One of the most popular and widely known methods of cleaning a chimney is the use of fire, or rather, the phenomenon of combustion. Not every owner of a country house in the country knows how to burn soot in a chimney safely. Of course, there is no absolutely safe and harmless cleaning method, however, radically reducing the degree of risk is an easily achievable task, the main thing is to set it for yourself.
From a practical point of view, soot is the most negative result of the constant operation of a chimney. Today, the modern progress of science has invented many different methods of cleaning a chimney, each of which has a certain set of advantages and disadvantages. However, it should always be objectively understood that the better the chimney is cleaned, the safer its subsequent continuous operation will be. (See also: How to clean soot from a chimney)
Before reaching the above situation, it is necessary to choose not only the fastest and highest quality method, but also take into account all the risks and ultimate advantages of a particular method. Of course, there are a huge number of different cleaning methods, but they are all divided into several large groups, namely:
- for chemical reagents;
- mechanical cleaning;
- physical;
- special engineering and structural devices;
- traditional methods;
- mixed group.
So, to create a flame, it is enough to set fire to several armfuls, the main thing is that they are located in close proximity to each other. The second point that you should definitely pay attention to is safety; the house needs to be well ventilated. Since there is a possibility of accumulation of various combustion end products, inhalation of which can lead to a number of negative consequences.
It is necessary to clean the chimney extremely carefully, since otherwise, there is a very significant probability of a variety of negative consequences, some of them: (See also: How to repair a stove with your own hands)
- loss of consciousness by persons who are in the house;
- unintentional house fire;
- poisoning by combustion products or cleaning chemicals;
- injury during mechanical cleaning, etc.
Of course, there is no ideal way to dispose of soot and it is unlikely that it will ever appear, however, at the moment there are many highly effective and almost completely safe methods. For example, cleaning a chimney in a bathhouse is not practically difficult. Firstly, the bathhouse is often small in size, and secondly, as a rule, the height of the chimney is also insignificant, which in turn greatly facilitates the complex process of soot disposal. In this case, you can even burn the chimney, while the risk of negative consequences is minimized, and the actual result itself will not take long to arrive.
Theoretically, the burning of soot in the chimney stops when it completely burns out. However, this axiom does not always work, since in most cases, the chimney itself, in addition to soot, contains many other flammable substances. Do not forget that the priority should not be the speed of disposal of accumulated products during operation, but safety. If there are children in the house or its surroundings, then cleaning the chimney is impossible. Because from a practical point of view, it is not easy to keep track of a child, it is very difficult, and almost impossible. One has only to think about something for a second, and the child immediately disappears from sight.
Damage to the smoke duct. Solutions.
Next to modern exhaust systems, old, proven chimney designs are smoked side by side. Let's start with common brickwork, which is suitable for wood stoves and fireplaces, but should not come into contact with smoke from burning diesel or gas. It is impossible to dispose waste from such boilers into open brickwork.
Even when fired with dry wood, a brick chimney shows signs of destruction after 2 to 5 years. Periods of freezing and thawing, rare use in combination with high humidity in the off-season allow the brick to become saturated with moisture - hence the delamination of the masonry and cracks.
When partially replacing bricks, chimney repairs are carried out only with fireclay clay (for high temperatures) and fire-resistant bricks.
Small cracks are sealed with heat-resistant sealant. To save the channel from further destruction, the following methods are used:
Method No. 1 - Gilding:
A metal pipe is placed in the chimney. In this case, the work must be carried out carefully - if the chimney is long and the joint is bent, then soot plugs will constantly form in this place. The pipe is connected with a sealant designed for temperatures from 1000 degrees. In such a “sleeve” made of heat-resistant stainless steel it is already possible to remove gases from the heating boiler.
Disadvantages of lining:
- suitable for direct channel only;
- the cross-section of the chimney is reduced;
- the pipe runs the same diameter throughout the chimney.
Method No. 2 - Internal lining
Heat-resistant mixtures restore and smooth the inner surface of the canal. Resistant to temperatures above 900 degrees, they increase the service life of the entire chimney. You can carry out the work yourself using Massan or Mordax compounds and special brushes.
Disadvantages of lining:
- only for brickwork;
- must be repeated every 3 years;
- only for straight vertical channel.
Method No. 3 - Polymer materials
Economical condensing and pyrolysis boilers produce smoke supplied with acids and temperatures up to 200 degrees. Cold acidic smoke is the main cause of condensation in the duct, which destroys not only the masonry, but after a few years also stainless steel (with characteristic leaks at the seams).
