Connection of solid fuel boilers. We make the boiler piping with our own hands

Solid fuel boilers are used to heat dachas and country houses when it is not possible to connect to the gas main. They are excellent and efficient heat sources. And the main mistake consumers make is choosing the simplest connection scheme. In fact, the operation of the system can be made more stable and correct. Let's see how a wiring diagram for a solid fuel heating boiler is created and what components are found there.

Traditional solutions and their disadvantages

If a solid fuel boiler is the simplest heating device, this is not a reason not to pay attention to the presence of the piping. Without it, it is almost impossible to make a well-functioning heating system that bothers users with its shortcomings. Let's look at the consequences of the absence of certain elements:

No expansion tank is the most serious mistake, since it must be present. When heated, water tends to expand, trying to rupture the pipes. Therefore, expansion tanks are built into heating systems. They can be traditional or membrane - for open and closed heating systems;
There is no safety valve in a closed system - there is a risk of overpressure in the circuit. Wood does not burn as evenly as gas fuel, so pressure and temperature fluctuations in wood heating systems are considered normal;
There is no circulation pump - if you throw thin polypropylene pipes onto the boiler, you will encounter their high hydrodynamic resistance. Therefore, a circulation pump, preferably with a bypass, should be included in the piping circuit of a solid fuel boiler;
There are no collectors - fraught with problems when using several parallel-connected circuits (uneven heating);
There is no air bleeder - the absence of this element in the piping diagram threatens to air the system;
There is no three-way valve - not the most necessary part, but it helps prevent condensation;
There is no buffer tank - a very interesting element in the piping circuit of a solid fuel boiler, which allows you to stabilize the temperature in the circuit. Its absence threatens temperature fluctuations and the need to add fuel to the firebox too often.

So, a solid fuel boiler must be properly wired to ensure that the heating system is balanced, durable and safe.

The piping of a solid fuel boiler must necessarily include an expansion tank. Not a single scheme can do without it. It can be purchased or homemade, but the fact is that it must be there. Open heating systems use the simplest tanks that communicate freely with the atmosphere. In closed heating circuits, so-called membrane tanks are used, inside of which there is a rubber membrane.

The wiring diagram for a solid fuel heating boiler with a membrane tank is not much different from the diagram with a traditional tank, except that some other elements are added to it, which will be discussed in the following sections of our review. The tank in closed heating systems is placed in an arbitrary place, for example, next to a solid fuel boiler or at any other point.

As for open-type heating piping schemes, here the tanks are installed at the highest point. This approach allows you to get rid of air in the circuit - air bubbles leave the system through the tanks. Safety valves are not needed here, since there is no excess pressure.

Security group

When developing a piping scheme for a wood-burning boiler using a closed heating system, it is necessary to install not only an expansion tank, but also a safety group. It includes three main elements:

Pressure gauge – indicates the current pressure in the circuit;
Safety valve – relieves pressure;
Automatic air bleeder - removes air from the heating system.

Let's figure out why certain elements are needed in the piping circuit of a solid fuel boiler.

Closed heating systems are airtight. The coolant in them does not come into contact with atmospheric air, as happens in traditional open circuits. If the coolant is overheated, a situation may arise when, due to its expansion, the pressure in the circuit becomes too high. The pressure gauge in the piping diagram allows you to monitor the situation and take action. To do this, the entire safety group is installed next to the solid fuel boiler.

Instead of pressure gauges, thermomanometers can be used - they show not only the pressure in the system, but also the temperature in the circuit.

The safety valve in the piping circuit of a solid fuel boiler allows you to instantly relieve pressure when it is exceeded. The coolant and air are partially released through it. Its presence in closed-type heating is mandatory. As for the air vent, it removes the air masses accumulated in the system.

The piping scheme for a solid fuel boiler with a circulation pump is used in open and closed systems. It allows you to improve coolant circulation. This is relevant for large households, including multi-storey ones. This approach is also practiced if thin plastic or metal-plastic pipes are used to connect the heating unit and radiators. Together with numerous bends and transitions, they create excessive hydrodynamic resistance, preventing the normal flow of coolant.

For example, piping a solid fuel heating boiler with polypropylene without a circulation pump can lead to the following troubles:

Overheating of the coolant due to lack of normal circulation;
Overheating of the boiler itself can result in damage to the heat exchanger;
Cold spots in the heating circuit – some rooms will feel cold.

Having installed polypropylene pipes on the boiler and radiators, be sure to take care of installing a circulation pump.

Circulation pumps are also used in traditional gravity heating systems with solid fuel boilers. The use of such piping schemes eliminates the need to install pipes at a slight angle, as required by a scheme with natural coolant circulation. They also allow you to increase the size of the heating system, which is important for large households.

In the piping scheme of a solid fuel boiler, the circulation pump is placed on the supply or return pipe. The installation is carried out using a bypass - this approach allows you to start natural circulation at any time when the coolant has already warmed up. Also, the presence of a bypass opens up the possibility of repairing or replacing the circulation pump without stopping and draining water from the heating.

Application of buffer tank

The wiring diagram for a solid fuel boiler with a battery tank is not widely used. It is quite cumbersome, but allows for more correct heating operation. Its advantages:

Stabilization of temperature in the system due to the increased volume of water in the circuit;
Possibility of reducing the number of approaches for adding fuel to the boiler furnace due to the accumulation of excess heat in the storage tank;
Possibility of accumulating clearly unnecessary excess thermal energy when using too powerful a boiler or excessive stacking of firewood.

The heat accumulator circuit has one drawback - it is necessary to allocate space for the device itself. The volume of the container used reaches several hundred liters, so you will need free space to place the tank.

There are many schemes for connecting buffer tanks. The simplest of them involve the use of the same coolant in the boiler and in the heating system. A more efficient scheme is using a three-way valve with a thermostat, which ensures a more uniform and economical consumption of thermal energy from the buffer tank.

Schemes with two circuits are also used. In this case, heat accumulators of heating systems are equipped with heat exchangers connected to solid fuel boilers. Heat exchangers heat the water in the tank, which is the coolant of the heating circuit. This option is distinguished by its efficiency and more uniform heating.

