Long burning boilers

Welcome to our guide to long-burning boilers, which covers insulation and heating for your house. Keeping your home warm becomes increasingly important as the weather gets colder and winter arrives. An economical and effective way to heat your house is with a long-burning boiler, which minimizes energy use while maintaining a constant temperature.

Wood logs or pellets are used as fuel in long-burning boilers, sometimes referred to as log boilers or wood pellet boilers, which are a kind of central heating system. These boilers are made to burn fuel slowly and steadily, giving off heat that is constant over an extended length of time. Long-burning boilers can run for hours or even days on a single fuel load, in contrast to conventional boilers that need to be refueled frequently.

The high efficiency of long-burning boilers is one of their main benefits. These boilers maximize fuel heat extraction while minimizing waste and fuel consumption through regulated fuel burning. This lessens the impact that heating your home has on the environment in addition to lowering heating bills.

The adaptability of long-burning boilers is an additional advantage. They can be utilized in a range of contexts, including bigger commercial buildings and tiny residential homes. Long-burning boilers can be sized to suit your needs, whether you’re looking to heat a single room or your entire home.

Long-burning boilers also provide a sustainable and renewable heating option. Compressed sawdust and other wood waste products are used to make wood pellets, which are one of the most popular fuels used in these boilers. Because the carbon dioxide absorbed by the trees during their growth balances the carbon dioxide released during combustion, this makes them a carbon-neutral fuel source.

Brand Features
XYZ Boilers High efficiency, automatic fuel feeding
ABC Heating Systems Low emissions, programmable settings

What is the good of a long burning boiler

Gas boilers are typically installed in private homes. But not every location has mains that use this kind of fuel. Furthermore, it will be very expensive to connect a separate gas line in the presence of the main line.

Installing such a boiler will only scare away the owners if you add to these costs the necessary procedures for approvals and drafting projects that fully comply with all requirements. particularly if there are respectable substitutes.

It would seem that if it is not possible to install a gas boiler, you can always buy an electric boiler. The choice of such equipment is quite large. Boilers have high efficiency, they are easy to adjust, the number of control systems, and also equipped with an automatic control system. However, all these pluses become disadvantages when owners start to remember the cost of electricity. An ordinary family can easily go broke on such heating. In addition, in settlements that are remote from regional and urban centers, the voltage is not particularly high-quality – in the network you can observe strong fluctuations. And the owner of an electric boiler puts himself in dependence on the quality and stability of the power supply.

The conventional practice of heating homes with wood and other solid fuels has become less commonplace due to the rapid advancement of technology. Furthermore, wood is a good and renewable energy source. There is no lack of wood available for heating. Homeowners can either buy or use firewood that they have already prepared. Additionally, a large number of wood processing businesses sell the leftover wood from their operations.

However, not every home has a stove. Yes, because of the way it is made, it is effective at keeping heat in. Enough to fill the furnace to the brim and keep the house warm for a full day and a half. However, there is one small detail to consider: how should the coolant be handled as it circulates through the heating system’s circuits? After all, there will be a significant fuel consumption if you simply leave the combustion going in the stove. Top-burning boilers that run on solid fuels can help solve this issue.

Owing to the unique construction of this apparatus, which takes into account the chemical and physical characteristics of solid fuels, firewood can be loaded once in a period of 12 to 15 hours. Some models have even greater capacity for one load.

Using a variety of other materials in addition to firewood is another benefit of long-burning boilers with top combustion. Anything that burns is utilized; this includes waste-derived briquettes, coal, and peat. Additionally, as a source of energy, "Euro firewood" has become increasingly popular in recent times.

Slow burning stove with your own hands

Let’s now examine the stove’s independent manufacturing process. A long-burning stove differs primarily from one another in that it has two combustion chambers joined by a grate or grates. Firewood is allowed to smolder in the loading zone. There is not much oxygen present during this process. The wood is sent to the second chamber, where it is burned, after it has smoldering and broken down into coke. Debris flows down the chimney.

To assemble this kind of basic stove, you’ll need:

  1. Sheet metal 3-4 mm thick.
  2. Metal corners.
  3. Steel fittings.
  4. Chimney pipe (steel or cast iron).
  5. Chimney.
  6. Welding machine.
  7. Measuring tools.

Laying firewood in the upper combustion hearth stove

In the hearth stove, the thickest firewood is placed at the bottom of the stove in a pyramid in one direction along the firebox, facing the door. In the openings between thick firewood, thinner chunks are placed in order to minimize the air space between the firewood and thus make it more difficult for air to move through the thickness of the wood stack. This is the main condition for a long-lasting upper combustion. The higher the stacking – the thinner the firewood, and on the very top stack kindling, wood chips, birch bark, luchina and other flammable fuel. It is more difficult to ignite the tab of a top burning furnace than a traditional furnace.

Air is supplied to the firebox’s upper section, which is located beneath its arch, during combustion. The tab’s upper region contains the center of combustion, which does not completely encircle all of its layers. There are no bursts of heat, no complete engulfment of the flame, and the lower wood stays unaffected by the fire. This causes the furnace to slowly heat uniformly and the stones to gradually heat. The Fehringer sauna stoves are designed in this manner.

The air temperature hardly changes during an hour of combustion—only the stone surrounding the firebox gets heated! Only an hour into the stove’s operation does the flame reach 70% of the firewood from top to bottom, and the air and stone heating rates rise at the same time. With this kind of combustion, the stone heats up to 350–400 degrees Celsius and the steam room reaches 50 degrees after two hours. These are typical opening circumstances for a Russian sauna, where the key selling point is the abundance of red-hot stone and the steam room’s walls and air at moderate temperatures.

