How to close a coaxial chimney decoratively. Typical coaxial chimney for a gas boiler - overview of the design and installation diagram

Due to the growing demand for small-sized heating units gas installations there was a need to develop new constructive solutions for removal of combustion products. The coaxial pipe became such a system.

The products are used primarily for gas boilers. The pipe allows:

reduce the length (footage) of the chimney duct, eliminating interruptions in draft;
remove combustion products through external wall housing.

The use of coaxial systems is indicated in smoke exhaust for heat generators with closed and open combustion chambers. The following devices can be such generators:

gas boilers;
convectors;
radiators, etc.

Advantages and disadvantages of coaxial pipes

Coaxial gas pipes have a number of advantages among analogues. The products not only ensure safe operation of the heat generator, but also eliminate the burning of oxygen in the room, since the dual-circuit system simultaneously removes combustion products and provides passage for fresh air from outside.

Target product benefits:

High performance indicators: fresh air entering the burners heats up significantly as it passes through the inner pipe. This results in minimizing energy consumption and increasing efficiency levels.
When installing a chimney, a hole with a small diameter is required: 200-250 mm. The small size of the systems is also an indicator of space saving.
An increased percentage of efficiency results in complete combustion of natural gas. This characterizes the environmental friendliness of the installation, since unburned fuel particles do not enter the external environment.
There is no heating to critical temperatures of the outer surface - the inner pipe transfers heat to the outer one, which as a result reduces the possibility of ignition of contacting surfaces.
When installing a boiler with a coaxial chimney, the issue of re-equipping the room is simplified (instead of several pipes - one).
Parts for installations are manufactured in various diameters. That is, for boilers with different power ratings, there are various designs coaxial pipes.

Main disadvantages:

The disadvantages of coaxial systems include the inability to remove smoke through ventilation ducts. Especially in apartment buildings. That is, the pipes are led exclusively through a hole in the wall directly to the street.
The exception is complex systems manufactured on a collective basis industrially. The peculiarity of the designs is that individual chimneys are connected into one common (central) one. But the installation of such a system must be carried out during the construction of the facility; in other circumstances, the efficiency of the installation decreases.
Another disadvantage is ignoring the boiler performance. If the device has a power of no more than 23 kW, then the volume of heated water per minute is about 9 liters. Moreover, after turning on the taps, the heating temperature immediately decreases.

Different manufacturers, relying on the listed design features, produce systems with different performance characteristics. This is how coaxial heat generators of European and Korean brands are distinguished.

Korean chimneys

Korean-made gas installations are more in demand, as they are most adapted to changes in gas pressure.

Advantages:

combination of indicators: high quality at an affordable price;
easy to use;
protection sensors are built-in and number 12 (in European systems, the elements require separate installation);
The tubular heat exchanger is durable and resistant to corrosion;
installation of systems is possible at residential and industrial sites;
have high efficiency indicators.

The disadvantage of Korean installations is the difficulty of repair. If any spare parts fail, they cannot be replaced with analogues from other manufacturers. Only “native” parts.

Nevien boilers have the most positive reviews. Especially the Atmo systems series. The advantages include:

resistance to pressure and voltage changes;
production of housing and individual parts from of stainless steel;
Russified control and control panel;
stability in operation at low water pressure.

European coaxial systems

Baxi is the leader among European companies. The company provides storage and flow-through installations in 70 countries.

Features of Baxi brand boilers are:

smoke removal through natural draft (due to an open combustion chamber);
resistance to changes in electricity, water and gas pressure;
corrosion protection is due to the enameled coating of the tank and stainless steel parts;
possibility of working on liquefied gas (reconfiguration);
has the ability to turn off the gas when blockages in the chimney are detected, controls the presence of a flame in the burner;
has the ability to connect to multiple water collection points, parallel connection, etc.

An important advantage of European systems is the ability to replace parts from different manufacturers.

Design of a coaxial chimney

The mechanism of the device performs two functions at once (dual-circuit) and assumes several types of direction:

horizontal (best);
vertical.

Gas boiler kit

The coaxial chimney kit includes various parts that differ in the characteristics of the manufacturers and the type of direction. But in standard set It is customary to define the following elements:

set of straight pipes (inlet/smoke exhaust);
connecting clamp;
coaxial elbow (with an angle of 900);
adapter for pipe connection;
flange and wall trim (decorative).

Additional elements of the coaxial system:

tee;
decorative trim for the outer wall;
cleaning;
tip protecting against gusts of wind;
collection for condensate;
coaxial chimney extension.

Coaxial pipe material

The main raw material in the manufacture of coaxial pipes is steel. Distinctive feature The following grades of material are considered:

Pipes with zinc coating: are characterized by minimal cost and have a limited (short) service life.
Stainless steel products with acid resistant coating: are optimal solution for this chimney, since combustion products contain aggressive chemical components.
Stainless steel pipes without coating.

Scheme. How does a coaxial chimney work?

