DIY boiler for a brick oven for a country house

The heating season is in full swing, and debates about how and what is the best way to heat a country house do not subside. Some people believe that there is no alternative to main gas. Others offer a method of cheap heating with electricity, and today we will look at the most popular method - solid fuel boilers (SF) and stoves. Our selection contains the experience of portal users on heating with wood, coal and pellets. Ways to reduce heating costs are suggested. Designs of solid fuel stoves. Methods for increasing the operation of furnaces on one fuel load and options for economical and budget heating systems based on TT boilers.

Types of stoves with built-in boiler

The design can be made of metal or brick with different placement of the heater, with a boiler for heating water for washing, if we are talking about a bathhouse. The dimensions are not limited: the choice of parameters is determined taking into account the dimensions of the room, the building materials, as well as the local climate.

It is necessary to consider the design features of two types of furnaces with heating boilers:

The boiler is built into the chimney. This model has a long service life, the walls of the stove completely receive heat from the firebox, and the heat transfer rates are unchanged. Disadvantage: you cannot heat a large area.
The boiler is located directly in the firebox. You can heat a large area of the room. It is possible to use different types of heat exchanger. Disadvantages: metal parts come into direct contact with fire, resulting in destruction. Due to the low temperature of the heat exchanger, condensation is generated, which later causes a lot of soot to stick to the surface, resulting in a decrease in efficiency.

Why is it profitable to heat with wood?

Not all settlements in our country are gasified. Therefore, for many homeowners, the problem of heating their homes is quite acute. Electricity is not always suitable as a heat source because it is very expensive. An electric heater will save the day when it comes to a country house, where you need to visit no more than once or twice a month. Moreover, it does not require special installation or complex maintenance. Constantly heating a house with electricity is very expensive and will require a lot of money.

Heating units running on liquid fuel are not popular due to a lot of disadvantages. You need to buy diesel fuel. This needs to be done in large volumes to make it cheaper, which means there is a question of storing it. It is impossible to get rid of the smell of diesel fuel; gradually it will take over the entire room. There are, of course, advantages - for example, the ability to work in automatic mode.

The cheapest and most accessible option is firewood. You can buy a whole truckload of this fuel very cheaply. Sometimes there is an option to get firewood for free if you heat the stove with wood waste, and it is possible to chop firewood in the forest.

Masonry and brick

The principle of brick laying

Stove makers have enjoyed well-deserved respect since ancient times. Masters of their craft create stoves with a heating boiler, which always have good “draft” and an evenly heated surface.

There are several general rules that all specialists follow without exception:

Combustion chambers are made of fire-resistant materials. Open fire can easily damage ordinary brick and even stone.
You shouldn’t skimp on materials by laying quarter-brick walls. This reduces the reliability and stability of the entire structure.
It is necessary to carefully monitor the tightness of the seams. Any gap will subsequently allow carbon monoxide to pass through, which is dangerous for the lives of the inhabitants of the house.

Sometimes home owners resort to a little trick by setting up separate chambers for heating and cooking in the summer. This is a completely justified solution that allows you to save fuel in the warm season.

Helpful tips and general expert advice

In some rooms it is necessary to build stoves into a niche or install them on rectangular / square bases. To do this, you will need to mark and pour the foundation. After assembling the body, taking into account the order, secure the doors, combustion chamber, hob and other elements.

During the first heating, you need to heat the stove to maximum. This will allow you to evaluate its performance and effectiveness.

Drawings of the future stove can be created with your own hands or ordered from professionals. If you do not have experience in design, it is better to entrust the work to specialists. They will offer ready-made schemes tailored to your requirements.

Laying the boiler and installing a horizontal heat exchanger in it

A do-it-yourself heat exchanger using any of the options is installed in a brick boiler. The latter is laid according to the same principle as a brick oven.

The dimensions of a solid fuel boiler must be proportional to the volume of the premises that must be heated by it. The values available in the article are given based on a house with an area of 90-100 square meters. m. with 6 cast iron radiators and a distribution of 2 pipes (25-50 mm).

The choice and design of the boiler piping should be based on many factors:

How many circuits are there in the system?
How complex is the system?
Is there any other equipment available?

The entire boiler must stand on a solid reinforced concrete foundation.
The size of the foundation is selected based on the dimensions of the furnace. When laying a solid fuel boiler, the heat exchanger must be positioned so that the outlet pipe is the highest point. The height difference must be at least 10 mm. This is necessary to ensure that a plug of air does not form in the boiler while filling with water. This slope will also improve fluid circulation. Brickwork is done with your own hands, following the rules for bandaging the seams. The pipes should be approximately 2-3 cm lower than the brick wall itself. To prevent a decrease in efficiency, it is necessary to have a removable cast-iron plate on top of the boiler for easier cleaning. The smoke is discharged into a separate or main pipe. The pipe can be brick or metal.

Radiator assembly

Assembling radiators is a simple process, because it completely repeats the process of disassembling them. The sections are connected by nipples that have left and right threads on both sides. This way, the sections at the top and bottom will be pulled tightly against each other when the nipple is turned. When the gap becomes 2 cm wide, you should wind the asbestos-impregnated cord and only then tighten the nipples completely.

When the entire structure is assembled, you should wait for the drying oil to dry, and then check the joints for leaks. that is, supply water under high pressure to the radiator. This will ensure the subsequent use of the radiator and there will be no leaks.

The return and coolant supply pipes must be connected diagonally to the radiators. Holes that remain open must be closed with plugs. It is better to take inch pipes. On one side of the radiator there will be a right-hand thread, so there will be no difficulties with connection. On the opposite side, use a coupling with a squeegee and a nipple.