Why the upper combustion in the furnace is better for Russian baths?

I’ll start by outlining the benefits of hearth stoves, particularly top-burning models.

  1. No fire volley, when the maximum amount of heat escapes into the chimney
  2. The consequence of the first point is low efficiency because of the high temperature of the exhaust gases (the colder the exhaust, the higher the efficiency)
  3. At volley combustion through the grate the whole area of the firewood does not always burn in the zone of full oxygen saturation, which has a bad effect on the combustion itself and reduces the efficiency of combustion
  4. Combustion through the grates is all-encompassing and faster in time than overhead combustion
  5. At the top burning the scheme of heating the stone and the stove, the sequence is as follows: the stones are heated through the bottom of the stove, the walls are heated slowly, the steam room is heated slowly, after heating the stones begins to heat the room of the steam room
  6. The mode of combustion of pyrolysis gases is gradual after the wood burns out and falls just in the moderate part of the heating of the steam room, when the room is already warm and you need a slight maintenance of the temperature at the bottom of the sauna heater, so that the stone does not cool down

Top combustion (top ignition) firing is an option for steel stove owners whose firebox walls feature a steam generator. I used the Sahara 16 stove to conduct this experiment. so as not to cut off the air supply. Personally, though, I’m happy with how quickly dry-air stoves heat up when the steam room’s ventilation is skillfully controlled (by keeping a window open) and a steam generator is used.

There are two methods for regulating upper and lower combustion in high-quality stoves. Castor sauna stoves, for instance, feature an enclosing plate that feeds some air straight to the firebox’s top.

The main feature of heating boilers with the upper combustion method

Manufacturers chose to employ both new and traditional technologies in the design of heating equipment in response to the challenges associated with maintaining solid fuel-powered heating devices. The primary goal of the boiler equipment modernization process was to extend the time that a single load’s fuel could be burned. This outcome was made possible by the application of the upper combustion principle in solid fuel boilers.

The upper combustion method of boiler operation is not a radically new technological advancement. The fuel that is put into the furnace burns vertically. Conversely, ΢.е. does not operate like conventional boilers. Starting with the topmost layer, where the movable distributor provides the required air flow, burning occurs. The air distributor falls under its own weight as the fuel mass burns off, allowing the next layer to burn. As a result, the loaded fuel burns uniformly layer by layer, producing a significant amount of combustible wood gas.

The furnace inside the unit reaches 450 0C at this point.

The pyrolysis principle starts to work at this point. Massive amounts of heat energy are released when the small combustion products and the released wood gas are fully burned. As a result of the unit operating, almost no fuel residue remains in the combustion chamber.

Just to refresh your memory, pyrolysis is an exothermic reaction that releases flammable gaseous matter after organic compounds decompose due to high temperatures. Burning wood gas provides the solid fuel boiler’s primary heating during the combustion process.

Through a metal disk, the wood (pyrolysis) gas enters the second chamber where hot air ignites it. Right now, the second furnace’s combustion temperature is reaching extraordinarily high levels—between 500 and 800 0C. Everything is understandable and straightforward. The heating apparatus’s design is the most important factor.

It is the combustion process that determines the burning rate of the fuel as well. In heating equipment of the classic type, wood is burned quite quickly, giving out the maximum possible heat in a short period of time. In other words, during a short period the unit reaches the peak of its capacity, after which without subsequent fuel lining the boiler starts to lose load. It is not always convenient or physically possible to constantly load a new batch of firewood. Solid fuel boilers with top loading work quite differently. One load with such an appliance can be enough for 12, 24 or more hours of work. The intensity of combustion depends on the load on the heating system.

Everything is understandable and straightforward. The heating apparatus’s design is the most important factor.

Advantages and disadvantages

Benefits [o 1][x 3]:

  • Uniquely long burning period without refueling – user friendly
  • High efficiency
  • No complex automatics
  • Wood-fired models are energy-independent (with natural circulation of the coolant), universal models consume relatively little fan power
  • Safety (compared to gas, electricity and liquid fuel boilers)

Drawbacks [c 1][o 1]:

  • Relatively high cost
  • When the fuel of significant ash content is burned out, the combustion and generation zone becomes clogged with ash, the intensity of combustion drops sharply (it is necessary to poke with a poker). In boilers with a supercharger ash is usually dispersed by air (although at strong sintering of fuel not always), to wood-fired can be attached a homemade fan.
  • Presence of poorly cooled metal elements in the combustion zone (especially the stascoblin burns quickly)
  • Complex recommendations for fuel loading, increased requirements for moisture and size of fuel pieces
  • It is difficult to get rid of condensation (possible cause – too high water flow or too strong draught)
  • Difficulty of kindling with incomplete loading (the firebox is very deep)
  • It is not possible to top up small fuels like sawdust "on the fly"
  • There are complaints about the lack of manufacturability

Quality and safety

Real Fireclay from REDSTON. The quality and safety of our products are confirmed by relevant certificates and expert opinions.
? The thickness of the heat-consuming vault of the furnace is 100mm. The thickness of the oven base and vertical walls of the oven is 90mm. Active multi-layer thermal insulation.
? Furnace is up and running in 1 hour. Keeps heat for 24 hours.
? The external body of the furnace, made of the innovative material BAZA-BAZALT, provides maximum reliability and complete tightness. It can be finished with any general building materials.
? Guaranteed reliability. The "Floating Vault" glueless stone jointing system allows the stove body to expand freely when heated and contract when cooled down. Our stoves are not afraid of overheating. Our ovens do not tear when heating up.
? The furnace does not need to be dried after installation. Installation and commissioning of the furnace in one day. No restrictions. Once installed, you can use it immediately!

