Coaxial chimneys vertical installation rules. Coaxial chimney for a gas boiler: installation nuances and design features. The material of the coaxial pipe

When installing any heating boiler (with the exception of an electric one), it is necessary to take care of the smoke exhaust system and the supply of oxygen, which is necessary to maintain the combustion process of the fuel. Boilers with a closed type combustion chamber can be installed in any room. At the same time, the classical scheme for extracting combustion products is completely useless. A coaxial chimney is enough. In this article, we will consider all the rules for installing a coaxial chimney for a gas boiler.

Design

The meaning of the word “coaxial” itself means “coaxial”. These are two tubes inserted one into the other and brought out. From the inside, the pipes do not contact each other due to the system of jumpers.

The reason for this is the different purpose of the tubes:

Small - designed to divert products formed during the combustion of fuel.
A large one is needed to supply air, and therefore oxygen, to the combustion chamber.

In this case, it turns out that fresh air and combustion products do not mix with each other. Such a system is reliably isolated, and the air from the room does not mix with the gases in the chimney.

Important! The most common coaxial structures are horizontal, although, in principle, a vertical chimney can also be equipped.

Advantages

The main advantage of this design is its versatility. It can be used for all types of heating boilers. The most efficient work is the installation of coaxial chimneys for gas boilers with a closed combustion chamber and forced draft. The boiler itself can be wall or floor type.

Here are some more benefits:

Location is horizontal. There is no need to punch a hole in the roof. It is enough to bring the pipe out the window or make a hole in the wall closest to the boiler.
The flue system is isolated and not connected to the air in the room. There is no risk of carbon monoxide penetration into the room.
The air that enters from the street comes to the combustion chamber already heated, due to the fact that it comes into contact with a hot chimney. This improves the efficiency of the boiler.
Ease of installation of a coaxial chimney. Work on its arrangement does not require special skills and special knowledge.
Safety. The coaxial gas duct is reliably protected from the risk of fire, since the system is cooled by relatively cold air from the street.
No need to equip a separate boiler room. Any place convenient for you - a kitchen, an entrance hall, an annex or a basement - is suitable for installing the boiler.

Rules for installing a coaxial chimney for a gas boiler

If the arrangement of a coaxial smoke exhaust system is planned, it is necessary to adhere to the installation and safety rules. This will avoid even the smallest risks associated with the ingress of exhaust gases into the room:

The maximum length of the outlet vertical pipe in a coaxial chimney is 3 m. Sometimes you can find chimneys of a greater (up to 5 m) length. For example, this applies to the installation of a coaxial pipe of a double-circuit gas boiler Ferroli floor type.
The pipe is brought to the street horizontally. In this case, the maximum length of the horizontal section is 1 m.
When installing forced fan draft, there is no need to equip a vertical section.
The height of the gas duct outlet above the ground is from 2 m, and relative to the boiler unit, the excess value is from 1.5 m.
The minimum distance of the chimney pipe outlet from any window or door opening, as well as ventilation grilles, is 0.5 m.
It is undesirable to equip the outlet of the coaxial flue pipe under the window. But if you cannot do without it, the minimum distance between the chimney outlet and the window is 1.0 m.
A slight inclination of the pipe ensures the removal of condensate.

Chimney slope

There is no consensus on this issue:

The most common recommendation is to slope the pipes “away from the boiler”. In general, this is quite logical. The condensate formed during the operation of the boiler flows out, and does not enter the boiler. However, such a system works flawlessly until the onset of severe frosts. In winter colds, the condensate flowing down simply freezes, sometimes even inside the pipe. All this worsens the air intake for the fuel chamber.
You still have to make a decision to make the slope of the pipe towards the boiler. To solve the problem of condensate entering the boiler, an additional condensate collector is installed.

Do you insulate the chimney?

The fact is that the insulation of the gas flue pipes does not solve the problem. The condensate still freezes. This problem can be more effectively solved by shortening the inner tube a little. Naturally, this is true if the pipes are tilted away from the boiler.

Mounting order

Unlike the usual vertical chimney, the coaxial system does not require any professional skills during installation. But at the same time, you must strictly follow the instructions. This is the only way to achieve complete security.

Installation of a coaxial chimney for a gas boiler is performed according to the following algorithm:

Determined with the location of the boiler. Wall models are located on the outer walls, floor - on a small elevation.