A modern method of chimney protection is FuranFlex materials. The polymer, in the form of a solid soft pipe 2-3 mm thick, fills the channel with slopes of 30 to 45 degrees and hardens. Protection is installed by specialists. The warranty on the material is 30 years, service life is unlimited.
Disadvantages of using polymer materials:
- not suitable for flue gases with temperatures exceeding 250 degrees (during prolonged combustion);
- the rectangular chimney is not completely filled (the cross-section decreases accordingly).
If metal pipes (or sandwich systems) are damaged, it is enough to replace 2-3 sections, again fastening the entire structure with heat-resistant sealant.
Ceramic chimneys rarely require repairs. An extreme case is cracks at the joints of sections due to improper installation or a sagging foundation (for chimneys heavier than 750 kg). To prevent this from happening, the chimney is attached to the ceiling and roof loosely and strictly vertically. Depending on the damage, the crack is sealed with a suitable sealant, or the entire section is replaced. You can cut the ceramic casing with a grinder, then plant the new section on a special acid-resistant solution.
Previously, ceramic water pipes and asbestos-cement pipes could be used for the chimney. Both options cannot withstand high temperatures and temperature changes, quickly deteriorate and crack. This threatens an unexpected fire. Open sand-lime brick is also unsuitable for smoke.
The durability of the chimney itself depends not only on the properties of the material, but also on proper selection regarding the power and waste of the boiler, as well as proper operation and timely maintenance. There is no need to skimp on fire safety.
What to do if smoke from the stove comes into the house?
Strong wind It happens that with strong gusts of wind, smoke is thrown into the room. The cause can be easily eliminated - you need to raise the head of the chimney higher, or change the cap on the chimney.
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Accumulation of soot inside the channel. Chimney burnout:
Combustion products settle on the walls of the chimney duct, especially on rough surfaces, protrusions, turns and corners, where soot and tar can form plugs. On smooth surfaces, soot is retained by condensation. A painful issue for long-burning boilers. By switching to smoldering mode, they lower the temperature of the exiting smoke. Which, cooling even more in the chimney, settles on the walls with soot and moisture.
You can notice a clogged pipe by the color of the gases: light smoke is normal, dark smoke is a blockage. As a result, the channel narrows, the draft decreases, it becomes more and more difficult for the unit to work and the threat of fire is imminent. Accumulated soot easily catches fire and can damage not only the pipe, but the entire building.
How to clean a chimney from soot?
It is rational to use two cleaning methods - mechanical and chemical. Moreover, the second one is more likely for preventive purposes.
The chemical agent for soot, in the form of a briquette, liquid or powder, is burned in the firebox together with firewood or separately. Gas compounds enter the chimney and corrode the soot. The preparations are produced for different thicknesses of soot, and have an amplitude of action from hours to several weeks. During this time, the soot falls down and is cleaned out mechanically.
Disadvantages of chemical cleaners:
- work with small accumulations (up to 1 cm);
- corrode the surface of the chimney.
Mechanical cleaning of the channel is the most effective way to remove soot, especially its resinous compounds. The lower part of the chimney (stoves, fireplaces) is cleaned from below with special brushes, the upper part is cleaned by lowering a brush and a load from the roof into the chimney.
Metal chimneys can only be cleaned with a nylon brush. The steel nozzle will scratch the surface, which means that even more soot will settle, the metal will rust, and the pipe will quickly need to be replaced.
By periodically throwing dry aspen into the firebox, you can clean the chimney of small deposits. Aspen firewood produces a high temperature at which the soot burns out. The main thing is not to burn the chimney itself. If a lot of deposits have accumulated, then the soot will burn at a temperature above 1300 degrees, which can only be withstood by a ceramic chimney (in the lining), if it is marked with fire resistance. And for sandwich systems and stainless steel pipes this is death.
In order for less soot to settle in the chimney, you must:
- burn with dry hardwood firewood (pine and spruce emit resins, and raw firewood smokes heavily and adds moisture);
- make the inner surface of the chimney smooth and sealed;
- reduce condensation formation.
Prohibited! Burn materials containing glue or plastic (for example, furniture scraps) in the firebox.
It would be a good idea to evaluate the quality of the pipes before purchasing, as well as the assembly process itself. Parts of sandwich systems must have a clear configuration (and practice shows that this is not always the case) and tight connections during assembly. Any difference in the internal joint will collect soot on the joint, and an unsealed installation will leave an opening for condensation. In composite versions (metal - filler - metal), the insulation must fill the entire space. This applies to both cotton wool materials and vermiculite. Good insulation prevents the pipe from cooling quickly, keeping the smoke “hot”. Higher temperature means less moisture means less soot deposits.