The mechanism of the coaxial chimney consists of a dual-circuit system that simultaneously separates two gas flows:

using a fan, fresh air from outside is supplied to the combustion chamber to maintain the combustion process;
Smoke is also released into the atmosphere by means of a fan.

A pipe of smaller diameter is considered the central channel for combustion products; accordingly, between the gaps, atmospheric air. The same distance between products is maintained along the entire line (main), which is fixed with jumpers.

Dimensions of coaxial pipe for a gas boiler

Define different formats of coaxial pipes. But the main criterion is to identify the size of the tip of the product:

60/100 mm (for all types of installations);
80/125 mm (for certain types).

Extension pipes and connecting elements are made taking into account the above parameters.

Requirements for installing a coaxial chimney

Before starting installation, choosing a location is a priority. The structure must be installed together with the boiler.

Please consider these parameters:

the distance from the chimney to the ground must be at least 1 m (preferably 1.5);
you can lengthen the chimney using no more than two elbows, so that the footage is equal to 3 m;
the diameter of the hole in the wall varies: 11-12.5 cm;
the pipe is installed at an angle of three degrees to remove condensate;
exit hole - at least 0.6 m from the window.

Preparation for installation

Safety precautions should also be taken into account:

Avoid contact with other objects.
Remove or protect flammable parts and substances from the pipe area.
Take into account the thermal insulation of the walls.

Installation of a vertical coaxial system

Installing the chimney vertically or at an angle is used if it is not possible to lead the pipes directly through the wall or the required distance is not maintained:

Afterwards the chimney is assembled. The connecting elements are clamps.
Mount decorative elements.

Installation of horizontal coaxial pipe

Installation of the unit in the horizontal direction is used if there is a circulation system in the boiler:

The coaxial pipe is connected to the outlet (neck) of the boiler. The connecting element is a clamp.
The fastening area is fixed with bolts on both sides.
Assemble the chimney. The connecting elements are clamps and swivel elbows.
During the process, the slope of the product is observed.
Install decorative trims.

Insulation of coaxial pipe

There is a problem with freezing of the coaxial pipe. But the solution to the problem does not include conventional insulation, because the chimney is exposed to high temperatures.

To eliminate the problem, simply shorten the length of the chimney. If the outlet on the pipe side freezes, it is also reduced. But at the moment, manufacturers have provided chimneys that prevent the ring parts of the pipe from freezing. This is due to the materials used in the manufacturing process, as well as technical characteristics.
Yulia Petrichenko, expert

Coaxial pipes are safe and effective method removal of combustion products. The chimney allows you to install a wall or floor heat generator, without large financial costs excluding refurbishment of the premises. Environmental friendliness and high efficiency indicators have been noted by various experts.

IN modern world The coaxial chimney has become very popular for gas boiler. At correct installation such a pipe performs two important functions at once: it removes combustion products and guarantees the necessary air flow for operation heating system. There are several types of chimneys, which differ in design, material and technical properties.

These designs differ in some characteristics

Main characteristics

In order for a heating system in which an open flame burns to function properly, two rules must be observed: a regular supply of air in sufficient quantities is necessary, and the safe removal of combustion products and exhaust gases into the air must be established. environment.

If in the private sector it is possible to use a stove chimney, then in a city apartment it will be very difficult to implement this option. However, in both cases this method will have many significant disadvantages:

For the flame to burn, a significant influx of air is needed, which will be borrowed from the living space. This promotes drafts and also increases the flow of cool air from the street.
Stove chimneys installed in private houses are most often made in the form of brick blocks with vertical or horizontal smoke channels. Manufacturers of gas boilers strictly prohibit connecting them to such chimneys.
In order to make a separate chimney with exhaust in the apartment, you will need a lot of money. This is a difficult task to achieve, since, in addition to the large financial costs of installation and production, permission will be required from the executive authorities that are responsible for the visual component of the city.

In this video you will learn how to modify a coaxial chimney:

In view of these factors, the installation of coaxial chimneys for boilers is considered the most rational. In addition, this is an economical option that does not require huge funds for purchase and installation.

Appearance and principle of operation

The design of such a chimney consists of one long metal pipe located inside another, shorter one, but with largest diameter. In addition, the set contains various connecting accessories - elbows, clamps, linings - as well as a receiver for collecting condensate.

The types of such equipment may have slight differences, but the device diagram and operating principle are almost identical for all systems:

A thin inner tube is necessary to remove combustion products. It is made of high quality and reliable stainless steel. The inner end is connected to the hole at the boiler outlet, and the outer end is led outside the living room to the street.
The outer pipe is responsible for the flow of air from the environment into the combustion zone. Its inner end is connected to the hole at the entrance, and the outer end is removed from the living area.
The spent waste is discharged into the atmosphere through the inner pipe due to draft, and in its place clean air enters the combustion area through the outer pipe.
The outer pipe does not come into direct contact with hot gases, but it is located in an area of strong temperature difference. This part can be made from cheaper steel.

Don't forget that the kit includes various connecting devices.