Important! Exceeding the outlet on the wall above the boiler, in accordance with the rules, is 1.5 m or more. The diameter of the hole in the wall should be slightly larger than the diameter of the outer pipe.

Install a special element for connecting the chimney to the boiler. All joints and turns are fastened with clamps. Under no circumstances should sealants or adhesive tapes be used.

Important! The number of swivel elbows for the entire system should not exceed 2.

Each heater requires the obligatory removal of combustion products. A particularly urgent task of removing smoke, soot and soot is becoming for owners of country houses where there is no central heating.

Recently, a coaxial chimney has become widespread, since it is the most efficient and practical device for a number of heating equipment.

One of the most affordable and reliable coaxial chimneys at the moment is the STOUT system. The equipment is designed to work with most modern gas boilers from European manufacturers. The elements are ideally suited to each other, do not require complex installation and are tested for operating conditions in our country.

Warranty for all products - 2 years. The number of elements will allow you to assemble any smoke exhaust system that will work perfectly in your home. STOUT equipment is produced at the same factories where premium brands order goods, but it costs significantly less - there is no need to overpay for a big name.

What is a coaxial chimney

A coaxial chimney is a structure that consists of two pipes of different diameters inserted one into the other. Also inside the device there are partitions that prevent parts from touching. A coaxial chimney takes air to maintain combustion from the street, and not from the room. It is this design feature that allows the device to be operated without additional ventilation equipment. The main difference from a traditional chimney is shown in the figure:

Such equipment is installed in thermal devices equipped with closed combustion chambers, namely:

Gas boiler.
Gas convector.
Gas generator.
Gas column.

The maximum length of the device, as a rule, does not exceed two meters. The bulk of this type of chimneys is designed for horizontal installation and is led out through a hole in the wall of the building. A vertical coaxial chimney is more difficult to install, the length of the device pipe is much longer and it is brought out through the ceiling and attic.

Coaxial chimneys for gas boilers help solve many problems that remained relevant when using traditional devices. The main changes were:

A gas boiler with a coaxial chimney is a safer device, since the coaxial pipe cools quickly due to the influx of cold air through the outer pipe and thus the risk of ignition is reduced.
A coaxial chimney for a gas boiler increases the efficiency of the heater by heating the air coming from the outside from the exhaust gases.
A boiler with a coaxial chimney does not harm the environment due to the complete combustion of fuel and the absence of harmful emissions into the atmosphere.
Gas boilers with a coaxial chimney are absolutely safe for humans, because the entire combustion process takes place in a closed chamber and does not disturb the comfortable microclimate in the room.
The small length of the device, which significantly saves space in the house.
A wide range of different power devices.

How is the installation of the chimney

Installation of a coaxial chimney can be done in two ways: vertically and horizontally. In both cases, the maximum length of the horizontal section cannot exceed 3 m.

Vertical installation is carried out only in cases where it is not possible to output the device through the wall. Most often this happens if:

There is a window next to the device, at a distance of less than 60 cm;
Insufficient street width.

A coaxial chimney for a gas boiler must be installed in accordance with SNiP, the main recommendations are:

A floor-standing boiler with a coaxial chimney is installed in rooms where it is not possible to provide a constant air supply.
The inlet pipe must be 1.5 m above the heater.
The diameter of the boiler nozzle must not exceed the cross-sectional diameter of the outlet channel.
The flue is introduced into the boiler room, where there is a turbocharged geyser or boiler for heating.
The pressure of the gas that passes through the channel should not exceed 0.003 MPa.
The combustion products of the fuel that the column or boiler processes can be removed through the outer walls of the structure.

When placing the flue at a great distance from the outer wall of the building, a special extension is used to carry out the passage of the smoke channel.

The height of the chimney must not exceed the height of the roof ridge.
To rotate the structure of the smoke channel, knees are used with a rotation of the corresponding degree.
It is not recommended to use more than two bends in one design. This will greatly complicate the operation and cleaning of the device.
The elements are fastened using socket technology.
It is forbidden to locate pipe joints at the point of passage through the wall.
Each heating device - a column, a boiler, a generator must be equipped with its own smoke channel, the use of combined gas ducts is prohibited, in order to avoid violating fire safety standards. However, the so-called. cascading devices.

