Condensing boiler: subtleties of installation and operation. The principle of operation of a condensing heating boiler: an overview of the main manufacturers Installation of condensing heating boilers

E. Chernyak

In order for the consumer to remember the boiler only during the scheduled maintenance, it is not enough just to choose high-quality and reliable equipment. It is important to mount it correctly, because often an illiterate installation leads to equipment failure and the prohibition of its delivery for warranty service. This is especially true when installing expensive condensing technology.

General principles

The key to the correct installation of the boiler and its further normal operation is the competent design of the entire heating system. It is that, for example, significant efficiency and comfort of equipment operation cannot be achieved without installing thermostats. Modern technologies allow you to create zonal heating systems. In this case, each heating zone under the control of a room temperature sensor maintains its own microclimate.

The temperature of the condensing heat exchanger must be below the dew point of the exhaust gases, and the formation of reactive liquid condensate on its surface is not only normal, but also necessary. Moreover, it must be taken out in one way or another and neutralized. Flue gas systems must be made of corrosion-resistant materials.

When installing systems with condensing boilers, it is important to accurately calculate the heat loss of the building and design heating taking into account the use of such equipment.

To reduce the required temperature of the coolant, additional measures to reduce heat loss are important - thermal insulation of enclosing structures, installation of windows with multilayer glazing.

Place for the boiler

Guided by regulatory documents, a suitable room is determined. At the same time, options with the installation of a boiler in bedrooms, bathrooms, corridors are not accepted in advance. common use, rooms with insufficient ceiling height, small volume and lack of windows (transoms, vents). The most suitable places are a kitchen or a separate non-residential premises of sufficient volume with opening windows or vents (Fig. 2). Indoor sewerage is highly recommended.

Rice. 2. The boiler room must have opening windows

When hanging the boiler on the wall, the hooks included in the delivery set are usually used. They are fixed to the wall with dowels. Then the unit itself is hung on these hooks. Unacceptable if top edge At the same time, the boiler is at a greater distance from the wall than the lower one, that is, in the common folk way, it is “overwhelmed”. For a traditional boiler, a forward roll of 0.5-1.0 cm per 1 m does not pose a significant danger, but in the case of a condensing boiler, the situation is different. After all, the condensation module is rigidly fixed to the frame. During the operation of the boiler, condensation of water vapor from the combustion products occurs in the secondary chamber of the module (economizer section). The resulting condensate is collected in a molded pallet and discharged first into a siphon and then into the sewer (Fig. 3).

Rice. 3. Formation and drainage of condensate from the condensing boiler module

When the boiler top rolls forward, the condensate overflows into the primary chamber, comes into contact with the heat exchanger tubes and begins to evaporate intensively. This leads to a short circuit of the flame control electrodes to the boiler body and its blocking.

Therefore, when attaching the boiler to standard hooks, the verticality of the boiler must be carefully checked and, if necessary, leveled. Tilting the boiler forward is not permissible. Also, the boiler is not allowed to deviate to the side.

Deviations from the vertical position are checked using a level gauge.

Chimney requirements

Most errors in the installation of condensing boilers are due to a violation of the manufacturer's recommendations or neglect of the smoke removal standards.

Often there are violations due to the use of coaxial pipes or separate sets from traditional boilers. The materials for the manufacture of coaxial pipes for traditional boilers are aluminum alloys and steel. Their purpose is to withstand high temperatures of the exhaust of combustion products (110 ° C and above). The specificity of the operation of condensing boilers is low flue gas temperatures in normal modes (40 - 90 ° С), while often below the dew point temperature (57 - 60 ° С, depending on the excess air ratio). Condensation of water vapor from combustion products occurs not only in the boiler module, but also in the chimney. The condensate has a low acidity at pH = 4, but with prolonged exposure to aluminum or steel chimney channels, it can destroy them. Therefore, the chimneys of condensing boilers along the exhaust path are made of special polymers (for example, polypropylene) that are resistant to acid corrosion of condensate and can withstand temperatures up to 120 ° C. For example, the company Baxi (Italy) supplies for its condensing boilers (Fig. 4), the efficiency of which is 108.9%, a plastic coaxial pipe with a tip 60/100 mm in diameter, 750 mm long. The delivery set includes: coupling and gasket; a tip that protects against gusts of wind; decorative stainless steel overlay on the outside of the wall.