Traditional recipes for burning soot
We can say with confidence that these means of cleaning channels for removing combustion products are dangerous and not every chimney can withstand this. Cracks appear in the walls of the chimney due to high temperature; sometimes it is better to use other means for cleaning.
Walnuts and aspen . Walnut shells have the amazing property of high heat transfer. Therefore, to clean the chimney, you need to place about two-liter jars of shells in the firebox. This product will make the rising smoke as hot as possible, which will burn the soot in the chimney.
Aspen was an accessible material in the northern and middle regions of Russia, so it was used quite widely. This method is one of the best for cleaning , but against the backdrop of modern chemicals it is undeservedly forgotten. When burning aspen logs, all stove valves and doors should be closed.
After combustion, white flakes begin to fly out of the chimney, which are a product of soot combustion. The stove will make a loud noise and the soot will burn out completely , but the cleaning method is dangerous for weak chimneys.
Chimney cleaning with mothballs
Before using this method, you must ensure the following:
- There are no cracks, damage or holes on the outside of the chimney; if any are found, they are carefully sealed with mortar and allowed to dry.
- Make sure that no objects or work items accumulate in the channel passage.
Naphthalene for small stoves in a private home is used in the amount of one tablet, which is thrown onto the burning fuel . Soot, as in the case of aspen, will fly out in white flakes.
Naphthalene is a substance with a crystalline structure with a sharp, characteristic odor; sometimes, when used as a chimney cleaner, it explodes, which can lead to destruction of the pipe and subsequent fire.
Formation of condensation in the chimney
Moisture in the chimney impairs draft; this is easy to notice with constant use. Sticky soot blocks the pipe. In the masonry of brick chimneys, smudges appear at the seams, the bricks are saturated and destroyed.
At the bottom of the channel the temperature of the exhaust gases is maximum. Moving upward, the flow cools, lingering at the bends, and settles in drops on the cold surface of the chimney. Metal pipes that are not insulated cool down in a few minutes (when switching to a smoldering combustion mode), brick and ceramics give off heat more slowly. Hence the ability of the metal to collect drops of moisture on itself.
Insulating the pipe helps keep the temperature of the exhaust gases above the “dew point”. With a “lined” chimney, the space between the masonry and the pipe is filled or filled with non-flammable insulation (expanded clay, stone or glass wool). The top and bottom of the gap are sealed with a plug.
If the diameter allows, it is reasonable to assemble an analogue of the sandwich system. Having insulated the outside of the existing metal pipe with a layer of 5-10 cm of mineral wool, it is necessary to protect the entire structure on top with metal sheets or a pipe of a suitable diameter. On the outside, the channel experiences less stress, so a more aesthetic material can be chosen.
Correct installation of the chimney is important. The joints of the insulation and pipes should be staggered. The metal is connected with heat-resistant sealant and fasteners, and the entire structure is tightly fixed with clamps. If the joints in a homemade or purchased sandwich system are not sealed, condensation will seep in and destroy the insulation. In response, the temperature and fire danger will increase. The chimney will more often than not be damp and clogged.
Conditions under which excess condensation forms:
- burning with raw wood;
- cold chimney (not insulated or not used for a long time);
- weak combustion of fuel (with a lack of air, too weak draft or too strong), for example, in boilers in smoldering mode.
In a poorly calculated chimney design, the escaping gases also cool quickly. Channels with high heights, complex bends or narrowing diameters slow down and cool the smoke. If the cross-section is larger than optimal, then the draft weakens and condensation also forms.
Wood-burning stoves with 5-7 channels are difficult to warm up with a small load. The smoke will go into the chimney cold. To warm the smoke and reduce the amount of moisture, the design makes a thin direct connection between the firebox and the upper last channel. Also, previously, firewood was sprinkled with rock salt before the firebox - it removed some of the condensation. An ancient method of prevention.
Cleaning if the pipe lumen is completely blocked
To do this, pour water (about three liters) into the chimney from above. After this, steam is released, which cleans the hole in the pipe. Soot flies out of the chimney in a compacted cloud of thick consistency. To prevent a chimney made of steel from rusting, they immediately begin to heat it and warm it up until the last moisture evaporates.
There are special cleaning logs or pellets , which are placed in the stove without opening the packaging, and the combustion lasts for about two hours. After this, the accumulation of soot and soot in the channel becomes loose, the separated light particles rise, and the heavy ones fall down into the firebox.