Operating principle

The operation of traditional solid fuel stoves is a widely understood concept. Fuel is added to the firebox, either coal or briquettes. The lower chamber provides a stream of air that is needed for the procedure. In this instance, the quantity of oxygen is the only factor limiting the degree of combustion intensity.

This is an ordinary fire, which is enclosed in a metal case that requires constant addition of fuel supply. Products of combustion are directly discharged into the chimney – this system has many turns and labyrinths. This improves the heat transfer and leads to an increase in efficiency. However, this does not increase the overall energy efficiency. Thermal decomposition of wood is a rapid process that leaves a mass of waste and releases unused energy into the atmosphere.This energy is obtained due to the special characteristics of wood, which, in turn, are determined by its biochemical composition. When the wood is heated, it is not just oxidized to coal, but also emits carbon dioxide and carbon monoxide gases. Exposure to high temperatures always leads to the synthesis of volatile compounds based on hydrocarbon. These compounds have a rather complex chemical formula. The gases themselves are an excellent fuel, which in an ordinary stove goes nowhere.

In today"s world, where energy efficiency and sustainability are paramount, long burning boilers stand out as a vital solution for heating homes efficiently while minimizing environmental impact. These boilers, designed to burn fuel for extended periods with optimal heat output, offer homeowners a reliable and cost-effective way to keep their houses warm during cold months. By maximizing fuel efficiency and reducing the need for frequent refueling, long burning boilers not only save money on energy bills but also contribute to reducing carbon emissions. Whether powered by wood pellets, logs, or other biomass fuels, these boilers provide a sustainable heating option that aligns with modern environmental goals. With their ability to maintain a consistent and comfortable indoor temperature while lessening the strain on natural resources, long burning boilers emerge as a practical and eco-friendly choice for households seeking to enhance their heating and insulation systems.

Main disadvantages

Numerous drawbacks are mentioned by customers:

  • Temperature sensitivity of the heat exchanger leads to condensation and corrosion at higher circulation rates. Solid cast iron devices are less exposed to condensate than steel ones.
  • Not always the supercharger copes with the burnt ash. Increasing its volume leads to a decrease in the heat output of the heater. Wood boilers with natural circulation require constant intervention with a poker.
  • Rapid combustion of the support stick and disk located in the flame to cut off the combustion zone of the fuel in the area of afterburning of volatile elements.
  • Large fractions of fuel, including not split logs, are not recommended for use, which is an obstacle for top burning of firewood. The supply of wet fuel is excluded. It is important to ensure maximum drying of the firewood.
  • Difficulty in igniting firewood when the firebox is not fully loaded (due to large dimensions).
  • High price.


The stove’s three sections are the gas combustion area, which is isolated from the chimney by a flame baffle, the ash collector, and the wood loading area with a grate from below.

The length of the crossbars and four legs, which are roughly a meter long, must first be cut out of the metal angle; these parts vary depending on the size of the stove you intend to purchase. The stove’s frame, to which the metal sheets will be attached, must then be welded from the crossbars. The legs and frame are then fused together.

Don’t use too thin metal for the stove’s walls if you want to boost its heat output and prolong its lifespan. After being cut to fit the frame’s dimensions, metal sheets are welded to it. A hole must be drilled in the front wall for the loading door and the ash pan door.

Even before the final assembly on the front part it is necessary to weld the curtains and bolts for the doors. Next, you need to make the doors themselves and attach them. In order to minimize the gap between the doors and the wall, it is not unreasonable to weld bars. On one of the side surfaces it is necessary to make an air distributor. To do this, it is necessary to make a hole in the wall, and weld a circle with a pipe and a damper to it. This is necessary to regulate the flow intensity. In order for the wood to smolder and not burn, the hole should not be more than 20 mm in diameter.

It is worthwhile to make the fasteners for the stove’s partition between the two compartments on the inside surface of the side walls beforehand. A partition wall can be created with a rebar or grate grate. You must install a flame arrestor and cut a hole for the chimney on the stove lid.


Boilers ranging in capacity from 8 to 40 kW are currently produced. There are universal models that use wood, coal, anthracite, peat briquettes, sawdust briquettes, shavings, and other wood waste and are energy-independent (natural draught). They also have a blowing fan. Fuel with a humidity of up to 20% is advised.

Boiler efficiency: 85-73%. The manufacturer states that the duration of combustion for a single load varies based on the mode and can range from 5-8 hours to 31 ̾ for wood and up to 5 days for coal. Conventional boiler designs only burn a load for two to eight hours.

For wood, the water heating temperature should be 70 °C, and for coal, 85 °C; an inlet temperature of 60 °C or higher is advised. There are two types of heating systems: forced circulation and natural circulation.

