Do-it-yourself pellet boiler design, manufacturing and installation

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Published: June 26, 2019

Reading time: 5 min

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Pellet boiler (PC) is a heat generator that is used to generate hot water for heating and hot water needs and uses solid fuel - pellets in granules.

They are made by pressing wood waste: shavings, sawdust, straw, sunflower and buckwheat husks with dimensions of 5-10 mm in diameter and up to 7 cm in length . The calorific value of pellets is 4500 Kcal/kg , which is almost equal to that of low-calorie coal and some wood output.

Modern PCs differ from conventional coal or gas boilers and consist of four main components: a boiler with a pellet burner for combustion, a pellet storage hopper, a fuel supply mechanism to the furnace and an accumulator tank.

The installation of a pellet boiler is carried out by a specialized installation organization. It is equipped with an automatic fuel loading system, which allows it to operate autonomously for several weeks.

• 1 Technical conditions for installing a pellet boiler
• 2 Requirements for the premises under the boiler
• 3 Installation location
• 4 Necessary tools and materials
• 5 Installation of a pellet boiler
• 6 First start of the boiler

Why is proper strapping so important?

Piping refers to pipes and mechanisms designed to supply coolant from the boiler to the radiators.
This is almost the entire heating system, with the exception of the batteries. The system consists of many components, but even a non-professional can install the simplest boiler piping. But if you need a complex circuit, it is better to contact an experienced craftsman.

It is better to install the boiler in a separate room, for example, in an outbuilding, boiler room or basement, because piping involves additional pipes and mechanisms, which is not always convenient. However, if there is not enough space, heating equipment is installed in the house

The choice of piping scheme for each specific house depends on the type of boiler, construction features, and type of heating system.

Any gas equipment is dangerous. Incorrect connection is fraught not only with heating problems, but also with explosions and destruction, so it is necessary to strictly follow the rules and regulations and comply with safety requirements. The main documentation that is relied upon when installing a gas heating system is SNiP.

The main unit of the system is the boiler. The piping scheme is chosen based on its type, location (wall-mounted or floor-mounted model), design features

It is necessary to carefully plan the heating scheme, the location of equipment, and the features of laying pipelines.

The boiler piping performs several significant functions at once:

• Pressure control. If the piping is installed correctly, thermal expansion is compensated, which means that the pressure in the system will not increase to critical levels.
• Removing air. Air bubbles form plugs, which reduces the efficiency of water heating: radiators do not warm up completely, but resource consumption remains the same. High-quality boiler piping is necessary to prevent this problem.
• Prevention of blockages in the system. If the boiler is not properly sealed, the risk of scale formation in radiators and pipes increases. Small debris in the coolant pollutes the system, which leads to excessive fuel consumption and increased heating costs while simultaneously reducing its quality.
• Possibility of connecting other circuits. You can install an underfloor heating system and a storage boiler.

In many ways, heat supply depends on the correct connection of the boiler to pipelines and other important components, so the gas boiler piping scheme must be carefully thought out and installed as efficiently as possible.

When installing a radial system, collector cabinets are installed where most of the boiler piping mechanisms can be mounted. It's convenient and practical

A correctly selected and installed boiler piping will last for many years without accidents or repairs, and its cost will be optimal.

What are pellets

The production technology was invented in the thirties of the last century. The birthplace of the invention is Idaho, USA. The essence of the method for producing pellets is to compress preheated wood waste. When heated, sawdust, wood chips or shavings release lignin. This substance has the ability to bind small wood particles together.

Under high pressure they are compressed into smooth granules. The finished product has high density and heat transfer during combustion.

No chemicals are used in the production of pellets. This makes them an environmentally friendly fuel. Granules are produced according to the DIN plus standard.

Agricultural waste can be used as a raw material for the production of pellets: corn cobs, husks, etc. The most common type of granules in the country are pellets, with a diameter of 6-8 mm and a length of up to 50 mm.

The efficiency of heating solid fuel boilers largely depends on the quality of the pellets: humidity, density, ash content. When burning 1 ton of pellets, thermal energy is released equivalent to 1.6 tons of firewood.

The main types of homemade boilers

If you are going to make a long-burning boiler with your own hands, then you will definitely need the information from our review. In the following sections we will tell you how to make a heating unit of one design or another yourself, give several of the easiest schemes, and publish information about the most common long-burning boilers

Let's focus on the last question for now.

The time has come to consider the most current options for long-burning boilers, which we can assemble with our own hands at home. They will all eat wood. As for coal, it is more difficult to obtain, and it also leads to high temperature loads on heating units. In the following sections we will provide drawings of long-burning solid fuel boilers and provide explanatory information.