What dimensions should the chimney have?

Chimney placement options.

The draft in the chimney channel will occur due to differences in the height of the inlet and outlet, as well as due to temperature differences. To ensure continuous operation of any heating device, you will need to make a strong draft

Before starting masonry, it is important to decide what type of heating device will be used, what dimensions it has and how many channels it is planned to make

The number of channels can be determined taking into account the power of the heating device, fuel and the special requirements of the device manufacturer.

If the diameter of the chimney channel significantly exceeds the calculated value, the draft in such a channel will greatly decrease. As a result, there will be frequent interruptions in the functioning of a gas boiler or other heating device. If the channel diameter is smaller, this may impede the removal of combustion products. It is for this reason that in most cases the operation of boilers stops.

To make brick channels, you will need to use ceramic brick grade M50-75. You can also use concrete blocks that have channels with a square cross-section.

If you plan to use ceramic bricks to make a chimney, then you should know that its minimum cross-section is 14x14 cm. If you plan to purchase material with a round cross-section, then the permissible diameter is 15 cm or more.

In a brick chimney whose height is less than 5 m, the dimensions of the channels must be increased to 14x20 cm or 18 cm in diameter. Such structures should be made in the walls between rooms that are planned to be heated. In this way, it will be possible to create a certain protection of supporting structures from cooling, which in most cases leads to a weakening of traction.

It is necessary to try to group the chimney channels so that in the device that will be installed above the roof, their number is maximum. In this way, it will be possible to reduce the cost of manufacturing work and significantly improve the performance of the chimney device.

What parameters should you use to choose an oven?

When the question arises of how to choose a stove that will run on wood, you need to know what parameters to focus on.

Power

The first thing you need to decide on is the power. The relationship is direct - for a large heating area a more powerful model is required. The standard formula suggests the following calculation: per 10 sq. m. you need 1 kW of thermal energy. If winters are very cold, then 10-20 percent is added.

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Sometimes less power is enough:

if your region of residence is southern;
winter temperatures remain at off-season levels;
The home has serious thermal insulation: thick walls, small windows with three-layer double-glazed windows and an attic with insulation.

On the contrary, in very cold northern regions it is expected that per 10 sq. m. area requires 1.2-15 kW of furnace thermal power.

In order for the stove to meet its declared power, all necessary parameters must be met, which relate to the size and location of the ash pan, grate, combustion and ash doors, the length and diameter of the chimney duct.

Laying a brick oven with a water boiler

Diagram of a solid fuel boiler.

Laying a brick oven with a water boiler is carried out in the following sequence:

The foundation is poured under the furnace location.
While the foundation is drying, mix a solution of clay and sand in a ratio of 1:2. Depending on the fat content of the clay, this proportion can be changed. Before preparing the mixture, the clay is soaked in water for 10-12 hours (large lumps of clay must be kneaded with your hands). Before starting masonry, sand and clay are thoroughly mixed.
Waterproofing is laid on the dried foundation - usually roofing material the size of the future furnace.
A layer of mortar is applied over the waterproofing, the first layer of brick is leveled and laid. It should be noted that it is better to use beautiful brick for the outer layer; it will look more aesthetically pleasing. The inner layers can be formed from defective or broken bricks.
Each layer of brick is carefully covered with mortar.
At the required height, a compartment for ash and the firebox itself are made.
A sheet of metal is placed in the ash compartment to make it convenient to remove ash residues in the future. The blower door is installed here.
Behind the firebox, in front of the chimney, a water boiler is installed. Brick ledges with metal corners are built for it. A level must be used to prevent air pockets from forming. A door for loading fuel is fixed in the firebox itself.
A metal plate is placed on top of the boiler, a chimney and a cleaning system are formed. It would be useful to make a separate door for cleaning the boiler from carbon deposits.
A metal sheet is fixed to the floor in front of the firebox in order to comply with fire safety regulations.

Boiler design diagram.

When you first light up a finished stove, you must ensure that the system is in good working order and that there are no leaks. The room must be ventilated, as often during the first heating there are unpleasant odors of burning industrial lubricants and heating clay. It is carried out for at least an hour with the maximum possible amount of fuel.

A brick stove with a homemade boiler is one of the best ways to heat small country houses, which will allow you to enjoy the warmth on cold winter evenings and save your budget.

Device Features

Having chosen stove heating as the main type, you need to correctly select the power of heating devices, their type and location in the house. And for this you need to take into account heat loss and the size of the premises of the house. Heat loss depends on many factors, such as the material of the walls and ceilings, as well as the level of their insulation, the size and type of windows. But, on average, we can assume that for 10 m2 you will need at least 0.3 m2 of usable oven area.

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The location of the stove should be such as to make maximum use of its heat to heat the room and at the same time make it convenient to heat it. It is best if the furnace door of the furnace is located on the side of the door, facing a corridor or a special room. Its heating surface should provide maximum heat transfer, so it is best to place it at a distance of 20-25 cm from the wall and not block it from furniture or other objects. In a wooden house, the distance to walls and other combustible structures should be 40 cm or more. If wooden walls are protected by a heat-insulating screen, then - at least 25 cm.

If you choose stove heating with a water circuit, then the stove itself must be located based on the convenience of pipe routing and its efficient operation. The dimensions of the furnace itself, that is, its firebox, must be coordinated with the dimensions of the selected heat exchanger, or it must be made according to the size of the selected furnace design.