Pros of top-loading appliances

  • High efficiency. In addition to the points mentioned above, this is also due to the specifics of fuel combustion. In conventional TT boilers, the flame gradually takes over the entire tab. In analogs with top loading, it is of the so-called shaft type. That is, the burning process directly affects only the lower layer of firewood (coal), while the upper part of the tab passes the stage of preliminary drying. Actually, such boilers – just one of the varieties of installations of long combustion. More information about the devices of this group is available .
  • Convenience of operation. This logically follows from the first point. If for TT boilers with front loading it is necessary to constantly monitor the combustion process and regularly add coal or wood to the furnace, modifications with VZ relieve the user of it. Time saving is obvious.
  • Energy independence. For the operation of the control and monitoring elements, the boiler does not need to be connected to the mains power supply.
  • Ease of use and maintenance. As a result – the cost of maintenance and repair compared to more "tricked-out" analogs is incommensurably less.

Types of stoves

There are several types of products that have the upper type of combustion. They are separated into heating and kitchen categories based on their intended use. by the kind of heat source—wood-fired, gas, or electric. Brick and metal are two possible basic materials for hearth products. Let’s examine the characteristics of several kinds.


These ovens, as their name implies, are intended to be installed in kitchens and used to bake bread and pastries. Can be made as small and basic as feasible; ideal for private residences. There are production models and functional models for restaurants and bakeries that let you cook multiple dishes at once.


A burner and up to 19 ring-shaped pipes that allow gas to pass through are located inside the casing. Inside are two to five tiers, with independent temperature controls for each tier. Gas stoves have a maximum operating temperature of 300 degrees Celsius. It is permitted to use it whenever it wants. The burner’s energy travels through three circles: the first heats the vicinity of the burner, and the second and third circles heat the combustible gas-heated pipes and bricks that make up the oven’s bottom and walls. Even heat is dispersed by heated areas.


Gas and electric deck ovens look the same from the outside. The "stuffing" is what makes the differences. There is a heating element inside in place of the gas burner and pipes (the heating element’s coils can be arranged in the center of the upper and lower tiers).

Electric ovens can have two to five independent chambers, just like gas ovens. It’s possible to adjust the temperature inside each chamber to suit your cooking needs.

Gas is a more cost-effective fuel, but electric ovens will be more advantageous in terms of safety and convenience of use.


Even our ancestors used wood-fired baking ovens. Food prepared on it, according to true connoisseurs, will taste far better than food prepared on an electric or gas stove. A hint of wood adds flavor to food. Cons: Wood stoves are the hardest to operate. Fuel must be added manually in order to keep an eye on it burning out.


The single-chamber design of kitchen stoves distinguishes them from heating stoves; with them, separate spaces for baking trays in the kitchen are not necessary. The only permitted heating system inside a residential building in Europe is the hearth furnace. This is explained by the system’s safety and environmental friendliness: no smoke enters the atmosphere through the chimney because fuel for the hearth stove burns completely.


Iron or steel alloy is used in the production of these stoves. One benefit of the design is that it is easy to install and maintain. Minus: If you touch the body, you risk getting burned because it gets extremely hot. 30 to 50 years is the service life if used correctly. Cons: Metal stoves are susceptible to cracking because they cannot withstand abrupt temperature changes.


This type of stove emits heat for a longer period of time and accumulates it better. It will become a decoration for any traditional interior because of its amazing appearance. twice as long-lasting as steel or cast iron construction, but it costs ten times as much. Installing a brick stove requires expertise; it is best to avoid doing it on your own without a professional.

Pavel Kruglov Stoveman, a 25-year veteran, provides expert opinion

The drawback is that once installed, it cannot be easily moved to a different location without requiring the design to be completely disassembled.

Gorgeous deck oven made of bricks


To the disadvantages of this equipment can be attributed demanding and finicky to the quality of fuel. If you make the unit work on raw wood, its efficiency will significantly decrease. Optimal level of humidity of long burning with top combustion is 13-20 %. If a more crude product is used, the boiler will produce significantly less heat. In addition, in this situation, the unit may even go out. In addition, if you burn raw wood in the boiler, a lot of soot and ash will be released. It is necessary to periodically clean both the furnace itself and the chimney. Also to the disadvantages can be attributed the need for manual loading.


You will be able to comprehend what a hearth furnace is by looking at the design. It is made up of the following 11 crucial components:

  • No. 1 – Convection chamber, which has louvers and valves on top.
  • No. 2 – Body, made of steel or chamotte.
  • No. 3 – "direct passage" gate valve (type "summer passage"), directing the smoke directly into the chimney.
  • No. 4 – Main firebox (chamber).
  • #5 – Side fireboxes.
  • No. 6 – fireclay brick of the side firebox (refractory element).
  • No. 7 – Underneath (the bottom horizontal surface of the stove)
  • No. 8 – Reinforced wall (made of SHA-94 brick).
  • No. 9 – Fireclay brick in the 4th combustion chamber.
  • No. 10 – 4th combustion chamber.
  • No. 11 – Chimney hole, here the chimney pipe is attached.

The diagram displays the stove’s specified details:

Every model has doors (made of steel or cast iron). Occasionally, a heat-resistant window is formed in the center of the door to let you see the flame.

It will be possible to set dishes on the stove if it is going to be used for cooking because it has burners and grates that lessen heat stress.


The benefits of using this solution are clear:

  • The period of operation without the need to refill the fuel is determined only by the size of the fuel box.
  • In front of us, in fact, another type of pyrolysis boiler. Accordingly, all its advantages, including high efficiency, remain. The deposited fuel burns without residue.
  • The equipment is very fail-safe. It does not have any complex automatics.
  • In 2007 Lithuania started to produce universal boilers that can burn not only wood and wood products, but also coal. Later, similar equipment started to be produced in Russia as well.

