Requirements and rules for installing a coaxial chimney. Choosing a two-channel coaxial chimney for a gas boiler, installation tips What are coaxial chimneys

Installation of a coaxial chimney requires a serious approach, as well as technical and theoretical knowledge. Know all the requirements for fire safety be able to follow these rules.

Only under this condition can the installation of a coaxial chimney be carried out successfully and safely. In this article we will talk about how to install a coaxial chimney from various manufacturers.

This article will cover the requirements and rules for the installation of chimneys "Baxi", "Navien", "Bosch", "Vaillant" and others. The topic of how to install a vertical coaxial chimney will also be touched upon.

Advantages and disadvantages

The assembled coaxial chimney kit has the following significant advantages:

Sufficiently high efficiency, which is ensured by a very heated incoming air flow (this effect is especially noticeable in the chimneys "Baxi", "Bosch", "Vaillant" and "Navien");
Compact design, ensured by one massive pipe (having, however, an impressive diameter) instead of two in other types of chimneys;
No need to add additional ventilation system(although in some cases it may be required in the Baksi and Navien chimneys);
Absolutely safe for both humans and animals, the air circulating in the hotel system;
For coaxial chimneys "Baxi", "Bosch" and "Vaillant" low price outlet systems;
No problems with condensate in the chimney system;
The coaxial chimneys "Baxi", "Bosch", and "Vaillant" have significantly reduced the total fuel consumption for saunas and baths.

Another undoubted advantage of this type of chimney is the circulating cold air, which perfectly protects the walls of the building from possible overheating.

But there is a significant problem with this type of chimney. It's about about the possible risk of freezing of pipes with a small diameter. The diameter of the pipes in this case plays a key role, since only pipes with a small diameter are susceptible to freezing.

And this problem is common for coaxial type chimneys manufactured by Baxi, Bosch and Vaillant.

Such frostbite occurs due to the fact that the temperature of the so-called "flue gases" at the outlet of the coaxial chimney becomes already minimal, since it indirectly heats inner tube. And this subsequently leads to the formation of condensate.

It is for this reason that such freezing of pipes having a small diameter in coaxial chimneys is the norm.

However, when operating chimneys in Russia, where the usual outdoor temperature quite often it is at -15 degrees Celsius and below, it can be fatal.

Even such advanced models of coaxial chimneys as Baxi, Bosch and Vaillant are not protected from this.

And moreover, there are this moment a completely justified opinion that coaxial chimneys are generally not suitable for operation in Russia. It's no secret that initially they were created to work in the regions of southern countries. Many people see this as the reason for freezing.

But there are also experts who think that such destructive freezing is only a problem of an initially improperly designed chimney and nothing more. In general, disputes have been going on for a long time, but the conclusion is the same.

It consists in the fact that turbocharging, together with a galvanized chamber and a chimney burner, fail very quickly due to freezing problems.

Repairing them takes not only a huge amount of time, but also requires serious financial costs. And this is at a fairly high cost of the coaxial chimneys themselves!

However, from practice it can be seen that those models are usually subject to freezing heating equipment, in which, chasing the highest efficiency, the flue gas temperature goes off scale.

At the same time, it reaches the so-called "dew point", for this reason the diameter of the chimneys is subsequently tried to be reduced to an absolute minimum.

The manufacturers of coaxial chimneys themselves answer all questions about freezing by the fact that they were not created for such a climate. And it’s not that they weren’t created, but simply weren’t tested for performance at average temperatures in Russia. And this must be taken for granted.

1.1 Chimney installation

Installation of coaxial types of chimneys does not differ from model to model. So chimneys such as "Baxi", "Bosch", "Vaillant" and others have the same general instructions.

At the same time, coaxial chimneys can only be installed in gas boilers, convectors and various radiators that have closed-type combustion chambers.

For the installation of a coaxial type chimney, the following structural elements will be required:

Knee:
Actually chimney pipe (its length does not matter);
Flange;
Specialized adapter for the boiler;
Crimp clamp.

Install the chimney at the shortest distance between the boiler and the wall. In this case, the entire length of the area from the boiler to the wall must be cleared of foreign objects and materials that can ignite.

