Which pipe to put in the flue from the boiler. Varieties of chimneys oriented for a solid fuel boiler
The chimney is an important part of the boiler equipment, ensuring the safe removal of combustion products. He is responsible not only for the removal of exhaust gases, but also for the supply of oxygen, without which combustion is simply impossible. There is a large selection of chimneys for solid fuel boilers made of various materials on the market. In this article, we will look at which of them are the most effective, as well as tell you how to make a chimney for solid fuel boiler with your own hands.
The chimney is an integral part heating system. Without it, not a single boiler will work, no matter what fuel it operates on. The main task of the chimney is to divert flue gases and fuel combustion products from the house to the outside. Without it, all the smoke will go into the room, creating a life-threatening situation. Choosing and installing a chimney on a solid fuel boiler is a responsible task, in which you need to pay attention to the smallest nuances and have certain knowledge and skills.
Traction force
One of the main criteria when choosing a chimney is the traction force that it is able to provide. It depends on it how efficiently and quickly the exhaust gases will leave the room, as well as the overall performance of the heating equipment. The draft in the chimney is determined by the speed of movement of gases, which are formed as a result of the collision of air flows with different temperature and changes in atmospheric pressure.
The magnitude of the traction force depends on many factors, but the main ones are the shape of the chimney (presence of bends and length) and the cross section of its pipes. To get the best possible draft, the chimney should be straight and tapering towards the top. The more bends in the pipe, the weaker the draft, since the air takes more effort and time to pass from the boiler to the outlet. For this reason, when installing a chimney for a solid fuel boiler, it is necessary to try to make as few turns, bends and slopes as possible. To do this, it is better to place the heating equipment in a room from which you can immediately bring the pipe out. Depending on the characteristics of the boiler, this can be a kitchen, an entrance hall or a separate utility room - a boiler room.
Parameters that determine the efficiency of traction:
- If the chimney is constantly buzzing or periodically starts to make noise, it is recommended to install a special damper (gate) in it. It will help regulate the traction force and allow you to achieve the highest possible performance.
- If you notice that flue gases and smoke gradually penetrate into the room, then the chimney has a low draft. Usually such signs appear during the first test. In this case, it is necessary to revise the structure of the structure, make it more direct and eliminate possible malfunctions.
- To obtain consistently good draft, the height of the chimney for a solid fuel boiler must be at least 5 m. In this case, the pipe coming out of the roof to the outside must rise at least 1 m above the ridge beam.
Design features
If you are familiar with the basics of physics, then you should know that the smoke exits the combustion chamber of the boiler in a spiral, and its speed gradually increases. A similar phenomenon necessitates the arrangement of the most direct and vertical chimney. If this is not done, then the trajectory of the movement of smoke will be disturbed, and the thrust will weaken.
You should also take into account the sectional shape of the pipe for the chimney of a solid fuel boiler. The optimal shape is a circle or an oval. Square and rectangular pipes cannot ensure the most efficient removal of flue gases. In this case, turbulence will form, soot, soot will quickly appear, the pipe will become clogged, and the draft will be insufficient. The choice of section shape and length of the chimney is determined by the heating system used, the type of boiler and the features of the building.
Types of chimneys
In any solid fuel boiler, the flue gas temperature can vary from 180C to 500C. Naturally, not every material is able to withstand such extreme conditions, therefore, for the manufacture of chimneys, special high-strength and temperature-resistant raw materials are used.
Varieties of chimneys depending on the material:
- asbestos-cement;
- brick;
- ceramic;
- metal;
- glass.
Each type is different operational characteristics, cost and method of installation.
Asbestos-cement chimneys
Asbestos-cement pipes were widely used for the construction of chimneys only some 20 years ago, but they were quickly superseded by more advanced materials. Despite the low cost, such chimneys often could not withstand high temperature combustion products and burst.
In addition, it is realistic to install asbestos-cement pipes only in vertical sections, since it is impossible to bend them. They weigh a lot, and cope with mounting on their own without the use of large lifting equipment is quite difficult. Another serious drawback is the inability to make absolutely tight joints between the elements. This is considered a gross violation of the rules for the operation of chimneys in private homes.
Due to the specific composition of the pipe, condensate is absorbed into its walls, which destroys it very quickly. In other words, although asbestos-cement pipes are cheap, they are very unreliable and it is not recommended to use them for chimneys.
brick chimneys
If you still want to save as much as possible, but not sacrifice quality, you can build a brick chimney. It will cost less than the analogues listed below. It is worth noting that for the installation of such a chimney, only burnt fire-resistant bricks (red or fireclay) can be used. Such a pipe will withstand any high temperatures and even the ignition of soot inside.
But if you remember, we said that a good chimney with consistently strong draft can only have a round or oval section. It will not work to build such a pipe from bricks - it will be either square or rectangular, which means that accumulation of soot and swirls cannot be avoided. In addition, the brick itself is very heavy, and given that the length of the chimney should be about 5 m, the load on the foundation will be quite serious. Before opting for this option, make sure that the foundation of the house can withstand the additional weight of several centners. For heavy brick chimney it is necessary to build an additional durable reinforced concrete floor. In general, such work requires professional skills, so it is often trusted to stove-makers.