Rice. 4. Wall hung gas condensing boiler

The use of chimney kits from traditional boilers on condensing boilers and vice versa is prohibited.

There are also violations due to use sewer pipes as chimneys. Due to the rather high cost of special chimneys for condensing boilers, it is often tempting to use sewer pipes, because the low temperature of the flue gases is one of the features of such boilers. The mistake is that the sewer pipes are not designed for continuous operation at high temperatures (80 ° C and higher). And the flue gas temperature may be higher than this value, for example, when the boiler is operating in DHW mode. At the same time, the sewer pipes are deformed, the O-rings crack and crack, the chimney path ceases to be dense. This puts human lives at risk and damages chimneys as they become soaked by condensation and gradually deteriorate. In this regard, the use of sewer pipes as chimneys for condensing boilers is unsafe and strictly prohibited.

Incorrect slope of chimney or air intake pipes. The installation options for condensing boiler flues may vary depending on the conditions (Fig. 5), however, the basic rule should be observed - the slope of the chimney should facilitate condensate drainage back into the boiler module. The slope of the air intake pipe must prevent the ingress of atmospheric precipitation into the boiler drum.

Rice. 5. Variants of chimney installation in accordance with the European classification for type C boilers (with combustion air intake from the outside or from a common shaft)

In fig. 6 schematically shows the right ways organization of chimney and air intake for various types of chimneys. So, in fig. 6a shows the use of one chimney and the transfer of the boiler to work with air intake from the room. The elbows (if any) are assembled in such a way as to ensure that the condensate drains through the pipe back to the condensation module. It is very important to avoid possible places with a negative slope, where stagnant condensation will collect and interfere with the operation of the fan.

How special case a single chimney is used, which exits the boiler straight up without elbows. If we deduce the emission of combustion products into the already existing (or total for multi-storey buildings) chimney (Fig. 6 b), then make sure that this chimney can be operated with condensing boilers and has a condensate collector with a siphon at the lowest point. The emission of flue gases from condensing boilers into brick chimneys leads to their destruction due to soaking. Emission into chimneys made of black steel or aluminum leads to increased corrosion. The most optimal are insulated chimneys made of polypropylene or stainless steel. If the customer has a chimney, for example a brick one, then it can be "sleeve" polypropylene pipes or a stainless steel pipe.

When assembling the chimney, it is very important to observe the order of connection: the next section is inserted into the socket with an O-ring from above smooth side... This allows the condensate to drain unhindered back into the boiler module. But often stainless steel chimneys are assembled from scrap materials, and even with gross violations (the lower pipe enters the bell of the upper one), thus the condensate flowing back through the pipe comes out through the joints, which in some cases leads to disastrous results. For example, condensate starts to fill the boiler.

In the case of using a standard coaxial kit, the upward slope of the chimney must also be observed (Fig. 6 c). For wall-hung boilers of low power, the slope is provided by the design of the end terminal - with a horizontal arrangement outer pipe the inner one has an upward slope.

Structurally, it is possible to install a boiler with a single horizontal outlet behind the wall. The slope, as in the above cases, is ascending (Fig. 6 d).

Rice. 6. Options for organizing the correct slopes of pipes

In fig. 7 shows diagrams of incorrect installation of chimney and air intake pipes. In this case, the formation of a stagnant zone is possible, which impedes the operation of the fan and leads to the blocking of the boiler (Fig. 7 a). In case of installation as in fig. 7 b or fig. 7c, a large amount of condensate flows out and freezes with the formation of icicles. The location of the air intake pipe is as shown in fig. 7 g, will lead to ingress of atmospheric moisture into the boiler drum, and then to the boiler blocking or short circuit.

Rice. 7. Incorrect installation of chimney slopes

Despite the fact that both the DBN and the manufacturer's recommendations strictly regulate the distance from the discharge terminal to the nearest objects, gross violations of these standards are often encountered. Among the most common are the coaxial terminal's low ground level and the close distance between adjacent terminals.