Types of chimneys

How combustion products will be removed is influenced by the type of gas boiler, as well as the layout of the room that will be heated. This process can occur in two ways: through the outer area of the building to the side or through the ceiling and roof of a private house. Therefore, coaxial chimneys for gas boilers are divided into two types: vertical and horizontal.

A vertical coaxial chimney for a gas boiler is used only in the private sector. It is designed to remove waste elements through the ceiling. This method is more environmentally friendly and allows for complete heat exchange between incoming and outgoing air. The placement of the pipe mouth affects the formation of good traction.

When placing the pipe vertically in its lower area, it is necessary to install a special receiver to collect condensate. The vertical type of chimney has more high cost, since it is more labor-intensive to install, more material is consumed to create it.

Horizontal type is the only one affordable option for boiler equipment that can be connected in a city apartment. You can arrange such an outlet yourself, since this will require a minimum of materials. Installation is also simple; a device for collecting condensate does not need to be installed. Water will be able to flow out into the street naturally due to the negative slope of the chimney.

The horizontal option is one of the optimal ones for the corresponding boilers

Advantages and disadvantages

The coaxial system has many advantages compared to other types of chimneys. The following advantages can be highlighted:

Clean air, which is needed for the flame to burn, moves from the street through a closed system of equipment. Air from the heated space is not used to operate the device.
This circuit prevents carbon monoxide or natural monoxide from entering the room. There will be no drafts in the house, the operation of the system will not affect the humidity and air temperature in any way.
Coaxial chimney increases the productivity of a gas boiler, natural gas consumption will be economical, and the amount of substances released into the environment will be reduced.
The smoke channel is reliably protected by a casing with an air gap, so there is no open contact with surrounding structures and objects.
With proper installation and operation, the possibility of fire or burns is eliminated.
The purchase and installation of a coaxial pipe will require much lower financial costs than the purchase and installation of another type of chimney.

This equipment has a lot of advantages

Such a system has only one drawback - freezing of condensate on the surface of the outer pipe in extreme cold. However, this is an absolutely solvable problem. The end of the chimney can be insulated with basal or mineral wool.

Some craftsmen are confident that condensate freezing can be avoided by shortening the pipe. Professionals do not advise changing the design with your own hands. Manufacturers have developed a model with a head against ice formation. It can be used to prevent freezing.

Air enters this pipe through its holes in the lower area. This invention is designed to work even in severe frost conditions. The device has a nozzle for inner tube, inside of which a special spiral is placed. The holes for air intake along the edge of the pipe are distributed from below.

Installation features

The horizontal type of chimney is quite easy to install, and it also takes a lot less space. To get the maximum quality work a number of requirements must be followed:

The outer pipe should be 2 meters from the ground.
Distance from pipe to doors, windows, ventilation ducts etc. vertically and horizontally should be at least 0.5 meters.
If there is a window above the ventilation hole, the distance to its lower area should be at least a meter.
There must be a free space of at least 1.5 meters under the coaxial pipe. There should be no obstacles, pillars, walls or fences at this distance.
If there is no receiver for collecting condensate, then the pipe must be placed with a slope towards the ground. Its angle should be from 3° to 12°.
It is prohibited to lead the channel into any space other than the street.
If gas pipes and chimney parts pass nearby, a distance of 20 cm should be maintained between them.

The chimney pipe can be placed under a canopy or balcony. The closer the chimney opening is located to the balcony, the longer the length of the outer part of the pipe should be. There is an opinion that with a horizontal installation scheme, the length of the chimney should not be more than 3 meters. This is not always true. Some types of equipment are 4-5 meters long.

To install a coaxial chimney with your own hands, you need to stock up necessary materials. The list of tools may vary depending on the situation, but most often the following devices are required:

the pipes themselves;
adapter connecting the chimney and boiler;
tee, elbow;
crimp clamps for effective fixation of parts.

Most often, all installation equipment is supplied with the chimney. To route a pipe through a roof, wall or ceiling, use fire-resistant gaskets. They are required to protect materials located near the chimney from ignition and overheating.

Installation and operation

Installation and correct connection systems to the boiler - simple process. To install a horizontal chimney, you need to follow the step-by-step instructions:

First, you need to place the gas boiler in its place, and mark the center of the intended pipe outlet on the outside wall of the building.
Now the boiler should be temporarily removed and using a hammer drill and a cutting bit, drill a hole in the load-bearing wall. Its diameter should be 20 mm larger than the size of the outer pipe.
An adapter must be connected to the boiler outlet hole. When connecting, use a sealing gasket. Then, using self-tapping screws or self-tapping screws, attach the adapter flange to the surface of the boiler.
The pipe must be connected to the external pipe of the adapter. To create a reliable fixation, do not use any sealants.
Be sure to check the tightness of the connections and the fixation of the fasteners. If everything is done correctly, the pipe is inserted into the hole in the wall.
Now the boiler can be returned to its original place and mounted on the wall. The chimney must be installed with a slope of 3-5 degrees towards the street. It should be fixed in the wall with small stones.
Holes between the outer casing and the wall must be sealed with polyurethane sealant.