When installing heating equipment, it becomes necessary to organize the output of gases burned during operation. Coaxial chimneys for boilers are the best option for the system for removing combustion products. What are the advantages of using a coaxial type chimney device and what is the peculiarity of its installation?

The device has a two-channel circulating system, through which air masses are simultaneously supplied to the boiler and the fuel products of combustion are removed. This type of chimney is used, usually for turbocharged or condensing heaters with natural or forced exhaust of combustion gases.

The principle of operation of a coaxial chimney is quite simple:

combustion products pass through the inner tube, heating it;
the air that enters through the outer channel is heated by contact with the exhaust outlet of the combustion products;
already warm air masses enter the fuel chamber, contributing to the full combustion of the fuel;
the cold air stream passing through the outer duct prevents the system from overheating.

As a result of this process, the efficiency of the heating system is significantly increased, and the fire safety of the entire device is increased. The presence of a device for collecting condensate protects against moisture entering the boiler, and a tip adopted from above the system protects against precipitation entering the channels.

When installing coaxial type chimneys for a gas boiler, the following parameters are taken into account:

heating unit power;
the level of thermal insulation in the room;
average monthly air temperature outside the building;
type of fuel used;
overall performance of the boiler.

Such factors are taken into account when choosing the size of pipes for installing a chimney.

Types of coaxial smoke exhaust pipes

Installation of chimney channels is carried out in two ways - vertically and horizontally. In the first, the pipe is led through the roof, and in the second, the output is made through a window opening or wall. Most often, horizontal mounting of the device is used.

The technical characteristics of a coaxial chimney and its service life largely depend on the material from which the pipes are made.

Aluminum

The material is quite light. Its main advantage is resistance to temperature extremes and good anti-corrosion characteristics.

Due to the inability to withstand high temperatures, aluminum is rarely used in a coaxial chimney system. It is mainly used in combination with plastic.

stainless steel

Stainless steel pipes are the most popular. They do not deform under the influence of sharp temperature fluctuations and endure heating up to 550 degrees. The material is highly resistant to aggressive substances and can be used as a chimney for 30 years.

Two types of stainless steel pipes are used for the coaxial combustion gas exhaust system:

Insulated. Mainly used for installation of vertical chimneys. Such a pipe greatly increases the aerodynamic qualities of the device and is installed during the construction of the building.
Uninsulated. It is used for both domestic and industrial coaxial-type chimney structures. Differs in longevity

The disadvantages of using non-insulated pipes include high vapor condensation.

Plastic

Chimneys made of heat-resistant plastic are used for condensing gas boilers. In addition to light weight and the ability to withstand heating up to 205 degrees, the material has a relatively low cost.

Plastic coaxial pipes are easy to install. But still, unlike stainless steel products, the duration of their use is low. Such chimneys are used exclusively in gas exhaust systems with low temperature conditions.

When selecting pipes, you should pay attention to the recommendations specified by the manufacturer for the type of heater.

Technical requirements for installing a coaxial pipe

The installation of a coaxial chimney system for gas heaters with a closed-type combustion chamber is carried out in accordance with regulatory documentation. In case of deviation from the required standards, the gas service does not give permission to operate the boiler.

According to the rules established by SNiP, the following technical requirements are prescribed for coaxial chimneys:

Coaxial smoke exhaust structures can be placed in a vertical and horizontal position. Their installation, regardless of the type of installation, is carried out after the approval of the provided project by the gas service.
It is not allowed to connect heating units with different types of outlets to the same network - forced and natural.
The placement of the chimney pipe on the facade should not be from the level, if below 2 meters. The diameter of the hole for the chimney outlet in the wall must be made 1 centimeter larger from the pipe. For wooden houses, it is recommended to increase the opening by 5 centimeters and protect it with non-combustible materials.
In multi-storey buildings, the distance from the pipe to the window opening above it should be at least 1 meter. If the doors and windows are on the same level with the chimney system, then a distance of 50 centimeters is maintained.
The outlet of the coaxial pipe should be 1.5 meters higher from the top point of the heat generator.
From the gas pipeline to the chimney, a distance of more than half the diameter of the outer pipe is observed.