Lower combustion high efficiency and low thermal inertia

Boilers using solid fuel and bottom combustion represent a new development in heating technology. These boilers can run on coal or wood. In these units, the fuel burns in the lower layer as opposed to traditional boilers that have upper combustion. The top layer heats up and descends toward the combustion zone as it burns out. Boilers with this design direct smoke and flame upward via side channels in the heat exchanger. Because of their low thermal inertia, new fuel requires more heating before it can be added, maintaining the boiler’s efficiency.

The benefits of lower combustion units over upper combustion boilers are as follows:

  • Higher efficiency
  • Quick payback
  • Long combustion time of one fuel charge
  • The possibility of adding fuel to the firebox without negative consequences for efficiency and reignition

The drawbacks are that they require more frequent cleaning and that high-quality coal (gas and long-flame), which is resistant to sintering, must be used. However, the rapid payback period of these boilers outweighs these drawbacks.

Boilers with a controller and fan from the Popter D and Popter DS series are examples of lower combustion Rakoczy boilers. These coal-fired boilers have an easy-to-use grate cleaning system and a high efficiency of 80%.

Advantages of the systems

The fuel box’s specifications define the burning time for wood and coal, and there are no restrictions. The pyrolysis unit has been modified in accordance with the operating principle, indicating a high efficiency resulting from the complete combustion of fuel masses without residue.

The fault tolerance of the devices is determined by the lack of complex automatics.

Lithuania has been producing a range of multipurpose devices that run on coal and wood since 2007. A short while later, other manufacturers—including Russian ones—started to produce comparable units.

The units’ design elements, which have a height of almost two meters and occupy a minimal amount of usable space, allow for space savings. For those looking to outfit a small boiler room that cannot accommodate traditional solid fuel equipment, this is a practical solution.

The fuel compartment receives air supply from top to bottom. The air is heated to its maximum temperature in the upper chamber before it enters the lower chamber and helps to maximize the reaction with the wood. The maximum efficiency, which varies from 10% to 100% of the nominal capacity, is created in this manner. This leads to another benefit of the units, which is their superior capacity to heat any size room. Boilers operate on the first charge for a few days at a time, depending on the size of the heated building. This removes the requirement for regular fuel loading.

The devices’ unique shapes are what give them their longevity. Superior quality, dense, and heat-resistant steel is used to make them. The shaky location of the wood-burning hearth is determined by design elements. It moves smoothly from top to bottom, preventing metal weighing more than 400 grams from overheating. All of the system’s components, which are prone to failure, are detachable, enabling you to alter them as necessary.

It is acceptable to use an additional device if one boiler is insufficient to heat a sizable space.

Advantages of wood heating

When selecting a boiler for home heating, consumers weigh the advantages and disadvantages of various options. After discussing a few different kinds of slow-burning wood stoves, let’s get acquainted with the benefits of wood heating in general. It has many advantages over other forms of heating, including the following:

  1. Environmentally friendly. Wood stove does not harm the environment, and in this respect it simply has no equal. When burning, wood emits no more carbon dioxide than when rotting in the natural environment. And compared to the environmental damage caused by other fuels, this is just a trifle.
  2. Economical. Unfortunately, many people think first of all about financial benefits, and then about ecology. But even in this plan wood stoves have succeeded. Wood costs less than other fuels.
  3. This unit can be used not only for heating homes, but also for cooking food. This is especially important for those whose house is far from the gas pipeline.
  4. With all the efficiency of wood heating, it is not at all complicated. If everything is done correctly, the stove even without radiators will warm up the house well.
  5. The stove draught creates a heat exchange between the street and the house, thanks to which an optimal temperature level is achieved and humidity is normalized
  6. Wood boiler gives a pleasant aroma, creates a cozy atmosphere and reminds us of our roots.

Boilers with upper combustion

These boilers with upper combustion were the first to hit the market. The underlying idea of the principle is that ignition occurs from above in a boiler furnace. A movable air distributor supports the flame and lowers itself gradually, so long as it doesn’t reach its final position. As a result, only the top layer of fuel will burn simultaneously.

Benefits of upper combustion boilers:

  • The air supplied to the furnace is preheated while passing through the distributor – this improves the quality of combustion.

Because they can function without electricity in the event of a natural draught and heat carrier circulation, boilers are regarded as energy-independent. In actuality, though, using a solid fuel unit of that kind without automatic regulation can result in boiler failure. First, due to the frequency of significant temperature variations, condensation, and corrosion. 2. as a result of overheating.

Benefits of top-burning boilers:

  • Air distributor and disk during combustion are under the influence of high temperatures and insufficiently cooled, which leads to accelerated burnout of metal;
  • The movement mechanism, the so-called "telescope pipe", can jam;
  • The combustion chamber is shaped like a cylinder – it is inconvenient to stack firewood in such a firebox;
  • Due to the principle of combustion there is no possibility to load the fuel during operation – it is necessary to wait until the load burns out completely;
  • During the initial phases of combustion, heat is only extracted in the upper part of the boiler;
  • The ignition, which is carried out from above, requires a full load of the firebox.

The second kind of long combustion devices, which debuted a little later, does not have these drawbacks.

Advantages of hearth furnaces

The primary benefit of this kind of stove lies in its working principle, which involves combustion moving from the top layers of fuel to the bottom layers. The air masses entering the furnace provide this movement of fire on the firewood levels. In the combustion zone, they aid in the oxidation of wood. Consequently, embers are created, which causes the lower levels to start heating. Pyrolysis gases are released when the thermal decomposition process is triggered.