It is also important to accurately determine the point where the pipe will subsequently be led into the external environment (street). In the best case, the location of the pipe should be one and a half meters above the chimney outlet from the boiler itself.

Holes should be made with a diameter of 110 - 125 millimeters. That is, to put it simply, exactly along the pipe. And here you can already understand that the requirements for the installation of coaxial types of chimneys are much less stringent than those of conventional models.

After the installation of the coaxial chimney, it is necessary to close the hole in the wall of the building with a specialized decorative overlay. It must be laid strictly under the diameter of the pipe, for which you can use building glue or the so-called "liquid nails".

At the same time, the end hole from the street is most often foamed to prevent cold air masses from entering the boiler room from the outside. Due to this, drafts and condensation can be avoided.

It is noteworthy that a coaxial chimney does not have to be carried out through the wall of the building. In modern realities, it is quite possible to implement a scheme of so-called "collective chimneys".

2 Fire safety requirements

There are quite strict and logical requirements and standards for the installation of coaxial types of chimneys. They are presented as follows:

0.5 meters horizontally directly to open various ventilation holes, windows and even doors;
1 meter vertically to all available windows in cases where the chimney exits exclusively under them;
0.5 meters vertically to all available windows in cases where the chimney exits exclusively above them (not to be confused with the previous paragraph!);
2 meters from the ground regardless of whether people walk on it or not.

In addition, when passing gas pipe directly below the coaxial chimney, the distance between the pipe and the chimney must be at least 20 centimeters.

At the same time, the distance from the corner of the house is no longer standardized and regulated in any way, there is freedom of improvisation and one's own desires.

The most significant advantage of coaxial types of chimneys is, of course, the absence of the obligatory need to install additional ventilation of the boiler room. But it is important to note here that Lately many experts still recommend installing ventilation.

In any case, this will definitely not be superfluous, and due to this it will be possible to significantly reduce the risks of fires and failure of the coaxial chimney.

2.1 Overview of the coaxial chimney for a bath (video)

The installation of a coaxial chimney on heating boilers has become widely and successfully used.

This is provoked primarily by the features of such a chimney, which give it advantages over other types of hoods for heating.

Increases the efficiency of the heating process, which is reflected in the air temperature in the room. This in turn affects the cost of heating, as for optimal temperature less fuel is needed, which costs money.

In order for the installation of a boiler with a coaxial chimney to be successful and it will serve you for a long time, it is necessary to properly install the coaxial chimney. And it is better to do this when you are familiar with the types of such chimneys and their features.

1 What are coaxial chimneys?

Installation of a coaxial chimney for gas boiler depends on the type of product purchased. The installation of a vertical coaxial chimney will differ from that intended for a horizontal arrangement.

For installation different types chimneys will need various auxiliary devices.

Proper installation of a coaxial chimney involves the selection of materials that will match each other. For example, a double pipe must be of such a diameter as to match the boiler for which a coaxial chimney is being installed for.

In order not to do everything at random, and then not to redo it, study technical certificate heating device. There must be the wishes of specialists regarding the installation and installation of this equipment.

The installation of a coaxial chimney of a gas boiler can also be done using technology that prevents icing of the chimney. As a rule, such chimneys are sold complete with the device.

2 What steps should be present when installing a coaxial chimney and what is important not to forget?

In order for the installation of a coaxial chimney with your own hands to be correct, it is important not to forget anything and to follow exactly all the necessary steps, which you can learn about from our article.

First, determine whether you will install the chimney horizontally or vertically. Vertical installation of a coaxial chimney is rarely done, since such a device is more overall.

In addition, to install this type of chimney, it is necessary to punch a hole in the roof, which is not always easy to do. But still, sometimes the installation of a baxi coaxial chimney of this type is necessary.

This happens in cases where, due to the layout of the premises horizontal installation is simply impossible. This may be hindered by protrusions of the wall, radiators, doors or windows.

But if all these obstacles are not present, then feel free to install the coaxial chimney horizontally, since such an arrangement, in combination with a fan, is the most optimal.

Horizontal installation is mainly assumed by the rules for installing a coaxial chimney in apartment building. This is also due to the fact that if the apartment is not on the top floor, then vertical installation is not possible.

