Are pellet boilers with automatic fuel supply worth the money?

The article was prepared with the participation of DOZATECH specialists

Despite the fact that our country is one of the largest exporters of blue fuel, there is no need to talk about widespread gasification. For many consumers both in Moscow and Siberia, the cheapest heating method is unattainable now, and it is not a fact that it will be available in the future. Therefore, we have to look for alternative heating sources; fortunately, the choice in this area is impressive. And in recent years, the range of heating equipment has been replenished with an interesting unit - a pellet boiler. Let us dwell in more detail on this type of equipment, for which we will consider the following aspects:

• What is a pellet heating boiler and what fuel does it use?
• Unit design.
• Advantages and disadvantages of a pellet boiler.
• What to look for when choosing a unit.

Pellets and their effectiveness as solid fuel

Pellets are cylindrical granules compressed under high pressure, obtained by processing waste from agriculture (husks of grain seeds, hay or straw) and wood processing (sawdust, chips, shavings or bark). Peat and coal pellets are less popular.

This is what different types of pellets look like.

The calorific value (specific heat of combustion) of pellets is 17.2–19.5 mJ/kg = 4.7–5.4 kW/h, which is significantly higher than, for example, wood, pure peat and even fuel briquettes . Burning 2 tons of pellets provides the same amount of energy as 960 cubic meters of gas, 1000 liters of diesel fuel or 3.2 tons of firewood.

In Russia, the production of pellets of the “Premium” and “Standard” varieties is permitted, which have an insignificant degree of ash content of 0.4–1% and 1.5–3%, respectively.

Reference . Contrary to popular belief, pellets are produced without the addition of synthetic substances: and although there are standards that allow chemicals in the composition, most pellets do not contain binding substances and improvers, and gluing occurs due to lignin released during heating.

The disadvantages include, perhaps, storage conditions - they cannot be left simply under a canopy, but must be stored in a closed room or container.

What you need to know about pellets?

Wood pellets used as fuel come in different sizes depending on the standards adopted by the state. Thus, pellets produced in the European Union reach a length of 30-60 mm. In Russia, where the rules have not yet been established, the granules may be longer.

Therefore, if you use such a product for a boiler manufactured in Europe, it will be difficult to configure the automation to the desired mode. As a result, overexpenditure, incorrect operation in modes specified by the owner, etc. are possible.

The bunker can be located at a significant distance (up to 10 m) from the boiler itself

Also, all heating boilers operating on pellets require that they be of sufficient quality. That is, the granules must retain their shape until they enter the firebox. Otherwise, overspending is inevitable.

The strength of pellets depends on the quality of production and humidity. It is important that it does not exceed 12%. If the norm is not observed, the calorific value will decrease, and in severe cases the granules will become completely unusable.

This type of fuel is:

• household (ash content up to 1%) - they are made from hardwood waste with minimal addition of bark;
• industrial (ash content up to 3%) - it is made from coniferous waste with the addition of bark (up to 10%);
• from agricultural waste (ash content more than 3%) - they are made from biomass of various origins (sunflower husks, straw).

Granules for household use are characterized by the highest calorific value, as they contain a small amount of dust and have low humidity. They are always white.

Cheaper ones are granules for industrial use. Low cost is their significant advantage. Their disadvantage is not the highest calorific value. In addition, the boiler will have to be cleaned much more often and this procedure will be more labor-intensive.

Industrial granules can be identified by color - they are dark brown. They are undesirable for domestic use due to their low calorific value.

There is another type of pellets made from agricultural waste. But you shouldn’t use them - they have extremely low calorific value and high ash content. This means that the boiler will become clogged often, and in this case it is quite difficult to clean it, especially with frozen ash.

You can set up the production of pellets yourself; more details about the manufacture of a special press are written in this article.

Operating principle of automatic pellet boilers

Hoval pellet boiler in section.
An automatic pellet boiler is a steel or cast iron heating unit, which, from a design point of view, is the same solid fuel boiler, but with the ability to fully automate the work process, i.e. it can function with minimal human intervention.

The principle of operation of a pellet boiler is the sequential interaction of 3 separate systems (a bunker for storing reserves, a mechanism transporting pellets into the combustion chamber and the burner itself), combined into a single device by the ACU attachment - a hardware control unit.

Accordingly, the equipment operation process includes 3 stages:

1. Supply of pellets from a bunker or from a fuel storage to the combustion chamber.
2. Ignition, achieving the required temperature and maintaining combustion.
3. Regular cleaning, including removal of ash and carbon deposits from device elements.

From the storage, the granules are delivered to the boiler bunker.
The dispenser supplies the required amount of granules into the combustion chamber. The pellets ignited by the burner heat the water circuit. In general, automatic pellet boilers designed for domestic use are very easy to maintain. The main thing is to initially correctly set the appropriate operating mode, so that later you can turn the heating on and off with one button and simply monitor the number of pellets.