The materials that are used for the interior surfaces of the furnace help to maintain its high temperatures. For this reason, a range of insulating materials and fireclay stone were used in this section of the furnace. The firebox’s walls hold in the heat generated during combustion. As a result, the ideal conditions are created for an even combustion process.

Unlike grate furnaces, which involve the entire charge, the combustion reaction only involves the upper levels with varying oxidation levels. As a result, the air supply in the hearth models does not need to be changed to achieve the appropriate level of combustion. Changes to the air supply can be made quickly.

As the fire moves through the layers of laying, the effectiveness of the hearth type equipment and the effectiveness of its operation do not decline. This could occur in grate stoves if the air supply is not appropriately controlled.

In addition to their longevity, underfloor combustion stoves are renowned for their fuel efficiency. The lack of a grate in the firebox design results in a 5% reduction in the amount of firewood used. The output of heat rises concurrently.

Where to buy a hearth furnace in St. Petersburg

By purchasing fireplaces and hearth stoves, owners of country homes can effectively heat their spaces. This is because the furnace’s inner surface, which cools down very slowly, is highly heated. These benefits more than make up for the equipment’s high price and difficult installation.

Find the answer to the question of where to purchase a wood-burning stove in St. Petersburg by visiting the INTELLECT Teplo online store. With such a large selection of equipment, you can quickly identify the best model for your requirements. Consultants will assist you in making a selection by providing a range of models with respect to cost, design, and dimensions.

Stoves and fireplaces of superior quality and dependability can blend in beautifully with the interior design of your house. They won’t last you twelve years if the installation and commissioning are done well.

Boiler design with top loading

Top-loading heating apparatuses are shaped like candles. This kind of solid fuel boiler has a cylinder-shaped body that stands vertically. The device’s operating principle dictates the vertical arrangement. Moreover, the device’s double-layered body functions as a heat exchanger. Boiler water circulates from top to bottom between the inner and outer walls, absorbing heat from the combustion of pyrolysis gas.

Currently, producers make solid-fuel long-burning devices in two different configurations:

  • units consuming wood and fuel briquettes;
  • Coal, wood and fuel briquettes devices.

The majority of the time, boiler manufacturers explicitly state in the technical documentation for the heating boiler how long the boiler will operate at one load. Typically, these durations range from 3-5 days when the boiler is filled with coal, to 24 to 48 hours when running on wood and briquettes.

For reference: The quality of the fuel has a significant impact on how long the fuel material burns. Hard wood, such as birch, oak, beech, and ash, burns for a very long time and produces a lot of heat. Since pine wood burns more slowly than coniferous wood, the boiler’s operating time will be significantly reduced.

Secondary products of wood processing can be utilized in place of firewood, briquettes, and coal for this kind of heater. The availability of the fuel resource must be considered when selecting the kind. You will need between 30 and 50 kg of finished fuel for a single load. The height of the deposit is determined by boiler output. The range of this parameter is 600-1500mm in various models. There is even more variation in the parameters concerning the power. Boilers for independent heating with capacities of 8, 10, 20, and 40 kW are currently being produced.

Control system of the top-loading heating device

With the inquiry regarding the boiler’s operating principle and loading technique resolved. Here, everything is accessible and clear. Let’s take a look at the control system of this kind of equipment below. The primary control mechanism of long-burning boilers is centered on controlling the airflow into the combustion chamber. Models are standard units with a mechanical device to control the air masses. The thermostat is what activates the standard flap, which is chain driven. There is one significant technical drawback to this approach, though.

There is a specific temperature mode selected on the thermostat. The damper changes position to lessen the intensity of combustion when the coolant reaches a specific temperature. A significant drop in temperature cannot be accomplished because of the operating unit’s high inertia. The coolant will keep heating up due to inertia for a while, assisting the heating system.

The temperature at which boiler water heats up is linked to the same operating principle. The coolant will rise very slowly in temperature until the boiler reaches its rated output.

With units that have a fan, this is not the case. If necessary, the electric device blows air to increase the combustion’s intensity. The air blower makes it feasible to lessen the heating apparatus’s inertia for prolonged combustion. Automation, which has sensors to record even the smallest variations in coolant temperature, is in charge of turning on and off the blower.

The blower can be turned off if it becomes technologically necessary, leaving the smoldering fuel on a meager oxygen supply. Naturally, air will enter the furnace. By using such a scheme, you can lower the coolant temperature at the slip, which is a phenomenon brought on by the heating unit’s inertial processes.

As an aside, it will take the heating boiler anywhere from half an hour to an hour to get back to normal operation. An expansion tank connected to a single heating circuit is activated if the heating is to be turned off. The excess heat from the cooling boiler is compensated for with a tank. The solid fuel long-burning boiler may take two to five hours to completely cool.

Principle of operation

With a Podovogo combustion furnace, you can use less fuel to achieve high efficiency. The apparatus facilitates "top" burning, distributing the firewood uniformly from the top to the bottom layers of the stack. Good oxidation of the fuel is provided by the air supplied through the furnace door, which enhances the combustion quality and intensifies the release of heat.

The burner’s body is constructed from an alloy of stainless steel, and the furnace’s lining is composed of fireclay or another refractory material. As a result, heating temperatures of up to 420 degrees Celsius are achievable. Because bricks are incandescent up to 700 degrees, stable fuel combustion is guaranteed even under challenging circumstances (such as a room with high humidity where the stove is located).