Smoke pipes

In order for stove heating to work efficiently, it is necessary to properly construct the chimney. Its height from the level of the grate must be no less than 5 m. Its cross-section can vary depending on the design and power of the heating device, and therefore on the amount of flue gases emitted. For a small stove with a heat output of no more than 3000 kcal/hour, it should be at least 14x14 cm, for a more powerful one - 14x25 cm. If you plan to build several stoves in the house, then it is not advisable to connect them to one chimney, especially if they are located on different levels. Traction problems may occur or reverse draft may occur.

Where the chimney passes through the combustible ceiling, cutting is carried out - thickening the masonry and insulating it with an asbestos gasket. At the point where it passes through the roof, the junction is sealed to prevent atmospheric moisture from entering through it. For slate roofing, as a rule, asbestos cord and cement mortar are used; for roofing made of metal tiles or corrugated sheets, special lower and upper abutment strips are used. To prevent moisture from getting inside, metal removable caps (caps) of various designs and shapes are most often installed on the heads of chimneys.

Cast iron radiators as a boiler

You can build old radiators into a brick stove, and they will serve as a boiler. Cast iron built-in water heating elements have their own characteristics, for example, cast iron does not react very well to open fire. Nevertheless, this method is used quite widely. You can use the M-140 radiator, which can easily be found at demolition sites of five-story buildings. If you weld a dozen sections, you will get a heater with an area of 3 sq.m and 18 liters of capacity. A flat boiler with the same characteristics would require a lot of space. Such boilers can heat large areas.

Before the radiators are welded together, they must be disassembled, cleaned of dirt and thoroughly rinsed with a hot 6% hydrochloric acid solution. Then rinse again with water. Then change the cardboard spacers located between the sections, as they will simply burn out. Instead, use asbestos cord impregnated with graphite powder and natural drying oil.

The radiator elements should be assembled in a certain sequence. Screw nipples with their right and left threads into the sections to be connected, then wind an impregnated asbestos cord around them and tighten both nipples with a wrench, making sure that there is no misalignment of the sections. After connecting two sections, you can attach a third, then compress the radiator to check the quality of the assembly. Now you can install the risers.

You can position the cold water inlet and hot water outlet diagonally. The other two holes can be plugged to allow water to circulate through the entire volume. The radiator must be mounted in the smoke duct located behind the firebox. This will help avoid contact of cast iron with open fire: the boiler will be heated by hot gases.

You can increase the natural circulation of water in such furnaces by running a return line pipe through its foundation and the space under the floor, which will increase the temperature difference between the return and hot lines. The battery in the furnace is installed with a slight slope to allow air to escape and enter the system. For cleaning, you can build an additional door into the smoke channel itself.

A little advice

For country houses that are visited only occasionally in winter, it is not recommended to install a stove boiler with a water heating system. This is due to several reasons.

Firstly, if the owners are absent for a long time, the water in the system will probably freeze, which may result in pipes or radiators bursting.
Secondly, using antifreeze in the system as a coolant will be economically unjustified.
Thirdly, it is necessary to take into account the fact that until the stove warms up, the radiators will not provide heat, and the rooms adjacent to the stove will receive heating faster from it than from a water heating system. And it will take too long before the distant rooms can warm up.

Boiler installation

When implementing plans to create a combined heating system, it is important to pay attention to some features. Water-heated brick stoves have many options, each of which differs in material, type of main element and other nuances. Ignoring technical and construction requirements will certainly lead to the rejection of the entire work

Ignoring technical and construction requirements will certainly lead to the rejection of the entire work.

The boiler must fit completely into the firebox. However, in practice there are incidental situations when part of the heat exchanger is located outside the stove. This is unacceptable, because the main task of the unit is to heat the coolant. The boiler is made in the shape of a “P” from pipes or sheet iron. All its elements are hollow and are designed to remove heat.

The preferred option is from pipes. It has a larger convection area and allows the flame to reach the cooking surface to cook food. In addition, attention is required:

Dimensions. It would seem that a massive product is needed that can heat a lot of water and provide heat to a decent-sized structure. But that's not true. The boiler itself is made of very modest dimensions - 75 * 50 * 30 cm (length, width, height). The convection surface of such a device is enough to heat a house up to 200 square meters. Installing a pump for forced circulation of coolant increases productivity by up to 50%. Boiler. Its shape is designed in such a way that the heated surface area is as large as possible

It is very important to install it in the center of the combustion center. This is the only way to achieve high efficiency of water heating. Peculiarities

A small gap must be left between the walls of the furnace and the surface of the boiler. The optimal distance is considered to be 5 millimeters. It is quite sufficient to level the free movement of the metal during thermal expansion.

The heat supply and outlet lines are carried out in strict accordance with the laws of physics. It is known from school that hot flows tend to go upward, while cold flows are always directed downward. Therefore, the pipe supplying hot water to the house is always adjacent to the boiler at the top point, and the channel with the “return” is at the lowest point. This arrangement eliminates the accumulation of hot steam, which poses a serious threat to the integrity of the system.

Stove water heating device

The furnace for the heating system in question should ideally be calculated and built at the same time as the house. If a residential building has already been erected, then it will be difficult to install a brick stove structure in it. And often this turns out to be completely impossible due to the need to build a solid foundation and rebuild the rafter system.

A furnace for water heating in a private house can be made not only of brick, but also of steel in the form of a potbelly stove with heat exchange pipes around the firebox for heating the coolant

Stove-based water heating consists of:

the stove itself (metal or brick);
a heat exchanger inside or around the stove firebox, as well as in the form of a coil around the chimney;
a circuit with coolant distributed throughout the house and an expansion tank in the attic.

Also, in some cases, this heating system is supplemented with a circulation pump and a hydraulic accumulator. However, this extended option is used extremely rarely, since it requires an uninterrupted power supply and leads to an increase in the cost of the entire circuit.