The rules for installing a coaxial chimney for a gas boiler provide that all adapters, tees and clamps, elbows must be selected in accordance with the diameter of the coaxial pipe.

It is important to ensure that the distance between the two pipes of such a chimney is always kept at the same level, including in the places where adapters and other auxiliary installation elements are used.

Everything auxiliary elements, which involves the installation of a coaxial chimney with your own hands, should fit snugly together, ensuring the system is sealed. This is important to ensure good draft, which enhances the heating effect of the boiler.

Also, the tightness of the system can guarantee that air with impurities of combustion products will not be mixed with fresh air, which is not a desirable phenomenon, as it can cause smoke in the room.

The rules for installing coaxial chimneys require that the structure be placed away from gas pipelines. Also, the installation of a coaxial chimney in an apartment building is done so that the exit is not located close to the window, and not very low above the boiler - these are safety requirements.

There must be at least 600 mm to the window, and from top edge boiler - not less than 1.5 meters.

Installation of a coaxial chimney in wooden house has its own rules. Wood is sensitive to moisture, so the walls of such a house must be protected from condensation, which can occur when the hot exhaust air is cooled.

For this, the installation of a coaxial chimney in a wooden house is carried out using thermal insulation materials so that the temperature on the surface of the pipe is even.

Where the pipe exits wooden coverings, you can use steel sheets for upholstery to reduce the chance of spontaneous combustion.

The rules for installing a coaxial chimney for a gas boiler are well known by a specialist who will do everything faster and better than you, unless, of course, you have solid experience in this area.

In some new buildings, when laying communications, individual heating is already provided.

Therefore, there is laid one system coaxial chimneys, which will save you from unnecessary trouble and give you confidence that all the requirements for the installation of a coaxial chimney of a gas boiler are met.

2.1 Rules for laying a coaxial chimney to the boiler - video

The coaxial chimney for a gas boiler is a new technical solution that has replaced the standard options. It is used for heat generators with closed camera boiler combustion). main feature and the great advantage of this chimney is that the combustion air enters the boiler furnace not from the house, but from the street.

purpose

Coaxial is designed to perform 2 functions at once:

removal of combustion products to the outside;
ensure the flow fresh air necessary to maintain the gas combustion process in the chamber.

Boilers with a closed combustion chamber, as a rule, are equipped with a chimney, the length of which is usually not more than 2 m. It should be noted that most often the chimney is installed outside through the wall. Less common is the option when it is taken out through the ceiling and roof.

If the place in the wall where the chimney is supposed to be led is located near the window, then it is best to place it just above the roof. However, in this case it is necessary to mount the vertical part of the chimney.

Coaxial chimneys are installed in vertical and horizontal positions. They differ only in the way they are installed, but the principle of their operation is the same.

Components

A coaxial chimney for a gas boiler consists of the following components:

several straight pipes;
tees;
cleaning;
condensate collector;
upper tip of the chimney;
knee (angle 90).

A chimney is formed from straight pipes. The purpose of the elbow is to connect a horizontal chimney with its vertical part, as well as a gas boiler.

If the chimney is located only in a horizontal position, the kit includes the following items:

straight pipes;
knee (angle 90);
chimney tip (side).

A coaxial chimney for a gas boiler, like all engineering systems, has its pros and cons.

Advantages of a coaxial chimney: customer reviews

Oxygen to support the combustion process comes from outside, and not from the room. This is the main advantage of a coaxial chimney. Its design includes two pipes, one of which performs the function of an external, and the other an internal shell. Through a pipe with a smaller diameter, combustion products are removed - exhaust gases, and outer pipe air is supplied to the combustion chamber of the boiler to support combustion.
The design takes up little space, which can significantly save space indoors.
The chimney heats the incoming outside air with exhaust gases, which significantly increases the efficiency of the boiler.
The system is fireproof. When exhausted, the flue gases are cooled by the air entering the combustion chamber of the heating unit, which reduces the risk of a possible fire. It is not necessary to additionally insulate the chimney with flame-retardant materials.
Ease of installation.