When removing the chimney outside the building, the joints should not be in the wall. All parts of the structure must fully fit each other in diameter. Chimneys for heating systems with a capacity of not more than 30 kilowatts are allowed through the walls. Under no circumstances should smoke escape through the connections of the combustion product.

In order to avoid problems with the assembly of parts and the tightness of the entire structure, it is recommended to purchase a chimney device as a set from one manufacturer.

Installation of additional equipment for gas heating appliances is carried out exclusively by specialists in this field. Also, every year a complete maintenance of the system is carried out - checking the connections for tightness, removing accumulations of condensate, and inspecting the integrity of the structure.

Installation options for coaxial chimneys

Coaxial type smoke extraction systems for boilers are quite safe to use if properly installed. The length of the horizontal elements of the chimney must be more than 1 meter, and the pipe itself must be more than 5 meters. The height of the device itself at the outlet is set below the roof ridge. The size of the pipes is calculated so that there are no joints in the wall opening.

Installation of chimneys is carried out in two ways - external and internal. Each option has its own installation features.

Outdoor unit installation

This method is used for finished buildings with heating not yet carried out. Initially, markings are made for the location of the chimney on the wall of the room. The installation of the device itself is quite simple:

a hole is made in the wall for the outlet of the pipe;
areas with low heat resistance are insulated with basalt insulation;
a pipe is inserted into the prepared opening;
using a single-circuit outlet of the chimney pipe 90 degrees and a double-circuit tee, the device is connected to the heating unit;
the elbow is used as a connecting element, and a tee with a removable slope for vertical fixation of the structure;
the connected system is attached to the wall with brackets.

After that, the assembly of the entire structure is carried out. All parts are fastened with clamps. The section of the opening for the chimney outlet is sealed, and the pipe is protected by a special casing. The joints of the opening are closed with an apron.

Installation of an internal chimney

Before installing the fuel combustion exhaust system, the compatibility of the diameters of the outlet pipe of the heating unit and the chimney is checked. The size of the pipe at the outlet of the boiler should not be larger than the volume of the exhaust pipe.

Installation is carried out in the following sequence:

A connecting elbow and a tee are attached to a special chimney outlet on the boiler. For double-circuit units, a transition node is also installed. All joints are fixed with clamps.
An opening is made in the wall to bring the chimney out.
If the chimney pipe is located on the side of the boiler, then after installing the transition elements, a horizontal chimney structure is assembled. At the same time, the opening for the outlet to the street of the pipe is located from the fixtures to the heater at a distance of 1.5 meters.
In order for the condensate to randomly flow down the channel into a special collector, the outer pipe is fixed at a slight slope.
The upper location of the outlet pipe on the boiler greatly facilitates the installation of a chimney structure. Vertical assembly is carried out using special brackets. An air gap is left at the outlet of the chimney roof and material with non-combustible properties is laid. The joints are covered with an apron.

After assembling the structure, the tightness of all joints is carefully checked.

Pros and cons of coaxial smoke exhaust systems

Coaxial type chimneys for boilers have many advantages:

Improving the performance of the heating system. Due to the heated air masses coming from the street to the furnace, complete combustion of the fuel is carried out, which, due to the air masses, is not spent on heating the boiler. Therefore, the efficiency of coaxial devices is much higher than that of simple chimneys.
Safety of use. Air, penetrating from the street into the channels, does not allow the outgoing gases to heat up strongly, the system thereby increasing the fire safety of the entire structure. The hole in the wall through which the chimney is taken out can not be additionally isolated.
Universal application. Coaxial devices for the output of burnt gases can be used for turbocharged units operating on any type of fuel.

One disadvantage of such chimney systems is the possibility of ice forming on the pipes at low air temperatures. This is due to the presence of condensate in the channels. It is formed due to the fact that the temperature of the outgoing combustion products falls below the dew point.

Coaxial chimneys are much more productive than conventional smoke extraction devices. They are easy to use, safe, practical and the installation of the system is quite simple. The relatively high price of products is fully justified by the effectiveness of the application.

Do-it-yourself installation of a coaxial chimney of a gas boiler is often done to optimize the functioning of the heating system. If it does not work on electricity, then without fail it requires smoke removal. Previously, standard chimneys were used for this, but today more advanced devices have appeared.