If special inspection holes are provided along the chimney, it is recommended to carry out preventive cleaning after using cleaning logs. There are special powders for cleaning the furnace outlet channel, for example, a Czech product called Kominichek, Smoke-Glas and others.
For their use instructions have been developed that will tell you how to use them correctly and what dosage to use. But all of them are used in the furnace to produce a chemical reaction, which results in substances that destroy the soot layer in the pipe.
In conclusion, it should be said that the smoke duct should be cleaned in any case, so that the misfortune of poor combustion of the stove is not added to the grief of sudden smoke in the room or a fire in the attic, where a pipe clogged with soot passes through.
Causes of insufficient and reverse draft in the chimney
A smoky room, difficult ignition and slow combustion are the main consequences of poor draft in the chimney.
The reverse draft can “knock” fire out of the firebox into the room or, in the minimum version, extinguish the boiler burner. With poor air flow, soot is retained in the pipe and condensation accumulates more. Traction disorders have four main causes:
Reason No. 1 - Incorrect chimney design
- low height relative to the roof (less than 0.5 meters or 1 meter above a flat form);
- the channel cross-section does not correspond to the characteristics of the boiler or furnace;
- the chimney consists of sections of different diameters;
- incorrect turns, slopes and angles of the channel (the norm is a bend of 45, a turn of 90 degrees);
- horizontal pipe sections longer than 1 meter.
For a chimney, it is better to focus on a cylindrical cross-section - in rectangular-shaped channels, vortices are formed at the corners. Soot settles there first, limiting traction.
Important! You cannot independently combine several exhaust chimneys into one network. Only professional calculations will help you do this. This is the case when savings at the beginning are reflected in wasted time and nerves in the end.
Reason No. 2 - Insufficient tightness
When the damper in the chimney (usually in stoves and fireplaces) does not close tightly, warm air from the room enters the chimney. Uninsulated metal chimneys are especially susceptible to cold. As a result, at sub-zero temperatures the channel can be completely blocked by frost. Changing the valve to a denser damper and insulating the chimney itself helps.
Unsealed joints in a metal pipe disrupt the flow of air during the fire and often extinguish the flame of a gas burner. Each joint seam must be tightly treated with a heat-resistant sealing compound.
Reason #3 - Ventilation
For good traction, uniform access of oxygen is necessary - properly functioning ventilation. Its violation or absence guarantees questions. Too strong drafts interrupt the draft and return it to the house. Lack of oxygen affects combustion. Thus, gas boilers often draw air back from the chimney, compensating for the lack of air with reverse draft. This is why the burner goes out.
By opening the access of fresh air to the room, you can properly organize the flow from bottom to top.
Reason #4 - External factors
The draft often worsens under the pressure of cold street air (when the stove has not been heated for a long time and the cold has accumulated in the chimney). With strong air currents or pressure differences - when the house is colder than outside. The weather is changing, and to restore draft, you can warm up the chimney in front of the main firebox, burning paper (preferably closer to the duct). The draft is also severely limited by fallen bricks, debris in the chimney, in the form of bird's nests, or banal soot.
How can you improve chimney draft:
- resolve issues regarding chimney design;
- insulate the outlet channel;
- organize a constant flow of air;
- Clean the chimney from soot in a timely manner.
Regular inspection of the chimney for leaks and damage helps resolve many issues already at the start.
Design mistakes or what you shouldn’t save on
When designing a house, engineering comes first, only then beauty. Once you make an indulgence, you can then pay double the price for the chimney, or lose the entire house.
Even a hollow decorative brick for the top of the chimney can be a surprise. It strongly absorbs moisture and quickly deteriorates, even if the sleeve is made of metal inside. Leaks pass down the main masonry and destroy the chimney. By replacing decorative brick with solid brick, you can protect the main masonry from destruction.
The passage of the chimney pipe through the floor ceiling, attic space, and roof must be secured according to all standards, or better yet, with a reserve. The fillers in a sandwich pipe shrink over time (sometimes 3-4 years of intensive work) and can crumble, causing the outer metal to heat up above normal.
The cutting on the roof and in the ceiling must be designed for this. Of course, quality is the responsibility of the manufacturer, but your own safety is a personal matter. “Hollow” stainless steel will last for years, but only with careful monitoring.
Umbrellas and caps over the chimney prevent precipitation from entering the chimney, but delay the draft and collect condensate. Perhaps, from different heights and shapes of umbrellas you can find protection for the pipe, but this is rather an individual selection to the features of the heating system.
Careful periodic inspection and competent operation help to reveal many issues, 99% of which can be completely resolved by one’s own efforts.