Pellet feeding system

The organization of an automatic pellet supply system directly depends on many factors (design features of the heat generator model, availability of free space in the room, financial capabilities, as well as other personal preferences) and can be carried out in several ways:

• bulk (spontaneous) - pellets fall into the burner under their own weight, which can only be realized from the built-in hopper;
• pneumatic (vacuum) – supply occurs using a powerful pump that can suck pellets even from another room (up to 30 meters);
• screw (worm) - the intake of granules is realized through a gear-screw mechanism, which involves the portion supply of new batches;
• conveyor (conveyor) – fuel is supplied via a standard (> 45°) or steeply inclined (< 45°) “endless” belt with blades.

An example of organizing the supply of granules using a vacuum method from an outdoor bin.
In addition, for greater ease of installation, the above options can be subject to various modifications and can also be combined with each other.

One load of pellets can be enough for a fairly long period - from 2-4 days to 1-3 months, up to the entire heating season (depending on the volume of the built-in or separate bunker). At this time, the ABU controller itself assesses the situation and ensures uninterrupted operation of the heat generator.

Ignition and combustion maintenance

After pressing the start button, the electric ignition system is activated:

1. The glow plug (or heating element) ignites the fuel, and the flame sensor turns on.
2. The fan pumps air and creates a stable combustion torch.
3. The photo sensor detects the presence of a flame and the glow plug is turned off.
4. The boiler switches to heating mode and pellets are regularly supplied to the burner.
5. When the temperature reaches 60–70 °C, the maintenance mode is activated.
6. The volume of incoming air and the pellet supply speed are reduced.
7. When the temperature drops (sharp cold snap), heating begins again.
8. The burner will periodically turn on/off in the specified mode.

The fully automated pellet boiler is also equipped with a temperature limiter and a coolant overheating sensor. When the supply of a new batch of fuel to the burner is stopped, the system goes into afterburning mode - the fan burns out the residues for 5–10 minutes at full speed.

Stopping work can be done by manually pressing the “Stop” button or (in case of any error) by a software command from the device. Modern GSM modules make life even easier: they synchronize with mobile gadgets and immediately notify about an emergency shutdown, the end of pellets, etc.

Removing ash and carbon deposits

The frequency of servicing heating equipment, i.e. removing carbon deposits and ash remaining from burning pellets, depends on the degree of its equipment:

• model without automatic cleaning – once every 3–10 days;
• model with self-cleaning function – once every 4–6 weeks

That is, the built-in self-cleaning system does not completely eliminate the need for manual cleaning, but only allows you to significantly reduce its frequency.

Boiler unit with automatic cleaning system.
Automatic ash removal occurs through the transportation of burnt-out residues into a voluminous outer container using a screw conveyor. When stirred, the ash is compacted, which saves space in the ash pan. The drive of this mechanism can operate either from the controller of the boiler itself or autonomously.

Automatic removal of carbon deposits from the burner is carried out using knives - moving parts of the grate. In fact, they simply cut off the charred resin particles and direct them to the ash bin. When it is full, the consumer is given a signal about the need to clean it.

Safety of combi boilers

During operation of the heat generator, the following emergency situations are possible:

• reverse draft with fire escaping into the bunker and igniting the entire supply of fuel pellets;
• when operating on wood, the working medium boils;
• clogging of the chimney and, as a result, the entry of carbon monoxide into the room.

During operation of the boiler, emergency situations are possible.

The following types of fire protection are used:

1. A plastic corrugated pipe installed between the auger and the pellet burner. During reverse draft, it melts, as a result of which a gap that is insurmountable for fire is formed between the unit and the bunker.
2. 2-screw feeding system. Its design provides for an air gap in the transport channel.

In case the coolant boils near the boiler outlet pipe (no further than 0.5 m), install the so-called. a security group consisting of the following devices:

• air vent;
• safety valve;
• pressure gauge.

It is prohibited to place shut-off valves in the area between the heater and the appliances.

To discharge excess energy, the piping is supplemented with an emergency radiator or heat accumulator. There are models with a cooling coil in the boiler tank connected to the water supply.

The draft in the chimney is controlled using a temperature sensor. If it detects that hot exhaust has stopped flowing into the pipe, the fuel supply is immediately stopped.

Reviews of household automatic pellet boilers: advantages and disadvantages

Reviews from owners of automatic pellet boilers indicate that this technique has both strengths and weaknesses, or rather, nuances:

Reference . An unexpected increase in pellet consumption is often associated with inadequate quality of the product itself: if they contain foreign impurities or their moisture content is more than 10–12%, then in order to maintain a given regime it becomes necessary to compensate for the loss of heat capacity in quantity.

Features of combined installations

The main type of fuel is pellets - calibrated granules up to 50 mm in size, made by pressing plant materials. It can be:

• sawdust;
• peat;
• straw;
• sunflower seed husks, waste of corn, other cereal crops, rapeseed.

The small size and dense structure of the pellets allow fuel to be supplied by a screw feeder. This process is easy to automate.

In the production of granules, phenol-formaldehyde resins or other substances harmful to the environment are not used. The binder is lignin, a natural glue released from plant cells under press pressure.

In the absence of pellets and in case of power outages, the combination boiler is heated with the following types of fuel:

• firewood;
• peat;
• briquettes;
• coal.

In the absence of pellets, the boiler can be heated with wood and peat.