The first is typical for private cottages. So, for the boiler and related components of the heating system (pumps, collectors, expansion tanks, boilers, etc.), semi-basements are most often allocated. The choice is obvious and correct - useful living space is not taken, all components of the system can be hidden and they will not disrupt the design of the premises. After all, the placement of a bulky boiler with piping and DHW boiler in the kitchen - the solution is not entirely aesthetic. And although the vast majority of adapted rooms have chimney and ventilation ducts, there is a temptation to save on the chimney and instead of “casing” the existing chimney and installing a separate kit for fume extraction and air intake, take the coaxial pipe from the boiler directly through the wall. As a result, the distance from the ground to the terminal is often several times less than the regulated one. This arrangement, in addition to the danger to people, also contributes to the active suction of ground dust and sand into the boiler fan, and then their entry into the mixing path and the combustion chamber. In the future, this can lead to a malfunction of the boiler, its premature wear and tear.

The second violation is typical for a cascade installation of boilers. In this case, the desire to save money often leads to a decrease in the required distance between terminals or the use of air ducts that are not intended for such an installation. It is clear that without the reconstruction of chimneys, such boilers cannot be started up and guaranteed. Therefore, it is best to use the kits provided by the boiler manufacturer. (For example, Baxi suggests for cascade installation not only chimney, but also hydraulic accessories, control automation).

Before installing the boiler, the minimum distances from the chimney terminals to the nearest obstacles must also be taken into account.

Condensate drain

The technology used by condensing boilers involves the formation of condensate from water vapor contained in the combustion products. Depending on the temperature regime and the power of the installed boiler, the formation of up to 50 l / day is possible. liquid that needs to be discharged into the sewer. The low acidity of the condensate allows it to be drained from the nearest siphon of household waste, which has an increased alkalinity. The neutralization reaction does not harm the environment. Nevertheless, the condensate drainage tract must be made of materials resistant to acidic environment (polypropylene, PVC).

Among the errors during installation is the drainage of condensate to the street. Installers sometimes lead the corrugated pipe directly to the street, by analogy with a split air conditioning system. In winter, this will lead to blocking the path with ice, filling the module with condensate and the boiler going out to emergency blocking.

If the sewerage level in the house is significantly higher than the boiler, it is necessary to use special condensate pumps with built-in tanks, for example the Conlift units (Fig. 8) offered by the Danish company Grundfos. They will allow, as condensation forms, to raise it by the desired height and pour into the sewer.

Rice. 8. Condensate removal unit Conlift

Security group

Some condensing boiler models do not have a built-in expansion tank and safety valve... Therefore, they must be installed during installation. Also in this case, a system filling valve should be provided. It must be located on the flow line after the boiler in order to prevent cold make-up water from entering the heated boiler heat exchanger.

In addition, there are such errors when installing condensing boilers (typical for traditional heat generators):

• heating system wiring and boiler piping with small diameter pipes;
• incorrect gas supply (narrowing of the gas pipeline, the use of inappropriate boiler capacity of the gas meter, the absence of gas filters or their illiterate installation, etc.);
• installation of boilers on wooden and other flammable walls without prior protection;
• lack of filters on the boiler return line and at the cold tap water inlet;
• errors in the organization of power supply (there is no stabilizer or voltage relay at the input to the boiler, there is no ground loop, generators or other power sources are used that do not have a zero phase or produce distorted characteristics, for example, a non-sinusoidal voltage).

Thermostat connection

A modern energy efficient heating system is impossible without the installation of thermostats. After all, as we have already noted, condensing boilers work most efficiently at low temperatures. And thermostats allow you to more accurately control gas valve boiler and maintain the coolant temperature at the lowest possible level.

The room temperature controller CR4, manufactured by Honeywell (USA), uses the OpenTherm digital communication protocol to control the boiler (Fig. 9). This technology means remote control of the burner, in which the boiler produces exactly the amount of heat that is required in this moment in response to a proportional request from a room thermostat. The digital connection used is immune to interference and protected against incorrect connection and short circuits. Low safety voltages are used. The OpenTherm communication protocol can be used with boilers from various manufacturers.