Long burning mine boiler

We can make the simplest mine boiler with our own hands. It is implemented according to a bottom combustion scheme. The basis of the unit is a capacious loading chamber, which is often called a shaft. Having a vertical design, it allows you to accommodate a large amount of firewood. As they burn, they fall down, and the combustion products are sent through the grate into the ash pan.

If we look at the diagram of a shaft furnace (boiler), we will find that the flame is raging not in the shaft at all, but in the adjacent chamber, from where the resulting heat enters the fire-tube heat exchanger. And the remaining thermal energy is sent to the chimney. The combustion here is long and is determined by the volume of the shaft - after loading a large amount of firewood here, you can safely go to bed.

Pyrolysis boiler

Let's see how a pyrolysis boiler works and how to make this unit with your own hands. The easiest way to explain the operating principle of this unit is to use the example of a potbelly stove. Here we see a volumetric combustion chamber that realizes long-lasting combustion. The resulting combustion products are sent to the afterburner chamber, into which secondary air is supplied. As a result, a large amount of heat is generated. All we have to do is retrofit the potbelly stove with a fire-tube heat exchanger.

There are dozens of drawings of long-burning wood-burning boilers built on the pyrolysis principle of operation. They differ in the location of combustion and afterburning chambers, the presence and absence of blower fans and automation, as well as methods for adjusting the intensity of the wood fuel combustion process. But in general, their operating principle is the same.

Boiler-furnaces Bubafonya

Bubafonya is a stove, and its modification is a water-heating wood-burning boiler with air supply from above, through a pressure piston. We have already written about such stoves more than once in our reviews, now it’s time to talk about units with a heating circuit. To implement the circuit, we can use three schemes:

• Installing a heat exchanger on a chimney is the easiest option;
• Build a continuous water jacket around the boiler body;
• Scald the body of the unit with the pipes through which the coolant will circulate.

Which scheme to choose is up to you. By the way, Bubafonya boilers, due to their spacious chambers, will help to realize long-term combustion lasting up to 24 hours or even more.

Long-burning boilers Bubafonya operate on wood and have an upper combustion scheme.

Boiler-furnaces Buleryan

Initially, Buleryans were (and are) convection-type ovens. They are equipped with powerful convectors, which allow you to warm up a large room in literally 20-25 minutes. Having originally appeared in Canada, these stoves reached Russia, which also boasts a harsh climate (true for some regions). Craftsmen turned stoves into boilers, having worked a little on the design of convectors - now not air, but coolant circulates through them. True, Buleryan boilers cannot boast of long-lasting combustion, since they do not have the largest combustion chambers. Some of them have the property of burning for up to 10-12 hours, some – a little longer. But you still can’t count on 24 hours. But they are characterized by high efficiency and the ability to quickly transfer heat to heating systems.

How to calculate the required volume of a heat accumulator

A tank that is too large or too small for storing heat in the form of a heated coolant is an ineffective solution, therefore the required volume of the tank is subject to mathematical calculation, the exact results of which are difficult to obtain due to the approximate initial data - heat losses in the room, the properties of the insulation of the walls and the foundation of the house, heat-insulating qualities of building materials of walls, ceilings and partitions, the same parameters of window and door openings. But it is still possible to roughly calculate the heat accumulator, and this technique is designed specifically for ignorance of the exact heat losses of the building, especially if it is just to be built.

The choice of size and volume of the tank for the heat accumulator can be made based on the following parameters:

1. Total area of ​​heated premises;
2. Thermal power of heating equipment.

These two parameters determine the volume of TA.

Let's say you need to calculate the volume of a heat accumulator for a heating system based on the heated area of ​​the room. The formula for calculation is simple: the area in square meters is multiplied by four (Sx 4). For example, a house with a total heated area of ​​50 m2 will require a 200 liter tank. With such a volume of TA, as practice shows, the boiler can be loaded with solid fuel only once a day. This is very good savings and very good efficiency.

Knowledgeable owners will say that you can simply install a pyrolysis boiler, which will work the same way. But the operation of such a boiler is a little more complicated and less efficient, since:

1. First, the fuel ignites and burns;
2. Then the air supply is limited;
3. The last thing to activate is the smoldering of the fuel (pyrolysis).

When the fuel ignites, the temperature of the coolant increases sharply, and the pyrolysis process maintains it at a given level, and during pyrolysis a lot of thermal energy simply disappears into the chimney pipe, heating almost nothing. Another disadvantage is that during heating peaks, the coolant can boil and splash out of the expansion tank, and when using PVC pipes for heating distribution, they quickly fail due to high temperatures.