The latter variety gives a higher temperature. Therefore, only those boilers for which the manufacturer’s instructions allow the use of this type of fuel can be heated with coal. Otherwise, the device will quickly fail.

Advantages of pellet-wood boilers

The strengths of such heat generators are:

1. Autonomy. Unlike a gas device, the device does not depend on external power sources.
2. Automatic fuel supply and ignition. If there are pellets, the user approaches the boiler once a week or less, depending on the volume of the bunker.
3. Comfort. Unlike diesel fuel, solid fuel does not emit an unpleasant odor when burned.
4. On-line power control. To change output, the boiler automatically increases or decreases the pellet feed rate and the volume of forced air.
5. Safety. Thanks to zero thermal inertia, energy production stops almost immediately after the feeder stops, which eliminates overheating of the working environment.
6. Versatility. Combined models operate on different types of fuel, while a pellet boiler operates only on fuel pellets.
7. Fuel availability. Unlike the main gas supply, solid fuel is available in every region.
8. When using pellets – high efficiency. It reaches 91-94%, while for purely wood-burning installations it does not exceed 75-82%.
9. Low fuel cost. The price of 1 kWh obtained by burning wood is 0.9 rubles, pellets - 1.3, liquefied gas - 2.5, diesel fuel - 2.8, when using electricity - 3.5.

Disadvantages of heating equipment

The negative aspects include:

1. Requirement for fuel storage space.
2. When using pellets - dependence on electricity supply.
3. High cost of equipment.

The high cost of equipment is a disadvantage of pellet-wood boilers.

What to look for when choosing a boiler unit

The efficiency factor (efficiency) is the most important point that is worth paying attention to, since it is it that shows the efficiency of the heating device. Manufacturers usually indicate an efficiency of 85–98%, but in reality it depends on the correct settings, the quality of the granules and design features.

Main characteristics of automatic pellet boilers:

Reference . If there are several heating systems, such as radiators, water supply and heated floors, or it is necessary to create climatic zones, then it is better to purchase dual-circuit equipment with additional automation that allows you to control several temperature conditions at the same time.

It is also worth paying attention to equipping the boiler with a device for swirling fuel gases: thanks to it, part of the heat does not go into the chimney, but is transferred as much as possible to the heating system, which increases efficiency, and also prevents ash formation, because The pellets burn out almost completely.

How to choose a room thermostat for a heating boiler and save up to 30% every month

Classification of combined equipment

There are several types of pellet-wood boilers. They can be classified according to several criteria.

By burner type

There are 3 types of devices for burning pellets:

• flare;
• volumetric;
• fireplace

The former have the following advantages:

• simple design;
• reliability;
• compactness;
• undemanding to fuel quality.

Flaws:

• limited power;
• horizontally directed flame, which causes uneven heating of the boiler.

Pellet-wood boilers differ in the type of burner.

Advantages of a volumetric burner:

• unlimited power;
• higher efficiency than flare.

Flaws:

• complex device;
• big size;
• high requirements for the quality of granules;
• dependence on the angle of inclination (as the amount of slag increases, the amount of slag increases until the feeding mechanism stops);
• long auger (generates wood dust, which negatively affects the operation of the device).

The fireplace burner allows you to admire the flames. It is equipped with a bowl into which pellets are dumped. Air is supplied to the combustion zone from below.

Such models have low efficiency; if there are no special requirements for aesthetics, it is better to choose flare or volumetric.

According to heat exchanger material

Boiler tanks are:

• steel;
• cast iron

Boiler tanks are made of steel.

The advantages of the former include:

• low cost;
• light weight;
• maintainability;
• plastic.

Disadvantages are susceptibility to corrosion and the presence of welded seams in the structure, which limits the service life to 12-14 years.

Cast iron heat exchangers are durable and do not rust, so they work for more than 25 years. But they:

• expensive;
• heavy;
• fragile - when exposed to cold water and impacts, they can crack;
• cannot be restored.

By download method

In different models, the granule feeding speed is adjusted by 2 methods:

• automatically;
• manually.

In most models, the supply of granules is manually adjusted.

The second method is inconvenient, because... the user has to independently monitor the temperature of the coolant.

By number of circuits

A simple boiler is equipped with 1 heat exchanger connected to the heating system. Such units are called 1-circuit.

There are models that additionally perform the function of a water heater. They are called 2-circuit and can be equipped with:

• secondary heat exchanger;
• boiler.

In the first case, flow heating is carried out. When the user opens a hot water tap, the 3-way valve shuts off the heating system and the working fluid begins to circulate through the secondary heat exchanger. With high consumption of hot water, the batteries do not receive enough heat.

A boiler with a boiler is more practical. It has the following advantages:

• heats water only at those moments when the heating circuit does not need heat;
• DHW performance is always high and does not depend on power.

The disadvantages of such installations are their large size and energy losses to maintain the temperature in the storage device.

The best known manufacturers and models: characteristics and prices

When choosing a pellet boiler with automatic feeding, you need to focus not only on the technical characteristics, but also on the manufacturer, since not everyone will be able to ensure timely delivery of replacement parts, as well as provide a specialist for installation, configuration and warranty service.