The rough surface of the bricks will inevitably accumulate soot, so the chimney will need to be cleaned periodically. In the past, European countries even had a special profession of chimney sweeps, since all houses had brick or stone chimneys. This profession is alive to this day, but the services of chimney sweeps are resorted to only in cases of severe blockages.
Masonry features:
- Chimney laying should be done only from solid bricks.
- For fixing use the usual cement-sand mortar.
- The walls of the chimney are laid out in half a brick so that their thickness is from 12 cm.
- The dimensions of the chimney and ventilation duct must be a multiple of the dimensions of the brick plus the width of the vertical joints (section 140x140 mm, 140x200 mm, 140x240 mm, etc.).
- Exhaust gases should not cool too much in the chimney, so it is better to place it in the masonry of the internal load-bearing wall of the building or attach it to the wall. Those sections of the channel that will pass through unheated rooms, for example, an attic or pantry, must be wrapped on the outside with non-combustible heat-insulating material (usually this is done with mineral wool).
Brick chimneys are perfect for solid fuel boilers, as they supply high-temperature exhaust gases, which does not allow condensation to form. On the contrary, if you build such a chimney for a liquid fuel, pellet or other boiler that constantly operates in slow burning mode, then the condensate will quickly destroy the brickwork.
Modern boiler designs are distinguished by a rather low flue gas temperature, so a brick chimney is more suitable for older models or conventional wood-burning stoves. Exhaust gases are saturated with sulfur, which, when mixed with condensate, forms destructive sulfuric acid. If you notice dark wet spots on the walls of the chimney, then sulfuric acid has already begun to corrode them.
Useful advice: To connect a brick chimney to a boiler with a low flue gas temperature, a special insert in the form of a metal or ceramic pipe must be inserted into the channel.
Ceramic chimneys
These chimneys can be used for any boilers, including solid fuel ones, since the material of the pipes is immune to extremely high temperatures and aggressive chemical environments. This type of product is considered the most durable and high-quality, as evidenced by its high cost.
Depending on the permissible exhaust gas temperature, ceramic chimneys are classified as follows:
- For solid fuel boilers, pipes that can withstand a maximum of 600-650C are suitable. They are resistant to soot fire and can be used dry.
- For oil and gas boilers, pipes must be used that can withstand a maximum of 400-450C, capable of functioning in a wet state. They have special drains for condensate.
Important: The peculiarity of the ceramic pipe is that it absorbs condensate, and therefore, during installation, high-quality ventilation of the outer walls should be ensured.
Since the walls of the ceramic chimney are completely smooth and even, soot practically does not accumulate on them. Cleaning them is very convenient, and it will have to be done quite rarely. A variety of elements are used for assembly: pipes from 60 cm to 1 m long. They are connected to each other by means of shaped parts and special adhesive heat-resistant mastic.
The image below shows a chimney device for a solid fuel boiler. It is quite difficult to make such a system with your own hands, so it is better to entrust the work to a specialist. In addition to the ceramic pipe itself, it is necessary to lay heat-insulating material so that the gases do not cool down too quickly and do not provoke condensation. It is also necessary to build a shell of concrete modular blocks with ventilation ducts and openings for vertical reinforcement. Ceramic pipes must be placed in special vertical channels, for the construction of which hollow bricks or concrete blocks are taken. The channel itself can be located in the ventilation unit of the building. In addition to ventilation ducts, concrete blocks must have holes for mounting fittings. The part of the pipe protruding above the roof must be reinforced without fail.
Insulation around the pipe is needed not only to prevent too rapid cooling of the exhaust gases, but also to protect surrounding structures from fire. Mineral wool is the best insulating material. It is inexpensive and has the proper temperature resistance.
Metal chimneys
Metal chimneys are perhaps the most popular today, mainly because of the ease of installation. However, their service life is significantly lower than that of ceramic products, and the cost sometimes exceeds the price of a good brick or ceramic chimney. For the manufacture of pipes, stainless steel with a thickness of 0.5 mm is used, capable of withstanding gas temperatures up to 400-450C and exposure to condensate with sulfur.
Important: For solid fuel boilers, pipes made of heat-resistant steel with a thickness of at least 1 mm should be selected.
Despite the short period of operation, steel chimneys are in demand because they are very easy to install, weigh little and do not require strengthening the base for installing or equipping ventilation ducts. If necessary, they can be easily repaired or replaced by one of the sections without dismantling the entire structure.
There are several types of steel chimneys:
Glass chimneys
It's hard to believe, but the chimney can even be made of glass. It is clear that such an exotic product is unlikely to be obtained at home. Nevertheless, factory glass chimneys are the most efficient than all the analogues described above. They appeared relatively recently, but immediately demonstrated their exceptional qualities. Since glass is not subject to corrosion at all, condensation is not terrible for it. It is easy to clean, if at all - the smooth glossy surface hardly accumulates soot or soot.
A glass chimney is the safest and most reliable, but it also has its drawbacks. Chief among them is the exorbitant cost and specific installation that requires the presence of a professional. However, compared to the benefits, the amount spent on a glass chimney will pay off in a few years.
