustion products escape unhindered, pipes, tees and elbows are attached by a specialist. It is better not to do the installation of a chimney yourself without having experience installing a coaxial chimney. It is easier to mount a vertical CD, the main thing is to stock up on brackets. The coaxial pipes themselves are connected into the system using a special transition unit. At the junction area, clamps are used to securely fasten the elements.

Chimney outlet and finishing work

The price of success is installation accuracy. When removing the pipe from the side of the heating device, there must be a horizontal section of the pressure pipe. In this case, the level of the pipe must exceed the level of both the boiler and the street by 1.5 m or more so that the pressure chamber does not become dirty. The angle of inclination of the outlet pipe is set from 3 degrees. This will prevent condensate from flowing back into the boiler. The pipe opening should be 60 cm or more from the window, and from gas pipes- half the diameter of the CD. In order to guide the device around an obstacle, you can use up to two knees of different angles. The joint between the wall and the pipe must be insulated with non-combustible materials.

If the pipe is installed vertically on the roof, fire safety requirements must be taken into account. Use fire-resistant insulation, insulating pipes and special protective covers for the smoke exhaust duct. The pipe and the ceiling must be separated air gap. The outlet itself must be covered with a special apron that insulates the joint.

If a working CD is always cool, even when the geyser is working intensively, then the installation was carried out correctly. However, everything comes at a price: in cold climates, the device can freeze up. As a rule, this happens when it is positioned horizontally. In this case, you should contact the office of Baxi or another manufacturer supplying heating products to purchase special protection.

Conclusion

To feel the desired comfort in your home, sometimes it is enough to know what a coaxial chimney is and how it is installed. In just a few days, as if by magic, your home will be transformed and life will become even more beautiful. You can install a coaxial chimney yourself, but if you have reasonable doubts about your abilities, it is better to hire an experienced specialist.

Any heating equipment: stove or heating boiler, fireplace or even a simple gas water heater connects general feature: they need to utilize air that is saturated with combustion products. This is not only a guarantee of comfort, but also safety. Failure to comply with chimney installation standards can even lead to dire consequences - carbon monoxide poisoning.

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

The principle of operation of a coaxial chimney

The smoke exhauster built into the boiler system allows air to be taken in from the outside through an external pipe at the same time as flue gases are removed through the internal pipe. Since air draft is practically guaranteed, the outer pipe has a small diameter and length corresponding to the installation layout. Exhaust air containing an admixture of combustion products is discharged from the boiler through an internal pipe. It is also shorter than the traditional one, and thus the boiler does not take up much space. The coaxial chimney is made from 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 smoke exhaust is such that when exhausting, flue gases do not enter the air channel. All this must be taken into account when designing a coaxial chimney, including installation and fire safety standards. Another important condition for its reliable operation is the tightness of the connection of the external air channel and pipe.

SNiP for installation

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

In the case of chimneys of this type, combustion products can be discharged into the atmosphere through external wall premises. In this case, in particular, there is no need to construct a vertical channel from the system through which combustion products will be forcibly removed. In this case, the opening of the smoke channel on the facade of the house is placed according to the instructions for installing gas equipment from the manufacturer, but taking into account the following conditions:

• at a distance of at least 2 meters from the ground level;
• minimum distance to doors, windows and open ventilation grilles(holes) horizontally should be 0.5 meters;
• the minimum distance to the top edge of doors, windows and open ventilation grilles (openings) should also be 0.5 meters;
• the vertical distance from the windows located above the smoke duct opening is from 1 meter;
• in the area of ​​1.5 meters from the coaxial pipe there should be no obstacles, say, walls, pillars, etc.

The chimney pipe, if there is no condensate collector, must be installed at an angle to the ground, preventing condensate from flowing back. Optimal slope is 6–12°.

• If the smoke duct is located under a balcony, canopy or roof eaves of a house, then it must extend beyond the circle with radius R. It is equal to the width of the part of the building protruding above the chimney.
• The smoke duct should not go through the external wall into passages (arches), underground passages, tunnels, etc.