Operating principle of a pellet boiler

Pellet boiler BURNiT PelleBurn

As noted, such boilers use pellets as fuel, that is, pellets made from pressed wood shavings, sawdust and other similar waste.

The operation of the boiler is based on an extremely simple principle. You load the pellets into a special hopper, from there they flow through an auger in small portions to the burner, in which the pellets are burned.

Under the influence of the flame, water is heated in a special tank connected to the heating system.

As a result, at minimal cost you get reliable, environmentally friendly and highly efficient heating.

Common faults

Errors in a pellet boiler can be caused by installation errors

You can pay attention to these errors:

1. Lack of control over heating of waste heat carrier. This leads to increased condensation and the formation of large amounts of soot and tar.
2. No boil protection or incorrect setting. This leads to heating of the coolant to high temperatures, which negatively affects the operation of the heat generator and the entire system as a whole.
3. Poor sealing of the heat generator and other components. As a result, productivity and leakage of pyrolysis gases decrease.
4. Lack of thermal insulation. In some cases, the boiler may freeze, causing condensation to form and negatively impact its integrity.
5. Incorrect installation of the burner tank. This is often the result of choosing the wrong burner model.
6. Insufficient area of ​​the heating room, which complicates the maintenance of heating systems.

To avoid such mistakes, it is better to rely on specialists who perform high-level work during installation, connection and commissioning of the boiler.

Page 2

When defrosting and transporting firewood and scaffolding, cubic meters and storage space dimensions are commonly used - the difference between these values ​​is not generally known.

Boiler Assembly Guide

Pellet boilers have a rather complex design. The instructions for assembling them will also be difficult and multi-step. For greater convenience, the assembly process of each main unit is considered separately. Buy or make the necessary elements, and then simply assemble them into a single system.

Burner

Burner

It is highly recommended to buy this element of a pellet boiler ready-made. The burner is where you will spend the most money.

Making a burner yourself is almost impossible for the reason that this part of the boiler is not simply a container for igniting loaded pellets, but a complex control and regulatory mechanism.

Pellet burners are equipped with special sensors and have several preset programs that allow you to achieve the most efficient fuel consumption and ensure the most efficient heating of your home.

Housing and heat exchanger

You can handle the assembly of the housing and the manufacture of the heat exchanger yourself. It is best to make the boiler body horizontal - with this placement of the unit, maximum heating efficiency is achieved.

It is recommended to use fireclay bricks to make the body. You simply assemble a kind of box without a top cover and place a heat exchanger in it with connected pipes and other elements. Brick is recommended for the reason that it accumulates heat much more efficiently than cast iron, steel sheets and other popular materials.

Fireclay brick

The heat exchanger of a pellet boiler is a system of pipes interconnected and connected to the heat supply pipes of a private house.

First step. Assemble a rectangular heat exchanger from square pipes. To do this, cut the pipes into pieces of the required length and weld them into a single structure.

Second step. Make holes in the profile that serves as a vertical post for connecting round pipes.

Third step. Prepare holes in the remaining front pipes for drainage and water connection pipes. Hot water will be discharged through the top hole, cold water will be supplied from below.

Use metal pipes with a length of 150 mm. Next, you can use polypropylene pipes. Be sure to install ball valves where the pipes connect to the boiler. Additionally, you can install filters if necessary.

Fourth step. Weld the back of the unit to its front and weld the side pipes.

At the same stage, select a convenient place to connect a chimney pipe with a diameter of 10 cm. At the bottom of the heating unit, provide a small chamber for collecting ash. Also, the design of a pellet boiler necessarily includes a firebox. More about him later.

Pellet boilers

Firebox

In the firebox, as already noted, pellets are stored and from here they are supplied to the burner.

First step. Prepare the necessary materials and equipment. You will need an auger with a diameter of 7.5 or 10 cm, an electric motor and a metal casing. You will connect the engine to the pellet burner control unit.

The function of a metal casing can be performed by any container of suitable volume with sufficiently thick walls.

Second step. Install the inlet pipe of your auger into the discharge mouth of the casing. Connect a corrugated plastic pipe to the other part of the auger to supply granular fuel to the burner.

In conclusion, all you have to do is assemble all the listed elements into a single structure. Do this and proceed to installing the boiler.

Automatic control mode

Pellet granules are stored in a separate bunker , which is connected to the combustion chamber. Automation allows you to set a weekly program for feeding pellets into the boiler. In addition, the automation will turn the burner on or off according to the established program, which allows you to save fuel consumption and maintain the set temperature depending on the time of day. Control can be done either using the remote control or using the buttons on the display.