Therefore, in order not to be left without heating at the wrong moment, it is better to choose a proven model from a company with extensive experience in this field.

ZOTA Pellet-15S

Wear-resistant pellet boiler made in Russia, supporting different types of fuel (pellets, firewood, briquettes). It is designed taking into account operation in harsh winter conditions that imported solid fuel boilers cannot withstand.

Those. parameters : power – 15 kW, bunker volume – 296 l, efficiency – 90%.

Average cost : 150,000–170,000 rubles with standard equipment.

Manufacturer : TPK KrasnoyarskEnergoKomplekt, Russia.

FACI 15

A compact boiler with a twin-screw feeding system ensures high combustion efficiency of almost any crushed biofuel. It is equipped with a retort cast iron burner of the “anti-slag” type, which allows you to reduce the ash content of even low-quality pellets.

Those. parameters : power – 15 kW, bunker volume – 352 l, efficiency – 92%.

Average cost : 130,000–150,000 rubles with standard equipment.

Manufacturer : FACI-RUS LLC (FACI Caldaie), Russia-Italy.

Teplodar Kupper OK-9 with APG 25 burner

A universal boiler equipped with an APG 25 pellet burner is also suitable for conventional solid fuels, including wood and coal. The simple combined design is easy to modify; if desired, you can switch to a gas burner.

Those. parameters : power – 9 kW, bunker volume – 200 l, efficiency – 68–95%.

Average cost : 80,000–110,000 rubles including a torch burner.

Manufacturer : Teplodar LLC, Russia.

Biopellet P-15

A boiler with an original but well-thought-out design, which is easy to assemble and maintain even by an untrained specialist. It is unpretentious to the quality of pellets; you can burn both white and gray varieties without the risk of the burner stopping due to contamination.

Those. parameters : power – 15 kW, bunker volume – 200 l, efficiency – 92%.

Average cost : 160,000–180,000 rubles with standard equipment.

Manufacturer : Dozatech LLC, Russia.

START-50-GR

A powerful, domestically assembled boiler with an impressively sized hopper and imported components (automation and burner). Known for its high reliability and durability, thanks to cast iron parts (burner, boiler door, grates) and a durable heat exchanger made of 6 mm thick steel.

Those. parameters : power – 50 kW, bunker volume – 400 l, efficiency – 95%.

Average cost : 230,000–250,000 rubles with standard equipment.

Manufacturer : LLC Heating boilers "START", Russia.

How to choose the right equipment

Even before deciding to purchase a pellet boiler, you should understand a number of points in order to avoid significant financial losses. It so happens that, in a hurry with the purchase, the owner cannot install the purchased equipment or fully operate it.

What to look for before buying

So, before buying, you should understand several nuances.

First , make sure whether it is possible to place the necessary equipment in the building. Usually it is installed on the ground floor, in the basement.

It is necessary to take into account not just the expected dimensions of a particular product, but also the requirements for its installation, for example, there must be gaps of 700 mm or more between the components of the boiler.

Secondly , you need to figure out whether it is possible to store fuel in the required quantity. It is also necessary to pay attention to the convenience of its delivery to the boiler (delivery from the supplier, movement from the storage location to the bunker). And fuel should only be stored in a dry room.

It should be kept in mind that there will be quite a lot of pellets. For example, to heat a house with a relatively small area (100 sq. m), when it is cold, you will need 25 kg of pellets per day

Thirdly , is the power of the electrical network sufficient? Since the control unit, together with the sensors, and the ignition system are powered by electricity, for normal operation, for a short period, they can create a significant load.

This happens during the boiler ignition procedure, when a special heating element raises the temperature in the combustion chamber to an impressive 1000°C so that the pellets ignite.

The line of boilers from the Teplodar company includes combined boilers COOPER PRO, which can be used as both solid fuel and pellet:

Image gallery

Photo from

COOPER PRO 42 with pellet burner APG 42

Boiler processing of wood and coal

Water tube heat exchanger

Automation for organizing boiler operation

Take care of fuel in advance

Also, before purchasing a boiler, you should find out whether there are organizations nearby that supply pellets. There should be several sellers - if there is only one and suddenly ceases to exist, then problems with operation will begin.

It is also necessary to pay attention to the fact that it is usually cheaper to buy fuel from the manufacturer. To prevent any accidents, a potential buyer of pellets should familiarize themselves with the sellers' offers before purchasing.

It is advisable to contact them directly and find out all the details - delivery costs, whether the organization will be able to deliver regularly, etc. And for industrial expenses, it is best to sign a supply agreement with the supplier before purchasing.

The bunker can be installed on any side of the boiler - the main thing is that it is convenient to use the equipment

Rules for choosing a pellet boiler

If there are no doubts about the possibility of installation and the provision of fuel, then you can proceed to choosing a boiler. This should be done by calculating the power.

Theoretically, it is not difficult to calculate - all manufacturers indicate this characteristic in their data sheets, and for simplicity they add how many square meters the boiler is ready to heat.