Rice. 9. Boiler control by means of a thermostat with a radio module

The thermostat CR4 can be set for a 7-day heating and cooking program hot water... There are 3 adjustable temperature levels and 5 factory heating programs. The display of the boiler operating modes and diagnostics of malfunctions are provided. There is frost protection.

Radio frequency communication is carried out using the 868.0-868.8 MHz band. Communication range: 100 m in open space, 30 m in a typical residential building. The receiving module is installed next to the boiler or inside it and is connected using a two-wire cable.

The advantages of remote control using radio communication are that there is no need to lay a cable during installation, which is especially important when reconstructing heating systems.

More important articles and news in the Telegram channel AW-Therm. Subscribe!

Viewed: 45 731

It is the main element of the chimney system. Used on straight sections to achieve the required height.

There are three types of lengths - 250, 500, 1000 mm. , which provides the ability to select elements in accordance with the design configuration. Chimneys of the "Sandwich" type consist of an inner welded pipe (of various grades of steels (AISI 430, 304, 321) of different thicknesses and an outer pipe of a larger diameter made of matt or polished (mirror) stainless steel AISI 430 with a thickness of 0.5 mm or galvanized There is a layer of insulation between the pipes - a non-combustible insulating material based on basalt rocks.

Throttle valve

This is a chimney element used to regulate the draft by partially blocking the chimney channel, and also as a damper on an unexploited fireplace with an open hearth to prevent warm air from leaving the room through the chimney.

It is a pipe with a built-in rotary damper and a handle brought out to the outside.

Mono-thermo transition

This is a chimney element used when connecting chimney systems different types or, if necessary, change the diameter of the smoke channel.

The transition is installed at the junction of parts of the chimney system with different diameters... As a rule, when changing from a smaller diameter to a larger one, in situations when several heat generators are connected to the main channel of the chimney at different levels

The branch is the main element of the chimney system, which allows you to change the direction of the chimney in cases where it is necessary to bypass an obstacle, or turn the chimney in the desired direction. Elbows are made of cylindrical sectors connected at a certain angle.

Tee 90 °

Tee 90 consists of two cylindrical elements connected at an angle by means of spot or seam welding.

When installing a tee on the turn of the chimney from a horizontal or inclined position to a vertical one, a plug or a condensate drain plug is installed in the lower part of the tee that closes the entire system.

A 90 ° T-piece is preferable to use in dry mode, since when the gas flow slows down during a sharp turn, active condensation can occur.

Tee 45 °

The 45 ° tee consists of two cylindrical elements connected at an angle by means of spot or seam welding.

When installing a tee on the turn of the chimney from a horizontal or inclined position to a vertical one, a plug or a condensate drain plug is installed at the bottom of the tee that closes the entire system.

The 45 ° tee provides Better conditions thrust than the 90 ° tee, since it has a larger angle (135 °) of rotation.

This is an inspection element of the chimney, designed to diagnose the condition of the chimney and clean the chimney by removing the products of incomplete combustion of fuel (soot). The revision facilitates the maintenance of the chimney.

As a rule, the revision is installed at the base of the chimney, below the connecting tee, as well as in horizontal sections of the connecting chimney with a length of more than 2 meters.

The revision is a modification of the 90 ° tee equipped with a special cover fixed with a pipe clamp. The revision consists of two cylindrical elements connected at right angles.

Plug

Installed at the bottom of the tee to collect soot and condensate, and can also be removed to remove foreign objects from the chimney.

Cap with condensate drain

Designed for collection and removal of condensate products from the smoke channel. It consists of a tubular element, a cone element or a pallet with a hole, connected to each other. The hole is designed for condensate drainage and is equipped with a branch pipe.

Conical ending

If no elements are installed at the mouth of the chimney special purpose, the end should be conical to protect the insulation from atmospheric precipitation.

Due to the closure of the inner pipe and the upper edge of the truncated cone, the access of atmospheric precipitation to the insulation is blocked.

It is used as the end of the chimney to protect it from atmospheric precipitation.