A bunker with a volume of 200 to 300 liters ensures continuous operation of the boiler for three days. For uninterrupted operation of an average-power boiler within 25 kW, the daily norm is 5 kg. You can install an external bunker, which will greatly increase the volume of pellet loading, thereby increasing the operating time of the boiler without your intervention. The control system is responsible for the operation of the burner ; granules are fed into the combustion chamber in small batches, which eliminates the possibility of overheating. If you need to turn off the boiler, then after pressing the function button, its operation will automatically stop after 5-10 minutes, which is required for complete combustion of the loaded batch of pellets.

Installation of boilers in individual houses

The method of placing a heating boiler in a residential building depends on its design and can be floor- or wall-mounted. It should be noted that floor-standing models in most cases exceed the thermal power of wall-mounted heat sources.

In addition, a freer coolant circulation pattern in such devices allows them to be installed for operation in autonomous heating systems with natural circulation.

Installation of floor-standing boilers in a separate combustion chamber

If it is necessary to install a heat source with a power of more than 32 kW, gas boilers with floor installation are chosen, since the thermal performance of serial mounted models does not exceed the specified value. The developed standard furnace schemes for private houses provide for the presence of:

• expansion tank;
• domestic hot water heater;
• capacitive or speed separator;
• distribution comb;
• at least two circulation pumps.

In addition, it is necessary to install emergency discharge lines and safety valves that are activated when the pressure in the pipelines increases.

Boiler installation work begins with the preparation of brick or concrete foundations not only for it, but also for all tanks, which, after filling with water, will become quite heavy. After this, distribution combs and pumping blocks with shut-off valves should be assembled and secured to the wall according to the design diagram.

Features of the scheme of primary-secondary rings

This scheme provides for the organization of the primary ring

, through which the coolant must constantly circulate. Heating boilers and heating circuits are connected to this ring. Each circuit and each boiler is a secondary ring.

Another feature of this scheme is the presence of a circulation pump in each ring.
The operation of a separate pump creates a certain pressure in the ring in which it is installed. The assembly also has a certain effect on the pressure in the primary ring. So, when it turns on, water comes out of the water supply pipe, entering the primary circle and changing the hydraulic resistance in it. As a result, a kind of barrier appears on the path of coolant movement. Since the return pipe is connected to the circle first, and after it the supply pipe, the coolant, having received considerable resistance at the supply pipe, begins to flow into the return pipe. If the pump is turned off, the hydraulic resistance in the primary ring becomes very small and the coolant cannot float into the boiler heat exchanger. The piping continues to work as if the disconnected unit did not exist at all.

For this reason, there is no need to use one complex automation system to turn off the boiler

. The only thing that is needed is to install a check valve between the pump and the water return pipe. The situation is similar with heating circuits. Only the supply and return lines are connected to the primary circuit in the opposite order: first the first, then the second.

It is advisable to include no more than 4 boilers in such a scheme. The use of additional devices is impractical.

Universal combined scheme

This system has the following harness:

1. Two common collectors or hydraulic collectors
   . The first one is connected to the boiler supply lines. To the second - return lines. There are shut-off valves on all lines. There are circulation pumps on the coolant return pipes.
2. The membrane tank is connected to a large return manifold.
3. The indirect heating boiler is the link between two collectors. On the pipe that connects the boiler to the supply manifold
   , there is a circulation pump and a shut-off valve. The pipe connecting the boiler to the return manifold also has a valve.
4. The safety group is installed on the coolant supply manifold.
5. The make-up pipe is connected to the manifold, which is located on the hot water supply line. To prevent leakage of hot coolant through this pipe, a check valve is installed on it.
6. A certain number of small hydraulic collectors (there may be two, three or more)
   . Each of them is connected to the above-mentioned common manifolds. These hydraulic reservoirs and large reservoirs form the primary rings. The number of such rings is equal to the number of small hydraulic collectors.
7. The heating circuits depart from small hydrocollectors. Each circuit has a miniature mixer and circulation pump.

A solid fuel boiler always requires constant attention from the residents of the house, because after the firewood loaded into it burns out, heat stops flowing to the heating radiators. Of course, a heat accumulator can improve the situation, but after it cools down, the heating system will cease to be a heating system. Combination wood-gas heating boilers or two boilers, one of which runs on solid fuel and the other on gas, can make life easier for the owners of a private home.

Any of these two options makes it possible to obtain the desired heat in the case when there is no firewood left in the firebox, but there is still gas in the cylinder. The gas-firewood unit is suitable for those people who do not want to spend much effort and money on organizing a complex installation. However, practice shows that it is better to combine two different boilers. The smallest advantage of this approach is the constant operation of the network, despite the possible breakdown of any of the devices. If the gas-firewood device breaks down, the system stops working and the rooms in the house will be cold.