And the main advantage of water stove heating is the low cost of the device. It is not worth supplementing it with expensive and breakage-prone elements.

Water circulation diagram in the circuit

The water heating system in houses is built with natural (gravitational) or forced circulation of the coolant. If it is made on the basis of a wood stove, then it is best to give preference to the first option.

The wiring diagram with natural water circulation is cheaper than the forced analogue, and also, unlike it, does not require power supply

It is recommended to install water stove heating only in one-story houses with an area of up to 150 m2. In this case, it can be made gravitational without additional pumps.

If you need to heat a cottage of a couple or more floors, then it is better to do this using a more powerful boiler. The furnace for such buildings will have to be built simply huge, which is expensive to implement. Yes, and you will have to put considerable amounts of fuel into it each time. But doing this is highly not recommended due to the increased risk of fires.

A classic stove heating system with natural water circulation consists of:

heat exchanger as part of the stove;
metal pipeline circuit;
radiators (usually replaced with thick pipes in rooms);
expansion tank.

If you decide to do water heating in a country house yourself, then it is better to design it according to this scheme. Installation and calculation of this option is easier than with forced water movement.

A system with a circulation pump is more suitable for boilers; based on a stove, it loses its increased heat transfer efficiency

If the boiler is automated and constantly heats water as needed, then the wood-burning stove is heated once or twice a day. It is at these moments that the coolant in the furnace firebox heats up to release heat into the rooms. Afterwards, driving it with a pump through the pipes of the circuit is pointless. Nothing will heat the water in a cold firebox anyway.

When choosing a wood or coal stove, owners of private houses usually expect to receive an autonomous heating system. If you install pumping equipment in it that requires power from the electrical network for operation, then it will be difficult to talk about autonomy.

Oven - brick or metal

A brick oven takes longer to heat up, but it also takes longer to transfer heat to the space around it. The steel counterpart, on the contrary, heats up quickly and cools down just as quickly after the fuel burns out. This problem is partially solved due to the presence of large volumes of coolant in the water circuit.

However, the more water that has to be stored in the system, the more expensive it becomes in terms of materials.

A metal potbelly stove with a water coil for the heating circuit in private homes can be placed directly on a wooden floor without installing a special foundation

A steel furnace for water heating with a power of 5–15 kW - without fuel and water it is a structure weighing 100–300 kg. Such a potbelly stove can be safely placed on reinforced logs. Stove foundations need to be poured when the stove weighs more than 700–800 kg. Now, if it is brick, then you definitely can’t do without concrete work.

Compared to a metal stove, a brick stove weighs more, costs more and is more difficult to install. However, it has higher efficiency and less risk of freezing the circuit with pipe rupture due to the formation of ice inside. If you decide to do everything completely for yourself and permanent residence, then it is recommended to choose the brick option.

Pipes - stainless steel or metal-plastic

If the heating system is built on the basis of a hot water boiler, then it can be piped not only with steel pipes, but also with metal-plastic and polypropylene pipes. However, if the water is heated by a wood-burning stove, then the circuit with the coolant from it should be created only from stainless steel.

With a large load of firewood, the water in the furnace coil can quickly heat up to 100 degrees and boil; only steel can withstand such temperatures for a long time

Metal-plastic is designed to work with coolant heated to 90–95 °C. For a short time it can withstand heating up to 110–120 °C. At the same time, the automation of boilers and boilers initially does not allow the water to warm up to such degrees. For heated floors it heats up to 30–45 °C, and for radiators up to 60–65 °C.

However, in the case of a wood-burning stove, temperatures under a hundred are not only possible, but far from uncommon. It is not recommended to take risks and play Russian roulette by piping this stove with metal-plastic pipes. It is best to give preference to more reliable stainless steel.

In addition, the pipes coming out of the furnace from the coil for connecting the circuit pipes will definitely heat up to very high temperatures. They are separated from an open fire by less than half a meter. It is dangerous to connect any plastic pipes to them due to the risk of them melting.

Heat dissipation - radiators or register

Heat is supplied from the stove to the heating circuit in portions of several hours, while wood or coal is burning in the firebox. If there is not enough water in the heating system, the house will quickly dry out. Therefore, in villages, such heating is usually made from thick steel pipes, and not on the basis of radiators more familiar to city dwellers. The heating register for wood burning stoves is simply perfect.

The classic scheme of water stove heating with natural circulation involves direct contact of water with the atmosphere through an expansion tank, but air in the coolant is contraindicated for conventional batteries

A stainless steel pipe with a diameter of 80–120 mm laid throughout the house is a heating register, consisting of a supply from the stove and a return to it. In the room farthest from the firebox, these lines are connected together, and in the remaining rooms they are laid in the form of two pipelines along the outer walls.

The register does not look as aesthetically pleasing as the radiator. But the first option is much cheaper and easier to make yourself than the second. To implement it, you just need to have experience in handling a welding machine.

The heat transfer area for such a circuit is calculated by multiplying the PI number by the diameter and length of the pipe. Plus, in the calculations it is necessary to take into account the thermal pressure in the supply and return, as well as the vertical distance between the pipelines.

However, often such calculations are not made, but a pipe with a diameter of 80–100 mm is taken and laid around the perimeter of the entire residential building with a loop in the back room. In this case, heat transfer is adjusted “by eye” and experimentally as a result of adding a particular volume of fuel to the firebox.

It’s not for nothing that register circuits coupled with water furnaces are so common. You don’t even need to calculate them, just take a suitable pipe and weld it together.

Selecting a heat exchanger for the furnace

The heat exchanger in the stove can be made of copper, steel or cast iron. It is better to immediately exclude the copper option due to the high price. Soldering such a device yourself is extremely problematic.