This scheme with a buffer tank is gentle for solid fuel boilers that are not designed for high heating pressure. And in this case, the coolants will be separated, the pressure in the tank and in the radiators will not in any way affect the pressure in the boiler itself and the heat exchanger.

Using a single-circuit solid fuel boiler often forces you to look for schemes for organizing hot water supply. For these purposes, you can adapt a storage or instantaneous water heater. It is also possible to use a more advanced heat storage tank with a built-in DHW circuit coil. This piping scheme will be an optimal and profitable solution, as it will solve the problem with hot water supply.

Application of additional boilers

You can include a rather unusual element in the wiring diagram of a solid fuel boiler - an electric boiler. It cannot be called a harness, it is rather a simple duplicating addition. Such schemes are used when there is no space for placing a heat accumulator. The electric boiler works in tandem with a wood-burning unit, automatically turning on when a drop in temperature in the circuit is detected. Advantages of the scheme:

Maintaining a stable heating temperature;
There is no need to spend money on a tank - the simplest electric boiler costs only a few thousand rubles;
Possibility of heating in the temporary absence of firewood;
A restful night's sleep, since you don't have to jump out of your warm bed to throw the next batch of firewood into the insatiable firebox.

There are also disadvantages:

In addition, using a backup electric boiler is extremely ineffective if your area experiences frequent power outages.

A backup electric boiler consumes a lot of electricity, which increases the cost of operating the heating system - this is not the most profitable scheme;
To power a powerful boiler you will need a separate line and good electrical wiring;
Particularly powerful models of electric boilers require connection to a three-phase network.

Therefore, investing in the purchase of a heat storage unit will be more profitable.

Using a three way valve

When creating a wiring diagram for a solid fuel boiler with your own hands, you should consider the need to install a three-way valve. A properly designed heating system should not show the greatest difference between the water temperature in the return and supply pipes - it usually fluctuates between 20-30 degrees. But sometimes this parameter goes beyond the norm, which causes the temperature in the “return” to drop.

It would seem that there is nothing wrong with this, since the solid fuel boiler will in any case bring the coolant to the set temperature. But in practice, this often leads to the formation of condensation, which causes corrosion. A three-way valve helps neutralize this phenomenon. It is installed between the supply and return pipes, mixing hotter coolant from the supply into the “return”.

As a result of mixing, the temperature in the heating return pipe rises, making condensation impossible. Together with the three-way valve, a temperature sensor is supplied that measures the return temperature. As soon as its temperature reaches normal, the addition of hot coolant will stop.

Please note that in this wiring diagram for a solid fuel boiler, the circulation pump should be located between the valve and the heating unit, and not somewhere else.

Indirect water heaters

An indirect water heater will ensure stable and efficient operation of the entire heating system.

The wiring diagram for a solid fuel heating boiler using an indirect heating boiler is not the simplest, but not the most complex either. Here, consumers are faced with the task of ensuring the supply of hot coolant from the heating circuit to the coil. To do this, a hydraulic arrow is installed in the system, distributing flows into two or more directions. Two pipes depart from the arrow - one goes to the batteries, and the second to the boiler.

Two circulation pumps are installed behind the hydraulic switch - the complexity of the piping scheme gradually increases. One pump sends the coolant to the radiators, and the second drives it to the boiler. The operation of the second pump is regulated by a thermoregulation system built into the water heater. This ensures that a stable temperature is maintained in the DHW circuit.

Water guns and collectors

The use of hydraulic arrows and manifolds in the piping schemes of solid fuel boilers makes it possible to ensure the supply of coolant in several directions - to radiators, heated floors, heated towel rails and boilers. The collectors distribute the coolant evenly, at each outlet it has the same temperature. Next, the coolant is picked up by circulation pumps and carried away in the required direction.

Hydro arrows allow you to distribute the coolant by temperature. If there are two collectors in the heating system (one is placed on the supply pipe, and the second on the return pipe), then the hydraulic arrow is installed alone and connected to two pipes at once. Inserts are made in it to allow coolant to be taken in at different temperatures - for example, heated floors do not need too high a temperature, so it can be taken closer to the return pipe.

Pyrolysis boiler piping

The wiring diagram for a pyrolysis solid fuel boiler is not much different from the wiring diagram for a boiler with direct combustion of wood. Here it is necessary to focus on the type of heating system (open or closed, with natural or forced circulation), the presence of additional circuits (warm floors), as well as the presence of connected water heaters. In accordance with this, we are developing a strapping scheme based on the elements described above.

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Content

Heating units operating on various types of solid fuel differ significantly in operation from electric, gas and liquid fuel heat generators. In this regard, the connection of a solid fuel boiler has a number of features. Let's consider how to properly install a heating unit so that its operation is efficient and safe, as well as how to install a heating system with two boilers.

Solid fuel boiler in the heating system

Features of solid fuel boilers

The difference between a solid fuel heat generator and boilers operating on other energy sources is based on the combustion characteristics of wood, coal and other types of solid fuel.

1. Inertia. Solid fuel that has flared up in the combustion chamber cannot be quickly extinguished, so there is always a risk of overheating of the coolant. The boiling of water in the boiler jacket leads to an abrupt increase in pressure in the system and its depressurization. To avoid an emergency, an automatic valve designed to relieve pressure must be included in the piping of a solid fuel boiler.

Due to inertia, it is more difficult to control the heating of the coolant - after the thermostat is activated, the valve closes, reducing the air flow into the combustion chamber, but for some time combustion continues in the same mode and the temperature of the liquid in the circuit manages to rise by at least another 2-3 degrees before stabilizing.

Attention! The pellet boiler is deprived of such a disadvantage as high inertia, since the design provides for the supply of fuel into the combustion chamber in small portions. The cessation of supply leads to a rapid extinction of the flame.

2. Moisture condensation in the firebox. Condensation is formed if a very cool coolant with a temperature below 50 degrees enters the water jacket of the unit. Condensation is fraught with rapid corrosion of the metal from which the walls of the combustion chamber are made, since this moisture is an aggressive environment. In addition, condensate mixed with ash forms a sticky substance that is difficult to clean from the inside of the firebox.

The connection diagram of a solid fuel boiler should include a mixing unit, due to which the liquid heated by the boiler is mixed into the cooled return coolant.