High-quality ventilation

Although waste substances exit through a sealed channel, and air enters from the outside, care must be taken to ensure good ventilation of the room in which the boiler is located. This will allow you to maintain ideal humidity levels in the room, which will have a positive effect on the operation of the equipment and extend its service life.

No matter how high-quality the system is, it may fail after some time. If a minor breakdown occurs in the boiler room, with good ventilation, carbon monoxide will escape naturally. In this case, the risk of gas poisoning is significantly reduced.

A coaxial chimney is a reliable, efficient and easy-to-install equipment. In order for the system to work efficiently, it is necessary to comply with the installation requirements and follow the operating instructions.

Heating equipment operating on solid or liquid fuel requires the installation of a complete system for removing combustion products. Previously, a classic single-wall chimney was used as an exhaust device. steel pipes, which has a lot of disadvantages. Nowadays more practical and effective solutions based on a coaxial pipe.

What is a coaxial chimney

The concept “coaxial” is used to designate any structure consisting of two objects located around common axis. In the case of a coaxial type chimney, this is a smoke exhaust channel consisting of pipes of different sections.

The distance between the pipes is the same along the entire length of the chimney, including rotary elbows, bends and other elements. This is achieved through special jumpers, which are located along the entire length of the chimney.

The coaxial chimney is made of two pipes with a common central axis, separated by special internal jumpers

The principle of operation of a coaxial chimney

The channel between the inner and outer pipes ensures a constant supply of fresh air, which is necessary to maintain combustion processes. The inner tube is a channel for excretion flue gases and other combustion products. In fact, the special design of the coaxial pipe allows the chimney to perform two functions at once: removal of harmful substances and supply ventilation.

Flue gases are removed through the internal channel, and fresh air enters the combustion chamber through the inter-tube space

The main area of application of coaxial chimneys is wall-mounted and floor-mounted gas boilers with a closed combustion chamber, geysers and convectors. Coaxial type chimneys are not used with equipment operating on solid fuel.

Advantages and disadvantages of the coaxial chimney design

Among the advantages of coaxial type chimneys are:

Despite many advantages, the design of a coaxial pipe is not without drawbacks. At temperatures below -15 o C, the coaxial chimney can freeze severely.

This is due to the fact that, in fact, this is an advantage of the design in question - cold air is heated due to the temperature of the flue gases escaping outside. The combustion products cool greatly and can condense at the outlet of the chimney, which leads to severe icing on the chimney head.

One of the main advantages of a coaxial chimney turns into its main disadvantage - at low temperatures outside, combustion products condense and ice freezes on the pipe head

To prevent icing, you should choose special devices designed to operate under negative temperature, and also more carefully calculate the cross-section of the chimney.

Types of coaxial chimneys

Depending on the method of laying the chimney, coaxial type chimneys are divided into two types:

Vertical - the chimney is located strictly in a vertical position. Gases and combustion products rise from the fuel chamber and are released into the atmosphere above the ridge level. Mostly vertical structures are used in residential buildings and provide a good level of natural draft.
Horizontal - the main chimney channel is represented by a structure located in a horizontal position, which is discharged through load-bearing wall. In this case, flue gases come out in the immediate vicinity of the heating equipment. It is most often used in private homes where closed heating systems are installed.

A vertically oriented coaxial chimney, despite some advantages, is a more expensive and difficult to install system. The total length of the smoke exhaust duct usually exceeds 5 meters, which significantly complicates the process of installation and fixation of the structure.

For the manufacture of coaxial type chimneys, they are used various brands steel and plastic. In accordance with this, several types of chimneys can be distinguished:

galvanized - the most affordable option for a coaxial type chimney. The average service life of the product does not exceed 5–7 years, after which the structure partially rusts or becomes damaged. The cost of the product depends on the manufacturer and technical parameters, but rarely exceeds 2–2.5 thousand rubles;
made of plastic and aluminum - combined option for private use. The internal chimney channel is made of aluminum up to 2 mm thick. The outer pipe is made of high-strength heat-resistant polypropylene. Such chimneys are used only in the private sector for collaboration with boilers of low and medium power;
Coaxial chimneys made of galvanized steel are designed for 5–7 years, plastic products will last much longer
stainless steel chimneys are more reliable and durable than galvanized ones. They are designed for 10–12 years of use. The cost is almost the same as stainless steel products. They are not used in industry and collective smoke exhaust systems, since “stainless steel” does not withstand high concentrations of chemicals;
made of high-alloy steel - the most durable and durable option for a coaxial chimney. High-alloy steel is not afraid of exposure to high temperatures and chemicals contained in flue gases. The average service life is at least 15 years.
A coaxial chimney made of high-alloy steel, unlike stainless steel, is not destroyed by aggressive chemicals contained in combustion products and lasts at least 15 years

The range of some manufacturers (Electrolux, Viessmann, Schiedel) includes models of coaxial chimneys with an additional thermal insulation layer. This is a classic design with two channels, which is located in another pipe. The voids between the outer pipes are filled with non-flammable thermal insulation material, preventing freezing and blockage of the air channel.