A similar chimney system can be installed on the following types of boilers:

on gas;
solid fuel;
on liquid fuel.

Disadvantages of coaxial chimneys

Freezing. According to user reviews, this is the most important and serious drawback. installed chimney. His first models that appeared on the markets were not designed for low temperatures operation (-15 - -30 °C), which can cause freezing of the structure and failure of the heat unit. A coaxial chimney for a gas boiler (photo presented in the article) was intended for countries with a milder climate.

But not all experts are so categorical. In their opinion, the main reason for the freezing of such a chimney is an incorrect thermal calculation. If the chimney is properly selected, it will not freeze over.

When installing a vertical coaxial chimney, there is a problem of collecting condensate. Since this drawback is known to manufacturers, certain models are equipped with a condensate trap.

Carrying out installation work

When installing a coaxial chimney on your own, you must definitely read the manufacturer's instructions and follow all the recommendations:

During installation, only those materials and components that have been tested by the state gas supervision should be used; it is strictly forbidden to make any changes to the design and configuration of the chimney.
When carrying out work, the use of materials that do not belong to the manufacturer of the chimney is strictly prohibited. All necessary additional components should be purchased only in a special service center.
All parts of the chimney are connected and tested for flue gas leaks.
It is forbidden to use sealants and adhesives.
Docking of pipes in the thickness of the wall is prohibited. The junction should be provided outside of it.
The installation of a horizontal coaxial chimney is carried out (if there are no other instructions from the boiler manufacturer): for condensing units 2-3 ° towards it, for classic version 2-3° from it, to remove condensate and prevent precipitation from entering the boiler.
The length of this chimney depends on the model of the heating boiler, the complexity of the chimney line.
It is forbidden to carry out the chimney exit equipment below ground level into the window pit of the semi-basement building.
It is important to remember that during the operation of the chimney, all responsibility for breakage and possible failure rests with the installer.

Mounting sequence

The chimney is attached to the boiler and taken outside the room. All unnecessary and flammable items are best removed before work.

Installation of a coaxial chimney of a gas boiler begins with the choice of a place for a thermal unit and a chimney. Gas boiler and it is better to install together. Most best option when the chimney is located 1-1.5 m above the boiler. If necessary, the chimney can be extended, but taking into account that there are no more than 2 knees, and their total height does not exceed 3 m.

Now you can start drilling holes. desired diameter(within 11 - 12.5 cm).

The next stage of work is the assembly of the chimney of the required configuration. Clamps are used for all connections. The chimney that leaves the room must have a slight slope to remove moisture (condensate).

This is over. It remains only for aesthetics to put on decorative overlays.

How to make a choice?

When choosing, first of all, you should pay attention to the recommendations provided by the boiler manufacturer. In some cases, service centers do not accept equipment for warranty due to the installation of a coaxial chimney that is not recommended for this boiler.

The function of a coaxial chimney is to ensure not only the removal of flue gases, but also the intake of oxygen from the outside, for this reason, the reliability of its operation is very important. We offer to consider proven foreign brands: Baxi, Vaillant, Viessmann, Navien.

Coaxial chimney Baxi

It is made of high strength polymer material. The standard kit includes a chimney pipe with a length of 1 m, a 90° elbow, a wind protection nozzle, and decorative rings. If necessary, you can purchase an extension cord. It should be borne in mind that the coaxial chimney for the Baxi gas boiler, whose length is up to 1 m, requires the installation of a narrowing diaphragm on the boiler air duct. This is necessary to compensate for the draft, since the boiler fan power is designed for a certain length of the chimney (5 m). If the diaphragm is missing, an excess amount of air will enter the combustion chamber, due to which the efficiency of the boiler will decrease. To avoid freezing, the coaxial pipe is installed so that its protrusion from the wall is no more than the length of the tip. When exceeds right size, in this case, the excess is cut off from the inside.

Chimney coaxial Vaillant

The coaxial chimney for the Vaillant gas boiler is included in the heating unit kit of this company. Compliance with the dimensions of the nozzles is the key to successful and long-term operation of the boiler. In addition, such chimneys can be purchased separately for boilers from other manufacturers.