What is a coaxial chimney

Construction involves placing one object inside another. Such a chimney is made in the form of a double-circuit product. As a building material, pipes of different diameters are used. Such "structures" are divided into several types:

External and internal. Devices are divided into these categories depending on the location. The first variety is placed outside the building and is fixed with special brackets directly to the facade. A distinctive feature of the appearance is the convenience during installation and use. Internal types of chimneys are mounted in shafts prepared in advance. This variety is quite difficult to mount and maintain, moreover, strict adherence to safety regulations is required.
Uninsulated and insulated. The second option is useful in the cold season, when the channel responsible for the entry of air masses into the system freezes with a high degree of probability. This leads to a reduction in the supply of oxygen to the combustion chamber, which reduces the efficiency of the heating equipment. Insulated systems are able to ensure the functioning of the boiler even at extremely low temperatures. This variety differs from a conventional chimney by the presence of an additional pipe, and the system is a nested element. The space is filled with any type of insulation.
Collective and individual. The second variety is used when it comes to servicing one boiler. It is a simple design without branches. When it is required to ensure the removal of combustion products generated during the operation of several heating units, a collective type of chimney is used. It is a mine system with several branches.

Each of the described varieties has its own characteristics and scope. Before installing one or another type, it is recommended to study in detail all the information about them.

Accessories for a coaxial chimney can be purchased from specialized stores

Device and principle of operation

The design of such a device allows you to perform several functions, that is, to provide a stable supply of oxygen to “stimulate” the flame in the furnace and remove smoke. The device includes several modules, which include:

Straight pipes. They are used to build the main building.
Decorative overlays, which are flanges that cover the places where the chimney shaft passes through building structures.
Tees that become part of the system if combustion products need to be removed from several heating units at once.
Seals (they are devices that ensure complete tightness of the housing at the points of passage through the wall).
Connecting devices. They are 90° and 45° bends or couplings.
Reinforcing elements, which include clamps, as well as brackets.
Devices designed to remove condensate. This structural element is located on vertical sections, equipped with a water-type shutter that does not allow air pressure to decrease.
Adapters. They are needed to connect the flue system to the boiler.
Accessories equipped with a special hole. Such a "viewing window" is needed to diagnose and remove contaminants from the chimney.
Nozzles. They are needed for the timely removal of smoky masses, air intake from the street.

The operation consists in the external intake of air masses from the street through an external channel. While moving through the pipeline, the air is heated due to contact with the channel inside a special shaft for the "transportation" of smoky masses. Heated oxygen enters the furnace, which increases the efficiency, reduces the consumption of gas fuel during the operation of the boiler.

It is important! The channel outside plays the role of a cooling device that lowers the temperature on the surface of the pipeline. Due to this, a chimney of this kind can be mounted in a private (made of wood) building without taking serious measures to ensure safety (fire).

As mentioned above, the internal channel provides "transportation" of smoky masses. It is often equipped with special heaters, which makes it possible to increase traction in vertical structures. This variety has three channels, one of them is designed to be filled with basalt-based insulation. To ensure the smooth operation of a home-made chimney, it is required to make calculations in advance and perform the installation with high quality, taking into account the structural features.

Chimney installation diagram

Pros and cons

The main advantage of the coaxial chimney is that the air masses used in the operation of the boiler are not taken from the room, but from the open air. This eliminates the need to make a powerful ventilation system, moreover, even a small room is suitable for use as a boiler room in such a situation.

In addition to the described features, the positive aspects of such a device include:

High installation speed. The design of the chimney cannot be called complicated, so the installation can be done independently (it is not necessary to involve specialists and pay for their services).
The possibility of using for the removal of combustion products from the boiler room of an apartment building.
The ability to use to increase the efficiency of almost any type of heating equipment.
A good indicator of traction, which is observed if the installation work is done with high quality.

Thanks to the listed positive aspects, the coaxial chimney is popular among a large number of people. In addition to the advantages, two-channel chimneys have a number of disadvantages.

These include:

The need to coordinate the installation with the sanitary and epidemiological supervision service. This is due to the fact that during operation a lot of toxic condensate is emitted. Pouring this substance on the ground is strictly prohibited, and disposal is carried out in specially designated areas. However, if you use this type of chimney in a private house, then all claims will be reduced to the individual wishes of its owners. But when installing collective-type systems, obtaining permission from the service mentioned above is a prerequisite.
The need to organize pipe insulation from coaxial condensate. Even small mistakes made during installation will lead to icing of the outlet, which will cause a decrease in thrust.