Attention! Cast iron solid fuel boiler is resistant to corrosion and is not afraid of condensate. However, a mixing unit is also added to the piping of such a unit, since the flow of cooled coolant into the water jacket of a hot boiler can lead to the destruction of cast iron due to temperature shock.

Basic principles for connecting a solid fuel unit

When considering how to properly connect a solid fuel boiler, it is necessary to pay attention to the basic piping elements that ensure the safety of the heat generator. We are talking about the safety group and the mixing unit.

The safety group, which includes a pressure gauge, as well as a safety valve and an air vent, mounted on one manifold, is installed directly on the outlet pipe of the boiler unit. The pressure gauge helps monitor the pressure in the system, the air vent serves to remove air pockets, and the safety valve releases excess steam-water mixture when the pressure exceeds the specified parameters.

Important! It is prohibited to install a circulation pump or shut-off valves between the pipe and the safety group.

A mixing unit based on a three-way valve with a thermal head is installed together with a bypass (jumper) connecting the supply and return pipes, thereby forming a small circulation circuit.

The system that protects the boiler from condensation and temperature shock operates according to the following scheme:

While the fuel flares up, the valve blocks the flow of cooled coolant from the large heating circuit. As a result, the circulation pump circulates a limited volume of coolant in a small circle.
A sensor is installed on the return pipe, connected to the thermal head of a three-way valve. When the coolant in the return pipeline heats up to 50-55 degrees, the thermal head is activated and presses on the valve stem.
The valve smoothly opens slightly and the cooled coolant begins to gradually flow into the boiler jacket, mixing with the heated coolant from the bypass.
When all radiators warm up and the return temperature rises to values safe for the boiler, the three-way valve closes the bypass, completely opening the passage of coolant flow through the return pipeline.

The basic diagram for connecting a solid fuel boiler to the heating system is as simple and reliable as possible; you can install the piping yourself.

It is important to know how to connect a solid fuel boiler using polymer pipes to avoid common problems:

It is unsafe to use polymer pipes for piping a boiler - they may not withstand an emergency increase in temperature and pressure. Therefore, it is recommended to make the piping with steel or copper, and connect the polymer pipes to the manifold that distributes the coolant through the heating circuits. As a last resort, a metal pipe is installed only between the boiler supply pipe and the safety group.
The use of a thick-walled polypropylene pipe for the return pipeline in the area between the three-way valve and the boiler nozzle leads to the fact that the overhead temperature sensor reacts to the heating of the coolant with a noticeable delay. It is better to install a metal pipe.

Connecting a solid fuel installation with a hydraulic boom

The pump for a heating system with forced supply of coolant is installed on the return pipe between the three-way valve and the boiler. This arrangement allows it to circulate water or antifreeze in a small circle. It is impossible to install the circulation pump on the supply pipe, since the device is not designed to work with a steam-water mixture that is formed when the coolant overheats. Stopping the pump will speed up or provoke an explosion of the heating boiler, since cooled coolant will no longer flow into it.

How to reduce the cost of harness

The basic connection diagram for a solid fuel boiler involves the use of a three-way mixing valve equipped with a thermal head and an overhead sensor. This equipment is quite expensive, and it can be replaced with a cheaper option - a three-way valve with a built-in thermostatic element. This device has a fixed setting - the valve is activated when the ambient temperature reaches 55 or 60 degrees (depending on the model).

Installing a valve that maintains a fixed temperature reduces the financial costs of installing protection for a solid fuel unit from condensation and thermal extremes. The ability to flexibly control the temperature of the coolant is lost; deviations from the set value can reach 1-2 degrees, but this is not critical.

Connection with heat accumulator

In order for the solid fuel unit to operate in optimal mode and its efficiency to approach the rated values, it is necessary to use a buffer tank, which serves as an accumulator of excess thermal energy remaining after heating the coolant in the heating circuit to operating temperatures.

If a wood or coal boiler operates without a heat accumulator, the draft must be reduced so that the wood does not burn too hot and the coolant does not overheat. But due to a lack of oxygen, an increased amount of carbon monoxide is formed, which enters the atmosphere. In advanced European countries, for this reason, it is prohibited to operate solid fuel heaters without installing a buffer tank.

Installing a heat accumulator has one more advantage: the fuel, which burns with an optimal supply of oxygen, releases maximum thermal energy, and its excess does not fly away into the chimney, but accumulates in a buffer tank. This allows you to maintain a high temperature of the coolant in the heating circuit for several hours after the fuel has burned out.

Connecting a solid fuel boiler to a heat accumulator involves connecting a buffer tank as follows:

Wiring diagram for a heat accumulator with a solid fuel boiler

To control the temperature of the coolant supplied to the radiators, a second and second circulation pump is installed on the supply line after the heat storage tank connected to the system.

The cooling time of the coolant in a system with a heat accumulator after the boiler is extinguished depends on the volume of the reservoir and the heating temperature. For a private house with an area of 150-200 sq. m requires a buffer tank with a volume of 1 cubic meter. m. You can purchase a ready-made heat accumulator of a suitable volume or make it yourself - it is a rectangular or cylindrical container made of steel sheet, equipped with reliable thermal insulation.

Important! The installation of a heat accumulator should be provided for at the design stage of the heating system. In order for the boiler to simultaneously heat water in the heating circuit, the DHW system and in, its power must be twice the design power.

Installation with electric or gas unit

Two heat generators can be installed in one heating system, the main one is a solid fuel unit, and the additional one is a boiler running on gas or electricity. This option is convenient because at night you can turn on the boiler, which operates in automatic mode. Gas in cylinders is inconvenient to use as the main energy carrier due to the need to take care of regular fuel supplies. Electricity is the most expensive energy source and it is most profitable to operate such a boiler unit only at night if the region has a system of cheap night tariffs.

How to connect solid fuel and gas boilers into one heating system for a large house? The simplest option is to connect two heat generators in parallel through a heat accumulator, which will additionally serve as a hydraulic separator.

The gas boiler operates in standby mode while the water in the buffer tank is heated by the solid fuel unit. After the fuel burns out, the coolant begins to cool, and as soon as the temperature sensor transmits the corresponding signal to the gas unit controller, it automatically turns on. When a solid fuel heat generator is restarted, the reverse process occurs - heating the coolant above a certain temperature leads to the gas burner turning off.