Cast iron batteries should be installed inside the firebox with caution - due to temperature shock, individual sections may become detached from adjacent elements

Cast iron is superior to steel in terms of technical parameters. However, making a heat exchanger for a wood-burning stove out of it yourself seems problematic. You can only take an old battery for this. But here we must take into account that the seal between its sections will burn out in the firebox. And this is a direct path to loss of tightness and water escaping into the combustion chamber.

If it is decided to make the heat exchanger from a cast iron battery, then it is best to take the MS-110-300 or MS-90-300 models for this. They are small and will easily fit in the firebox. Their heating surface area for each rib will be about 0.14–0.16 m2.

Based on these numbers, you can estimate how many sections will be required for a particular circuit. For every 10 square meters of house area, 1 kW is needed, which will be approximately equal to 0.1 m2 of heating area of a cast iron heat exchanger.

The fins of a cast iron radiator are usually connected using heat-resistant rubber gaskets. In a stove firebox, such a rubber seal will burn out; it needs to be replaced with an asbestos cord

Another point about using a cast iron battery as a heat exchanger is the difficulty of cleaning it from soot from inside the firebox. From time to time the combustion chamber needs to be cleaned, and the raised ribs of the cast iron will greatly interfere with this.

The most optimal option for a heat exchanger is steel in the form of:

a coil of several tubes;
sheet steel shirts.

They are made from low-carbon steel St10...St20 with a thickness of 4–5 mm. If you take tubes, then with a diameter of 30–50 mm.

The easiest way to make a steel heat exchanger is from sheet steel - however, only the surface facing the inside of the firebox towards the fire will participate in heat exchange

The tubular version is more efficient in terms of heat transfer, but it is also more labor-intensive to manufacture.

To calculate the heat exchanger, use the formula:

Qy=K*(Tcp-Tk)

Where:

K is the heat transfer coefficient of the material (15–20 is taken for low-carbon steels, and 50 for gray cast iron);
Tcp – average temperature of the heating medium in the furnace (Tmax+Tmin)/2;
Tk – average coolant temperature (Tsupply + Treturn)/2.

If wood is burned in the stove, then Tcp=(700+300)/2=500 °C and Tk=(80+60)/2=70 °C. As a result, Qy=15*(500-70)=6450 kcal/hour. That is, per square meter of the heat exchanger surface facing the fire will be approximately 7.5 kW/hour.

For coal, the calculations are as follows: Tcp=(1000+600)/2=800 °C and Tk=70 °C. Qy=15*(800-70)=10,950 kcal/hour=12,734 W/hour. A square meter of heat exchanger surface will give about 12.7 kW/hour.

Next, we divide the power required to heat a particular house by the calculated figure, depending on the plans for using a particular type of fuel.

For example, for a cottage of 150 m2 you need about 15 kW. If it is heated with wood, then a heat exchanger with a heat exchange area of 15/7.5 = 2 m2 will be required. This is the surface that faces the flame and heats up.

If a tubular coil is selected, then its length is calculated by the formula:

S=2*3.14*D*L

Where:

S – design area;

D – tube diameter;

L – required length.

The parameters of a steel sheet jacket are even easier to calculate; it usually consists of two rectangles on the sides of the combustion chamber.

Flat-plate heat exchanger

A popular option, which is used both for stoves in the bathhouse and for the home. They are the simplest to manufacture, the surface is easy to clean from soot accumulations, installation is possible both vertically and horizontally, and the efficiency is relatively high.

A flat boiler can have a high volume, so you can take hot water for washing directly from the heating system. An expansion tank with an increased linear size is installed, into which water constantly flows after the level drops below critical. This option is quite convenient and helps solve several problems at once, but there is also a condition - the room temperature in winter should not drop to minus.

Key disadvantage: a sharp decrease in heat transfer from the furnace walls. This type of heat exchanger is made in the shape of the letter “P” and is installed around the perimeter of the firebox, bypassing the door. As a result, it turns out that the temperature of the external walls is quite low, as a result, warming up the room takes much longer. This is critical only if the stove is installed in a bathhouse; for residential buildings, where the stove is constantly heated, increasing the warm-up time by several hours does not play any role.

Thus, when choosing a flat boiler, think about how you can increase the heating rate. One option is to enlarge the heater and place it directly above the firebox. Second option: using a metal chimney for heating, increasing its length.

Simple rules for an efficient heat exchanger

The operating principle of stove heating.

If the house has a ready-made brick stove, then organizing water heating with your own hands is a fairly simple task. To do this, it is enough to place a homemade boiler in the firebox in the form of a coil or any other shape. The main thing to consider is:

The height difference between the fluid outlet from the heat exchanger and its inlet;
It is necessary to ensure the maximum possible surface area;
The heat exchanger should not interfere with the loading and combustion of fuel.

If you are building a stove with your own hands, then the boiler for a brick stove can be made as efficient as possible. To do this, several important conditions must be met:

Combustion products must leave the chimney as cold as possible;
Greater heat transfer of furnace gases inside the furnace increases its efficiency;
It is best to place the heat exchanger in the chimney rather than in the firebox.

These rules may seem somewhat strange, because logically, the heat exchanger should be heated best by the open flame of the firebox. However, it is necessary to take into account other processes occurring in the furnace. From a physics point of view, flames are burning fuel particles. And if we take heat away from these particles, then they will not burn completely, which will reduce the usefulness of the stove.

Diagram of connecting the boiler to the heating system.

In addition, for better heating, the coolant must move towards the heat flow. Only in this way is the temperature difference between different parts of the coolant maintained, increasing the heating efficiency and ensuring better circulation within the system.