Despite the shortcomings described, chimney systems of this kind are often installed both in private houses, cottages or cottages, and in multi-apartment buildings. However, the installation procedure must be treated with maximum responsibility and attention. This will help you avoid unnecessary expenses in the future.

Moreover, installation errors can lead to deformation of the chimney communications during operation. Some problems can be solved by specialists, but if problems are ignored for a long time, it may be necessary to purchase a new system and install it.

The diagram clearly shows how a coaxial chimney works.

Do-it-yourself installation of a coaxial chimney of a gas boiler

There is nothing complicated in the installation algorithm, however, there are features that have a tangible impact on the functioning of the system in the future. Before purchasing a finished chimney system, you need to carefully study the diameter of the pipeline that will be connected to the boiler.

It is important! An important role in the installation and further operation is played by the requirements of SNiP. Their observance is a prerequisite, since neglect of such rules can lead not only to problems with sanitary and epidemiological supervision, but also to accidents.

Regulatory requirements SNiP

The rules for installing chimneys for a gas boiler, as well as the relevant standards established by the state, are detailed in SNiP 2.04.08-87 and 2.04.05-91. Drawing up individual projects, calculation procedures and installation are carried out in accordance with them. Violation of these rules will lead to the failure of the gas service and make legal installation impossible. SNiP is regulated by:

Placement of the chimney on the facade. The head should be at least two meters from the ground. The size of the hole in the wall should be 1 cm larger than the diameter of the chimney for a brick wall and 5 cm for a wooden wall.
Maintenance. It should be carried out at the beginning and end of the heating season. It is required to remove condensate and check the joints for leaks.
Application of similar systems in MKD. The structure should be mounted at least half a meter from door and window openings. There must be at least 1 m to the window above the pipe.
Installation. The chimney pipe must be at least 30 cm from the wall. If we are talking about turbocharged boilers - from 1 m. A narrowing diaphragm must be installed without fail, which is required to limit the flow of air into the closed combustion chamber.
Fire safety standards. The minimum gap between the chimney pipe and the wooden wall should be 5 cm. This is due to the fact that during operation the outer surface is practically not subject to heat. Non-combustible materials must be placed between the wall and the pipeline. The best option is basalt insulation. The chimney pipe should be at least 1.5 m from the windows and doors of neighboring houses. There should not be poles, trees or other objects in this gap. It is forbidden to use a standard chimney to discharge combustion products (only coaxial varieties).
Restrictions on output through the facade. The ban on the flow of condensate to the ground must be observed without fail. Therefore, the pipeline must be installed at an angle to the boiler. If the design includes a special device designed to drain condensate, then the slope of the outlet pipe to the ground is allowed (in order to drain rainwater). If we are talking about the use of a collective type of chimney, then the disposal of condensate should be agreed with the sanitary and epidemiological supervision service.
Features of each type of chimney system. It can be horizontal or vertical. It is strictly forbidden to connect to the same network of chimneys with forced and natural type of removal of combustion products.
Features of laying a horizontal section. It is allowed to lay through an adjacent room that is not intended for human habitation, if the length of the pipeline section that will pass through it does not exceed 3 m. If we are talking about a turbocharged system with forced removal of combustion products, then it is allowed to increase the pipe section passing through the non-residential premises , up to 5 m.

The described safety requirements may change over time, therefore, before starting installation work, it is necessary to obtain expert advice.

Requirements of sanitary norms and rules for distances between objects

We make the installation

If you want to independently install the chimney of the internal variety, then all actions are performed in the following sequence:

Check that the dimensions of the boiler nozzle and flue pipe match.
Prepare a hole through which the pipeline will be brought out. Its diameter must be made slightly larger than the same parameter of the pipeline.
Connect the appropriate element of the flue system to the gas boiler nozzle.
Fix the connection with bolts and clamps.
Consistently assemble the entire chimney system. Each element is installed in its “own” place, after which it is fixed with clamps (they increase the level of connection reliability).
Install overlays that perform decorative functions over the fasteners. They will help maintain the aesthetic appearance of the structure.
Take the chimney pipe outside.
Ensure joint tightness.
Put on a casing with protective properties on the pipe. This will help to increase the level of safety of the occurrence of uncontrolled fire.