Thermo-thermo transition

These are chimney elements used when connecting different types of chimney systems or when it is necessary to change the diameter of the flue duct.

Transitions are installed at the junction of parts of the chimney system with different diameters. As a rule, when changing from a smaller diameter to a larger one, in situations when several heat generators are connected to the main channel of the chimney at different levels.

The chimney is one of the most important parts in the design of a boiler house based on any boilers operating on fuel combustion, including condensing ones. Correct design, choice of material and high-quality installation of the chimney are necessary conditions for a long and efficient operation of the boiler house as a whole.

The main feature of the flue gases from condensing boilers is their low temperature compared to the flue gases from traditional boilers. In turn, the low temperature leads to the obligatory formation of a certain amount of condensate in the chimney. It is these two factors - low temperature and condensation - that are decisive when choosing a chimney material for a condensing boiler. In addition, the need to ensure constant removal of condensed moisture must be taken into account in the design and geometry of the chimneys.

Against the background of the above, we will analyze three main aspects regarding chimneys for condensing boilers:

1. Materials used;
2. Design features;
3. Basic installation schemes.

Materials for the manufacture of chimneys for condensing boilers

The two most common materials used to make chimneys for condensing boilers are flame retardant polypropylene and stainless steel.

Flame Retardant Polypropylene (PPs)

In domestic use PPs chimneys are the most affordable and convenient in terms of installation. Generally speaking, polypropylene chimneys are also used with traditional boilers of the most modern designs, but nevertheless, the service life in this case is limited due to the relatively high temperature of the flue gases.

In the case of condensing boilers, the emission temperature is low enough to have no influence on the strength of the chimneys. In addition, polypropylene is inert to the acidic composition of condensate formed during combustion of hydrocarbon fuels. That is, from the point of view of durability, this material is ideal for use with condensing boilers.

Another feature of chimneys for condensing boilers is the requirement to work under excess pressure. That is, the connections of the elements must be tight. Typically, silicone seals are used to ensure tightness. Polypropylene is convenient here because, due to its elasticity, it does not require the use of additional clamping clamps, unlike stainless steel.

The main disadvantage of this material is its vulnerability to ultraviolet radiation, that is, such chimneys cannot be laid outdoors in the open.

It is also important to note that polypropylene must be fire resistant. This is usually indicated by the letter “s” in the material designation (PPs). This type of polypropylene is more resistant to high temperatures and, just as important from a safety point of view, does not support combustion. In past years, the mistake of using ordinary polypropylene sewer pressure pipes for the installation of a chimney was quite common in order to reduce the cost of the material. In no case should this be done for the reasons indicated above.

Stainless steel

Acid resistant stainless steel grades are the second most popular chimney material for condensing boilers in domestic applications, and the main one in the industrial and commercial segment!

The basic requirements are the same: work under excess pressure and resistance to chemical composition condensate. In terms of temperature, stainless steel provides a huge margin of safety.

Chimney types

Three main structural types of chimneys, each of which has a specific area of ​​application:

• single-walled;
• double-walled (sandwich);
• coaxial.

Single wall chimney

From the name it is clear that these are just pipes and fittings made of the corresponding material. It can only be used indoors or in heat-insulated ducts (for example chimneys during reconstruction). Usually used for flue gas emission when air is drawn from the boiler room.

It is often also used for the manufacture of a channel for supplying combustion air from the street. These air ducts, of course, do not have special requirements for temperature and chemical resistance and tightness. That is, they can be made from almost any available material. However, from the point of view of uniformity and ease of installation, the same type of single-walled chimney is usually used as for flue gas discharge.

Single-wall chimneys can never be used outdoors. The main problem is the constant formation of condensation in the duct. From the point of view of chemical resistance, as noted above, this is not scary, but there is a great danger of freezing of the liquid inside the chimney and, as a consequence, a narrowing of the flow section of the pipe. The drop in natural draft due to cooling of flue gases is not critical for this type of boilers, since they have powerful fans that provide a high value of the residual pressure.