Installation rules
From all that has been written above, we can conclude that in order to know how to make a chimney for a solid fuel boiler, you need to perfectly know the characteristics of the material used, have a clear action plan and a scheme for laying a pipe from the boiler to the roof. To do such work yourself, and even without the proper skills, is almost unrealistic. It is much easier and safer to purchase a finished product in a store and assemble it or invite a specialist.
In order for the chimney to serve you for a long time and not break, make it a rule to look inside the pipe at least once every six months, check its condition and clean it if necessary. Finally, we suggest watching a video about chimneys for solid fuel boilers:
When an actual problem arises in the equipment of an autonomous heating system of a private house, it is often necessary to decide how to competently make a chimney for a solid fuel boiler in order to ensure its efficient operation. There are several proven and reliable ways to equip chimneys, the selection of which depends mainly on the type of boiler installed.
Classification
Chimneys are classified according to the design features.
- Brick built-in channels of vertical direction. They are placed in the inner walls adjacent to the furnace room, adjacent to the shafts of the ventilation system.
- External type chimneys, which are an extension of ceramic bricks to the wall of the building.
- Vertically directed metal pipes mounted inside the building and having access to the roof.
- Reliable steel cylindrical chimneys for outdoor use. They are attached to a wall or to a mast made of rolled metal.
Not widely distributed, but have excellent quality glass chimneys, which are not affected by negative impact high temperatures. They are not subject to corrosion and destruction. It should be noted that these models have a high cost. It is difficult to mount them with your own hands, so it is advisable to turn to qualified craftsmen.
Arrangement of a brick chimney
Brick, being one of the traditional materials for laying chimneys, is valued for its high resistance to high temperatures. Laying out the structure with complete sealing of all joints requires certain skills, so competent craftsmen are needed. Due to the rather large weight of the brick chimney, a foundation will be needed.
Experts note that the rectangular shape and rough surface of the brick contribute to significant soot settling and make it difficult to clean the chimney. Of the positive aspects, it becomes important that the high intensity of fuel combustion in a solid fuel boiler prevents the accumulation of condensate with subsequent destruction of the chimney walls.
Ceramic construction
Ceramics, unlike brick, does not receive damage when exposed to aggressive substances, withstands heating up to 1200 degrees. This circumstance is due to its high durability. Thanks to the smooth cylindrical surface inside, these chimneys are easy to clean. A special brick or block channel is equipped, inside which they are placed.
A layer of thermal insulation, which can be mineral wool, not only protects nearby objects from high temperatures, but also reduces the formation of condensate. Installation is available for do-it-yourself. Ceramic pipes produced in a metal sheath do not require the construction of additional structures.
Steel pipes
The features of steel chimneys for solid fuel boilers are easy installation, the ability to quickly make repairs, and light weight. The wall thickness is one millimeter or more. Such pipes easily resist high temperatures without getting corrosion and deformation.
Chimney! How to make the right choice
By design, the chimney consists of two steel pipes nested in each other with a layer between them made of insulation. Since the kit contains separate lightweight sections, the length of which can be 1 - 2 meters, then assembling them with your own hands becomes a simple action.
The absolute smoothness of the internal planes makes it possible for condensate to run off unhindered, which is removed from the bottom through a pipe designed for this purpose.
Selection criteria
When deciding which chimney to install for a solid fuel boiler, it is advisable to be guided by several basic criteria.
- The traction force is estimated, on which the performance and quality of the boiler depends. Its value is influenced by various factors - the cross section of the pipe, its height, the presence and location of knees in the structure. The highest level of thrust is demonstrated by straight pipes. It is possible to judge the intensity of this indicator by indirect signs.
A clearly audible hum in the pipe indicates an extremely high level, which should be regulated by a special damper. An indicator of low traction is the smell and the presence of smoke in the room. The reason may be the imperfection of the design. According to the standards, optimal draft will be provided by a chimney height of five meters or more. Above the ridge, the pipe should rise one meter.
- The design of the chimney becomes an important criterion, since any roughness and bends that change the trajectory of smoke flows reduce draft.
- An equally significant indicator is the cross section of chimneys for boilers operating with solid fuel. The shape is more effective oval or round than a rectangular diameter.
Additionally, parameters such as the temperature of the flue streams are taken into account, since each material has a maximum heating limit. Each type of chimney is designed to function optimally with a specific amount and type of pressure - forced draft or natural draft.
There is universal models flue pipes. If we take into account the susceptibility to deformation, then chimneys of the 2nd and 3rd class of corrosion resistance are suitable for solid fuel boilers.
Mounting Features
Starting the installation of the chimney required for a solid fuel boiler, it is necessary to study the technical documentation with your own hands, which indicates the permissible distances to ceilings and other structures that can ignite.
When assembling pipes from several sections, all joints are coated with a heat-resistant sealant that can withstand high temperatures reaching 1400 degrees. If pipes are connected different diameters, then you will need to purchase adapters to ensure complete tightness.
With the seeming simplicity of installation work, if standard ceramic or steel pipes are installed with your own hands, it is necessary to take into account all the subtleties in order for the solid fuel boiler to function flawlessly and efficiently.
Measures for improvement
Increasingly, in the reconstruction of collapsing brick chimneys, reliable steel pipes are used, simply by inserting them into the existing channel. The remaining gap is filled with basalt non-combustible insulation. It is recommended to carry out such a replacement if a transition from solid fuel to its gaseous counterpart is predicted.