Chimney coaxial Navien

The coaxial chimney for the Navien gas boiler from the Korean company has proven itself in the heating equipment market. It is available for both wall-mounted and floor-standing boilers with a power of up to 75 kW. The price of the coaxial chimney "Navien" is lower than that of European competitors, but the quality of workmanship, judging by the reviews, is not inferior to them at all.

Viessmann coaxial chimney for gas boiler

Its advantages:

Natural heating of the absorbed oxygen in winter period time.
The cost of a chimney and its installation is much cheaper than other types.
It takes less time to install the chimney.

Coaxial chimney - new technical solution, which replaced the standard chimneys. A feature and a big advantage of this device is that oxygen for combustion in the boiler furnace is taken from the street, and not from home.

Coaxial chimney designs

Chimneys are used for different types of boilers:

B - chimneys for boilers with open cam burning;
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 consider them.

Advantages

Structurally, the chimney consists of two pipes, one plays the role of an outer shell, the other is an inner one. Through a pipe of smaller diameter, combustion products are discharged - exhaust gases. Air enters the combustion chamber of the boiler through the outer pipe to maintain combustion. This system provides a compact and aesthetic appearance, takes up little space. The system provides heating of the incoming outdoor air with exhaust gases - this 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 heat unit, reducing the risk of fire to zero. Additional insulation of the chimney with flame-retardant materials is not required.

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

on gas;
on 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 operating temperatures - -15 - -30 ° С. They are designed for countries with milder climates. As a result - the possibility of freezing of the chimney and failure of the heat unit.

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

When installing a vertical coaxial chimney, we face the problem of collecting condensate. Since the problem is known to all manufacturers, coaxial chimney models designed for vertical installation, complete 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 supervision; it is forbidden to make any changes to the configuration and design of the chimney.
During installation, it is forbidden to use materials not from the manufacturer of the chimney; the necessary additional components must be purchased only at service centers.
All parts of the chimney are firmly connected and tested for flue gas leakage.
The use of sealants and adhesive compositions forbidden.
It is forbidden to join pipes in the thickness of the wall; it is necessary to provide a junction outside it.
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° to the outside, to ensure condensate drain and prevent precipitation from entering the boiler.
The length of the coaxial chimney depends on the model of the boiler, the complexity of the chimney route and ranges from 1 to 7 m (the maximum length for a straight installation for a boiler with a turbine installed, with a power of more than 30 kW.).
It is forbidden to equip the exit of the coaxial chimney below ground level into the window pit of the basement.
Remember, for breakdowns and accidents during the operation of the chimney, the installer is responsible.

Coaxial chimney installation diagram

The exit of the coaxial chimney through the building envelope 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 of the ventilation system and the volume of the room itself, it is necessary to adhere to several norms. The photo shows the requirements for installing a coaxial chimney in different versions:

a- minimum distance from the axis of the chimney to any opening element of the facade of the house;
b - minimum distance from the axis of the chimney to any air intake;
c - the minimum distance to the sidewalks (to reduce the distance, a grate with a deflector is installed, in this case the distance will be 0.15 m);
d - minimum distance from the ground;
e - 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 in the presence of a deflector);
f - 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 - 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 were cases when the service center did not accept equipment for warranty through the installation of a coaxial chimney that was not recommended for this boiler.

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

Coaxial chimney Baxi

Chimneys are made from of stainless steel and high strength polymer materials. The standard kit includes a chimney pipe 1 meter long, a 90° elbow, a wind protection nozzle, and decorative rings. If you need an extension cord, please purchase it 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 for maximum length chimney (5 m), and in the absence of a diaphragm, the combustion chamber will receive a large number of air, which will reduce the efficiency of the boiler. For frost protection coaxial pipe should protrude from the wall by 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.

Photo of the main coaxial chimneys Baxi:

Chimney coaxial Vaillant

Vaillant completes boilers own production coaxial chimneys. Compliance with the dimensions of the nozzles is the key to the successful operation of the boiler. Also coaxial chimneys Vaillent can be purchased for boilers from other manufacturers.

Navien coaxial chimney

Navien smoke exhaust systems from a Korean company have proven themselves well 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 its European competitors, while the quality of workmanship is not inferior to them.