Another advantage of this arrangement of the heating tank is that less condensation forms on it, which contributes to the absence of corrosion.

Application of pyrolysis furnaces

Long-burning stoves using wood, pellets or sawdust are often used to heat utility rooms and workshops, garages, and greenhouses. They can also be used to heat a house, but it is necessary to ensure that the stove is sealed, as carbon monoxide may be released.

If you use a pyrolysis stove to heat a garden or residential building, it is better to equip it with a water circuit connected to the heating radiators, and install the heating unit itself in the boiler room.

This article talks about how to simply make a smokehouse for cold smoking, which at home will help you prepare real delicacies from the most ordinary products. You can find out how to make a smoke generator for cold smoking by looking here. Here you will find the most understandable drawings for creating an effective potbelly stove with your own hands: https://gidpopechkam.ru/pechki/burzhujki-chertezhi.html

Laying a furnace with a boiler

If you decide to delve deeper into the topic, you may decide to install a Kuznetsov bell furnace, the operating principle of which is the free flow of gases, which does not require additional external energy. The drawings are available on the Internet. Here we will talk about a simpler design. So, first you need to pour a foundation, the depth of which is 50-70 cm. Sand should be poured onto the base in a layer of 10-15 cm, crushed stone, gravel or construction waste should be laid on top, and a space of 25-30 cm should be kept for pouring cement. It is best to prepare the solution for the foundation without using sand, replacing it with screenings, the ratio will be approximately 1:6. Roofing felt should be laid under and on top of the screed for waterproofing.

Then you should make a solution of clay + sand in a ratio of 1: 2.5, however, the proportions may vary depending on the level of fat content of the material

It is important not to leave lumps, and therefore the clay should be soaked in the evening. If the mixture slides off the trowel, leaving small streaks on it, then the concentration is appropriate

Before starting masonry, it is necessary to lay out roofing felt over the area of the poured foundation and cover it with mortar. The first row is laid out with a pallet completely made of bricks, where the furnace will then be laid. Then the first row of the furnace contour is laid out, then the next, etc. During laying you will need order.

Now the firebox, ash compartment and ash pit are made. The doors are secured using galvanized wire or a strip of galvanized sheet. It is necessary to trim the brick above the doors using a grinder, but it is best to make one of them with a wedge, so that the masonry will not crack. Make protrusions for the boiler on the brick in advance, which can also be cut with a grinder. Do not forget that the instructions require level installation, and therefore you should use a level. Then the firebox and the rear part of the structure are installed, where the chimney with cleaning is located. The pipe should protrude at least 50 cm above the roof.

You can make your own stoves for heating your home without being a pro in this matter. They are versatile and have a high heat transfer coefficient. The big advantage is their autonomy, since they do not depend on external energy sources. Such boilers can have any size depending on the area of the heated room.

Fire safety requirements for stove heating at home

Stove heating in a wooden house is installed in accordance with the building codes set out in SNiP 41-01-2003. Stoves are subject to fire safety rules, which require measures to prevent fires.

A separate column is environmental legislation regarding stove heating, which limits the use of heat generators in urban areas. In particular, to connect a stove, in addition to meeting fire requirements, the building must have an appropriate number of floors (no higher than 5 floors) and a special ventilation duct for smoke removal.

In 1-2 storey buildings, the height of the chimney relative to the roof of the house must be at least 0.5 m. In densely populated areas of the city, the elevation of the chimney above the building is calculated separately, depending on the location of neighboring buildings.

How to secure the ceiling and floors

Fire protection is aimed at preventing accidental fire caused by the operating characteristics (high heating of the housing and chimney) of solid fuel stove equipment.

The activities cover the following work:

When burning, inside the combustion chamber the smoke heats up to 450-550°C. A brief ignition of soot raises the temperature to 1200°C. The surface of the chimney becomes very hot. Manufacturers do not recommend connecting galvanized and corrugated steel chimneys to stoves. The best choice is sandwich pipe or ceramics.

For stove heating in one-story wooden houses, a special penetration is installed. The ceiling in the area above the stove is protected with a metal insert. The penetration is made of non-combustible basalt insulation. A spark arrestor is installed at the head of the chimney.

Where the chimney passes through the attic, the rafter system is treated with fire retardants. The chimney is wrapped in thermal insulation material. Properly pass the ceilings of the chimney, providing for fire breaks. The minimum distance between the surface of the chimney and the ceiling is at least 25 cm. The gap is filled with basalt wool.

The operating rules for furnace equipment indicate the need for annual inspection and maintenance of the smoke removal system. Brickwork is checked for cracks, pipes for depressurization. Violations are corrected.

Measures to protect the walls around the stove

Fire safety measures include the need to install wall protection around installed furnace equipment. A gap of 1.25 m is left from the stove to the nearest surfaces, and at least 1.1 m towards the opening firebox.

The distance to the walls can be reduced after carrying out the following work:

The surface of the wooden wall is covered with basalt insulation. For this purpose, 5 cm thick basalt wool is used.
The insulation is covered with a metal sheet.

After the work is completed, the gap between the furnace body and the walls is reduced to 0.5 m.

Existing requirements for stove heating of a private house require the need to protect the walls around the chimney. Often, the distance between the chimney and the combustible surface is no more than 25 cm, which is due to installation features. The protection is carried out in the same way as the insulation of the walls surrounding the furnace boiler.

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The fire safety requirements for stove heating in a residential building indicate the need for regular inspection of the condition of the device by an inspector from the Ministry of Emergency Situations and a stove fitter. A condition audit will allow you to identify potentially dangerous defects and eliminate them in a timely manner.