Video: coaxial pipe for parapet gas boilers

Basic elements of a chimney

The coaxial chimney consists of various elements, allowing you to manufacture a chimney of the desired configuration for specific operating conditions and structural features.

The coaxial chimney kit contains everything needed for its installation.

Fittings, connecting elements, nozzles and other structural elements are manufactured according to a certain standard, which simplifies the process of assembling and installing the chimney. The range of leading manufacturers includes more than 80 elements of various configurations.

A ready-made coaxial chimney kit from the manufacturer includes the following elements:

To ensure the tightness of all connected parts of the structure, special sealing rings made of heat-resistant material (thermoplastic) are used. When heated to high temperature the ring expands into a more elastic form, which allows it to maintain a seal even at high pressure.

Making a coaxial chimney with your own hands

In order for the chimney to cope with its tasks throughout its entire service life, it must be correctly calculated and correctly installed.

Calculation of chimney parameters

When designing a chimney, attention should be paid Special attention settlement transactions, since the performance of the system as a whole will depend on the parameters of the smoke exhaust. The cross-sectional area of the outlet channel of the coaxial chimney should not be less than the cross-section of the connecting pipe of the heating equipment.

The cross-section of the smoke duct of the coaxial chimney is selected to match the dimensions of the heating equipment pipe

In collective systems, when connected to two or more heating devices, the channel cross-section increases in proportion to the size of their pipes. This is necessary in order to ensure sufficient throughput smoke exhaust duct during simultaneous operation of several boilers.

Table: dependence of the cross-section of the chimney channel on the rated power of the heating device

The cross-sectional diameter of the outlet hole is calculated by the formula - F = (K * Q) / (4.19 * √H), where:

K - constant coefficient equal to 0.02–0.03;
Q (kJ/h) - maximum power of the gas boiler specified in the device specification;
H (m) - design height of the smoke channel.

For example, let's calculate the cross-section of the chimney outlet for the Ariston CLAS B gas boiler. The maximum thermal power in heating mode is 24.2 kW. The height of the smoke channel is 8 m.

To convert power from W to kJ/h, we will use one of the online programs that are easy to find on the Internet. We get that Q = 87 120 kJ/h.
We find the cross-sectional area using the above formula: F = (0.02 * 87,120) / (4.19 * √ˉ8) = 147.03 mm.

After calculations, the resulting value must be compared with the data in the table. It indicates the optimal cross-sectional area of round chimneys for domestic gas boilers. If necessary, the value is adjusted up or down. In our case, you can use a pipe with a diameter of 130 mm.

Necessary tools for installing a coaxial chimney

For installation ready-made kit coaxial chimney you will need:

To make a coaxial chimney yourself, you will need two pipes of a suitable diameter, which are connected using stainless steel jumpers. Steel rivets or self-tapping screws are used for connections.

It is important to understand that it will not be possible to completely replicate the design of finished industrial chimneys. You can only make a straight section of coaxial pipe yourself.

Preparatory work before installing the chimney

According to statistics, coaxial type chimneys are the safest. The rules for their assembly and installation are described in detail in SNiP 2.04.08–87, SNiP 2.04.08–87 and PB 12–368–00. Before installing the chimney, you should carefully study the attached instructions and become familiar with the requirements outlined by the manufacturer of the structure.

In general, when installing a coaxial chimney, the following rules must be observed:

When installing a coaxial type chimney in wooden houses the place where the pipe meets load-bearing wall or the ceiling is sheathed with non-combustible material. Usually an asbestos pipe or a box made of asbestos-cement slabs is used.

Step-by-step instructions for installing a coaxial chimney

Before installing the chimney, you should carefully check the completeness of the purchased device. If any parts are missing, the chimney assembly should be postponed. In addition, it is imperative to check the diameter of the outlet pipe and the cross-section of the internal channel.

The technology for assembling a coaxial type chimney consists of the following steps:

In the designated location, markings are applied for the exit of the smoke duct to the street. For a floor-standing gas boiler, the chimney outlet should be located 1.5 m above the combustion chamber. For wall-mounted installations, it is possible to remove the pipe immediately after installing the rotary elbow.
The chimney of a wall-mounted boiler can be removed immediately after installing the rotary elbow on its pipe
After applying the markings, a hole is drilled using a hammer drill with a crown attachment required diameter at an angle of 3° to the wall surface. It must be taken into account that in addition to the pipe, an insulating gasket is installed in the hole.
An adapter is connected to the outlet pipe of the gas boiler, onto which a straight section of pipe or a 90° coaxial elbow is mounted. To connect the elements, a crimp clamp is used, which is tightened with a Phillips screwdriver.
A special adapter is used to connect the chimney to the gas boiler
An asbestos pipe is installed in the wall hole and sealing collar. Next, the straight section of the chimney is led outside. From the inside, the pipe is connected to a rotary elbow or extension nozzle and secured with a crimp clamp.
The hole in the wall is additionally insulated using special pads. To do this, the contact point is treated with heat-resistant sealant, and the nozzle is screwed onto galvanized screws. If necessary, a deflector or blow-out protection is placed on the end of the pipe.
The deflector protects the boiler from blowing out through the chimney

When installing a vertical structure, a hole in the ceiling is cut using a grinder with a wood saw. A box of asbestos-cement slabs is installed at the junction point. In this case, the distance from the outer pipe to the ceiling should not be less than 20 cm.