So that the brick shaft does not receive a harmful effect from condensate, it is recommended to insulate it from the outside with one hundred millimeter slabs of basalt wool. If the channel is located inside the wall, the part passing through the space of the unheated attic, as well as above the roof, is insulated. If the smoke shaft is attached to the house, then its outer planes are completely lined with thermal insulation, supplementing it with an outer layer of galvanized metal having a thickness of 0.5 mm.
Dimensions
In the process of arranging the chimney, its optimal height must be observed, on which the reliable operation of the boiler depends. The basic requirements for this indicator are almost the same for all types of pipes.
To prevent the exit of the chimney from entering the sector of the wind backwater, where the draft is very weak, it is necessary to draw a line from the highest point of the ridge of the house at an inclination of 45 ° to the ground. This will be the bad zone.
If the height of the chimney is such that its outlet falls within this gap, measures should be taken to increase it by half a meter above the marked line. According to the regulations, an angle of 10 ° should be maintained so that the height of the chimney pipe fully provides the necessary draft, which allows the solid fuel boiler to function effectively.
Video: How to choose the right chimney for a solid fuel boiler
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Chimneys for solid fuel boilers - very important element: not only removes combustion products from the furnace, but also creates the necessary traction in it. However, one should not forget that these structures are subjected to high thermal loads, and if not correct installation may cause a fire. So it is necessary not only to be able to choose chimney for the boiler, but also comply with all requirements during installation.
In order for the solid fuel apparatus to be able to produce the necessary power, the chimney connected to it must be as straight as possible and high enough. These parameters directly affect the draft, and hence the intensity of combustion of firewood and heat generation. Flat sections of the circuit allow the internal flow to pick up speed, and the height of the extreme point determines the pressure difference due to which it is created.
The level of the pipe outlet in relation to the roof surface is determined by the features of its device:
- Flat - not lower than 0.2 m.
- Pitched - at the level of the ridge, if the pipe is 1.5-3 meters from it, and at least half a meter higher at a closer location.
After installing the chimney on a solid fuel unit, each turn of the channel and the knee slows down the movement of smoke, forcing the spiraling flow to constantly rebuild its trajectory. The length of horizontal sections also affects the decrease in its speed - when drawing up the installation diagram, make sure that they are not longer than 1 m.
To reduce the number of obstacles in the path of outgoing smoke, the walls of the pipe are made as smooth as possible. So they create minimal resistance and do not clog with soot. It is equally important to choose the correct internal section of the chimney - it must correspond to the diameter of the outlet hole that the solid fuel boiler has. It is allowed to use pipes with a large channel size, but the draft in them will be worse.
Other requirements for the smoke exhaust circuit no longer relate to its design, but to the correct installation and device. However, they should also be observed:
- Thermal insulation.
Non-combustible materials are used for it, since the insulating layer provides additional fire safety. Due to the high temperature of the outgoing gases, the building structures through which the pipe passes can catch fire. Insulation also shifts the dew point outside the walls of the chimney, which in the case of metal reduces the risk of corrosive wear.
- Tightness of connections.
Provides full removal of products of burning which are given out by a solid propellant copper, from a fire chamber outside. Leaks, especially within indoor areas, are life threatening. In addition, sparks can break through leaks in the pipe walls, so the chimney scheme is calculated so that the joints do not end up in the ceilings.
- Deflector.
This simple device (fungus) at the top of the chimney protects it from debris, rain and wind. It is also desirable to install a spark arrester mesh in the pipe under the deflector, especially if the roofing is combustible.
As for the materials from which the chimney for the boiler should be made, they are required only for temperature resistance and the ability to create a sealed circuit. These conditions are met by steel and ceramic products. But there are enough nuances here, so the selection of a set of chimneys will have to be approached with all seriousness.
Varieties and nuances
Modern ceramic chimneys are superior to obsolete brickwork in all respects, but they are also able to withstand extremely high temperatures (sometimes up to + 1200 ° C). Simply put, they can be installed on any powerful solid fuel unit. The three-layer design ensures that the requirements for a chimney are fully met:
1. The smooth inner surface of the duct does not interfere with the outgoing flow.
2. The warming layer allows you to get away from the problem of condensation.
3. The outer shell of expanded clay concrete partly performs the functions of thermal insulation, but mainly provides mechanical strength to the sections.
But the ability of ceramics to absorb moisture through external pores cannot be attributed to advantages. But the problem is solved by organizing ventilation for the outer walls of the pipe. Thus, of the minuses, only labor-intensive assembly and high price remain. But if the heating solid fuel boiler runs on coal, these systems cannot be avoided.
Steel chimneys are the most popular today. Moreover, they clearly win in those parameters where ceramics were not up to par. However, their metal walls have good heat transfer capacity, so they must be insulated from building envelopes and cold air. Plus, the life of steel in such aggressive conditions is small.
They do the thermal insulation of a single-circuit chimney themselves, but it is easier to purchase ready-made multilayer sandwich pipes. By their design, they vaguely resemble the already considered ceramic ones. The outlet is insulated with basalt wool, the outer sheath can be made of galvanized or enameled steel. But the inner tube is only made of corrosion-resistant metal.