Alternative options for DIY

In addition to solid fuel and electric boilers, a number of alternative heating units are suitable for self-production:

1. Induction boilers

They are transformers consisting of a primary and secondary winding. In such a boiler, the electricity on the external winding is converted into an eddy current, and the created magnetic field is transferred to the internal winding, which transfers energy to the coolant.

1. Condensing boilers

They retain the thermal energy of condensate, therefore they are considered more efficient than gas and even solid fuel ones. Steam condensation occurs in a heat exchanger with a special design - it is this that provides such boilers with a 15-20% efficiency advantage over traditional gas equipment.

1. Liquid fuel boilers

Such units evaporate waste and then burn its vapors. The energy thus obtained is transferred to a heat exchanger, which heats the heating agent of the heating system. Equipment of this type has two significant disadvantages - low efficiency and a large amount of emissions into the atmosphere.

1. Combination boilers

This equipment is universal in use, but to manufacture it yourself will require remarkable skill and excellent knowledge of the operating principles of various types of heating equipment. The individual components of such units can be quite expensive, but in general, combined boilers can pay for themselves in no more than 5-6 seasons.

Device

Any burner has one goal - creating a powerful flame to heat the air or water jacket of the boiler. At the same time, the combustion power itself can be adjusted independently.

A pellet burner has similar goals. The device is a wind tunnel into which solid fuel is supplied and air is pumped for combustion. Fuel is supplied to the pipe using a special screw-type conveyor. The fuel itself is located in the loading hopper before combustion. The bunker can have a different volume, and it depends on the volume how long the burner can burn on its own without human intervention (adding fuel).

Pellet burner structure: 1 - The pellet enters the burner under the influence of gravity; 2 - Air enters the burner due to the vacuum created by the draft of the chimney; 3 - Pellet combustion occurs in the combustion chamber, which is called the “basket”; 4 - Due to the high temperature, thermal decomposition of wood occurs in the basket, which forms a flow of flammable gases; 5 - A secondary air flow passes under the basket; 6 - In the burner nozzle, the flow of combustible gases and secondary air mixes, forming a torch; 7 - Solid combustion products are ejected from the burner into the ash pan of the boiler or furnace by a stream of secondary air; 8 - Ventilation of the supply channel does not allow hot gases to diffuse up the channel and destroy the pellets, ensuring a stable supply of pellets.

Air is forced into the combustion zone by means of a fan.

The combustion chamber in the burner can be round or rectangular. Round burners are the most common due to their ease of manufacture. A pipe connection is attached to the outside of the combustion chamber, through which fuel is supplied from the conveyor.

The design also includes an ash pit in which combustion waste accumulates. During the combustion of pellets, a little ash is formed, so you need to clean the ash pan no more than once a week when the burner is actively used.

There are several types of pellet burners, each of which has its own advantages and disadvantages.

Flare type

Initially, the device was used to generate heat by burning grain, but later it was converted to burn solid compressed fuel.

Side view of a flare type burner

• Small overall dimensions;
• Can be used in conjunction with boilers with a small combustion chamber;
• Simplified operation;
• Increased reliability;
• You can burn low quality pellets.

• Low power compared to other burners;
• The flame is directed horizontally, which is why it heats the boiler locally.

Volumetric type

Unlike the previous model, they have increased power and high efficiency. The disadvantages of the device include a complicated design, large overall dimensions, and dependence on the quality of the pellets used.

General view of a volumetric combustion burner. Combustion of pellets in a fireplace burner.

Such designs are mainly used in domestic conditions, installed in fireplaces and boilers. The operating principle of the device is as follows: pellets fall into a special bowl, where they are burned under the influence of air supplied from below.

The disadvantages of the model include the size of the device and the need for precise adjustments for proper combustion.

Polypropylene - the optimal solution

Many experts are in favor of tying gas equipment with polypropylene. Their main argument is versatility and the ability to implement any scheme without any problems. On the other hand, an inexperienced master is unlikely to have to deal with systems of increased complexity.

It is better to entrust the development and installation of highly complex piping schemes to a specialist. An inexperienced technician may make mistakes that will lead to a decrease in the efficiency of the system or even jeopardize its performance

The main advantage of polypropylene pipelines is reliability. According to the manufacturers, their products last 40 years or more.

The material is resistant to high pressure (can withstand up to 25 bar), tolerates water hammer and temperatures of 95 degrees. There is also a drawback that must be taken into account: such a boiler piping reduces the efficiency of the heating system.