A system with an electric boiler in large houses is installed according to a similar principle. But for small private houses, a simpler and cheaper option for connecting a TT and an electric boiler is relevant (see diagram).

Connection diagram for solid fuel boiler and electric boiler

Boiler units are connected in parallel with the installation of check valves at each outlet. The electric boiler is equipped with a built-in circulation pump, which cannot be turned off, so for a solid fuel heat generator it is necessary to select a more powerful pump so that the TT boiler has an advantage over the electric one when operating together.

The system is being supplemented:

a thermostat that turns off the boiler’s TT circulation pump when the coolant cools down;
a room temperature sensor, which turns on the electric boiler when the room temperature drops after the fuel burns out in the TT unit.

Method of primary and secondary rings

How to connect two boilers into one system using a minimum amount of electronics? The use of the method of primary and secondary circulation rings allows for joint piping of the CT of the unit and the electric boiler. Hydraulic separation of flows is carried out without installing a hydraulic arrow.

Option for connecting two types of boilers to one heating system

Both boilers, the DHW boiler, as well as all heating circuits, are connected by both supply and return pipelines to a single circulation ring - they are the primary one. The minimum pressure drop is ensured by the small distance between each pair of connections (no more than 300 mm). The pressure of the pump installed on the main circuit ensures the movement of the coolant along the primary ring, while the flow intensity is not affected by the pumps of the secondary circuits (to which heat consumers are connected).

In order for the system to function properly, it is necessary to perform complex hydraulic calculations and select the optimal pipeline diameter for all circuits. It is also important to calculate the pump performance. The actual performance of the pumping unit on the main circuit must exceed the coolant flow rate on the “volumetric” secondary circuit itself. Both boilers are equipped with shut-off thermostats so that they can operate instead of each other.

Conclusion

Before proceeding with the independent installation of the solid fuel boiler piping, it is recommended to contact professionals who will perform a competent calculation of the system and give advice on the correct arrangement of its elements. The connection diagram must ensure the safe operation of the solid fuel boiler and create optimal conditions for efficient fuel consumption.

The wiring diagram for a solid fuel boiler refers to the entire set of necessary devices and elements that together form a single heating system for the house. It includes the boiler itself, heating devices (radiators, heated towel rails, heated floors), control and automation devices, shut-off and control valves, pipelines, etc. Choosing the optimal connection diagram and following the basic rules when installing the boiler are the key to reliable and safe operation of the heating device throughout its entire service life.

When installing any boiler TT piping circuit yourself, a number of mandatory requirements must be met.

Mini boiler room with solid fuel floor boiler

Installation requirements:

The operating temperature and pressure of the heat-carrying liquid at the outlet of the boiler should not exceed the values established for them, for which the use of special automatic protective devices and emergency connection circuits is provided.
The temperature difference between the coolant at the boiler outlet and inlet should not exceed 20 degrees. This is necessary to prevent the formation of condensing moisture inside its housing, which especially important for steel boilers.
It is advisable to include automatic devices in the boiler piping scheme that allow you to regulate its power and maintain the optimal temperature of the coolant. You also need to include devices to increase its efficiency and versatility (storage tanks for hot water, etc.).

It should be noted that compliance with these requirements is much more convenient to implement in forced circulation circuits, which is why they are most widespread among owners of home boiler rooms.

In this article:

Basic strapping patterns

Depending on the number of boiler circuits, the type of heating system and the need to connect additional devices, the piping circuit of a solid fuel boiler can have many options.

Let's look at the most common methods of connecting TT boilers.

To an open type system with natural circulation

This scheme considered the easiest to implement, since it contains a minimum number of connected devices. Its main advantage is its complete independence from the availability of power in the house.

Disadvantage: it is impossible to regulate the temperature of the coolant at the outlet of the boiler and the entry of oxygen into the coolant from the open expansion tank. This can cause accelerated corrosion of the inner surface of metal heating pipes and steel boilers.

Piping diagram for an open system with natural circulation

It requires special installation rules:

the heating boiler must be located at least 0.5 m below the installation level of heating radiators (to create stable natural coolant circulation);
the pipes must be located at a slope in the direction of coolant circulation and have a sufficiently large diameter to reduce their hydraulic resistance;
the open type expansion tank should be located at the highest point of the system;
In the heating system, it is desirable to use a minimum number of shut-off valves and control devices that reduce the flow area of pipelines.

About the natural heating system.

Towards a closed system with natural circulation

This scheme uses a closed-type membrane tank, which is usually installed on the return line of the heating system. Its capacity must be at least 10% of the total volume of coolant used in the heating system.

Piping the boiler to a closed system with natural circulation

With this scheme for connecting the boiler at the outlet of its supply pipe must be present an air vent and a pressure relief valve, which is connected by a drain hose to the sewer.

These devices can be installed separately or included in the so-called TT boiler safety group, which is a separate device.

It includes:

pressure gauge for visual control;
safety valve for pressure relief;
air bleed valve to bleed air from the system.

In some models of solid fuel boilers, these safety elements are already built into the boiler body.

To a forced circulation system

Here for forced circulation of heat-carrying fluid through the pipelines of the heating system. The pump is usually installed on the return coolant supply line between the boiler inlet pipe and the membrane tank.

The operation of the pump is controlled by a temperature sensor mounted on the return line.

Connecting the boiler to a forced circulation system

The use of pumps for forced circulation significantly increases the efficiency of the system through the use of various temperature control equipment. However, for its operation it is necessary to connect to a household power supply, which increases energy consumption and makes the system energy dependent on an uninterrupted power supply.

Collector connection method

The collector method of connecting a solid fuel boiler is used in forced circulation systems and involves the inclusion of special devices in the piping circuit - collectors, also called combs.

They are sections of larger diameter pipes with one inlet and several outlets, connected to the inlet and outlet of the boiler.

Piping the boiler heat exchanger with the manifold system

Advantage of the scheme:

possibility of separate connection of each heating device. This allows you to supply them with coolant of the same temperature and pressure, as well as more efficiently control their operation.

Flaw:

high consumption of pipes and the complexity of their installation during installation of the system.