For example, if the description says that the power is 30 kW, then the manufacturer will indicate that his boiler is capable of heating 200-300 square meters. m of premises. But all these are average values, which are of little use for determining exact values.

Also, any person can perform the calculation himself, since it is believed that 1 kW of power is needed for every square meter. The formula is relevant only for buildings with insignificant heat loss. Effective heat-insulating materials were used in their decoration, and the doors and windows also matched them.

Otherwise, it is necessary to calculate heat loss, which only a specialist can do. This will cost money, but it will guarantee that the building will be warm and you won’t have to overpay for it.

Without the necessary calculations, the purchase will be made at random, which is unacceptable, given the cost of purchase and installation

In addition to the rated power, it is worth considering such a moment as its modulation. Although it sounds incomprehensible, everything is simple here - this is the ability of a pellet boiler to operate at conditions below its maximum productivity.

This is true for regions where temperatures are not the coldest for most of the season. Therefore, heating equipment does not need to operate at full capacity, but rather use only 30-40% of it.

If the boiler does not have such an opportunity, then, at first glance, this is not a problem - having reached the highest temperature specified by the user, it will turn off. When it drops to the minimum set level, it will turn on again. But during such switching on/off wear occurs, which significantly reduces the service life of the equipment.

Heat exchangers are made of steel or cast iron. The former give off heat better, are less massive, the latter are more resistant to corrosion

You should also pay attention to dynamic power. The owner may encounter this characteristic rarely, but in unpleasant moments (if the boiler is chosen incorrectly).

To understand dynamic power, it is enough to look at an example: there was a sharp drop in temperature and the boiler began to not cope with heating.

If it has enough opportunities to briefly, but significantly, increase its productivity and quickly bring the temperature to the set point, then the boiler has sufficient dynamic power. If this does not happen, then the specified characteristic is insufficient and it is better not to buy a boiler - it will sometimes make the owners freeze.

How to choose the right equipment model

When the power is determined, you can proceed to choosing a model. At this point, the potential buyer will understand that there are many manufacturers, as well as models. In order not to get confused in this variety, you should decide which boiler to buy from a well-known domestic or foreign manufacturer.

You should only buy equipment from a well-known seller in the country or region who provides service, updates of all software, and repairs of the sold boiler.

The larger the bunker, the greater the autonomy of the equipment. This will allow you to avoid adding fuel longer.

Also, when choosing, you should pay attention to the type of model you like, advantages, versatility, etc.

But in any case you need to check:

• is the boiler certified by Rostechnadzor;
• are there conclusions from independent specialized institutes confirming the high efficiency of the selected equipment and the amount of harmful emissions;
• is there a fire extinguishing system and can the boiler automation prevent a “backfire” when for some reason the flame begins to move from the burner to the hopper;
• what methods are used to prevent overheating of a working boiler.

Since the boiler will operate in different modes, it is worth checking information about efficiency and emissions in all of them. It would also be a good idea to check the noise level and worry about safety.

In addition, you should look at how easily the equipment is programmed, controlled, and whether it has automatic ignition so that all household members can handle it. Cleaning the product from ash should also be simple.

Since the boiler will be connected to other heating equipment, you always need to find out the standards, connection diagram, manufacturer’s requirements in this case, and pipe diameter. The last point is especially relevant if they are already installed or purchased.

Calculation of the minimum required power

The simplest way to calculate the required boiler power ( N ) is using the formula:

N =S×W beats /10

• , where S is the heated area of ​​the house, taking into account all residential and domestic premises;
• W beat – power required to heat 10 m2 (according to the climate).

In central Russia, a moderately insulated room with a ceiling height of 2.5–2.7 m and an area of ​​10 m2 can be fully heated with a power of 1.1 kW.

Thus, the minimum required power of a pellet boiler for heating a house of 10x15 m will be calculated using the formula 150 m2x1.1 kW/10=16.5 kW.

Sawdust boiler cost

Scheme of operation of a solid fuel boiler.

Heating with sawdust is quite profitable. It is necessary to clarify that the design itself usually has a decent cost, but during operation it justifies itself. After all, you can heat your apartment with any waste; a long-burning boiler will process everything. You don’t have to constantly search for fuel; it is consumed very economically. Such a boiler can warm the space around it for about a week, depending on how much raw material is put into it. Of course, the most profitable thing would be not to buy it in a store, but to make it yourself.

If we talk about how long a long-burning furnace can operate, we cannot fail to mention the Popov boiler. It has a very high efficiency, as it is capable of generating 1 kW of energy per hour from 100 g of sawdust. That's a pretty decent amount of heat. In practice, this figure causes a lot of controversy. Some owners of such heating devices confidently state that they are not capable of producing more than 500 W per hour. Whether this statement is true or not, a long-burning boiler is very expensive on the market. How to make a long-burning boiler with your own hands? Now no one doubts that it is very profitable to use sawdust on the farm. Making it yourself is not as difficult as it seems. Although it is necessary to have a good understanding of the principles of its operation. The raw materials that enter the oven must be well compacted; they are laid in several layers. The more firmly it is compacted, the better, thereby increasing the efficiency of the device. After all, even an ordinary stove can show good results if you use carefully dried firewood (but it will take at least 2 years to dry). This is too labor-intensive a process, which is why no one does it.