When designing a harness, it is better to give preference to a scheme that involves a minimum of surges. This will increase the chances of maintaining the integrity of the system in the future.

The connection of the boiler to the gas pipeline must be rigid (“American”, metal fitting). Of all types of gaskets, only paronite gaskets are suitable, because... plastic materials (rubber, foam, tow) are deformed, which leads to loss of tightness or a decrease in the internal diameter of the gas pipeline.

Common mistakes

If you neglect the installation rules, problems will arise even when you first start the device. The most common installation errors are:

• Soot appears too quickly, the boiler does not produce heat well, although all the settings on the panel are set correctly. Reason: during installation, the installation of a system for monitoring the level of heating of the return water was ignored. This is a serious mistake that can soon lead to failure of the heating system.
• Too much condensation occurs. The reason may be that the room temperature is below +10 degrees. This creates sudden temperature changes when the device is turned on and off. If condensation forms under the boiler, it means that it was placed on the wrong foundation (the situation will be corrected by thermal insulation of the floor).
• A leak of pyrolysis gases occurs. Reason: during installation, sealing of the boiler, fuel bunker, and chimney was not ensured.
• The boiler smokes, and unburnt pellets remain in the ash pan. Reason: incorrect settings are set, the system needs to be re-configured.
• The burner goes out regularly. Reason: there is no supply ventilation hole in the room, the device does not have enough oxygen.

Advantages and disadvantages of pellet boilers

The popularity of pellet boilers is growing due to a series of advantages. Among them:

• efficient heat transfer; The efficiency of such devices is comparable to the efficiency of gas heating devices and is significantly higher than the efficiency of wood-burning stoves;
• fuel efficiency;
• complete environmental friendliness; absence of any harmful substances in the granules;
• autonomy; provided there is an automated system, the user is deprived of the need to control the combustion process - the automation does almost everything for the person;
• independence from main power systems;
• almost complete non-waste - when burned, the granules leave a very small amount of ash; cleaning the ash pit is rarely required;
• equipment safety and no need to coordinate installation with the relevant services;
• aesthetic design of boiler-fireplaces - the ability to “fit” the unit into any interior.

It is not without its drawbacks. These include:

• the need for electricity, without which ignition of fuel, operation of the auger and control unit are impossible;
• high cost of equipment; average price range – 100,000-1,000,000 rubles;
• dependence of European models on Russian energy systems and pellet quality; devices can be sensitive to power surges and require fuel; When choosing a stove, you should definitely consider protection against voltage surges and the possibility of purchasing pellets suitable for a specific model.

Conclusion

Installing a pellet boiler is a complex process and requires great care. The performance and safety of the device depends on correct installation and configuration. That is why, if you do not have the necessary skills to work with connecting the heating and plumbing systems, it is better to entrust this matter to specialists.

Sources:

• https://tehno-gid.net/dacha/kotly-na-pelletnom-toplive-ustrojstvo-printsip-raboty-luchshie-modeli.html
• https://remont-system.ru/kotly/kak-vybrat-pelletnyy-kotel-dlya-otopleniya-chastnogo-doma
• https://eco-kotly.ru/otopitelnye-kotly-na-pelletah-mehanizm-raboty-vidy-kriterii-vybora/
• https://teplo.guru/kotly/tverdotoplivnye/kotel-na-pelletah-otzyvy.html
• https://MirCli.ru/kotly-otopleniya/pelletnye/
• https://GradusPlus.com/kotly/tverdotoplivnye/pelletnye-kotly-s-avtomaticheskoj-podachej-topliva/
• https://kotlobzor.ru/princip-raboty-pelletnogo-kotla/
• https://pechnoy.guru/otopitelnoe-oborudovanie/kotly/tverdotoplivnye/pelletnyj-kotel/printsip-raboty-pelletnogo-kotla.html
• https://kotle.ru/tverdotoplivnye/ustanovka-pelletnogo-kotla
• https://pechnoy.guru/otopitelnoe-oborudovanie/kotly/tverdotoplivnye/pelletnyj-kotel/ustanovka-pelletnogo-kotla-svoimi-rukami.html

Installation

Pellet boilers must be installed in compliance with certain requirements for the installation site.

Choosing a place

It is better to install the unit in a separate room due to its impressive dimensions. The best option is a room with a temperature of at least +10 °C.

Installation outside the building is not recommended. However, when placing equipment outdoors or in a garage, pipes should be located underground below the freezing level to reduce heat loss.