A similar condition is met when the pipe exits through the roof. To do this, a special passage element is mounted at the junction point, which is attached directly to the roofing material using galvanized screws.

Video: coaxial chimney in a private house

Chimney insulation

Freezing and icing of the head of a coaxial chimney is associated with condensate entering the air intake duct. To prevent moisture ingress, you should check the slope of the coaxial pipe relative to the combustion chamber. If the slope angle is at least 3 o, then freezing of the tip will only occur at temperatures below -15 o C.

The main mistakes when installing a chimney are related to incorrect inclination of horizontal sections

Additionally, a special element can be installed on the head, which extends the internal channel by 10–40 cm relative to a pipe of larger diameter. In addition, several holes can be drilled in the lower part of the outer pipe. This will allow air intake even when the tip is partially frozen.

If the slope is insufficient, freezing cannot be eliminated, since the condensate will not flow towards the combustion chamber, but, on the contrary, towards the outlet, which will lead to the formation of icing and icicles at the end of the pipe. Insulation by sheathing heat-insulating material With outside pipes won't help.

Video: removing condensation from the air supply pipe in winter

Chimney cleaning and periodic repairs

To operate heating equipment with a closed combustion chamber, natural gas - methane - is used. During the combustion of gas, harmful aromatic hydrocarbons, toluene, benzene, etc. are formed. The formation of soot and burning does not occur as such.

Almost all gas combustion products are discharged through a coaxial chimney. At the same time, complete cleaning of the smoke channel is not required even with daily use. Enough once every heating season check and clean the condensate collector. Once every few years, it is recommended to inspect the smoke duct using special video inspection equipment.

A highly sensitive thermal imager is used to inspect and inspect the chimney

To repair a chimney, you will need to dismantle all elements of the smoke exhaust channel down to the damaged area. After replacement, the structure is assembled taking into account regulatory requirements.

The coaxial chimney is a highly efficient and practical design that significantly increases the efficiency of heating equipment. Subject to the rules described in regulatory documents, a coaxial chimney does not require periodic repairs and reliably removes all flue gases.

Warmth in the house is the main component of coziness and comfort. There are many ways to heat your home. And if for apartment buildings Since this is centralized heating, homeowners prefer to install a variety of boilers. Heating devices operating with fire cannot do without a smoke removal device. Traditional pipes are being replaced by new, more advanced equipment. An increasing number of homeowners are deciding to install a coaxial chimney, which is more practical and effective device for smoke removal.

The term “coaxial” implies the presence of two objects inserted into one another. Thus, a coaxial chimney is a double-circuit structure made of pipes of various diameters, located one inside the other. There are jumpers inside the device that prevent the parts from touching. The equipment is installed in heat generators equipped with closed combustion chambers. These include, for example, gas boilers.

The coaxial chimney is designed in such a way that the inner pipe is designed to discharge combustion products into the atmosphere. The outer one, which has a larger diameter, is used to supply fresh air to ensure combustion

Thanks to the special design of a standard coaxial chimney, it performs two functions at once: it creates an uninterrupted supply of air necessary to ensure the combustion process, and removes combustion products outside. The length of the device most often does not exceed two meters. It is mainly intended for horizontal placement and is exposed to the street through the wall. Less often you can find a structure that extends through the ceiling and roof.

The special design of a coaxial chimney allows it to function according to a completely different principle from a conventional device. The oxygen required for combustion enters the boiler from outside. Thus, there is no need to ensure a constant flow of fresh air into the room through ventilation, which is inevitable for traditional smoke exhaust ducts. In addition, a number of problems typical of standard chimneys are successfully solved:

Reduction of heat losses by heating the air coming from outside from the internal hot smoke exhaust pipe, which results in higher system efficiency.
Reducing the risk of fire in areas of contact between flammable surfaces and the smoke exhaust duct, since the internal pipe, transferring heat to the external one, is cooled to safe temperatures.
The high efficiency of the system allows for complete combustion of fuel, so unburned particles are not emitted into the atmosphere and do not pollute it. A boiler equipped with a coaxial chimney is environmentally friendly.
The combustion process, including the supply of oxygen and the removal of gases, takes place in a closed chamber. This is safer for people, since hazardous combustion products do not enter the room. Therefore, additional ventilation is not required.
Save space due to the compact size of the device.
A wide range of chimneys designed for systems of varying power.