When exiting through a wall, the length of the horizontal section of the channel is taken to be no more than 3 meters. However, manufacturing plants have different interpretations on this issue. 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 all this we can conclude that, first of all, even before At the beginning of design, you must carefully study the instructions for the gas equipment that you intend to install, since for different boilers some of the basic parameters may not be the same.
(below are the SNIP documents and installation rules for chimneys of some manufacturers)

Coaxial chimneys from the best manufacturers are the key to reliability and quality

Coaxial chimney Ariston
Chimneys Ariston Italian made Suitable for most modern boilers. They also come with sealing gaskets and wall trims.

Coaxial chimney Baxi
The chimney in its design should have a length of up to 5 m. If it is directed towards the street, it is given a slope at the rate of 1 cm for each meter of its length. For Russian climate conditions, insulated options with the following changes made to the design are more suitable:

• head lengthened
• the design of the air intake duct is especially protected,
• made of 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.

Coaxial chimney Proterm
These products are very easy to install and help increase 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 other.

Coaxial chimney Vaillant
This company is considered one of the leaders in the European market. Its products are in great demand in last years. When choosing chimney It is especially important that its cross-section corresponds to the cross-section of the Vaillant boiler pipe. When installing, it is necessary to ensure a distance between the chimney and flammable structural elements at least 100 mm.

Viessmann coaxial chimney
In addition to the coaxial outlet (diameter 60/100, 90°), the kit usually includes: a coaxial pipe equipped with a tip (diameter 60/100, length 0.75 m) and wall linings. His special design prevents pipes from freezing in winter.

Coaxial chimney - new technical solution, which replaced standard chimneys. The peculiarity and great advantage of this device is that the oxygen for combustion in the boiler furnace is taken from the street, and not from the house.

Coaxial chimney designs

Chimneys are used for different types boilers:

• B - chimneys for boilers with an open combustion chamber;
• C - chimneys for boilers with a closed combustion chamber.

In high-rise buildings you can find a variant of a collective chimney, to which individual boilers are connected. This chimney goes to the roof

Coaxial chimneys are mounted in two positions:

• vertical;

• horizontal.

Only the installation method differs, but the principle of operation of the chimney is the same. Like everyone else engineering systems, it has both advantages and disadvantages. Let's look at them.

Advantages

Structurally, the chimney consists of two pipes, one acts as an outer shell, the other as an inner shell. Combustion products - exhaust gases - are discharged through a pipe of smaller diameter. Air enters the combustion chamber of the boiler through the outer pipe to maintain combustion. This system provides a compact and aesthetic appearance and takes up little space. The system ensures heating of the incoming outside air with exhaust gases, which increases the efficiency of the boiler.

Another important advantage of this system is its fire safety. When flue gases are removed, they are cooled by air that enters the combustion chamber of the heating unit, reducing the risk of fire to zero. Additional insulation of the chimney with highly flammable materials is not required.

A similar chimney system can be installed on Various types boilers:

• on gas;
• liquid fuel;
• on solid fuel.

Disadvantages of a coaxial chimney

Freezing. This is probably the main and most serious drawback when installing a horizontal chimney.

The first models of coaxial chimneys that appeared on the Russian market were not designed for such low temperatures operation - -15 - -30°С. They are designed for countries with milder climates. As a consequence, there is the possibility of freezing of the chimney and failure of the heating unit.

Although not all experts are so categorical. In their opinion, the main reason for freezing of a coaxial chimney is incorrect thermal engineering calculations. In this case, the boiler efficiency depends on the supply air temperature. In pursuit of increasing efficiency, designers reduced the diameter of the exhaust pipe. In this case, the temperature of the flue gases drops below the dew point, which leads to an increase in condensation formed inside the exhaust pipe and freezing. To reduce the effect of this factor, it is necessary to increase the temperature of the flue gases by increasing the diameter of the pipe. A properly selected coaxial chimney should not freeze.

When installing a vertical coaxial chimney, we are faced with the problem of collecting condensate. Since the problem is known to all manufacturers, models of coaxial chimneys designed for vertical installation, equipped with a condensate collector.