Selection rules
First of all, when choosing a chimney, it is necessary to take into account the fuel on which the solid fuel apparatus operates. It's all about the temperature of the outgoing gases:
- Firewood - when burned in the furnace of a solid fuel boiler, they give out +300 ° С.
- Coal - about + 500-700 ° С (depending on the brand).
- Pellets - only + 120-250 ° С.
- Sawdust and granules - short-term + 220-240 ° С.
Pyrolysis boilers also have a low outlet temperature, since their operation scheme is based on the selection of thermal energy from the combustion products themselves while still in the furnace. So under the gas generating equipment, you can take a stainless steel chimney. Wood-burning units normally work with ferrous metal, and only ceramics are suitable for coal units. But even here it is necessary to look at the marking - the number after the letter "T" will show at what temperature the pipes are allowed to be used. However, these are only general tips - the recommended type of chimney is indicated in the passport of the solid fuel boiler itself.
In addition to thermal resistance, corrosion resistance must also be taken into account. Most of the considered chimneys have the necessary properties, but ferrous metal pipes in this regard are in last place. Therefore, it is desirable to purchase rolled products with the maximum possible wall thickness, regardless of the cost. Things are better with stainless alloys, but before you buy such a chimney, take an interest in the steel grade used.
AISI 321 (similar to 12X18H10T) and 316L (aka 03X17H14M3) copes well with its task. By the way, it is by the Russian marking of stainless alloys that it is easier to determine which chimney is better to choose for a solid fuel boiler. The percentage of chromium (the second digit after the letter X) must be equal to or greater than 17%. This means that the metal is resistant to corrosion even when exposed to aggressive flue gases in the pipe.
Price
chimney | Material | D inside, mm | Wall thickness, mm | Price, rub/m |
Craft Ф150 | AISI 316 (08X17H13M2T) | 150 | 0,8 | 2 490 |
Loki | enamelled steel | 120 | 1,0 | 970 |
Kamintherm | black steel | 150 | 2,0 | 2 590 |
Sandwich C52 | AISI 430 (12X17), galvanized outside | 200 | 0,8 | 2 355 |
Ferrum | AISI 439 (08Х17Т) | 250 | 0,8 | 1 810 |
DSS | Cink Steel | 115 | 0,5 | 288 |
Schiedel UNI | Ceramics (chamotte) with a box | 140 | — | 6 070 |
Tona Tec ISO | Ceramics | 120 | — | 10 260 |
Solid fuel boilers are still the most common heating equipment in the Russian Federation. This is facilitated by the availability of fuel, ease of maintenance and easy commissioning. At the same time, there are certain requirements set forth in SNiP and PB, which must be followed when using TT boilers. In particular, the rules related to the choice of a chimney are detailed.
The high temperature of the exhaust gases, the large amount of soot resulting from the combustion of wood, coal and other solid fuels - all these factors are important to consider when choosing a suitable smoke exhaust system. By choosing the right chimney for a solid fuel boiler, you can increase energy efficiency and heat transfer, as well as extend the life of heating equipment.
Requirements for chimneys for solid fuel boilers
Chimneys for solid fuel boilers must comply with the general requirements set forth in SNiP for construction 2.04.05-91, 41-01-2003; SP 7.13130.2011, SP 60.13330.2012; DBN V 2.5-20-200 and NPB 252-98. AT normative documents the norms related to installation and safety rules are listed in detail. Additional requirements are in the SDS.Manufacturers of heating units list in detail the standards associated with the diameter, height and cross section of the pipe. The stability of draft, the amount of condensate, the rate of heating of the chimney and the output of the boiler to operating power depend on compliance with the standards.
What is the cross section of the chimney for a solid fuel boiler
The cross section of the chimney for a solid fuel boiler is selected taking into account the technical characteristics of the heating equipment. When choosing, they are guided by two parameters:- Type of section - the smoke coming out picks up speed gradually. There is a swirling of smoke residues, which creates the thrust necessary for the operation of the boiler. The speed of passage directly depends on the type of section and the presence / absence of corners, bends and horizontal sections. A round or oval section is considered acceptable for TT boilers.
Square and rectangular smoke exhaust systems cannot provide normal traction performance. Therefore, the traditionally square section of a brick chimney does not meet the requirements for connection to modern TT units, but can be used when connected to conventional wood stoves. - Cross-sectional diameter - the narrower and smoother the chimney channel, the better the draft in it. The diameter of the pipe has practically no effect on the speed, but indicates the total possible volume of simultaneous passage of flue gases. This indicator is calculated individually, depending on the volume of the combustion chamber.
Poor draft in the chimney indicates that the flue duct is wider than necessary. To eliminate the problem without dismantling the system, a draft deflector is installed on the pipe head, which allows you to manually change the speed of the smoke flows.
- The dependence of the height of the pipe on the diameter of the chimney. As a general rule, the wider the duct, the higher the chimney should be raised to provide the required draft.
- The dependence of the diameter of the chimney on the power of the boiler. The technical documentation states minimum size internal channel of the chimney. The calculation is carried out depending on the volume of the combustion chamber and takes into account throughput channel.
The correct chimney for a solid fuel boiler must be round or oval, with a diameter specified by the manufacturer in the technical documentation.