What is better for a country house – stove or boiler heating?

Modern heating standards impose identical requirements on both stoves and solid fuel boilers. The operating and safety rules, operating and heating principles are the same.

The thermal efficiency of boilers is slightly higher than that of stoves, but they are also more expensive. Owner reviews and comparisons of performance characteristics clearly indicate the following.

For complete water heating of a heated house, it is better to choose a solid fuel boiler. In buildings that are not constantly heated, it is better to install furnace equipment that operates on the principle of convection heating.

Calculation of power and temperature of a warm water floor

Water boiler made of cast iron radiators

M-140 radiators are suitable for this type of boiler. They are quite easy to find, since large quantities of them are sent to scrap when radiators are replaced with more modern ones or old buildings are demolished. Each section of such a radiator has a capacity of 1.5 liters, and their area is 0.254 square. That is, if you combine 12 sections, the volume of the heat exchanger will be 18 liters, and the area will be 3 square meters. Such a boiler has a capacity of up to 100 square meters. So it’s quite enough for a residential building.

In order to use the radiator, you need to modify it a little. Initially, you should remove the cardboard gaskets located between the sections with your own hands. The best replacement for them would be an asbestos cord, which must be impregnated with drying oil with the addition of graphite. Thus, the gaskets will be protected from burning through at high temperatures.

In addition, before starting assembly, the sections should be washed from the inside using a 6% solution of hydrochloric acid, and then washed with water. This will clean the pipes from dirt and rust that has accumulated there during operation.

Calculation and design of the heating system

The main principle of calculation is that the heating system must compensate for the heat loss of the house. Therefore, first of all, heat losses are assessed, on the basis of which the power (kW) that will be required to heat the house is determined. It is impossible to perform such a complex thermal engineering calculation on your own. If it is not possible to entrust the calculation to engineers, you can try to perform it using special programs: Auditor OZC 6.9, nanoCAD otoplenie, VALTEC H2O. Or you can trust the practical experience of heating engineers and assume that for every 10 m2 of area of a heated building, 1.2-1.5 kW of heating power is required. Based on the calculations, a drawing of the heating system is made, which indicates the location of all elements and the movement of the coolant.

Heat exchanger construction

Installation diagram of the heat exchanger and storage tank.

You can easily build an effective boiler with your own hands. If it is made in the form of a tank, then high-quality steel is required, which can withstand thermal loads and corrosion due to the coolant. In addition, the manufacturing material must have high thermal conductivity to increase the efficiency of the system.

The thickness of the tank walls should be within 4-5 mm, which ensures its strength while simultaneously heating quickly. There are no standard sizes for such a heat exchanger; it all depends on the configuration of the existing or planned furnace. The main thing is that the height of the tank is at least 500 mm for better circulation.

If the heat exchanger is a coil or another circuit of pipes, then there are also some nuances. Pipes for the manufacture of such structures must be thick-walled and have no seams. If it is difficult to find a seamless pipe, then it is necessary to weld the existing seams to prevent possible coolant leakage.

The inlet pipe is best located at the top of the structure, and the return pipe is located in any convenient place. The pipes are not butt welded, but with chamfers to avoid unwelded areas that will leak in the future. The minimum distance between the knees of the structure is 5-6 cm, so that the heating of each knee is maximum. Before placing such a boiler directly into the oven, it is necessary to fill it with water and check for leaks, which are promptly eliminated.

When placing the boiler directly into the furnace, you should adhere to the level, but minor deviations are allowed.

Brick chimney construction

Brick chimney laying diagram.

Laying should begin with the mounting tube. It should be laid out in compliance with the brick dressing. After this, a cutting (fluff) is formed. It needs to be laid out from 5 bricks. The channel will have dimensions of 270x140 mm. The external dimensions of the cutting are 450x590 mm. This can be achieved by inserting brick halves. To maintain the dimensions of the channel, you will need to insert brick plates inside. In this case, the channel will not change.

The next row will have dimensions of 650x510 mm. Brick plates 6 cm thick are mounted inside. At this stage, the cutting will begin to take its shape. In the next row, the external dimensions will be 710x570 mm. Inside you will need to install material 9-10 cm thick.

After this, the fluff ends. In the next row, be sure to observe the dressing. If you need to make a cut of greater height, you can install another row; the dressing should be done under the bottom row.

To allow the riser to exit outside, you will need to prepare a hole in the roof. Next, the riser should be routed through the roof. The rest of the work is done on the roof.

At the next stage, the riser is laid out. You need to carefully monitor the dressing of the brickwork. The riser must be placed several rows above the roof. After this, the otter lays out. The internal plates are selected so that the channel does not expand.

After this you will need to form the neck and head. The actions will be the same as in the case of erecting a cutting.

Benefits from combining the two systems

A traditional stove-heater consists of a combustion chamber, grates, ash pan and channels for smoke removal. All the attributes of a familiar Russian stove are known to every village resident. Modern boiler furnaces are practically no different visually.

But they have different characteristics:

An ordinary rural stove can produce a little more than 6500 kcal of heat in one hour of full operation. This energy is enough to create a comfortable microclimate in a small house. For example, this heating method is suitable for a summer house.
If you install a water boiler, its productivity will be 2.5 times greater. Naturally, the area of the heated room will also increase proportionally. The amount of fuel burned is the same. And savings are achieved through improved heat extraction. That is, less warm gases are released into the atmosphere.
Next, a very important nuance becomes clear. If you combine convection (oven) and water (boiler) heating systems, the efficiency increases multiple. The point is that when both systems are running, their performance is additive. In other words, a tandem of two heating methods produces about 21,000 kcal per hour of operation. This is quite enough to heat about 300 square meters of living space.
The positive aspect of this method of heat supply is the availability of energy resources. In most cases, firewood or a combination of wood and coal is used. The cost of these types of fuel is low, and acquiring them is not particularly difficult.
The oven does not need to be lit all the time. Fuel is added 2 times a day. A comfortable microclimate is created in the house, regardless of the temperature outside the window.
If the efficiency of a traditional stove did not even reach 50%, then the combined option reaches 85%. And for wood heating this is almost an ideal indicator.
The price of materials is low. The cost is usually determined by installation work.