Features of installation of such a chimney system

There are two main types of arrangement of coaxial chimneys: horizontal and vertical. The direction of the smoke exhaust duct is determined individually for each boiler. It must be taken into account that horizontal devices installed only when using a heating device with forced ventilation. At the same time, according to SNiPs maximum length horizontal section coaxial chimney should not exceed 3 m. However, some manufacturers set other restrictions for their products. Therefore, before designing a structure, you should carefully read the characteristics of the device.

When properly designing and subsequently installing a standard coaxial chimney, you must take into account the dimensional parameters indicated in the diagram

Vertical ones are used if, for a number of reasons, it is impossible to arrange a channel outlet for smoke removal directly through the wall: closely spaced windows, small street width, etc. Installation of a coaxial chimney can also be done obliquely. We begin installation of the system with the correct selection of the device.

According to the installation standards for an internal coaxial chimney, the diameter of the boiler outlet should not be larger than the diameter of the outlet channel. We make sure to control this point by checking the chimney passport, which indicates its diameter. Connection to the boiler is made using an elbow, tee or pipe. In this case, each subsequent element is attached to the previous one so that no obstacles are created for the removal of combustion products.

The list of elements required for installation depends on whether the outlet pipe is located on the side or at the top. In the second case, the chimney will be easier to remove. For the first option, horizontal assembly of device parts is used. The structure is brought into a vertical position using brackets of various modifications. For installation of coaxial pipes, a special adapter unit is used. In this case, the clamps rigidly secure the junction area with other elements. Application homemade adapters and extension by winding tape and applying sealant is unacceptable, since this is a very unreliable and unsafe option.

The outlet pipe can be located either on the side or on top of the heating device. In the first case, the mandatory presence of a horizontal section is assumed

When installing a coaxial chimney, remember that the outlet pipe must be at least 1.5 m above the heating device. The pipe outlet is arranged at an angle of at least 3°, this ensures unhindered drainage of condensate. In addition, the outlet of the coaxial chimney is best located at a height of at least 1-1.5 m above the surface, otherwise it may become clogged. If mounted a complex system, then its total length should be about 3 meters.

Requirements! The simultaneous presence of more than two elbows in the design is undesirable. There should be a distance of about 60 cm from the outlet pipe to the nearest windows, and at least half the diameter of the outer chimney pipe to the gas supply pipes.

The fragments of the structure must fit very tightly and fit into each other at a distance of at least half the diameter of the channel cross-section. To guide the chimney around the obstacle, we use special bends with different angles of inclination. It is possible to use two elements at once.

The most critical area of work is the roof. Here it is necessary to carry out work to ensure maximum fire safety of the structure. To do this, we use special insulating pipes, attach non-flammable insulation and be sure to leave an air gap between the ceiling and the pipe. Based on the requirements for the installation of coaxial chimneys, in order to avoid possible contact of the smoke exhaust duct with various items special ones are used protective covers. If the chimney is brought out through the roof, then we carefully seal the exit and cover it with a special apron, which should cover the joint well. If through the wall - any non-combustible materials. A coaxial chimney is always cold - this is one of its distinctive features.

Sometimes homeowners complain about icing on the chimney when installed horizontally. In this case, it is necessary to use special protection:

You should know that each heating device must have its own chimney installed; “combining” is unacceptable.

The coaxial chimney must be equipped individually for each heating device. However, with proper design, a “cascade” connection option is possible

Coaxial chimney is an active design that improves fire protection and environmental characteristics heating boilers, as well as increasing the efficiency of their operation. You can install the device yourself, however, if in doubt, own strength, it is better to entrust this very responsible work to professionals. After all, as practice shows, the work of installing chimneys requires skills and compliance with safety regulations, and competent installation of revisions or condensate drains without the help of specialists is almost impossible.

Coaxial - This word means the presence of one object within another. The coaxial chimney for wall-mounted gas boilers is built using a “pipe-in-pipe” system. . The chimney is a double-circuit design, in which a pipe with a smaller diameter is located in a pipe with a larger cross-section. Inside, the pipes are connected to each other only using jumpers that prevent them from touching.

Coaxial chimneys are used for heat generators with closed combustion chambers. Such heat generators can be not only gas boilers, but also convectors, radiators and others.

A coaxial chimney for a gas boiler performs 2 functions at once: it removes combustion products outside and provides an influx of fresh air, which is necessary to maintain the gas combustion process in the chamber.

As a rule, for boilers that have closed chamber combustion, the length of the chimney does not exceed two meters. It is worth noting that often the chimney is laid simply through the wall to the street. It is very rare, but you can find a vertical coaxial chimney, led out to the street through the ceiling and roof.

Advice! When installing a coaxial chimney, you should try to ensure that the pipes have only a horizontal direction.

If the place in the wall where the chimney is supposed to be installed is located next to a window, then it is better to install the chimney just above the roof. In this case, you will definitely have to assemble the vertical section of the chimney.