After completing the described installation process, it is required to check the tightness of the joints, cover them with a special apron.

If we are talking about an external chimney system, then the installation procedure has its own characteristics. When it is required to install such a chimney, it is necessary to adhere to the following algorithm:

Determine the exit point and mark its location on the wall of the building.
Make a hole at the mark. The diameter must match the cross section of the pipe.
Connect the chimney to the heater. This requires the use of a double-circuit elbow and a special tee. It is needed to ensure the stability of the finished structure in a vertical position.
Fix the "structure" to the wall with brackets.
Seal the section of the chimney exit from the wall and continue to collect it to the desired height.
Fasten the structure to the outer wall using clamps.

To ensure a reliable connection of double-circuit pipes, it is required to use transitional nodes.

Transition nodes connecting double-circuit pipes are important design elements of the device

Features of horizontal and vertical mounting

If we are talking about a horizontal installation option, then this procedure must be carried out taking into account the technical features of the building. The following parameters must be calculated in advance:

Pipe height. The distance from the outlet pipe to the hole in the wall must be less than 1 m. The direct outlet of the pipe from the outlet pipe to the street is not allowed.
Number of rotary couplings (less than three).
The maximum length of the horizontal section. Should not exceed 3 - 5 m.

An increase in condensate production is a feature of the operation of the chimney system in the cold season. Excess moisture loss is due to harsh operating conditions.

When it is required to install a vertical chimney, it must be remembered that this procedure can be carried out in two ways:

Cascading. It involves connecting several heating units to one pipe at once. A similar scheme is quite often used in MKD.
Individual. The maximum length of the vertical elements is 7 m. This allows installation in a two-story private house.

Chimney installation options in a private house

If we are talking about a brick building, then the chimney system can be installed both inside and outside. However, effective thermal insulation is required in any case. This will avoid unpleasant consequences, which are likely to occur during intensive operation of the boiler, if the insulation is neglected.

Video: options for connecting a coaxial chimney to gas boilers

Installing a chimney is a procedure that can be performed by any tenant of a private or multi-apartment building who has basic skills and knowledge in the relevant field. If these are completely absent, then contacting specialists in the installation of such systems is the best solution. This approach will help to avoid unnecessary costs, as well as problems with certain services associated with errors that are made during installation, and their consequences, which manifest themselves during heavy use.

Content

Device and principle of operation
Advantages of coaxial chimneys
Installation and connection to a gas boiler

Introduction

The main feature of gas boilers with a closed combustion chamber is that they use outside air for combustion. They also need a chimney to vent the products of combustion into the atmosphere. Both of these functions are combined in a unique device - a coaxial chimney for a gas boiler.

In this article we will talk about the device, the principle of operation and the advantages of coaxial chimneys, the requirements and regulations governing their installation in private houses and apartments, as well as what you should pay attention to when doing the installation yourself.

Device and principle of operation

Wall and floor gas boilers are divided into two large groups: with an open and with a closed combustion chamber. The first ones use the air from the room for work. That is why, in the place where such a boiler is installed, there must be good ventilation. To remove gases, traditional chimneys made of a material suitable for working with aggressive media are used.

Boilers with a closed combustion chamber are completely isolated from the room. The air supply to them is carried out from the outside, and flue gases are also removed there. To perform both of these functions at the same time, a coaxial chimney is designed. What is its device?

Photo 1: Coaxial chimney device

The term coaxial in technical markings means two-wire. An analogue of the cores in the chimney is performed by two pipes of different diameters, inserted one into the other. To hold the inner pipe in the center of the outer pipe, they are interconnected by special spacers. In addition to performing their main function, they also give the structure additional rigidity.

The principle of operation of a coaxial chimney is very simple. Gas combustion products are discharged into the environment through the inner pipe, and at the same time, the air necessary for combustion enters the gas boiler through the outer pipe.

Most often, in conjunction with gas boilers, horizontal coaxial chimneys of short length are used. They are brought out directly through the wall of a country house or an ordinary apartment. There is also a vertical structure, which is mounted in the usual way through holes in the ceilings and roofs.