Preparing the floor and walls

It is necessary to level the floor in the place where the equipment will be installed. The platform must be strong enough to support the weight of the device itself and the pellet hopper. Non-flammable plates should be fixed to the walls and floor. There must be a place for pellets near the device.

Ventilation and chimney

We install ventilation and a chimney made of non-combustible material. The latter, as a rule, is displayed on the roof, protruding above its surface by at least half a meter. It should be protected from precipitation and insulated.

The cross-section of the chimney pipes must be larger than the diameter of the hole intended for removing exhaust gases from the equipment.

Installing equipment

Having prepared the site, we install the device itself. We install and connect the burner, hopper, auger and automatic control panel. Communications are connected to the equipment through ball valves.

This will make the system easier to maintain. It is advisable to install filters. After connecting all the elements, a test run of the heating system is performed.

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.

Advantages and disadvantages

The equipment has a number of advantages:

• Pellets are a safe fuel compared to gas and electricity;
• Allows you to significantly reduce space heating costs compared to using electric boilers. At the same time, pellet installations are more expensive than gas equipment, but do not forget that it is not always possible to supply gas and purchase gas cylinders;
• Homemade installations guarantee high efficiency - 95%. Some store installations are over 97%;
• They are used not only for heating the room, but also for producing hot water;
• There are no rules for transporting and storing fuel. When near a person, pellets do not cause allergic reactions, and there are no toxic fumes when burning;
• Fuel is available for purchase. Equipment owners complained about the lack of fuel and the need to prepare a supply of pellets from the winter when the devices appeared; now there is no need to store a large volume of pellets at home; if necessary, they can be bought everywhere;
• The price of pellets is on average at the same level, unlike gas and electricity, the tariffs for which periodically experience seasonal fluctuations;
• Installation of the device does not require special skills, and there is no need to coordinate the installation with authorized bodies;
• After combustion of pellets, natural mineral ash is formed, which does not require special rules for disposal.

Along with the advantages of such equipment, there are also a number of disadvantages:

• High cost of ready-made store equipment. Despite the popularization of devices in recent years and some reduction in prices, pellet boilers are still more expensive than gas or electric equipment of similar power;
• The equipment requires constant maintenance (especially outdated models). The user will have to clean the ash pan and heat exchanger from accumulated ash once a week. In modern models, cleaning is provided at an automatic level;
• In the absence of automatic fuel supply, the user has to load pellets into the bunker manually;
• It is necessary to ensure minimum humidity conditions in the rooms in which pellets will be stored awaiting use;
• Imported equipment is practically not designed for the conditions of the harsh domestic winter, as a result of which breakdowns and malfunctions often occur;
• In remote areas, fuel for the winter still has to be stored due to the instability of supplies.

Polypropylene pipes in heating systems

Fittings and pipes made of polypropylene (PPR) are popular due to their low cost and ease of installation. They are not subject to corrosion, have smooth internal walls and serve no less than the 50 years declared by the manufacturer.

There are several types of these pipe products, which differ in technical characteristics and purpose. In the construction of heating systems, as well as in the installation of hot water supply circuits similar to them in operational parameters, the following is used:

• Pipes marked PN 25. Products with reinforcement made of aluminum foil. Used in systems with nominal pressure up to 2.5 MPa. Operating temperature limit +95º C.
• Pipes marked PN 20. Reinforced version used in DHW branches of double-circuit heating boilers. They will work for the period stated by the manufacturer if the coolant temperature is not higher than +80º C and the pressure is not higher than 2 MPa.
• Pipes marked PN 10. Thin-walled polymer products. They are used if the boiler supplies coolant to the water heated floor system. Operating temperature not higher than +45º C, nominal pressure up to 1 MPa.

Polymer pipes are suitable for all known installation methods: open and hidden. But this material has a high coefficient of thermal expansion. When heated, such products begin to slightly increase in length. This effect is called thermal linear expansion and must be taken into account when constructing pipelines.

The boiler should be tied with polypropylene pipes, which are marked as operating class 5, operating pressure of 4–6 atmospheres and nominal pressure PN of 25 and above

To prevent destruction of polypropylene heating pipelines, compensation loops can be installed. But it’s easier to take multilayer pipes, the reinforcement in which is specifically designed to compensate for this stretching. A layer of foil inside PN 25 polypropylene pipes reduces their thermal elongation by half, and fiberglass by five times.

Image gallery Photo from Welding of polypropylene pipes with a diameter of 63 mm or more is carried out using the butt method using a specialized device. The advantage of butt technology is the absence of connecting parts

Welding of wide pipes for assembling pipelines of single-pipe systems and risers of two-pipe circuits can be carried out using couplings, if available.