The simplest homemade sawdust boiler may outwardly resemble the familiar potbelly stove. But such a stove will be able to work for a good half of the day with only one refill. A similar design can be used not only for heating, but also for smoking meat or fish.

Before starting work, you need to prepare all the materials:

Diagram of a long-burning boiler.

• raw material tank;
• steel sheets 2-3 mm thick;
• steel sheets 4-5 mm thick;
• welding machine;
• Bulgarian;
• brick;
• cement mortar;
• rectangular pipes with a profile 60x40 mm;
• round pipes with a diameter of 40 and 50 mm.

The first step is to make 2 cylinders from steel sheets. The diameter of one cylinder should be slightly larger than that of the second. The smaller cylinder will need to be inserted into the larger one and a lid attached on top. You can also make the lid yourself from the same steel. The bottom must be welded from below. The thickness of the bottom and lid should be twice that of the walls of the tank (approximately 5 mm).

The pipes need to be selected so that they fit perfectly into each other: then it will be easier to assemble the structure. The rectangular pipes will be in a vertical position, and all the others should fit into them. Therefore, holes of the appropriate diameter must be made in rectangular pipes. 2 pipes must be connected to the boiler. One for hot water output, and the second for cold treatment. Therefore, holes with a diameter of 5 mm are also made in the walls of the boiler.

Now you can start welding the pipes. This must be done very carefully so that there are no gaps left. Water pipes should be welded last. The open ends of the pipes are thoroughly welded with small pieces of steel.

A homemade sawdust boiler should not allow water or smoke to pass through. Therefore, it must be checked for leaks. This is easy to do with ordinary water. It just needs to be poured into the pipes. If a leak is found, the holes will need to be sealed.

Now that the entire structure is fully assembled, it will need to be mounted into the furnace frame. This frame may look like a regular box. To assemble it, you will need bricks and cement mortar. It is best to assemble such a frame in advance, and not at the last moment.

Installation standards and requirements

Installation of long-burning boilers with automatic loading of pellets is carried out taking into account existing fire safety rules (FSR):

• placement in a separate room - boiler room (basement or annex);
• covering the floor in the room with the boiler exclusively from non-flammable material;
• a room without high humidity, equipped with a ventilation system;
• the minimum distance from the boiler to the pellet storage place is at least 1 m;
• fireproof partition between the external fuel storage and the boiler;
• organization of the chimney in accordance with the building codes SP and SNiP.

Despite the fact that before installing a pellet boiler you do not need to contact any regulatory authorities (for approval and examination), as practice shows, it is quite difficult to independently install and connect weather-sensitive equipment, so it is better to entrust these matters to professionals.

Starting and maintaining the boiler

Before the first launch of the structure, you will need to invite a specialist to check all elements for compliance with safety requirements. It is not recommended to switch it on yourself.

Start-up is carried out only after checking the unit for compliance with the selected scheme. The tightness of the chimney, bunker and the boiler itself must be checked. Before starting, you need to make sure that the heating system is full and the pressure in it corresponds to parameters suitable for operation. All instruments and automation must be in working order.

Caring for the unit is not difficult. As it burns out, it is necessary to add fuel, clean the stove from ash, and also monitor the performance of the automation elements. Separately, you will need to check how the burner and ignition system work.

How much fuel will you need for the heating season?

Pellet consumption ( Mx of time is calculated using the formula:

M x =X/ fuel heat capacity

, where X is heat loss during the heating season, determined by the formula:

X = S×D×24×0.9×70

• , where S is the heated area of ​​the house, taking into account all residential and domestic premises;
• D – duration of the heating season;
• 24 – number of boiler operating hours per day;
• 0.7 – boiler operating coefficient;
• 70 – average heat loss per hour (for a typical residential building).

For the calculation, you can take a house of 150 m2 from the previous example. If you heat it for about 6 months (175 days) a year, then the heat loss will be X = 150 × 175 × 24 × 0.7 × 70 = 30870 kW for the entire season or 177 kW per day. Accordingly, the consumption of pellets for the same period will be equal to M1=30870/5=6174 kg (season) and M2=177/5=36 kg (day).

Heating costs per month are calculated by multiplying the average daily consumption of pellets by the number of days and the price of pellets per 1 kg, i.e. 36×30×8.5=9180 rubles.

Consumption of pellets for heating a house

Pellet consumption depends on factors such as:

• Calorific value of pellets
• Room volume
• Maintained temperature
• Heat loss
• Duration of the heating season

You can calculate the annual consumption of a pellet boiler for heating your home using our online calculator:

Price

Cost of pellet boilers with automatic fuel supply:

Quality control

Before loading and igniting the unit, it is necessary to check the tightness of the water jacket and check the quality of the welded joints. This will require an air compressor. You can test seams in two ways, which are very reliable:

• Hydraulic. The entire container is filled with water, a compressor is hermetically connected to the fitting, which should create an excess pressure of 2-3 bar. Water does not have the property of being compressed, so it will flow through all uncooked places.
• Pneumatic. Pressure is created without water, and all welds are coated with soap foam using a brush. The bubbles will show where air is leaking through. During the test, the pressure drop can be monitored using a pressure gauge on the compressor.