This is a special type of piping using the so-called hydraulic arrow, which is a large diameter pipe installed vertically, connected to the inlet and outlet of the boiler.

Heating devices can be connected to the inputs and outputs of the hydraulic arrow at different heights.

This method of connecting heating devices allows you to select the optimal coolant temperature at the inlet and outlet for each of them.

To a system with an indirect hot water boiler

Piping a solid fuel boiler according to this scheme can be used in systems with any type of coolant circulation.

Connection to a system with a DHW boiler

The output supply line of the boiler is connected in parallel to heating radiators and a heat exchanger (coil), built into a separate thermally insulated container (boiler), in which water is heated for the DHW system. This expands the functionality of the TT boiler, allowing it to additionally provide hot water to the home during its operation.

An automatic valve can be installed at the entrance to the DHW heat exchanger, shutting off the supply of coolant to it when the water in the boiler is heated as necessary.

To a system with a heat accumulator

This connection diagram can be used in systems with any type of coolant circulation.

During the tying process, two circulation circuits are formed:

between the boiler and the heat accumulator (TA);
between the heating unit and the main heating system.

Connecting a solid fuel boiler with a heat accumulator

During operation of the boiler, the hot coolant enters the TA, which is a separate storage tank with a thermally insulated body. The heat exchanger gradually accumulates the heat generated by the boiler and, if necessary, transfers it to the heating system for heating devices.

After the boiler stops (fuel combustion stops), the hot coolant stored in the heat exchanger continues to flow into the system for some time, depending on the internal volume of the heat exchanger.

This connection scheme can significantly increase the boiler efficiency and reduce fuel consumption, and is also an effective means of protecting the boiler and all system elements from overheating.

Connecting emergency systems

Elements of emergency systems in the wiring diagram are used for the following purposes:

protection against increasing the maximum operating pressure in the system;
protection against exceeding the maximum permissible output temperature of the coolant, overheating of the boiler and heating system elements;
preventing the formation of condensation in the boiler due to a large temperature difference of the coolant at the inlet and outlet of the device.

Safety valve

Protection of the boiler and system elements when the operating pressure of the heat-carrying liquid is exceeded is provided by a safety valve installed on the supply line at the outlet of the boiler. Such a valve can be part of a boiler safety group, which is built into the boiler itself or connected separately.

How does a safety valve work?

A drain hose is connected to the pressure relief port of the valve. When the valve is activated, excess heat-carrying liquid from the system is drained into the sewer through a hose.

Emergency heat exchanger

An emergency heat exchanger is needed to protect the boiler and system elements from overheating.

Equipment overheating can occur in two cases:

when the power generated by the boiler exceeds that required for heat consumers;
when the circulation pump stops working due to its breakdown or power outage.

The heat exchanger consists of a cooling module and a thermal valve with a remote thermal sensor set to a certain temperature. They can be installed inside the boiler itself or separately on the coolant supply line to the heating system.

How does a heat exchanger work?

When the permissible temperature is exceeded, the thermal valve is activated by a signal from the thermal sensor.

It supplies cold water from the water supply line to the cooling module, in which excess heat is removed from the coolant. From the cooling module, the water that has removed the heat goes into the sewer system.

Additional circuit

Protection of the boiler from overheating in systems with forced circulation can also be ensured using an additional circuit with natural circulation, to which a storage tank for hot water is connected.

Boiler piping with an additional circuit

During normal operation of the system, the pressure created by the circulation pump in the main circuit closes the additional circuit using a check valve, preventing the heat-carrying fluid from circulating in it.

When the pump is turned off for any reason, the forced circulation of the coolant in the main circuit stops and natural circulation begins in the additional circuit. Due to this, the heat-carrying liquid in the system is cooled to the required temperature.

Thermostatic mixer

Maintaining the minimum required temperature at the boiler inlet to prevent the formation of condensation in it is ensured by a thermostatic mixer.

The device is installed on the return pipeline and connected to the supply line using a jumper (bypass).

Installation of a thermostatic mixer

When the temperature of the coolant in the return line is low, the thermal mixer opens and mixes hot liquid into it. After reaching the desired temperature, the thermal mixer closes and stops supplying hot coolant through the bypass to the return.

This scheme can be used in systems with any type of circulation.

Can it be made from improvised materials?

What is the advantage of double-circuit solid fuel heating boilers over similar devices with a single circuit. How can you use an additional circuit to increase the power of the boiler? available via the link.

Unlike electric and gas heating units, solid fuel boilers are almost never equipped with circulation pumps, a safety group, or adjustment and control devices. Everyone solves these issues independently, choosing a heating device piping scheme in accordance with the type and features of the heating system. Not only the efficiency and performance of heating, but also its reliable, trouble-free operation depends on how correctly the heat generator is installed. That is why it is important to include in the diagram components and devices that will ensure the durability of the heating unit and its protection in the event of emergency situations.

In addition, when installing a solid fuel boiler, you should not give up equipment that creates additional convenience and comfort. you can solve the problem of temperature differences when rebooting the boiler, and an indirect heating boiler will provide the house with hot water. Have you thought about connecting a solid fuel heating unit according to all the rules? We will help you with this!

Typical piping schemes for solid fuel boilers

The opinion that a solid fuel boiler is an obsolete unit covered with dirt and soot is wrong, isn’t it?

The complexity of controlling the combustion process in solid fuel boilers leads to high inertia of the heating system, which negatively affects the convenience and safety during operation. The situation is further complicated by the fact that the efficiency of units of this type directly depends on the temperature of the coolant. For efficient heating operation, the piping must ensure the temperature of the thermal agent is within 60 - 65 ° C. Of course, if the equipment is not integrated correctly, such heating at above-zero temperatures “overboard” will be very uncomfortable and uneconomical. In addition, the full operation of the heat generator depends on a number of additional factors - the type of heating system, the number of circuits, the presence of additional energy consumers, etc. The ones presented below take into account the most common cases. If none of them meets your requirements, then knowledge of the principles and structural features of heating systems will help in developing an individual project.