Fire requirements for chimneys
The chimney of a solid fuel boiler must comply with fire safety regulations. A feature of operation is the high temperature of the exhaust gases, above 300 ° C. When soot ignites, heating reaches 1000 ° C. As a result, the probability of a building fire is quite high.Fire safety standards stipulate the need for fire breaks during the passage of floor slabs, roofs, load-bearing structures. The PB states the following:
Fire standards for chimney arrangements may vary depending on the area. Therefore, before starting installation work, it is necessary to find out about the existing requirements in the fire inspection (Ministry of Emergency Situations).
The temperature in the chimney during the operation of a solid fuel boiler ranges from 70 to 1000 ° C. This parameter must be taken into account when choosing a suitable pipe for the flue system.
Steel chimneys for solid fuel boilers
Steel chimneys are very popular due to several significant advantages:- Low price for a chimney - in comparison with and even brick counterparts (if we take into account the cost of consumables and building materials), the cost of construction is much cheaper.
- A simple design - it is quite possible to make a chimney for a solid fuel boiler with your own hands. For assembly, you will need to calculate the required pipe height and purchase components or a ready-made kit. Installation takes place in the "father-mother" way. Joints are treated with sealant.
- Chimney aerodynamics - steel pipes are produced in a round or oval shape, which provides the best traction. The absence of internal sags reduces the settling of resins on the walls. Chemical fuel briquettes can be used for cleaning.
- Availability of components and materials of all required standard sizes. Due to the wide range of segments, choosing the configuration and diameter of a stainless steel chimney for a solid fuel boiler is quite simple.
Insulated sandwich pipes for TT boilers
Sandwich pipes have two contours, between which there is a non-combustible insulation. AISI 316 L and AISI 321 stainless steel grades are used for production. Other characteristics of sandwich chimneys:Stainless steel sandwich pipe is optimally suited for the chimney of domestic boilers long burning on coal or wood. The inner wall warms up quickly, despite low temperature exhaust gases (a feature of long-burning boilers). The chimney reaches its operating power almost immediately, which ensures the almost complete absence of condensate.
Single wall flue pipes for TT boilers
Single-wall chimneys for solid fuel boilers are also popular, although they cannot compete in their technical specifications, with sandwich systems. Manufacturers offer the following modifications of smoke exhaust systems:- Stainless pipe.
- Metal enameled modular chimneys made of heat-resistant steel.
- Galvanized chimney.
For this reason, the only, truly effective method the use of single-wall pipes is to make a chimney liner. Steel pipe installed in an existing brick pipe helps to achieve the following:
- Reduce the temperature in the chimney - the liner helps to speed up the removal of combustion products, soot deposition on the walls is reduced, which reduces the risk of internal fire.
- Increase thrust performance - rapid heating of the pipe wall leads to improved aerodynamics and, accordingly, improves thrust performance.
- Simplifies system maintenance - smooth pipe walls reduce the amount of tar deposits. To keep the system working, there are special chemicals for cleaning the pipes from the combustion products of coal, firewood and pellets. Maintenance is carried out once a year.
Coaxial type steel chimney for solid fuel boiler
The special design of the stainless steel coaxial chimney for solid fuel boilers is designed to simultaneously remove combustion products and supply oxygen to the combustion chamber. Coaxial pipes are used to connect to heating equipment with a closed combustion chamber, as well as a forced smoke exhaust system.Quite effective to use coaxial chimney, for long burning pellet pyrolysis boiler. To bring the unit to the gas generation mode, are created certain conditions: sufficient oxygen and steady stable thrust.
Stainless corrugation for chimney TT boiler
flexible corrugated stainless steel chimney are used for two purposes:- Sanitation, partial or complete repair of an existing chimney.
- Connection from a TT boiler to a flue system with stainless steel corrugations inside the room.
Ceramic chimney for solid fuel boiler operation
Modern chimneys made of ceramic blocks are the optimal solution for the manufacture of a solid fuel boiler smoke exhaust system. Ceramics has the best thermal performance. Only glass chimneys have similar parameters, which, due to their high cost, have not taken root in the Russian Federation.The consumer is offered several options for ceramic products:
The main device standards for direct-flow chimneys of wood-fired heating boilers provide for the following recommendations:
- The arrangement of the attached chimney is carried out with installation on a concrete reinforced base.
- The connection of a ceramic pipe with a solid fuel boiler is carried out using an adapter.
- Chimney joints are treated with acid-resistant sealant.
- The location of the chimney and the boiler should match as much as possible in order to avoid, if possible, horizontal pipe sections over 1 m.
At the moment, ceramic smoke exhaust systems have no analogues in terms of service life and thermal characteristics, and are the best choice when connected to solid fuel equipment of any type.
Brick chimney system for solid fuel boiler
Basically, in old houses, in the chimneys of individual solid fuel boilers, fire-resistant ceramic bricks are used. Although such a solution has certain advantages, but as practice shows, over time, significant disadvantages become apparent, which include:Brick chimney, not suitable for modern equipment, according to its technical characteristics. If you plan to connect to an existing brick channel, it is sanitized using a stainless pipe.