Features of wood stoves

Wood-burning stoves reduce the cost of heating a home when it is not possible to connect to a gas pipeline.

However, the construction of such a furnace comes with its own requirements, which you should be aware of.

It is necessary to prepare the place where the firewood will be stacked. After all, several cubes of wood may be needed for the winter season. For storage you need to choose places protected from precipitation.
A stove for heating a house with wood requires constant maintenance - you need to clean the ash pan, keep the chimneys clean, preventing soot from accumulating.
Heating a stove with wood means that from time to time you need to add new portions of fuel to the firebox. It will not be possible to heat in automatic mode.

But with all these features, it must be recognized that firewood is the way out when heating a dacha or house when there is no gas. Having purchased a country house, you can install a stove there, buy firewood and not worry about the heating method.

It is extremely rare for a gas pipeline to be laid in holiday villages. It is not required, since people do not live there permanently. However, it often happens that city residents move to country houses for permanent residence, especially when such villages are adjacent to the city limits. And then modern wood-burning stoves for heating a house will be indispensable.

Quite popular are stoves from the well-known manufacturer of heating stoves and fireplaces Teplodar. They are distinguished by quality and reliability. A wide range of heating equipment allows you to choose the best option for each individual case.

Advantages of the stove heating option:

furnace equipment is one of the cheapest;
installation of wood-burning boiler stoves for a home is simple; the only difficult part is the construction of a chimney;
if the house consists of one room, then you can’t imagine better heating;
if you position the stove correctly, you can heat several rooms at once;
the wood-burning stove provides a very good microclimate in the room, good for health;
It is possible to select a unit for water heating.

Rules you need to know when building a chimney

Diagram of a brick chimney.

The structure for solid fuel boilers is made together with the walls of a private house. These elements are constructed according to a single principle, and it does not matter whether the channels will be used as ventilation or smoke. You will definitely need to build a foundation for the chimney. The base structure can be made of brick or concrete.

In all cases, a foundation project is prepared. During the design process, it must be taken into account that its height must be at least 30 cm, and its width must be such that the base structure extends beyond the border of the chimney device by 15 cm or more. If the chimney is made as an element of the external wall, then you need to know that the lower part of the chimney base must be placed at the lower level of the wall base.

During the construction of chimney structures, special attention should be paid to the quality of tightness. To make a durable brick chimney, you will need to follow the rules

The material should be laid so that the seams overlap the elements of the next row. In most cases, the same mixture is used as for the construction of load-bearing walls of the structure.

In the process of making a chimney for a solid fuel boiler, it must be taken into account that its internal base must be smooth.

Therefore, when performing construction work, you need to use a template. The walls between the elements must be at least half a brick thick. For ventilation elements, the thickness of the partition should be 2 times less.

At the end you will need to make a header. The extreme parts of the element must protrude beyond the structure by 10 cm or more. The outlets of the ventilation ducts must be created under the head; in most cases, 2 walls are used, which are placed opposite each other. This placement method will prevent air from being blown in.

Design and installation nuances

Stove heating is a potentially dangerous system, so special attention should be paid to its design and proper installation.
What should you pay attention to when drawing up a project?

Typically, a stove heating scheme is developed simultaneously with a construction project, since it is closely related to the layout of the premises. The location of furnaces should, if possible, be carried out in the area of internal walls. Access to the combustion part should not be hampered in any way and it is best that it can be approached from the corridor.

Particular attention should be paid to the fire safety of the system. Since a common cause of fire is excessive heating of wooden parts, an air gap or indentation must be left between the stove and wooden partitions

Also, the surface of a combustible structure can be lined with bricks or so-called cuttings can be arranged - insulating structures made of fire-resistant materials.

Preparation for installation of the stove begins with strengthening and thermal insulation of the area of the floor on which it will be installed. When installing a stove weighing more than 750 kg, a special foundation must be installed for it. It must be taken into account that the design differs from the traditional foundation for a house, from which it must be separated by a 50 mm wide gap filled with sand.

The stove model is selected taking into account the size and configuration of the room in which it will be installed. Brick layout options can be found in special reference books or on the Internet. The hydronic heating part of the system is designed in the same way as any traditional hydronic structure.

Installation features

As practice shows, a water heating stove can be installed in two ways:

Design and fold for a specific register.
Install a heat exchanger into an existing furnace.

The second option is considered the most time-consuming and complex. It involves dismantling the existing structure, installing a carefully sized register and re-installing the structure. The process may be complicated by the need to replace worn-out elements.

In any case, the thickness of the so-called “water jacket” should not be less than 4 cm, otherwise the water may begin to boil. This rule is especially relevant for systems with natural circulation; when installing a pump, the danger of boiling is reduced.

Stove heating with a water circuit is a successful variation of the traditional heating system

Building a country house with stove heating is quite simple. Properly designed and installed equipment guarantees long and trouble-free operation. Stove heating with coolant is considered especially successful, which is everywhere replacing traditional stove heating. Such a practical, economical and effective solution will provide warmth and comfort in your home.