The standard set of coaxial chimney for wall-mounted boilers contains the following components:

straight pipes;
tee;
cleaning;
condensate collector;
upper chimney tip;
knee (rotation angle is 90°).

Straight pipes are the direct former of the chimney. The elbow is intended for connection between the horizontal part of the chimney and the vertical, as well as connection horizontal chimney with gas boiler.

If the chimney has only a horizontal orientation, then the kit includes the following elements:

set of straight pipes;
knee (rotation angle 90°);
side chimney tip.

At the moment, the industry offers coaxial chimneys for gas boilers in the following range:

chimneys made of stainless acid-resistant steel;
chimneys for gas boilers made of stainless steel;
coaxial chimneys for gas boilers made of galvanized steel.

In addition, it is worth considering that there are chimneys that have different combinations, that is, the outer and inner pipes can be made of different steel.

Advantages of coaxial chimneys

The first and main advantage of coaxial chimneys is that the air to support the combustion process is taken not from the room, but from the outside. A conventional furnace takes oxygen from the room where it is installed, so it often has to be ventilated to get rid of the lack of fresh air.

The principle of operation of a coaxial chimney is slightly different (see). The combustion product enters the inner pipe, but fresh air flows through the outer pipe.

This design solves several problems at once that are typical for conventional heating devices and chimneys:

The air that comes from the outside comes already hot, since it is heated by the inner pipe due to the passage of highly heated combustion products through it. This greatly reduces heat losses, and as a consequence, increases the coefficient useful action the entire heating system.
Higher efficiency results in natural gas being burned completely. This ensures that particles of unburned fuel are not emitted into the atmosphere, this increases the environmental friendliness of the boiler.
Of no small importance is the fact that the inner pipe, transferring part of its heat to the outer one, becomes less hot. This reduces the risk of fire at the point of contact between the pipe and flammable parts of the room (wallpaper, wood paneling and others).
All heating processes, from the moment of receipt clean air and until the combustion products are removed, they occur in a closed space - the combustion chamber. This makes it more comfortable for a person, since there is no need to take care of additional ventilation of the room into which smoke and carbon monoxide could enter, that is, maximum safety is ensured;
Availability large assortment the size of the pipes - both external and internal - contributes to the fact that It is possible to choose a coaxial chimney for a gas boiler of any power.
Small size, which greatly saves space indoors.

The advantages include the simplest installation. If during the installation of a conventional chimney pipe many difficulties arise, then the installation of a coaxial chimney can be done independently. We can also talk about the relative ease of operation and maintenance of such a heating system.

Installation of coaxial chimneys

All the advantages that a coaxial chimney for a gas boiler has, including safety and environmental friendliness, can be reduced to zero. This situation occurs when the coaxial chimney was installed incorrectly.

Advice! Before you start installing a coaxial chimney, you should make sure that all necessary elements the chimney itself, as well as tools and other materials.

In order to install a chimney, you need:

coaxial pipe or several pipes;
smoke exhaust pipe;
connection adapter;
wall linings - 2 pieces;
flange for linings;
connecting clamp;
tip on the pipe.

The chimney is attached to the heating installation pipe and goes outside the room. If there are any obstructing objects, it is better to remove them before removing the chimney. In addition, if possible, you need to remove flammable substances and objects from the pipe at a safe distance.

In any case, installation begins with choosing a location. This is easier to do when you have already decided on the choice of installation location for the boiler itself. Gas boilers It is better to install it together with a coaxial chimney. The best option will be if the distance from the chimney to the boiler is approximately 1–1.5 m. If there is a need, the length of the chimney can be increased, but so that there are no more than 2 bends in total, and the maximum length is 3m.

The opening of the smoke channel should be located in compliance with certain rules:

distance from the ground – at least 2 meters;
the minimum distance from the door and windows is at least 50 cm

Next, as already noted, you need to remove everything unnecessary from the selected location to a safe distance. After this, you can begin installation by starting to drill a hole of the required diameter, which can vary from 11 before 12.5 cm.

Next, the pipe is connected to the outlet neck of the heating installation using a clamp, which is clamped with bolts on both sides. After this, the chimney of the required configuration is installed. All connections are made using clamps. The chimney exiting the room should have a slight slope so that moisture (condensation) can easily be removed on its own.

After the chimney is installed, installation is carried out decorative overlays, which perform only an aesthetic function.

Insulation of coaxial chimneys

Sometimes a problem arises that coaxial chimneys for gas boilers freeze.

A simple solution seems to be simply insulating it (see). However, this doesn't help. It is for this reason that insulation of coaxial chimneys is not practiced. The only way out of this situation is to reduce the size of the chimney itself.

If the tip freezes due to condensate entering the air intake pipe from a pipe with combustion products, then the length of the inner pipe must be reduced relative to the outer one.

The most the best option there will be an option to install 2 separate pipes, the insulation of which has a much greater effect than the insulation of a coaxial chimney.