There is such a type of solid fuel heating source as a sawdust mine boiler. Its design and operating principle are different and more complex, although it is also quite possible to make it on your own. It works due to the fact that sawdust is burned in the lower part of the unit, pouring there from the bunker, this can be seen in the figure.

The process continues in smoke pipes, which intensively heat the coolant. The principle of afterburning wood gases (pyrolysis) is used. Operation efficiency is increased by installing an air blower - a blower fan. Making a boiler using sawdust and tyrsa with your own hands is not so difficult in practice, but it will definitely give a noticeable economic effect both during production and during further operation.

Where to buy a pellet boiler with automatic feed?

In Moscow

• Hermes , st. Bulatnikovskaya 20, off. 17 from 9:00 to 18:00, tel. +7(495)384–19–66;
• Stoves -Fireplaces , st. Yubileinaya 4-A from 9:00 to 18:00, tel. +7(495)215–56–94.

In St. Petersburg

• TechnoDom , Stachek Ave. 57 from 10:00 to 19:00, tel. +7(812)671–00–88;
• TeploTorg , st. Yakornaya 10 from 9:30 to 18:00, tel. +7(812)612–40–02.

And in conclusion: an automatic pellet boiler, despite the fact that it is, of course, easier to maintain than many other options (for example, coal, wood, pyrolysis), still requires attention - both in terms of cleaning and in terms of purchased fuel. These factors should be considered before purchasing.

Pellet boilersAutomatic feedSolid fuel boilers

How to load fuel correctly

Firebox and chimney

The picture shows an empty firebox. How does the stove work and how to use it?

Unlike, for example, “bubafoni”, the blower pipe is inserted directly into the firebox with the pins down. They should rest against the bottom, with the blower located in the center.

• Fuel loading begins.
• Fuel is loaded up to the chimney level.
• Sawdust must be compacted.
• The better the sawdust is compacted, the more efficiently the stove operates, and this significantly affects the operating time.
• In this case, as the fuel is compacted and loaded, the blower must be slightly rocked to the sides so that a small gap is formed between the blower and the compacted fuel.
• Otherwise, the ignition process will be significantly delayed.

Automation

Controlling a pellet boiler involves dosing and supplying fuel to the combustion chamber. The thermostat controls the temperature of the coolant in the heating system and regulates the power of the air blower in the burner. In addition to the thermostat,
more advanced sensors can be optionally installed.
The lambda probe
monitors not the temperature, but the amount of residual oxygen in the hot flue gas, and regulates the speed of the fan in the discharge chamber. Thanks to it, the efficiency of the boiler increases significantly.

Many systems allow you to program not only a constant temperature, but also its change over the course of one day, divided into 6 time periods, and the entire week. Modern models provide for connecting boiler automation to remote control systems.

Local line control

– included as standard. Usually performs a function that signals emergency situations that have occurred.

GSM control

— the ability to install a GSM modem is included as standard in some new models, but the modem itself must be purchased separately. Management occurs by sending SMS with command codes. The set includes several primitive commands - turn on, turn off and get information about the current state.

Internet control

. A very expensive additional option that gives full control over management via SMS, e-mail, and commands via the Web interface.

Pellet feeding mechanism

Screw feed.
The most common and reliable, but not the ideal type. Although the use of a rigid auger guarantees the flow of fuel into the boiler, with a length of more than 2 m, most of the granules are ground into dust. If the hopper is distant from the boiler or the supply hole is not at the same level as the burner, the supply design becomes significantly more complicated. Another auger for feeding pellets directly into the boiler, a transfer chamber, an electric motor interface module, and a fire protection system against reverse draft are required. Chain feed can be used for pre-delivery. With this type, the granules are not damaged, but a lot of noise is produced. Flexible screws with polymer feed pipes are a more unpretentious, albeit less reliable system. The distance to the hopper can be increased to 12 m. The pipe can be bent up to 45 m. Among the shortcomings, one can notice a more complex and thorough system for fixing the supply pipe.

Pneumatic supply.

When using flexible hoses, the range to the storage bin increases to 80 m, but this method requires a powerful compressor. New developments involve the use of a special vacuum transition chamber, which helps reduce the required pump power. A screw feed is used to directly deliver pellets to the combustion chamber.

Automatic ignition mechanism

In operating mode, the turn-on interval of a correctly configured boiler allows you to take advantage of the residual fire from the coals of pellets that have not yet burned. But during initial startup or non-optimal settings, the automatic ignition system comes into operation. This part represents a high-temperature hair dryer
in a fail-safe housing.

When it starts, the amount of energy consumed increases sharply (150-200 kW/hour) compared to normal operation (up to 0.5 kW/hour). This system is included as standard in most models. But it can be installed additionally. Most manufacturers produce such hair dryers for separate sale, but with 2-3 times more power. This is explained by the need for a higher temperature for ignition if the hair dryer is installed in a place that is not optimal for its functioning.