Open type system with natural circulation in a private house

First of all, it should be noted that open gravity-type systems are considered the most suitable for solid fuel boilers. This is due to the fact that even in emergency cases associated with a sharp increase in temperature and pressure, the heating will most likely remain sealed and operational. It is also important that the functionality of the heating equipment does not depend on the availability of power. Considering that wood-burning boilers are installed not in megacities, but in areas remote from the benefits of civilization, this factor will not seem so insignificant to you. Of course, this scheme is not without its drawbacks, the main ones being:

free access of oxygen to the system, which causes internal corrosion of pipes;
the need to replenish the coolant level due to its evaporation;
uneven temperature of the thermal agent at the beginning and end of each circuit.

A layer of any mineral oil 1–2 cm thick, poured into the expansion tank, will prevent oxygen from entering the coolant and reduce the rate of evaporation of the liquid.

Despite its shortcomings, the gravity scheme is very popular due to its simplicity, reliability and low cost.

Installation diagram of a solid fuel unit in an open heating system

When deciding to install using this method, keep in mind that for normal coolant circulation, the boiler inlet must be at least 0.5 m below the heating radiators. The supply and return pipes must have slopes for normal coolant circulation. In addition, it is important to correctly calculate the hydrodynamic resistance of all branches of the system, and during the design process try to reduce the number of shut-off and control valves. The correct operation of the system with natural coolant circulation also depends on the installation location of the expansion tank - it must be connected at the highest point.

Closed system with natural circulation

Installation on the return line will avoid the harmful effects of oxygen and eliminate the need to control the coolant level.

Diaphragm expansion tank design

When deciding to equip a gravity system with a sealed expansion tank, consider the following points:

the capacity of the membrane tank must contain at least 10% of the volume of the entire coolant;
a safety valve must be installed on the supply pipe;
the highest point of the system must be equipped with an air vent.

Additional devices that are included in the boiler safety group (safety valve and air vent) will have to be purchased separately - manufacturers very rarely equip units with such devices.

The safety valve allows the coolant to be discharged if the pressure in the system exceeds a critical value. The normal working indicator is considered to be a pressure from 1.5 to 2 atm. The emergency valve is set to 3 atm.

Learn more about this system from our next article:.

Features of systems with forced coolant movement

In order to equalize the temperature in all areas, a circulation pump is integrated into the closed heating system. Since this unit can provide forced movement of the coolant, the requirements for the level of installation of the boiler and compliance with slopes become negligible. However, you should not give up the autonomy of natural heating. If a bypass branch is installed at the outlet of the boiler, then in the event of a power outage, the circulation of the thermal agent will be ensured by gravitational forces.

The use of a bypass will allow, if necessary, to switch to the natural method of coolant circulation

The electric pump is installed on the return line, between the expansion tank and the inlet fitting. Thanks to the lower coolant temperature, the pump operates in a more gentle mode, which increases its durability.

Video: Tying a solid fuel boiler

Correct installation of a solid fuel boiler in a closed heating system

A huge advantage of solid fuel boilers is that their installation does not require any permits. It is quite possible to carry out the installation yourself, especially since this does not require any special tools or special knowledge. The main thing is to approach the work responsibly and follow the order of all stages.

Boiler room arrangement

The disadvantage of heating units used to burn wood and coal is the need for a special, well-ventilated room. Of course, it would be possible to install a boiler in the kitchen or bathroom, however, periodic emissions of smoke and soot, dirt from fuel and combustion products make this idea unsuitable for implementation. In addition, installing burning equipment in living rooms is also unsafe - the release of fumes can lead to tragedy.

A solid fuel boiler is best installed outside residential premises

When installing a heat generator in a boiler room, several rules are followed:

the distance from the combustion door to the wall must be at least 1 m;
ventilation ducts must be installed at a distance no higher than 50 cm from the floor and no lower than 40 cm from the ceiling;
There should be no fuel, lubricants or flammable substances and objects in the room;
The base area in front of the ash pit is protected with a metal sheet measuring at least 0.5 x 0.7 m.

In addition, at the location where the boiler is installed, an opening is provided for the chimney, which is led outside. Manufacturers indicate the configuration and dimensions of the chimney in the technical data sheet, so there is no need to invent anything. Of course, if the need arises, you can deviate from the documentation requirements, but in any case, the channel for removing combustion products must provide excellent traction in any weather.

How to properly install a chimney

When installing a chimney, all connections and cracks are sealed with sealing materials, and windows are also provided for cleaning the channels from soot and a condensate catcher.

Preparing to install a heating unit

Before installing the boiler, select a piping scheme, calculate the length and diameter of the pipelines, the number of radiators, the type and quantity of additional equipment and shut-off and control valves.

Despite all the variety of design solutions, experts recommend choosing combined heating, which can also provide natural circulation of the coolant. Therefore, when making calculations, it is necessary to consider how a parallel section of the supply pipeline (bypass) with a centrifugal pump will be installed and to provide for the slopes necessary for the operation of the gravity system. You shouldn’t give up on buffer capacity either. Of course, its installation will entail additional costs. However, a storage tank of this type will be able to level out the temperature curve, and one load of fuel will last for a longer time.

Connecting the boiler to a heating system with a dual-purpose buffer tank

Particular comfort will be provided by a heat accumulator with an additional circuit, which is used for hot water supply. Considering the fact that due to the installation of a solid fuel unit in a separate room, the length of the hot water circuit increases significantly, an additional circulation pump is installed on it. This will eliminate the need to drain cold water while waiting for hot water to flow.

Before installing the boiler, it is imperative to provide a place and do not forget about devices designed to reduce pressure in the system in critical situations. A simple strapping diagram that can be used as a working design is shown in our drawing. It combines all the equipment discussed above and ensures its correct and trouble-free operation.

You will learn even more information about the arrangement of the boiler room and installation of equipment from our article:.

Installation and connection of a solid fuel heat generator

After carrying out all the necessary calculations and preparing the equipment and materials, installation begins.