Rules for installing a coaxial chimney for a gas boiler

When installing a coaxial chimney yourself, you must read the manufacturer's instructions. Be sure to follow the rules for installing a coaxial chimney.

• During installation, use only materials and components that have been tested by the state gas inspection; It is prohibited to make any changes to the configuration and design of the chimney.
• During installation, it is prohibited to use materials not from the chimney manufacturer; Purchase necessary additional components only from service centers.
• All parts of the chimney are firmly connected and tested for flue gas leaks.
• Use of sealants and adhesive compositions forbidden.
• It is forbidden to join pipes within the thickness of the wall; it is necessary to provide a joint location outside the wall.
• A horizontal coaxial chimney is installed (unless otherwise specified by the boiler manufacturer): for condensing boilers 2-3° towards the boiler, for classic 2-3° outwards, ensuring condensate drainage and preventing precipitation from entering the boiler.
• The length of the coaxial chimney depends on the boiler model, the complexity of the chimney route and ranges from 1 to 7 m (the maximum length for a straight installation for a boiler with an installed turbine with a power of more than 30 kW).
• It is prohibited to install a coaxial chimney outlet below ground level into a window pit in a semi-basement.
• Remember, the installer is responsible for breakdowns and accidents during the operation of the chimney.

Coaxial chimney installation diagram

The exit of a coaxial chimney through the enclosing structures must comply with a number of rules and requirements. Since type C boilers have a closed combustion chamber, they can be installed in all types of premises. Regardless of the presence of windows in the ventilation system and the volume of the room itself, several standards must be adhered to. The photo shows the requirements for installing a coaxial chimney in different versions:

• a - the minimum distance from the axis of the chimney to any opening element of the facade of the house;
• b - the minimum distance from the axis of the chimney to any air intake;
• c - minimum distance to sidewalks (to reduce the distance, install a grille with a deflector, in this case the distance will be 0.15 m);
• d - minimum distance from the ground;
• e - the minimum distance from the axis of the chimney to the wall at an angle of 90° with opening elements or air intake openings; (0.15 m with a deflector);
• f - the minimum distance from the axis of the chimney to the wall at an angle of 90° without opening elements;
• g - minimum distance to green spaces;
• h is the minimum distance to the drainage system or vertical pipeline.

Choosing a coaxial chimney

When choosing a coaxial chimney, first of all you need to pay attention to the recommendations of the boiler manufacturer. There have been cases when the service center did not accept equipment under warranty due to the installation of a coaxial chimney that was not recommended for a given boiler.

A coaxial chimney must ensure not only the removal of flue gases, but also completely ensure the intake of oxygen from the street, so the reliability of its operation is very important. It is worth choosing from proven foreign brands: Baxi, Vaillant, Navien, Ferroli, Ariston, Viessmann.

Coaxial chimney Baxi

Chimneys are made of stainless steel and high-strength polymer materials. The standard kit includes a 1 meter long chimney pipe, a 90° elbow, a wind protection nozzle, and decorative rings. If it is necessary to use an extension cord, it must be purchased separately. It should be noted that for a chimney up to 1 m long it is necessary to install a narrowing diaphragm on the boiler air duct. The procedure is carried out to compensate for draft, since the boiler fan is designed to maximum length chimney (5m), and in the absence of a diaphragm, a large amount of air will enter the combustion chamber, which will lead to a decrease in the efficiency of the boiler. To protect against freezing, the coaxial pipe should protrude from the wall to the length of the tip, no more. If the length of the pipe is longer than necessary, the excess is cut off from the inside.

Photos of the main Baxi coaxial chimneys:

Coaxial chimney Vaillant

Vaillant company completes boilers own production coaxial chimneys. Compliance with the size of the pipes is the key to successful operation of the boiler. Also, Vilent coaxial chimneys can be purchased for boilers from other manufacturers.

Coaxial chimney Navien

Navien smoke removal systems from the Korean company are well established in the heating equipment market. Chimneys are produced for wall-mounted and floor-standing boilers with a power of up to 75 kW. The cost of Navien coaxial chimneys is slightly lower than their European competitors, while the quality of workmanship is not inferior to them.