In the assembly of pipelines with a diameter of up to 63 mm, socket and coupling connections are used. If it is necessary to provide a threaded connection, a coupling with a socket is used

Connecting pipes with a diameter of up to 40 mm is usually carried out using a manual welding machine. Welding of pipes larger than 40 mm is performed using a device with centering devices

Large diameter PP pipe welding machine

Features of welding wide plastic pipes

Connection of narrow polypropylene pipes

Apparatus for connecting small diameter PP pipes

Features of installation of PPR pipelines

Fittings with polypropylene pipes into a single heating system when piping the boiler are connected using the threaded method, as well as by cold or hot welding. Screwing on is much more convenient, but because of them, assembling the system will cost significantly more. True, if you want to connect a polypropylene pipeline to a metal counterpart, you cannot do without threaded fittings.

An extensive line of fittings is produced to form linear and nodal connections of polypropylene pipes

“Hot” welding is done with a special apparatus (soldering iron, “iron”). The pipes are heated using a suitable nozzle to a melting temperature of 260 degrees, and then the parts with softened edges are pressed against each other. The result is a reliable and monolithic connection.

Before welding, the foil must be cleaned. Otherwise, it will interfere with the connection of polymer products, making the seam fragile. With fiberglass, these unnecessary steps will not be required. It melts easily along with the plastic.

PPR soldering technology is extremely simple, all work can be done with your own hands (+)

Cold welding involves the use of a specialized adhesive composition. In recent years, this method has rarely been used, because the result is not reliable enough.

In heating systems, threaded connections should be sealed with paronite or high-temperature sealant. Do not forget about the fairly high operating temperature of the coolant.

There is one more nuance of using polypropylene for piping a heating boiler. Antifreeze and plastic are a pretty bad combination. It is recommended to use water as a coolant for a system of plastic pipes.

We make it ourselves

Having decided to do everything yourself, you should first develop a project. Guided by the drawings, you should purchase everything you need, as well as prepare the tools.

What will you need?

It is better to purchase the most complex elements already assembled. Thus, a factory-assembled pellet burner is always preferable to one assembled by yourself. The same applies to sensors and programmers, a fan, an electric motor for the auger, a grate, two oven doors, if you do not plan to manufacture them yourself. You will also need:

• steel sheet 3mm and 6mm thick;
• steel square and round pipes (wall thickness 4 mm);
• asbestos sheet and in the form of a sealing cord;
• fireclay brick for the combustion chamber;
• round bar (20 mm);
• electrodes.

To carry out the work, you need to prepare a grinder, a welding machine, a ruler, and a drill.

Pellet supply unit

We are preparing a bunker for pellets. We connect it to the auger shaft. The latter can be in the form of a pipe. If a fuel dispenser is provided, install it at the entrance to the auger shaft and connect it to the electric motor.

Heat exchanger

Square pipes are used as front pipes, round pipes are used as connecting pipes. In the front ones, round holes are cut for supply and removal of coolant.

The spatial arrangement of the connecting pipes at the time of welding is carefully controlled. After completing the welding work, check the tightness of the seams by filling the heat exchanger with water.

Case manufacturing and assembly

The body is made from sheet steel 6 mm thick. We provide two doors for subsequent maintenance of the equipment, located in the front and rear parts. We lay fireclay bricks inside the chamber.

We place the heat exchanger inside the housing, providing a small gap between the outer surface of the first and the inner surface of the second. Install the fan at the top of the case.

In many regions, the problem of heating private houses still remains relevant. Of course, the modern market offers a huge range of equipment that uses a wide variety of materials as fuel, be it gas, firewood, electricity or oil, etc. However, access to gas mains and stable power grids is not available everywhere, so solid fuel heating remains the most preferable in many regions.

One of the best options for a solid fuel heating unit is a pellet boiler, which you can assemble with your own hands.

Contents of step-by-step instructions:

A few words about the chimney

The efficiency of a pellet boiler largely depends on good draft. A properly designed chimney will provide sufficient draft in any wind and air temperature. First of all, remember that the diameter of the chimney must be equal to the size of the outlet. In such a chimney it is necessary to install a condensate drainage device. A properly installed hood will not create aerodynamic draft and will not block the pipe section.

The photo shows two options for installing a chimney for a pellet boiler. The wrong version is shown on the left, the chimney is installed correctly on the right

For chimneys, metal pipes are usually used, which should be equipped with hatches for cleaning and also carefully insulated. The distance between the outer surface of the chimney and the ceiling and roof elements must be at least 130 mm. It should be remembered that too much draft and too little draft are dangerous for pellet boilers. To fix this problem you will need a gate damper or traction stabilizer.