Chimney from asbestos-cement pipe for TT boiler
connect asbestos-cement pipe to a solid fuel unit is prohibited. When heated above 300 ° C, the walls, unable to withstand the thermal effects, begin to crack and explode. Asbotpipe, if necessary, can be installed for pyrolysis equipment and double combustion boilers, with a low temperature of exhaust gases.It is possible to use an asbestos-cement brick chimney for an automatic solid fuel gas-generating boiler. During operation, exhaust gases do not enter the chimney immediately, but pass through an additional circuit. The flue gas temperature is reduced to a minimum. It is forbidden to connect an asbestos-cement pipe to ordinary TT boilers.
Which chimney is better to choose for a solid fuel boiler
A wide range of chimneys manufactured by different manufacturers, differing in technical characteristics and design, makes the choice of a suitable smoke extraction system a difficult task. It is better to seek the help of professionals in this matter.A recent survey showed that it is most problematic to decide on the type of pipe and the manufacturer of the smoke exhaust system.
Which chimney pipe is better to choose - brick, ceramic or steel?
When choosing a suitable smoke exhaust system, they are guided by several parameters:- Draft indicators - rectangular chimneys do not provide the necessary traction force for the operation of a solid fuel unit. To ensure the swirling of heat flows, a pipe with a round or oval cross section is required.
- Thermal insulation characteristics - in order to reduce the amount of condensate, it is important that the walls of the chimney warm up quickly, and the temperature becomes above the "dew point".
- Fire safety - the surface temperature of the pipe should not exceed 40-45°C. For this reason, a single-walled stainless or galvanized chimney lining steel pipe, inside a wooden house, is possible only after careful thermal insulation.
- Minimal condensation.
- Ability to withstand high temperatures.
Pay attention to the products of the following companies:
Features of the operation of smoke exhaust pipes from TT boilers
Modern solid fuel boilers are sensitive to deviations from operating parameters. The change in traction force, the lack of normal speed during the removal of combustion products are the main reason for the loss of equipment performance and a decrease in efficiency by 15-20%.To prevent this from happening, it is important to correctly connect the chimney to the boiler, as well as carry out regular maintenance of the smoke exhaust system.
How to get rid of condensation in the chimney
The appearance of smudges on the pipe, oxides on the brickwork, indicates an increased production of condensate in the pipe. There may be several reasons for this:- Insufficient thermal insulation - basalt wool, if it is incorrectly wrapped around the pipe, will surely sag, opening up fresh air to the walls of the chimney. The thermal insulation should be checked and any damage repaired.
- Chimney pipe with a large diameter - in order to eliminate the influence of the chimney diameter on the combustion process, a draft regulator is installed that increases the pressure in the duct by 1.5 times.
- Failure to comply with the requirements regarding the height of the chimney. Ceramic and sandwich pipes are being built up. Installation is carried out according to the type of constructor, so at any time you can add 1-2 sections.
Why is the chimney at the boiler clogged
The cause of pollution is the large amount of resinous substances released during the combustion of solid fuels. The main difference between the vapors released during the combustion of solid fuels is the high moisture content. As a result, when burning a wood-burning boiler, tar deposits form on the walls. This is a normal and natural residue.A problem is considered to be situations when the rate of overgrowth of the inner diameter of the pipe increases compared to normal indicators factor of. There are several reasons for this:
The temperature of flue gases in the chimney when burning coal reaches 500-700°C, when soot ignites 1000-1100°C. Rupture of the walls due to high temperature is the main reason for the failure of the flue pipes.
How can you clean the chimney from soot
To protect the chimney from damage due to soot fire, it is possible only with the help of regular maintenance of the system. Pipes should be cleaned at least every six months and as soot accumulates. This is done in two ways:- mechanical way.
- Chemical way.
Wall chimney repairs and cleaning must be carried out by a qualified and licensed worker. Commissioning takes place only after a complete inspection and certification of the system. The use of wall-mounted chimneys is permitted only if the room is well ventilated and convenient inspection wells are available.
Is it possible to connect solid fuel and gas boilers to the same chimney
In short, no. There are several reasons for this:- Different requirements regarding the design of the chimney. AT gas system smoke removal, it is forbidden to install soot removal wells, and coal-fired units need them to clean soot.
- In adverse conditions, the draft of one boiler can block it from another.
How to connect a chimney to a solid fuel boiler
When connecting the chimney to the boiler and carrying out the final work, several important recommendations are followed:- The connection is made with an adapter or heat-resistant stainless steel pipe.
- The top end of the chimney pipe must not have a cap. It is allowed to install a spark arrester and a draft regulator.
- The connection is made in accordance with the manufacturer's recommendations. The documentation indicates the required height of the chimney, depending on the power of the equipment, the permissible difference in the cross section of the exit of the solid fuel boiler and the external chimney, and other parameters.
- Special regulatory requirements for chimneys during the installation and operation of wood-fired pyrolysis boilers. Unlike conventional stoves, gas generating equipment will require a higher pipe.
Calculator for calculating the choice of heat gun
Selecting the power of the air conditioner
Continuing the topic, I think to discuss in this review a chimney for a solid fuel boiler. Why him? Because this kind of "chimney" will be universal. Buying, for example, sections of sandwiches with good insulation, and mounting a chimney for a TT boiler, you “kill four birds with one stone” at once - it will be suitable for installing a wood-burning boiler, coal, pellet, as well as for installing steel or cast iron heating furnace.