The boilers’ capacity is an indicator that changes based on the final destination.

  • Boilers of Lithuanian production Stropuva have a minimum heat output of 7KW. Younger models of such boilers are designed for relatively small private houses.
  • Power of Ukrainian Burans reaches 40 kilowatts.
  • Russian-made boilers, designed for the heating system of private houses, have a capacity of 95 KW.
  • Boilers made in Poland Logika can have a thermal capacity of 200 kilowatts, so they can heat a house with an area of 2000 m2. However, most often they are used for heating offices and greenhouses.

Steel or cast iron can be used to make the heat exchanger and housing.

A heat exchanger made of cast iron is more robust. It should be noted, though, that the cast iron boiler weighs a lot more than the steel one, which presents some installation challenges.

When discussing steel heat exchangers, it is important to note that a variety of high-grade, high-temperature-resistant steels, from low-grade to high-grade, can be used in their manufacture. Furthermore, fireclay brick protection is frequently present on steel boilers.

These boilers have a substantially larger furnace than other heating system-related equipment. This apparatus has the capacity to heat the house as well as provide hot water for it. In this instance, the water heater heat exchanger needs to be operating or have a dedicated storage tank. This heating boiler should have a long-burning water circuit and a reasonably high effective heat output if the heat exchanger is operating.

How to choose correctly

Because there are so many different types of under-floor stoves and fireplaces available in specialty stores, it can be easy to become confused. Let’s take a quick look at the most crucial factors to consider when selecting a heating appliance for kitchens and other residential and commercial spaces.

For the kitchen

It is essential to select a model with the appropriate number of tiers if the oven is being purchased for cooking purposes later on. The oven should have enough depth to hold as many baking trays or cooking pots as you require. The oven should have a greater variety of programmable modes so that you can cook a greater range of foods.

An illustration of a deck oven for bread baking

The following models of kitchen stoves are in demand:

  • BASSANINA steel deck ovens for bakeries – models FM 2T-4T , 3T-6T for 2-6 trays 40×60 // 46×66 cm in size.
  • ZOOM stainless steel oven. It has a wide bottom, where large containers can be placed. In the upper part finds 4 rows of independent compartments.
  • Electric model PAVAILLER. Contains 4 tiers, with 2 separate doors. The area of the "cooking" zone is 9.5 in.м.

For home heating

When selecting an oven, it’s important to consider the space in which it will be placed.

Initially, it’s critical to determine the device’s proper dimensions. Making sure the chimney is at least one meter long is essential when installing the stove because only then can living rooms be heated.

Consider the power when making your purchase; a powerful model will heat the house more effectively but will use more fuel.

Tiny hearth heater for indoor heating

When it comes to heating systems, the following choices are important to consider:

  • Heating fireplace stoves WGO. Quality German model, made of refractory HBO fireclay+. Size from 52x54x11 cm.
  • ECO hearth fireplace stove+. Distinctive features – the simplest possible design, affordable price of the hearth stove. Made of fireproof chamotte. Dimensions – 56x56x89 cm.

For bathhouses and garages

Selecting products that meet the exact same specifications as a residential home is essential for heating non-residential buildings. The size and capacity are the most crucial factors. The floor-standing stoves for garages and bathrooms can be less stylish than the models designed for homes. The price will be much lower because there isn’t any exterior decoration. Models that work well are:

  • Oven in the form of a fireplace series KIV. Narrow rectangular shape allows you to put it even in a small room (up to 45 square meters).м.).
  • Round heating stove PKO-40 with metal body. Thanks to the "barrel" shape
  • the device is evenly heated. The body of the furnace is steel, painted with powder enamel, inside the furnace is finished with wedge-shaped heat-resistant bricks.

Advantages and disadvantages

Compared to other kinds of heating and cooking appliances, stoves of this kind have benefits and drawbacks. The primary benefits are:

  • It is possible to arrange several tiers to cook many dishes at the same time.
  • Quickly warms up rooms of large area.
  • Does not pollute the atmosphere with its smoke (unlike grate stoves).
  • Easy to handle.
  • Durable (if the rules of operation are observed).

Not to mention the stove’s high efficiency (79–82%) and lengthy burn time (10 kg of briquettes in a wood stove burn for 10–12 hours).

The design’s assumption of a single heat source—wood, electric heat, or gas—is a drawback. There are no coal-burning hearth stoves using peat.

How it works

Two sections make up the combustion chamber. Firewood is burned at the top, and a reserve of firewood is located at the bottom. Unlike with conventional solid fuel devices, wood is burned from the top rather than the bottom. The combustion process proceeds to the lower layer of fuel involved in this process as the upper layer burns. This lengthens the fuel deposit’s burning period. There is a 50 kilogram fuel reserve.

Air is supplied through an air distributor (two plates for wood and a tube for coal and peat) from the top along the cylinder of the firebox. The spreader rotates freely in a vertical direction while it is stoking firewood. It is raised with a cable and rests on a metal beam that is fixed above the fuel that is slowly burning at the furnace’s edge. The area where firewood burns and produces combustible gas is where the upper layer is located.

Placing a metal disk (staskoblin) above the beam allows all combustible materials in the gases to burn out when it enters the chamber of complete combustion, which is a cylindrical space between the wall of the furnace chamber and the air distributor pipe. A cylindrical air-heating tank sits above this chamber, with a freely installed distributor pipe in the center. The flue gases exit the unit through the chimney pipe on the side after passing through the opening in its wall and the inner wall of the unit.