The heating unit is installed in place, leveled and secured, after which the chimney is connected to it.
Heating radiators are mounted, a heat accumulator and an expansion tank are installed.
A supply pipeline and a bypass are installed, on which a centrifugal pump is installed. Ball valves are installed in both sections (direct and bypass) so that the coolant can be transported by forced or natural means.
We remind you that the centrifugal pump can only be installed with the correct orientation of the shaft, which must be in a horizontal plane. The manufacturer indicates diagrams of all possible installation options in the product instructions.
The pressure line is connected to the heat accumulator. It must be said that both the inlet and outlet pipes of the buffer tank must be installed in its upper part. Thanks to this, the amount of warm water in the container will not affect the readiness of the heating circuit. We definitely note the fact that cooling the boiler during the reboot period will reduce the temperature in the system. This is due to the fact that at this time the heat generator will work as an air heat exchanger, transferring heat from the heating system to the chimney. To eliminate this shortcoming, separate circulation pumps are installed in the boiler and heating circuits. By placing a thermocouple in the combustion zone, you can stop the movement of coolant through the boiler circuit when the fire dies out.
Installing separate pumps on the boiler and heat exchange circuits can solve the problem of heat leakage through the boiler when it cools down
A safety valve and an air vent are installed on the supply line.
Connect the emergency circuit of the boiler or install shut-off and control valves, which, when the water boils, will open the main line for its discharge into the sewer and the channel for supplying cold liquid from the water supply.
Install a return pipeline from the heat accumulator to the heating unit. A circulation pump, a three-way valve and a settling filter are installed in front of the boiler inlet pipe.
An expansion tank is mounted separately on the return pipeline.
Note! Shut-off valves are not installed on pipelines that are connected to protection devices. These areas should have as few connections as possible.
The upper outlet of the heat storage tank is connected to a three-way valve and the circulation pump of the heating circuit, after which the radiators are connected and the return pipeline is installed.
After connecting the main circuits, they begin to install a hot water supply system. If the heat exchanger coil is built into a buffer tank, then it will be enough to simply connect the cold water inlet and the outlet to the “hot” line to the corresponding pipes. When installing a separate indirect heating water heater, use a circuit with an additional circulation pump or three-way valve. In both cases, a check valve is installed at the cold water supply inlet. It will block the path for heated liquid into the “cold” water supply.
Some solid fuel boilers are equipped with a draft regulator, the function of which is to reduce the flow area of the blower. Due to this, the air flow into the combustion zone is reduced and its intensity, and, accordingly, the temperature of the coolant is reduced. If the heating unit has this design, then install and adjust the drive of the air damper mechanism.
Installing an automatic draft regulator will allow you to control the fuel combustion process

The places of all threaded connections must be carefully sealed using plumbing flax and a special non-drying paste.

After installation is completed, coolant is poured into the system, centrifugal pumps are turned on at full power and all connections are carefully inspected for leaks. After making sure that there are no leaks, fire up the boiler and check the operation of all circuits at maximum modes.

Features of integrating a solid fuel unit into an open heating system

The main feature of open heating systems is the contact of the coolant with atmospheric air, which occurs with the participation of an expansion tank. This container is designed to compensate for the thermal expansion of the coolant that occurs when it is heated. The expander is installed at the highest point of the system, and in order to prevent hot liquid from flooding the room when the tank is overfilled, a drain tube is connected to its upper part, the other end of which is discharged into the sewer.

Open type expansion tank design

The large volume of the tank forces it to be installed in the attic, so additional insulation of the expander and the pipes suitable for it will be required, otherwise they may freeze in winter. In addition, you must remember that this element is part of the heating system, so its heat losses will lead to a decrease in the temperature in the radiators.

Since the open system is not sealed, there is no need to install a safety valve or connect emergency circuits. When the coolant boils, the pressure will be released through the expansion tank.

Special attention should be paid to pipelines. Since the water in them will flow by gravity, the circulation will be influenced by the diameter of the pipes and the hydraulic resistance in the system. The last factor depends on turns, narrowings, level changes, etc., so their number should be minimal. In order to initially impart the necessary potential energy to the water flow, a vertical riser is installed at the outlet of the boiler. The higher the water can rise along it, the higher the coolant speed will be and the faster the radiators will warm up. For the same purposes, the return inlet should be located at the lowest point of the heating system.

Finally, I would like to note that in open systems it is preferable to use water rather than antifreeze. This is due to higher viscosity, reduced heat capacity and rapid aging of the substance upon contact with air. As for the water, it is best to soften it and, if possible, never drain it. This will increase the service life of pipelines, radiators, heat generators and other heating equipment several times.

Pay attention to the article on choosing coolants for heating systems:.

Video: Connecting a solid fuel boiler with your own hands

As you can see, the choice of boiler integration scheme depends on many factors, including the features of the heating system and the need to install additional equipment. If you have successfully understood all the nuances, then you can safely get to work. Finally, I would like to note that heating is one of the most complex and critical engineering systems. If you don't have confidence in your own abilities, don't experiment. Remember that installation errors will sooner or later result in serious problems, so do not hesitate to ask specialists for advice.

Any modern solid fuel boiler is characterized by high efficiency, and therefore with its help you can maintain the temperature in the room at the desired level and save on energy consumption. However, achieving maximum heat transfer from the heating circuit in the house and achieving the efficiency of the heating system as a whole will only be possible through the correct piping of a solid fuel heating boiler. The strapping pattern may be different. The choice is based on the financial capabilities of the owner of the house or apartment, and the geometry of the premises itself.

What is the correct heating scheme with a solid fuel boiler?

This is how heaters using wood, coal, briquettes or pellets are connected.

The heating circuit of a private house with a solid fuel boiler is a combination of heating elements, additional devices to the boiler and heating circuit, structural units of the wiring itself, which together form the house heating system with its operating characteristics. A complete heating system includes a boiler, heating elements (radiators, pipes, heated towel rails, etc.), control and safety devices, an expansion tank, etc. A correctly executed circuit is a heating circuit that complies with modern state standards and regulations.

List of basic state standards according to which the installation of solid fuel heating boilers in a private home is carried out:

state building standards and basic regulations on residential buildings from 2005;
state standard on devices operating on solid fuel from 1995;
state standard, which describes heating elements with a capacity of 100 kW (1993);
building regulations on heating and air conditioning systems for residential buildings (1991);
construction standards on motor ship networks.

Anyone who intends to connect solid fuel boilers to the heating system on their own must familiarize themselves with the above documents and adhere to the standards specified in them during the work.

The ideal option is to rely on specialists. They not only know all the necessary requirements for successful installation of the system, but also have relevant experience in this matter. They will do everything in the best possible way.