The same applies to single wall stainless steel pipes with a wall thickness of 0.8 - 1.0 mm. That is, the chimney can be used not only for a TT heat generator, but also for some other types of boiler equipment.
Although, as you know, very good - also not good. Some models of gas and diesel boilers do not work correctly with old chimneys. The excessively large diameter of the chimney for the solid fuel boiler, which was installed before, is to blame for this.
So let's get started.
"Smokestack" in a cut or "Where's the diagram, brother?"
This paragraph provides a chimney diagram for a solid fuel boiler - it is quite versatile and can be used in many installation cases. This option is suitable for installation in any type of house, with any type of wall materials - from brick and monolithic concrete to a wooden frame.
A typical chimney scheme for a solid fuel boiler implies the possibility of leading the chimney through the wall to the side and then upward, or through the ceiling vertically upward and then through the roof.
If we talk about the effective removal of flue gases from the furnace, then the main factors affecting the efficiency of this process will be:
- Chimney height
- Chimney diameter
- Acceleration section length
- Chimney insulation
These 4 points are important, the rest are optional.
How much to hang in grams, or choose the height and diameter of the chimney
Let's start with the first two points. The height of the chimney for is a critical parameter. What does it mean? This means that if your chimney is not high enough, the draft in the boiler furnace will also be insufficient. This can lead not only to poor combustion of the fuel, but also to “draught overturning”, when, instead of being discharged to the outside, the flue gases will penetrate into the room.
This is fraught with the release of carbon monoxide into the living quarters, which is deadly to humans.
Carbon monoxide is colorless and odorless. Therefore, you can not noticeably “burn out” and die without waking up.
Did I convince you that there is no need to save on the “extra” meter of pipe?
The required height of the chimney for a solid fuel boiler or for a heating furnace, for each individual model of the boiler or furnace, as well as for different thermal outputs, is mandatory written in the passport for. At the same time, sometimes the “minimum” height is written in the passport, and sometimes “just” the height.
It is obligatory to observe the minimum height, and “just” height is the lower limit for conducting experiments with the HT boiler draft. Poor pulling at minimum height? We add another half a meter - a meter of a chimney. And so on.
When conducting these experiments, do not forget that in summer, especially in wet warm weather, traction will be worse than in frosty and dry winters. Therefore, if the installation of the chimney of a solid fuel boiler is carried out in winter, you must understand that in summer the draft at the set height will be worse than at the time of installation.
The minimum chimney diameter for a solid fuel boiler or furnace is also indicated in the passport for the purchased boiler or furnace. If you do not have a passport, then for almost any model there are now tables on the Internet.
You can slightly narrow or expand the cross section of the chimney by changing the diameter by no more than 5 mm in one direction or another.
It won't affect traction much. If, for example, you take 120mm pipes instead of 150mm, you can easily get problems with efficient fuel combustion in some models of TT boilers and.
This effect is usually “treated” by lengthening the chimney, however, an increase in height does not always lead to the desired result.
As for the excessive increase in the diameter of the chimney, this is fraught with the fact that the flue gases, not having time to give off heat to the heat exchanger, will quickly leave the boiler furnace. What is called "heat will fly away into the pipe."
Accelerating section of the chimney
In the case of using an accelerating section, the solid fuel boiler can be connected to the chimney vertically or horizontally. Immediately after the initial short pipe or tee, there will be at least 1 meter of an accelerating vertical pipe. It serves to "start" traction. Further, you can already install horizontal sections and branches, but not more than 0.5 meters in length.
This means that the outgoing flue gases, entering the chimney, already have an extremely low temperature. And if they still continue to give off heat through the walls of the pipe into the surrounding premises or outdoor air, then their movement will slow down more and more. So, again there will be no normal draft in the chimney.
To prevent this from happening, the chimney for a solid fuel boiler or stove must be insulated. For this purpose, the easiest way is to use ready-made sandwiches, which are double stainless steel cylinders, the space between which is filled with basalt insulation or vermiculite.
The better the sandwich is insulated, the less the outgoing flue gases lose temperature, the better the draft in such a chimney compared to an uninsulated one.
A chimney pipe for a solid fuel boiler, assembled from sandwiches of 1.0 and 0.5 meters each, has a number of advantages, in addition to the main one - improving traction:
- Ease of assembly, tk. easy installation of sections of 0.5 and 1.0 meters is possible
- Corrosive
- Convenient removal of condensate from the chimney with a drain cock on the tee
- Attractive appearance, you can run a pipe from sandwiches along the facade of the house
In addition to the use of sandwiches, an insulated chimney for a solid fuel boiler can be obtained in 3 more ways:
- Insulate the old chimney with basalt insulation or vermiculite.
- Use an old brick pipe from a boiler or stove, sleeved with stainless pipe inserts.
- Install insulated ceramic chimney
The first two methods are classified as budgetary. The third way is the most expensive. But he will make you forget about the "chimney issue" for many years.
The chimney device for made of ceramic sections is clearly visible in the diagram below.
Such a chimney is not afraid of condensate and it is not subject to corrosion. In addition, ceramic pipe is extremely fire resistant and does not burn through like steel pipe.
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