A valve in the air chamber’s lower section opens when coal burns, adding additional secondary air to the combustion chamber as a whole. A bi-thermal draught regulator is located at the top of the unit, at the entrance to the air chamber. It regulates the temperature based on the thermal expansion of the unit body elements, which determines the temperature regime. Users make manual adjustments. The room’s air intake occurs either directly or via a box equipped with a ventilation device.

Long-burning units have a unique metal component that directs air from above onto the top of the fuel to ensure even burning of the firewood. Air delivery is accomplished through the use of the remote control and the fan. The wood smolders concurrently but does not burn. This is made possible by the oxygen deficit that is provided to the combustion chamber via movable nozzles; the automatics regulate the amount of oxygen supplied. Layer by layer, fuel burns in the chamber in phases. The equipment is not designed with a grate or an ash pan; the tray does not contain any components that facilitate combustion.

Water that has been heated is forced to circulate in a cylindrical pattern around the firebox, door (which is cut through the unit’s bottom in height), chimney (above), and cleaning door (below). Exceeding the estimated water flow rate is not advised as this could cause condensation inside the equipment.

Make sure the cleaning door is tight and shut it right away after adding firewood to the top of the coals so that fuel is burned only in the designated area.

Table for contrasting this heating system with others:

Grate combustion bottom combustion

Firewood is placed on the grate (grate) in grate furnaces. For this reason, the firebox’s bottom is the grate.

When using damp firewood, the grate mode works well for quickly heating the space. The ash box makes it easier to remove ashes from the burner.

High intensity combustion is produced by allowing primary air to flow through the whole fuel volume in a spike firebox, from bottom to top.

You can attain a high level of furnace efficiency by having the ability to control the main air supply.

The main characteristics of the grate combustion system:

– The grate provides primary air for burning fuel, such as wood. Air is supplied by a specially designed duct from the street or basement or by the blower door from the room.

– A cut jet of air is fed into the furnace by the heated grate, which functions as a burner.

– The minimum CO emission at various air supply variations into the furnace is 0.6%.

– The highest possible efficiency is 85.3%. In other words, grate fuel combustion is required if the stove’s maximum efficiency is the primary consideration during construction.

Spike fireboxes are arranged in such stoves:

  • Heating fireplace
  • Cooking stove
  • Shvedka or Dutch stoves
  • Brick heating stove
  • Cast-iron fireplaces
  • Metal fireplace stoves
  • Bath stove

Circular stove with a grate firebox and fireplace door

Water, soot, and smoke (forum posts):

"…At the first laying with the bottom ignition the oxygen content in the flue gases drops in ten-twenty minutes to 2-5%! And for diffusion flame to burn, you need to have at least 7% O2, for pure combustion (without CO) at least 10%, and for smokeless combustion at least 13%.
At the second laying of firewood (on coals?) are even worse.
But at 2% O2 the flame simply does not burn, there is nowhere to diffuse oxygen. So, there is not only white smoke (tar mist from the logs) and not only blue smoke (tar recondensed in the volume of the hot firebox), but also black smoke (soot) from the unburned flame. The CO content jumps to 4%! And how much CH? It"s scary to think about. And you say that top burning is not necessary…"

"…a big, tall stack of wood will heat up first, sending a "volley of water" up the chimney. Concurrently, a significant volume of volatiles (creosote, or "turpentine and tar") are produced. And tests conducted in Europe have already formally acknowledged this. Thus, it would seem wise to use top ignition in icy conditions. However, the problems of organizing flame throwing upward at secondary starts and boosting the "power" of the start at the initial ignition must be resolved."

In addition to saving money and consuming less energy, long-burning boilers are a cost-effective way to heat homes. These boilers maximize heat output and reduce waste by burning fuel slowly over an extended period of time thanks to advanced technology. By lowering carbon emissions, this helps homeowners save money while also promoting environmental sustainability.

The capacity of long-burning boilers to sustain a steady temperature for a considerable amount of time is one of their main advantages. Long-burning boilers can run for hours or even days on a single fuel load, in contrast to traditional boilers that need to be refueled frequently. This makes them perfect for heating homes in isolated locations or during extremely cold spells when it might not be feasible to constantly monitor and refuel.

Furthermore, compared to traditional heating systems, long-burning boilers are frequently more environmentally friendly. They lessen emissions from burning fuel more effectively, which lowers a home’s carbon footprint. Because of this, they are a more environmentally friendly option for homeowners who wish to have as little of an impact as possible on the environment.

Long-burning boilers can also, over time, result in significant cost savings. The long-term fuel cost savings can swiftly balance the higher initial investment compared to traditional boilers. To further lower the initial cost for homeowners, numerous governments also provide incentives or rebates for the installation of energy-efficient heating systems.

To sum up, long-burning boilers provide a useful and environmentally friendly way to heat homes. They are a desirable alternative for homeowners wishing to upgrade their heating systems because of their effective operation, advantages for the environment, and possible cost savings. A long-burning boiler can save energy costs and the environment while providing homeowners with dependable warmth and comfort.

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Long burning boilers Pavlodar

✅ Long-burning solid fuel boilers LIEPSNELE ARCTIC.

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Sergey Ivanov

I like to help people create comfort and comfort in their homes. I share my experience and knowledge in articles so that you can make the right choice of a heating and insulation system for your home.

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