Pipe from a gas boiler. The main materials for chimneys of solid fuel boilers. Coaxial type steel chimney for solid fuel boiler
If there is an actual problem with the equipment of the autonomous heating system a private house often has to decide how to competently make a chimney for solid fuel boiler to ensure 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.
Glass chimneys, which are not adversely affected by high temperatures, are not widespread, but have excellent qualities. 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 you need not only to be able to choose a chimney for the boiler, but also to comply with all the requirements during the installation process.
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 |
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 consider which of them are the most effective, and also tell you how to make a chimney for a solid fuel boiler with your own hands.
The chimney is an integral part of the 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 manner, 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 violated, 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 the high temperature of the combustion products and burst.
Besides, asbestos-cement pipes it is realistic to install only on vertical sections, since it is impossible to bend them. They weigh a lot, and cope with mounting on your 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 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 a 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 pipe material 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 a 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:
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 layout 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 chimney of a solid fuel boiler is installed 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, getting into the chimney, already have a limit 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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Today we’ll talk a little about how flue gases can be removed from boilers, what should be the chimney for gas ...
The chimney is one of the most important components of the heating system, without which it is impossible to imagine the normal functioning of the boiler. Both a steel and a brick chimney for a solid fuel boiler are used to remove flue gases and fuel combustion products to the outside, excluding their penetration into the room and providing draft.
The process of selecting and installing chimneys should be approached responsibly, paying attention to even the smallest details, because not only the efficiency of the boiler equipment, but also the safety of all residents of the house depends on this.
Traction force is the basis for choosing a chimney
Before choosing a specific chimney for a heating boiler, it is imperative to determine the draft that is necessary for the normal functioning of the equipment. This term should be understood technical specification chimney, which reflects the quality and performance of its work.
The draft in the boiler pipe is reflected by the speed of movement of flue gases, which are formed due to the collision of several air flows with different temperatures and pressure drops in the atmosphere directly in the furnace of the heat generator. The amount of draft in the chimney is influenced by many factors, among which are the length and cross section of the pipe, the presence of knees and bends in the structure.
It is important to remember that if the pipe is as straight as possible, and even narrows towards the exit, then the level of thrust in it will be the highest. That is why when designing a heating system and choosing a heat generator, it is important to pay attention this fact, try to exclude all kinds of turns, slopes and bends.
The quality of traction can be characterized by several parameters:
- High performance. There is a hum and buzz in the chimney. In this case, it is customary to use a special gate (damper), thanks to which you can effectively adjust the level of traction, achieving optimal performance;
- Low thrust. It is the reason that smoke and flue gases penetrate into the room. If such signs appear during testing of the chimney, the design and execution must be reviewed.
Advice. According to existing standards, the length of the pipeline for the removal of flue gases should not be less than 5 meters. At the same time, the height of the pipe must be 1 meter above the roof ridge.
Chimney design: what to look for
For those who are familiar with the basics of physics, it is no secret that smoke comes out of the boiler's combustion chamber in a spiral, increasing its speed. This is precisely what explains the need to obtain the most even chimney, without any bends, otherwise the trajectory of the movement of smoke changes, and traction may deteriorate.
Also, it is important with what section the chimneys for solid fuel boilers are made (see also). An oval or round section is considered the most optimal - the most efficient removal of flue gases is ensured. If, however, the pipe is made rectangular or square, then during the movement of smoke turbulences are formed, traction is lost, soot and soot quickly appear.
The selection of the length and section of the pipeline for the chimney is made for each heating system, boiler and building on an individual basis.
The main materials for chimneys of solid fuel boilers
As you know, the instruction for any solid fuel boiler says that the flue gas temperature in the chimney can reach 180-500 C (see also). Therefore, the material for the pipe should be chosen very carefully, paying attention only to heat-resistant options.
Among the most popular materials for chimneys are:
- brick chimneys. Able to withstand temperatures up to 900 C, but at the same time they are not recommended for systems with low efficiency - the walls of the chimney heat up for quite a long time.
Not ideal for solid fuel heat generators, since under the influence of condensate (formed during the combustion of fuel), brickwork can collapse; - Chimneys made of stainless steel and steel. Plain steel chimneys are subject to negative impact environment(humidity, temperature changes), and therefore stainless steel is more preferable.
Such pipes are more resistant, withstand about 700-800 C, and will last much longer.
Steel smoke pipelines are low cost, easy to install and maintain. As a rule, certain steel grades are used - AISI 316L, AISI 310S;
- Glass structures. They have not yet become widespread on the domestic market (the price of glass chimneys is much higher than that of others), but they are very popular in Europe and Asia.
They have excellent performance, are not subject to corrosion and impact high temperatures, have low rates of inertness;
Advice. If you choose glass chimneys, you should be prepared for a rather large financial outlay.
And it’s quite difficult to independently mount such smoke exhaust systems from the boiler - you will have to spend money on qualified craftsmen.
- Chimney pipes made of ceramic materials. Some of the most common in the domestic market, are resistant to high temperatures (up to 1200 C), fire resistance. Also, they perfectly resist the negative effects of aggressive factors, including high humidity and condensation.
A significant advantage of such structures is also safety in case of accidental ignition of accumulated soot - the chimney will perfectly withstand any temperature. In addition, the chimney diagram for a solid fuel boiler is very simple, and even without special preparation, installation can be done by hand.
Advice. Modern ceramic chimneys are universal, but they show themselves best when working with slow-burning solid fuel boilers, for example, the same pyrolysis ones.
Choice of chimney: fundamental factors
In order to decide on any one type, it is necessary to take into account a lot of parameters:
- Flue gas temperature. Previously, it was agreed that each of the materials for chimneys has its own temperature maximum, and therefore flue gases should not have a temperature that exceeds the established rating;
- Gas pressure in the pipeline. Currently (and this can be seen in the photos and videos presented on our portal), each type of chimney is designed to operate at a certain pressure - natural draft or pressurization. Universal models are also produced;
- The presence of condensate in the pipe. Previously reviewed brick pipes it is preferable to operate in dry conditions, without the possibility of condensation;
- Corrosion resistance. There are three classes of chimney resistance to corrosion, of which only two are designed for solid fuel boilers- 2nd and 3rd;
- Permissible distance to flammable materials. The technical documentation for each pipeline for the removal of flue gases and combustion products indicates the minimum distance at which ceilings and other structures that can ignite from high temperatures should be located.
This is a critical parameter when choosing a certain type of chimney, because the safety of everyone who lives in the house directly depends on it.
Installation of smoke exhaust pipes: rules, features
In most cases, connecting a solid fuel boiler to a chimney does not cause trouble - this process is quite simple, it does not require any special skills and abilities. But, nevertheless, it is important to study the design of the chimney, some principles and characteristics of the connection.
To begin with, it should be noted that all parts of the system for removing flue gases are connected to each other by means of a heat-resistant sealant - it can withstand up to 1400 C. In addition, if pipes of several diameters are used, then it is necessary to purchase a special adapter, thanks to which smoke leaks can be completely eliminated , loss of traction.
Fastening steel pipes to remove smoke to the wall of the house, it is made using special materials - rivets or self-tapping screws. In some cases, you can not do without additional supports, stands and other elements - often, they are all spelled out in the instructions for the technique.
Conclusion
Chimneys are an important and integral part of any modern system heating, where solid fuel boilers are used. In order to get the most efficient heating and eliminate various troubles (including situations that threaten the lives of residents of the house), the choice of pipe design and materials should be approached with all responsibility, taking into account technological requirements and standards.