Double-walled chimney (sandwich)

Elements of this type of chimney consist of two concentric pipes of various diameters, the space between which is filled with heat-insulating material, usually stone wool not supporting combustion.
There are no special requirements for acid and heat resistance to the outer pipe, only resistance to atmospheric conditions (precipitation, ultraviolet light) and mechanical strength... Therefore, in the case of double-walled stainless steel chimneys, the inner and outer pipes are usually made of different steel grades to optimize cost. There are options with the execution of the outer tube made of aluminum.

Double-walled chimneys can be used both indoors and outdoors.

Due to the low temperature of the flue gases and the absence of the likelihood of burns, in the case of condensing boilers, only the outer part of the chimney is usually performed with a double-walled version, and for the internal one you can use a conventional single-walled pipe.

Coaxial chimney

Again, based on the name, it is clear what this chimney is: two concentric pipes with an empty space between them.

The main feature of this type is that it is used both for the discharge of flue gases (through inner tube) and for intake of combustion air (through the space between the pipes). Accordingly, when using it, it is not required to constantly ensure the flow of combustion air into the boiler room. In addition, the incoming air is heated by the flue gases, thereby increasing the overall efficiency of the boiler room.

Laying coaxial chimneys is also allowed only indoors, the length of the outdoor section in our conditions should be no more than one meter. Ice build-up at the end of the chimney is a common problem in cold winters. This happens due to the sharp cooling of the flue gases at the outlet when in contact with cold air entering the combustion through the gap between the pipes. To solve this problem, you can cut the section of the outer pipe in the zone of the end of the chimney in order to spread the emission of flue gases and air intake; or use the factory winter options the end of the coaxial pipe.

This type of chimney is made from both plastic and stainless steel.

Basic schemes for installing chimneys for condensing boilers

All chimney schemes for condensing boilers are divided into two main types: with combustion air intake from the room and from the street. Naturally, in the domestic regulatory documentation these types of smoke removal and the requirements for them are described, but in the documentation for boilers, names are usually found in accordance with European standards. A chimney with air intake from the boiler room is designated as “Bxx”, from the street as “Cxx”. The first index varies depending on the specific scheme, the second - on the location of the fan relative to the boiler heat exchanger. In all modern condensing boilers, the fan is located in front of the heat exchanger, which is indicated by the index “3”. Below are the basic diagrams using the example of wall-mounted boilers:

For domestic capacities, the calculation of the chimney is usually not necessary, it is enough to follow the recommendations of the boiler manufacturer for the maximum length, taking into account the shaped elements (elbows, tees, etc.). In the case of industrial boiler rooms, the calculation of the smoke exhaust is mandatory, you can contact the chimney manufacturer for it.

Combustion air intake from the room

The easiest way to organize the flue gas outlet. Almost always used for large capacity boilers: industrial or commercial, when floor-standing boilers are used. It is also often found in household use. There are two main requirements when using such schemes: ensuring the necessary air flow into the boiler room and its purity. For boiler houses of large capacities, this is usually not a problem, since these points are carefully taken into account at the design stage. In private boiler rooms, a situation often occurs when a sufficient air flow is not ensured; or it is carried out through adjacent rooms, where after starting the boiler finishing work continues, which contributes to the presence of fine dust in the air and clogging of the internal elements of the boiler. Naturally, this state of affairs should be avoided or special air filters on boilers.

In this case chimney must be brought out above the roof level from the zone of the so-called “wind support”.

This is necessary in order to exclude the influence of fluctuations in air pressure on the smoke exhaust process.

Combustion air intake from outside

In this case, two main subtypes of the chimney are used: coaxial and separate.

Coaxial chimney

As mentioned above, it is distributed mainly in domestic use with wall-mounted boilers. In a private house, a coaxial chimney is especially convenient because it is enough to simply bring it horizontally behind the wall, without constructing a vertical trunk extending beyond the roof level. Perhaps this is due to the fact that the air intake and smoke discharge sections are located side by side in the same pressure zone, and, thus, are not affected by the wind.

There remains, however, the question of dispersion of flue gases in the atmosphere. The emissions of modern condensing boilers are environmentally friendly, but the chimney must comply with the standards for distances to windows, doors, ventilation grilles and neighboring land tenure plots. In order to combine the convenience of installing a coaxial chimney indoors and using a double-walled chimney outdoors, you can use special adapter kits.

In case of modernization of the existing boiler house with brick chimneys there is a variant with a coaxial pipe up to the zone of this chimney. Next, a new stainless steel pipe is laid inside it (single-wall can be used). Air intake is carried out through the gap between steel pipe and a brick chimney.

The most varied option in terms of design options for organizing a chimney. Nevertheless, it is rare in private construction and in industrial boiler houses. Since for condensing boilers in the first case it is usually easier to use a coaxial chimney, in the second - air intake from the room.

It is often found in apartment buildings with separate heat generators for each apartment, according to the following scheme:

For the selection and purchase of a chimney for a condensing boiler, please contact our .

Conventionally, the installation scheme (as an example, we consider the Victrix 50 boiler) can be divided into several connection stages:

• safety kit;
• storage boiler;
• solar collector;
• hydraulic separator.

Let's take a closer look at each stage.

Security kit

When connecting a boiler with a capacity of more than 35 kW, European legislation obliges to pay more close attention security issues. Therefore, a special safety kit is provided, which includes a safety thermostat, a maximum water pressure switch (4 bar), a pressure gauge and a system filling valve (a sleeve for connecting a thermocylinder of a gas shut-off valve).

There are also fittings for connecting an expansion tank and an immersion alcohol thermometer sleeve. The pressure switch and the overheating thermostat are manually unlocked and connected in series to the boiler supply circuit (Fig. 2). The operating limit of the safety devices is adjustable and is 3 bar and 105 ° C, respectively. This kit allows for a compact, fast and reliable installation of safety devices, and also guarantees reliable protection against emergencies under any circumstances.

Storage boiler

Since the boilers are single-circuit, it is proposed to use a storage type boiler to meet the needs for hot water. Several standard sizes of boilers are offered, with a capacity from 80 to 200 liters. Boilers have a rectangular white body. The material of the body and the boiler coil is high quality food grade stainless steel. To reduce heat losses, the boiler is enclosed in high-performance polyurethane foam insulation.

The boilers are equipped with spiral heat exchangers with a large heat exchange surface, which are connected in a counterflow scheme (Fig. 3). This allows you to quickly heat up the accumulated water supply. To ensure the preparation of a large amount of hot water, you can use two boilers with a volume of 200 liters, in which the heating medium and sanitary water circuits are connected in parallel. To connect the boiler to the boiler, you must use a special kit, which consists of adapters and a three-way valve. As in all others mounted boilers, hot water operation is based on the principle of hard DHW priority.

Connecting solar collectors

A special feature of 200-liter boilers is the ability to work with solar collectors. In fig. 4 shows an example of connecting solar collectors to a heating system based on a condensing boiler. High-quality solar collectors and a home heating system coordinated with them make it possible to consider the economic use of solar energy as necessary condition building an effective system.

In our latitudes, the total radiation (reflected and direct) in optimal conditions(cloudless clear sky, middle of the day) is a maximum of 1000 W / m2. Solar collectors, depending on their type, make it possible to use up to 75% of the total radiation. It only remains to note that, from our point of view, the combination of a condensing boiler + solar collector (heat pump) is the most promising direction for the further development of autonomous heat supply systems.

Low loss header

Since the boiler is designed to handle a significant heat load, this presupposes separate heating circuits with zone control. Therefore, the issue of independent regulation of circuits becomes relevant. There is a possibility of a change in the amount of coolant circulating through the boiler, which adversely affects its hydraulic mode.

A natural solution in this situation is the use of a low loss header (low loss header). At the same time, the transition to pipes of a larger diameter is carried out, which makes it possible to connect the "hydraulic switch" directly to the supply and return distribution manifolds. For one boiler, a compact solution of this unit is proposed, in the form of a rectangular pipe (Fig. 5).

This unit is located directly under the boiler, which significantly reduces the overall dimensions of the installation. Since the collector is installed horizontally, in order to remove sludge from the heating system, it is necessary to install a sediment filter on the return line, in front of the collector.