Basic wiring diagrams for a solid fuel boiler

The drawing according to which the heating will be made depends on the number of circuits of the heating element itself, the geometry and area of the room where the circuit will be located, and the presence of additional and auxiliary devices.

Heating with solid fuel boiler, circuit diagram:

open with gravity circulation;
closed with natural circulation;
closed with forced circulation;
collector type.

Regardless of which connection diagram for a solid fuel heating boiler is chosen, the circuit must be organized correctly. The temperature delta of water at the inlet and outlet of the system should not exceed +20 degrees. Otherwise, side effects will occur. Condensation forms on the heat exchanger, which leads to corrosion of the latter.

Open circuit with gravitational coolant circulation"> Open circuit with gravitational coolant circulation

This is the easiest way to tie, which you can do yourself. In this case, the movement of coolant through the system occurs due to the difference in density of cold and hot water. The heated coolant flows upward, since its density is low. As it cools, the density of the liquid increases, and therefore the coolant sinks down.

Gravity circuit with open expansion tank.

This installation scheme for a solid fuel heating boiler requires compliance with a number of rules. So, for complete circulation of the coolant in the system, the heating equipment must be installed below the level of the radiators by at least 0.5 m, and the expansion tank must be located at the highest point of the circuit. To reduce the hydraulic resistance of the system, choose pipes with a diameter of up to 50 mm (for distribution pipes to radiators, a pipe diameter of up to 25 mm is sufficient). A large number of locking devices and fittings significantly impair the circulation of the coolant, and therefore their number should be kept to a minimum.

The heating scheme for a private house with an open-type solid fuel boiler with natural circulation has a significant advantage in its simplicity and low cost. However, here it is impossible to control the coolant temperature at the boiler outlet, which generally reduces the efficiency of the circuit. Through oxygen enters the coolant. It leads to corrosion of the heating circuit itself and the boiler heat exchanger. A similar heating scheme with a solid fuel boiler, in particular, can be considered as a budget option for a house that is visited from time to time.

Closed heating system with natural circulation"> Closed heating system with natural circulation

If you need an inexpensive but high-quality piping for a solid fuel heating boiler, the diagram indicated above is the best option. A closed gravity system works due to the difference in density between hot and cold water. Due to its simplicity, the circuit is inexpensive to install and subsequently maintain, and is durable. The closed safety tank prevents free oxygen from entering inside. As a result, pipes, radiators and the boiler heat exchanger are less susceptible to corrosion.

Gravity circuit with sealed expansion chamber.

In addition to the main heating element (boiler), expansion tank, membrane tank, there is “ ", which makes home heating efficient and safe with a solid fuel boiler. The circuit is complemented by a pressure gauge (pressure control inside the circuit) and a safety valve (pressure is released through it).

Disadvantages: it is impossible to control the temperature of the coolant at the outlet, the heating efficiency as a whole decreases, since the coolant moves naturally.

Closed system plus circulation pump"> Closed system plus circulation pump

Such an installation of solid fuel heating boilers in a private home is considered energy efficient and cost-effective. Here the efficiency of the circuit increases due to the high heat transfer of the coolant. The volume of water in the system decreases, which reduces energy consumption for heating it. In a closed system with forced circulation, there is no need to install large-diameter pipes, since hydraulic resistance to the coolant helps overcome the circulation pump. Important The coolant itself does not evaporate. After all, a sealed membrane tank is installed in the system. The closed piping of a solid fuel heating boiler prevents the formation of corrosion inside the system, which prolongs its service life.

A circuit in which the coolant does not come into contact with air.

The disadvantages include energy dependence (when the electricity is turned off, the circulation pump stops working) and expensive installation, as only a specialist can correctly connect a solid fuel boiler to a closed-type heating system, and you need to pay for his services.

A characteristic feature of the closed-type piping is the circulation pump. It forces the coolant to move through the system, thereby increasing the heat transfer of heating pipes and radiators. The operation of the pump is controlled by a temperature sensor. The pump is always installed on the pipe through which the cooled coolant returns to the boiler. In this case, the service life of the equipment is significantly extended. The installation of a solid fuel boiler and a heating system with forced circulation of the coolant is carried out in houses and apartments that are constantly used.

Collector circuit"> Collector circuit

It is difficult for an unprepared person to independently perform the collector connection of a solid fuel heating boiler, and therefore the services of a specialist are necessary here. However, this method of heating a house is considered energy efficient. Everything is explained simply: each radiator or any other device for transferring heat from the coolant to the air in the room is connected to the circuit individually through the collector. The last device plays the role of a kind of coolant distributor and has the form of a large diameter pipe, from which there are exits to each battery in the house.

The collector wiring is very convenient and practical.

Do not know how a collector heating system is installed on a solid fuel boiler? The scheme is quite complicated for a person without the appropriate education and experience. That is why the services of a specialist are simply necessary here.

The advantage of collector wiring is that it can be used to control the temperature of each radiator in the house. After all, the batteries are connected individually. This is convenient if one of the heating devices breaks down. To replace it, you do not need to completely turn off the heating in the house. On the other hand, if one of the rooms in the house is not used, it can not be heated at all, blocking the flow of coolant. to each battery is performed under a rough floor screed, which improves the aesthetic characteristics of the interior and additionally heats the floor. The collector system allows you to create several circuits in the house with different temperature conditions, since you can connect a solid fuel heating boiler using a hydraulic arrow.

Selecting a connection diagram for a solid fuel heating device

When organizing a heating system at home, it is not enough to have a drawing of a solid fuel heating boiler in front of you. In this case, you need to decide on the type of heating circuit for the house. To solve the problem, experts today offer several options. These are open and closed wiring with forced and natural circulation. The open contour is suitable for a summer house or holiday home. Forced circulation will help maintain the air temperature at the desired level in ordinary residential buildings, while allowing significant savings on energy consumption. Collector wiring is a new type of home heating that allows you to create your own temperature regime in each individual room. However, if you don’t know how to connect a solid fuel heating boiler to the collector circuit, trust the work only to specialists, because the wiring itself is difficult to perform.

If you have questions about how to install a solid fuel heating boiler, the video below will help you understand some aspects of the job.