Arson using a ceramic or metal incandescent heating element. It is installed mainly in retort burners at the lower level of pellet combustion. Some models use the electrode method, but it is very sensitive to the moisture content of the fuel pellets.

Possible options for fluid movement

There are many schemes. But all methods can be divided into two main groups depending on the principle of movement of the coolant through the pipes. Therefore, a specific scheme is selected depending on whether natural or forced pumping is used in the system.

Features of natural circulation

The simplest and most inexpensive solution is piping the boiler, where the coolant will move through the pipes using the laws of physics. Even a beginner can implement such a scheme, and it will take a minimum of time.

The peculiarity of a heating system with natural circulation is the absence of a pump. In this case, the movement of liquid in the pipeline occurs due to the ability of a colder medium to push out a hotter and less dense one.

When organizing a heating system without a pump, the radiators should be located higher than the boiler. At the same time, the number of bends and turns of pipes must be minimized (+)

The advantages of this solution include:

• low installation cost;
• low cost of service;
• ease of installation;
• the ability to quickly restore system operation if a breakdown is detected.

But the scheme with natural fluid movement also has its drawbacks. First of all, it can only be used with a single-circuit system. In addition, such a solution will be effective only in small houses.

Forced circulation option

The greatest demand is for heating systems that use a circulation pump. And this is not at all surprising, because such a scheme is convenient, versatile and practical. It can be used in houses and buildings of absolutely any size.

But even despite the unique advantages, schemes with forced coolant circulation have some significant disadvantages:

• high cost of installation - the average cost of a pump is about 150-160 dollars;
• complexity of implementation - the circuit consists of a large number of elements, which significantly complicates its implementation;
• the need for balancing - all components of the home heating system must be precisely aligned with each other;
• dependence on the availability of electricity - the heating pump will only work if current is supplied to it.

When organizing a heating system for a building with two or more circuits, it is recommended to use the option with forced movement of the coolant.

The heating system with forced liquid pumping operates thanks to a circulation pump. Therefore, it is better to give preference to reliable devices from trusted manufacturers

However, in this case, the fundamental performance factor is the power of the heating boiler. Please note that if it is not enough, the equipment will not be able to heat a sufficient amount of coolant.

What is boiler piping?

The piping consists of all those elements that are located between the heating radiators and the boiler. Today, many home craftsmen do not pay special attention to it; they organize it without adhering to any standards or recommendations of specialists.

However, properly implemented strapping can solve many problems:

• the pressure in the pipeline will never exceed the maximum permissible level;
• scale, slag, sand and similar debris that may be in the water will be removed;
• excessive thermal expansion will be compensated;
• provides the ability to connect more than one circuit to the system;
• the air dissolved in the coolant will be removed;
• allows you to automatically turn on the boiler and accumulate hot water, which will help you save money.

If we talk about pellet boilers, they are not always characterized by high operating autonomy. But if you approach pipeline laying responsibly, you can achieve greater efficiency from such equipment.

Proper piping allows you to make your home heating system more reliable, safe and productive

Recommendations for making a boiler

The first thing to do is choose the design of the unit. Here the recommendations are as follows: do not complicate your work and choose the boiler design taking into account the future. In simple words, it is worth separating those elements that you can make yourself from others that you will have to purchase. The latter includes a burner device with a set of automation.

Some craftsmen suggest making a burner with their own hands, but this unit is quite complicated, you can spend a lot of time and effort on it, and as a result, the functioning and consumption of the pellet boiler will be unpredictable. It’s probably easier to buy a finished product and put it in a homemade unit, but everyone decides this question for themselves.

To choose a design that takes into account the perspective, you need to make it universal. That is, it is proposed to make a homemade pellet boiler in the image of a conventional solid fuel unit, in which it is possible to burn wood and coal. In essence, the heat exchange processes occurring in both types of heaters are identical, only the fuel and the method of burning it differ, as shown in the figure:

So, we boldly accept the design of a traditional solid fuel boiler with the possibility of embedding a burner device on a mounting plate instead of the loading door. This will provide the following benefits:

1. Since the production of pellets is not yet very widespread in our country and there may be interruptions in the fuel supply, you can remove the pellet burner at any time and heat your home using wood or coal.
2. It will be possible to use natural gas or diesel fuel by installing a gas or diesel burner instead of a pellet burner.

To fire the boiler, it is best to use heat-resistant steel 5 mm thick. The ideal option is steel alloyed with chromium and molybdenum (stainless steel), but it is quite expensive, and special skills are required to weld it. For this reason, pellet boilers are made of ordinary carbon steel St20, and for the casing of the water jacket, grade St3 with a thickness of 3 mm is suitable. It is preferable to take blanks for doors and flame tubes for the heat exchanger from the same metal as the combustion chamber. The grate is cut out of steel 10 mm thick or simply purchased ready-made. Well, for the chimney and coolant pipes you will need pipe sections of appropriate diameters.

Assembly is carried out by welding, using the drawings of the pellet boiler. Particular attention should be paid to strengthening the walls of the water jacket with pieces of steel strip or angle, as well as the removable design of the loading door. Upon completion, the welds must be tested for permeability and defects must be eliminated.