Photo 2: Anti-icing coaxial chimney kit

To combat icing in horizontal installations, a special design is often used. Its peculiarity is that the pipe for the removal of combustion products protrudes from the air intake pipe for a considerable distance. Openings for air intake are located only in the lower part of the outer pipe, which excludes the ingress of atmospheric precipitation.

The most common are coaxial chimneys 60/100 with an inner pipe with a diameter of 60 mm and an outer 100 mm. Models with such parameters are produced by many manufacturers, such as: Baxi, Vaillant, Buderus, Bosch, Viessmann, Ariston, Ferroli, Electrolux.

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Advantages of coaxial chimneys

Despite its simplicity, the advantages of a coaxial chimney are quite significant. In addition to the obvious advantages of this design, there are a number of advantages that do not immediately come to mind. Let's look at them all in order:

Photo 3: Vaillant 60/100 coaxial chimney system

The combustion chamber is completely isolated, so the boiler does not burn out the air in the room. It also excludes the entry of carbon monoxide into the living space. For this reason, the installation of a heater does not require the organization of a special boiler room, such as for. It can be installed even in the room of an ordinary apartment of a typical multi-storey building.
Passing the way from outside to inside, the air is heated by flue gases going in the opposite direction through the adjacent channel. Due to this, the efficiency of the gas boiler increases.
The outer walls of the chimney have a safe temperature due to the cooling of the central channel by the flow of outside air directed into the system. This increases the fire safety of the system in contact with the elements of the cladding and ceilings of the building.
Installation of a coaxial chimney is very simple. For installation, you do not need to connect expensive specialists and carry out serious redevelopment with large-scale construction work. All work can be done by the owner with his own hands.

Despite all the seeming simplicity of connecting a gas boiler to a coaxial chimney, some requirements must be met during installation, in many respects similar to the rules for installing chimneys at. The safety and efficiency of the entire system depends on their implementation.

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Installation and connection to a gas boiler

As we have already found out, the coaxial chimney can be installed both vertically and horizontally. It is much easier to build a horizontal chimney, however, due to poor natural draft, it is only suitable for those models that are equipped with exhaust fans.

Works on the installation of gas chimneys are regulated by regulatory documents SNiP SP 42-101-2003. We will list the basic rules and points that should be considered when installing coaxial chimneys. Let's start with horizontal structures:

When purchasing a set of coaxial chimney, you should make a choice according to its cross section. It should not be less than the outlet pipe of the gas boiler.
According to the regulated rules for the installation of chimneys, the length of the horizontal section should be no more than 3 m. Some manufacturers recommend longer lengths for their models, relying on the increased power of exhaust fans.
The installation of a coaxial chimney should be carried out at an inclination of 3 ° for each meter of pipe away from the boiler. This is done in order to set the direction for the flow of the resulting condensate.
When planning a place for a hole in the wall, it should be borne in mind that there should be a distance of 0.5-1m from the outlet pipe of the boiler to the wall. This is done in order to avoid icing of the chimney inside the room at low temperatures in winter.
When installing a gas boiler near windows, it should be borne in mind that the distance from the outer pipe of the coaxial chimney to the nearest window must be at least 0.5 m. It is strongly not recommended to bring the pipe under the window. If there is no other possibility, then it should be at least 1 m below the window level. The distance to the gas supply pipe should be at least half the diameter of the coaxial chimney.
In order to avoid contamination, the outer pipe must exit at a distance of at least 2 meters from the ground.
If the coaxial chimney is located under a canopy or balcony, then it must have a certain length of the protruding part. How to determine it is shown in the following figure:

Photo 4: Rules for installing a coaxial chimney under a canopy

A vertical coaxial chimney is installed if for some reason it is impossible to install a horizontal one. The installation of such a design is more complicated and the same requirements apply to it as to the installation of a chimney for a solid fuel heater, such as. Here are the main points to pay attention to:

When assembling the chimney elbows for a gas boiler, each upper elbow should be inserted inside the previous one and connected with clamps. If this rule is violated, condensate will penetrate through the joints and flow down the outer walls of the chimney.
To collect condensate, ease of cleaning and maintenance, a tee is required at the bottom of the structure.
Particular attention should be paid to the section of the coaxial chimney located on the roof. How to build this part of the chimney is clearly shown in the following figure: