Sale floor-standing condensing gas boiler. What are the benefits of condensing boilers? Operating principle of a condensing boiler

Owners of private housing construction are interested in cheap ways to heat their homes in winter. Condensing gas boilers that have recently appeared on the market have the highest efficiency among analogues. In addition, with their help, they save from 10 to 35% of energy, which has a positive effect on the consumer’s budget.

Operating principle

This unit is designed on the basis of a conventional (convection) heat generator. The energy source for both types of boilers is natural or liquefied gas.

The operating principle of a convection boiler is extremely simple. When fuel burns, it transfers energy to the coolant (most often ordinary water) through a heat exchanger. The heated water circulates through the heating system, warming the home.

Combustion products at a temperature of 140–150°C, consisting of carbon dioxide and water vapor, are removed through the chimney. As a result, the efficiency of this heat generator ranges from 90 to 93%, the remaining 7–10% of unused energy evaporates into the atmosphere.

This is important! When the flue gas temperature is below 140°C, condensation forms on the walls of the chimney, which, when it enters the boiler, negatively affects metal components, reducing the durability of the unit itself.

Differences in the operation of conventional and condensing boilers

In a condensing boiler, the combustion products, having passed through the main heat exchanger, enter the after-cooling chamber with a secondary (condensation) heat exchanger, through which cooled water (return) moves. Passing through this heat exchanger, the gases cool down. At temperatures below 56°C (dew point - vapor condensation temperature), water vapor is converted into condensate. The thermal energy released in this case is used to preheat the “return”. The temperature of the gases entering the atmosphere through the chimney is reduced to 40–60°C.

Thus, slightly heated water enters the main heat exchanger. As a result, the boiler needs to spend less fuel to heat the coolant to the required value.

Manufacturers claim that the efficiency of these units reaches 104–108%. From a physics point of view, this is impossible. This meaning is conditional and is a marketing gimmick. In this case, 100% efficiency is taken to be the energy released during fuel combustion.

Scheme of formation of efficiency in gas boilers.

Wall-mounted boilers are used to heat small detached buildings.

Floor

The power of floor-standing units reaches 1000 kW. They have large dimensions and weight. Space is required to install additional equipment and place the harness. A separate room is usually allocated for them.

They are characterized by simplicity of design and complexity of installation. Used for heating industrial and commercial buildings with large areas.

Floor-standing boilers are installed in large rooms

By purpose condensing boilers divided into double-circuit and single-circuit.

Dual-circuit

In addition to heating the room, a hot water supply system (DHW) is supplied with water. For this purpose, the boiler is equipped with an additional heat exchanger. In addition, a three-way valve is installed in the boiler, which regulates the flow of water into only one of the systems. When using hot water for domestic purposes, the valve automatically stops the supply of coolant to the heating system, as it is configured for DHW priority.

The performance of the DHW circuit is relatively low. Turning on hot water at several points simultaneously quickly leads to a decrease in its temperature.

The use of double-circuit boilers is advisable when hot water is consumed infrequently and in small volumes.

Single-circuit

Intended for room heating only. However, many models provide the ability to connect an indirect heating boiler to the boiler - a storage tank that automatically maintains the required temperature. Its volume is selected depending on the owner’s needs for hot water. This allows you to use hot water for your own needs without restrictions, without turning off the heating system. It is convenient to install a single-circuit boiler in a house with three or more residents.

Advantages and disadvantages of a condensing gas boiler

Thanks to a large number advantages compared to conventional boilers, condensing heat generators are increasingly popular among the population. But these units also have disadvantages that must be taken into account.

Popular brands

Having decided to purchase this type of heat generator, it is better to pay attention to modern, reliable models from well-known manufacturers.

"Buderus Logamax Plus GB172i" (Germany)

Wall-mounted condensing boilers of a new generation with a power from 20 to 42 kW, embodying the latest developments in the world of heating engineering. They have excellent performance characteristics and modern design:

• Standard efficiency - 109%;
• Impact-resistant Titanium glass is used to make the front panel;
• Highly efficient long-lasting heat exchangers WB5 and WB6 made of ALU plus aluminum alloy;
• Built-in pump with class A energy efficiency;
• Burner with increased efficiency, modulation range - 1:8;
• Automation "Buderus Logamatic BC 25" with the ability to integrate additional automation to expand functionality;
• Availability of weather-dependent mode (burner operation relative to external or internal temperature);
• Work on antifreeze;
• Branch pipe for coaxial chimney 80/125;
• Possibility of adding automation “Buderus Logamatic TC100” or “Logamatic web KM200” to control the operation of the boiler via the Internet;
• Energy efficiency class - A.

Buderus boiler models

There are double-circuit and single-circuit models. An indirect heating boiler can be connected to the latter.

Price – from 88,000 rubles.

"Viessmann Vitodens 100-W" (Germany, Türkiye)

Models in this line are a good combination of high efficiency, reliability and price.

Available in power ratings from 19 to 35 kW.

Viessmann Vitodens 100-W boilers, operating on liquefied and main gas, are ideal for heating private homes and office premises:

The price of models running on liquefied gas is from 76,000 rubles.

The price of models operating on main gas is from 96,500 rubles.

Vaillant ecoTEC plus VU OE (Germany)

This range of single-circuit boilers is environmentally friendly and economical. The power of manufactured units is 30–65 kW.

Ideal for low temperature heating systems:

• Nominal efficiency - 108%;
• Simulated burner with a wide range of 28–100%;
• The primary and condensing heat exchangers are made of stainless steel with increased corrosion resistance;
• Environmental friendliness;
• Automatic air vent;
• Two-stage circulation pump with automatic switching;
• Fan with adjustable speed;
• Integrated expansion tank;
• Siphon for condensate drainage;
• System for increasing the efficiency of the condensing heat exchanger “Agua-Kondens”;
• Electronic ignition;
• Flame control system;
• Built-in switching module for interface;
• Smoke exhaust pipe 60/100 mm.

For the DHW system, an indirect heating boiler is connected.

All Vaillant models have a degree of protection IPX4D.

Price - from 91,500 rubles.

"Baxi Duo-Tec Compact" (Italy)

The line is represented by a single-circuit boiler with a power of 24 kW and two double-circuit boilers with a power of 24 and 28 kW.

They are distinguished by the implemented advanced technologies, ease of installation, operation and maintenance at a low price:

• Nominal efficiency - 109%;
• Conversion to liquefied gas;
• Primary and secondary (double-circuit) heat exchangers are made of AISI 316L stainless steel;
• Steel burner with modulating ratio 1:7;
• Flame control system with ionizer;
• High energy saving circulation pump;
• Built-in automatic air vent;
• Electric three-way valve (all models);
• Operating mode relative to built-in weather-compensating automation;
• Control of separate different temperature zones;
• Protection systems against overheating, freezing, blocking;
• NTC sensor that monitors the level of pollution in exhaust gases;
• Self-diagnostic electronics.

If necessary, an indirect heating boiler is connected to the single-circuit model.

Gas boiler "Baxi Duo-Tec Compact"

Price - from 50,500 rubles.

The described models have gained popularity due to their efficiency, impeccability, and reliability of operation.

Due to their design features and operating principle, condensing boilers use fuel energy much more efficiently and economically than traditional gas units. Despite the fact that the price of condensing equipment is still high, homeowners are increasingly choosing it. And this is not surprising - the boiler efficiency reaches up to 98%, and gas savings reach 20%. Experts say that condensation technology is the future.

Operating principle of condensing boilers

The cost of fuel is becoming higher from year to year, so energy-saving technologies are confidently gaining popularity. Condensing boilers appeared in the middle of the last century, but they were not immediately able to win the trust of consumers. At that time, the devices were unreliable, and manufacturers had to modify their design. As a result, they ensured that these models of heating boilers took leading positions in the market.

An interesting fact is that European countries stimulate and support their citizens who decide to buy a condensing gas boiler by providing loans at minimal interest.

A conventional heating boiler running on natural gas uses only part of the energy obtained from combustion of fuel. Exhaust gases, which have a fairly high temperature and powerful potential, are discharged into the atmosphere through the chimney, giving off unused heat to the outside air. A condensing gas unit more efficiently uses thermal resources released not only during the combustion of gas, but also during the condensation of water vapor contained in the smoke. The steam entering a separate heat exchanger, when cooled, turns into a liquid called condensate. This releases a certain amount of heat. Moisture is discharged into the condensate collector, and thermal energy is discharged into the heating system.

A conventional gas boiler uses a lower calorific value during operation, while condensing-type equipment uses a higher calorific value, consisting of the heat released during fuel combustion and the heat generated during condensation. This is the more efficient use of natural gas and efficiency, as well as increased efficiency indicators, which distinguish not only floor-standing units, but also wall-mounted heating devices.

The condensation-type equipment under consideration is ideal for radiator heating and hot water supply systems, as well as for underfloor heating.

Design of condensing heating devices

Any of the boilers has a heat exchanger in which the coolant is heated, which then enters the heating system of the house through pipework. Gas boilers of the condensing operating principle are equipped with two heat exchangers, the first of which operates according to the traditional scheme, and the second, condensing, is put into operation later.

The secondary heat exchanger is a structure of pipes of complex cross-section with spiral fins. This shape allows you to significantly increase the area in contact with steam. Flue gases in an additional heat exchanger heat the coolant coming from the return line. At this point, the water vapor cools to its dew point, resulting in condensation.

In other words, in a condensing boiler, part of the energy is returned for reuse, whereas during operation of a conventional boiler it is irretrievably lost to the atmosphere along with the steam.

For the manufacture of secondary heat exchangers, stainless steel is used, as well as coatings made of aluminum-silicon alloys called silumin. This protects the device from chemically aggressive condensate.

Gas condensing boilers are equipped with high-tech burners. Their peculiarity is that in combustion mode they provide constant control over the mixing proportions of the gas-air mixture, maintaining the optimal ratio. The design of heating devices has a closed combustion chamber, isolated from the room. Therefore, the boilers in question are relatively safe equipment.

Externally, energy-saving and traditional gas boilers are practically no different. Manufacturers produce wall-mounted and floor-mounted models, in single-circuit and multi-circuit versions. But you should pay attention to the fact that condensing equipment has more power with the same dimensions. For example, wall-mounted boilers that use the heat of air steam can have a power of up to 110 kW, while conventional gas units with a power of more than 40 kW are available in a floor-standing version.

Modern models of heating boilers using the condensing principle of operation are available in two modifications - with dry or wet heat transfer. The first option is intended for residential buildings, and the second, more efficient and expensive, for boiler houses. But boilers with wet heat transfer have not yet been fully developed, because... are still under development.

Condensate disposal

A condensing boiler produces a fairly large volume of condensate per day. It depends on the power of the equipment and can be 30 or more liters. It is not allowed to pour aggressive liquids directly into the household sewer system, which is why manufacturers equip modern gas heating appliances with neutralizers.

The additional device is a separate tank into which acid condensate enters. It passes through a layer of alkali metals (magnesium and potassium), resulting in a chemical reaction. As a result, the condensate decomposes into carbon dioxide and water, which can already be drained into the sewer system.

How profitable is it to use condensing boilers?

There are many opinions about the economic benefits of using condensing gas equipment in domestic conditions. The fact is that for consumers in Russia the price of gas is significantly lower than for residents of European countries. Therefore, some experts claim that condensing boilers in our conditions will pay for themselves in at least ten years. But this is not true.

Firstly, gas is not as cheap as we would like. Secondly, reviews from owners of heating boilers indicate that significant savings can be visible already in 2-4 years of operation. This period depends on the technical characteristics of the equipment, such as power, and on additional equipment.

For clarity, we should consider some examples.

Budget option

A condensing boiler with a built-in heat exchanger for a private house, involving a heat load of up to 30 kW with the simplest wiring and connecting only heating radiators, will cost a third more than a traditional boiler. But operating costs at maximum loads will make it possible to return this difference in 3.5-4 years, taking into account the annual increase in gas prices. In the future, the condensing boiler will begin to significantly save fuel costs, becoming more profitable every year.

Advanced option

The price of a traditional boiler (including the purchase of a set of additional devices) for a house requiring a heat load of approximately 35 kW, with a multi-circuit heating distribution system and the presence of a 200-liter hot water tank will be higher than condensing gas equipment. Therefore, there is no need to talk about payback here. It turns out that a condensing boiler, designed for medium heat loads, begins to save the owner’s money from the first day.

Highly advanced option

In this category, you can consider multi-circuit boilers with a thermal load reaching 60 kW. In this case, the condensing boiler will need to be completed, so its price will be 15-20% higher. But the difference, taking into account the rise in gas prices, will be equal sooner than with the budget option. We can talk about payback in 2.5-3 years.

Reviews from experts and consumers indicate that condensing heating boilers are preferred by those owners who know how to count their money. They understand that in addition to saving on gas bills, such equipment will last at least twice as long as a conventional gas appliance.

But do not forget that the efficiency of condensing equipment will depend on several factors:

• boiler age;
• correct ratio of heated volume and power characteristics of the unit;
• use of modern gas burners.

Installation of floor-standing gas boilers

High-power boilers are manufactured in floor-mounted versions. They are installed in separate rooms in which it is possible to organize additional ventilation. The installation process is carried out in stages.

1. At the stage preparatory work a foundation is constructed in the form of a concrete pad 100-200 mm high or a support frame is installed.
2. The connection points for the chimney, supply and return heating pipes to the boiler equipment are determined and organized.
3. The gas boiler is installed horizontally on the prepared base. It is adjusted using screw feet.
4. The unit is connected to the pipelines of the coolant circulation system. It is taken into account that double-circuit and multi-circuit boilers have additional pipes and flexible piping.

Before entering the heating boiler, a special coarse filter must be installed on the return pipe to prevent scale or rust from entering the heat exchanger.

1. The unit is connected to the gas pipeline using copper pipes or flexible hoses. A valve is mounted on the inlet pipe. The outlet pipe is connected to the chimney.
2. Seams and connections are checked for leaks, and gas pressure in the pipeline is checked for compliance with regulatory requirements.

Regardless of the model, floor-standing gas boilers can be installed in rooms with a ceiling height of at least two meters. One unit requires a minimum volume of space of 7.5 m3 and a mandatory ventilation hole to allow air flow from outside.

The minimum distance from a wall made of non-combustible materials is allowed to be 100mm. Roofing steel with a thickness of at least three millimeters is used as an insulating material.

Non-flammable coverings must be laid on the floor under the gas boiler. It could be:

• steel sheet;
• tile;
• natural stone;
• cement screed;
• expanded clay concrete slabs.

Installation of wall-mounted boilers

Wall-mounted devices are installed after preparing the electrical connections and connections to the hydraulic and gas circuits, which is done using the supplied templates. Before this is determined:

• location of the heating device;
• possibility of communication arrangement;
• admissibility of organizing the correct removal of combustion products.

The wall-mounted heating boiler must be secured to a reliable base. In most cases, load-bearing walls or a specially installed frame in the form of frames, consoles, hangers, racks, etc. are used for this. Manufacturers provide a range of fixtures and fittings, supplied complete with equipment or purchased separately. Also, the wall-mounted unit can be fixed to a vertical fence using a mounting frame made for a specific model of heating device. Its use in combination with decorative panels and covers allows the condensation equipment to harmoniously fit into the interior of the room.

After installing the boiler on the wall, they begin to directly connect it to the supplied utility networks and communications.

The pipe responsible for removing carbon monoxide is connected through corrugated pipes to the chimney. In this case, their sharp bends are not allowed. The chimney should not be located at a distance of less than 100mm from flammable surfaces. In any case, it would be better to isolate them.

Valves are installed on gas pipes and gas pipelines are checked for leaks. The wall-mounted boiler must be connected by a specialist, carrying out appropriate tests and purging of the pipes.

To be able to connect the equipment to a 220V power supply, you will need to install an outlet and have a stabilizer. We should not forget about the grounding of condensing boilers, and also that contact of the cable with hot elements can lead to its melting and failure. Safety requirements must be observed unquestioningly.

The water circuit is connected to the wall-mounted boiler following the appropriate diagrams supplied with the equipment.

Features of chimneys for condensing boilers

Ready-made chimney pipes made of plastic or aluminum are installed on wall-mounted and floor-standing condensing-type boilers. By design they can be:

• coaxial, which is a “pipe-in-pipe” design;
• two-pipe, divided into smoke exhaust and air intake segments.

The low temperature of the exhaust gases exiting through the chimney allows the use of plastic in the exhaust system. At a temperature of 35-70 degrees it does not deform, does not melt and copes with its functions perfectly.

This circumstance significantly helps when replacing an old boiler with a brick chimney with new equipment. A conventional gas boiler will require dismantling the old chimney, since temperature fluctuations and aggressive condensation will cause the masonry to collapse too quickly. To prevent emergency situation, you will have to think in advance about installing an anti-corrosion, gas-tight chimney made of stainless steel or polymer liners, the price of which is quite high.

For a condensing boiler, you can limit yourself to lining the old chimney with plastic, which will be much cheaper.

Myths about condensing boilers

The popularity of any product always gives rise to numerous rumors and myths, which do not always reflect reality. Condensing boilers, both wall-mounted and floor-mounted, are no exception. Let's try to understand some of them.

Price

Experts say that condensing boilers are more expensive than traditional gas units. But this is only with a superficial glance at the price tag or price list. Having understood the issue, you can understand that the equipment differs not only in price and design option (wall-mounted or floor-mounted, single- or double-circuit devices), but also in thermal power.

Paying attention to technical specifications gas boilers of different operating principles, and by comparing two units with the same performance and capabilities, you can be convinced that the final price of traditional equipment is often higher than condensing equipment. And if we take into account that for conventional gas boilers it is necessary to purchase additional devices, the price of which can be significant, then the question of the higher cost of condensing equipment will disappear by itself.

Efficiency

Many manufacturers claim that their condensing boilers have an efficiency of more than 100%. This statement evokes a double feeling. On the one hand, it is quite attractive to consumers, but on the other, it causes confusion.

The use of additional heat, of course, increases the efficiency of using this type of equipment and increases efficiency. But talking about a coefficient exceeding 100% is only conditional.

The fact is that to facilitate the comparison of two types of gas heating equipment, efficiency calculations are carried out using the method for determining the indicator for traditional boilers that use only the lower calorific value. And here the heat of condensation is not taken into account, which adds 7-9% to the efficiency. Condensing units use 100% of the lower heat and its part resulting from the condensation process, which makes up the figure of 107-109%. In fact, the efficiency does not rise above 98%.

Chimney

Despite opinions about the need for condensation devices to install chimneys made of acid-resistant materials, the price of which is quite high, they are not much different from conventional chimneys installed in systems of gas units with a closed firebox.

Waste combustion products are removed forcibly, so the boilers in question can be connected to various smoke exhaust systems. The main thing is to maintain the tightness of the structure.

Condensate

Many consumers are sure that when the boiler operates, problems arise due to the appearance of condensation. But manufacturers of condensing equipment include systems for neutralizing and recycling aggressive moisture into the design of their devices. For conventional gas units, in the chimneys of which condensate is present, although in smaller quantities, diverters and neutralizers are installed additionally.

Famous manufacturers

The heating equipment market is diverse and extensive. Domestic and foreign manufacturers offer a huge range of boilers, differing in their dimensions, power and type of fuel used. Among the most well-known manufacturers of condensation equipment, several companies can be distinguished.

The German company appeared in 1917 as a workshop for the production of agricultural machinery, and 10 years later its founder Johann Wissmann developed and produced the first boiler. Until now, the company is headed by one of the family representatives, already in the third generation.

Today, Viessmann includes several companies specializing in heating systems, as well as ventilation and refrigeration systems. Its products are largely produced for export, and production sites are located in 11 countries. The company released its first condensing boiler in 1992.

The small private company was founded by Prussian engineer Johan Vaillant in 1874. Thanks to the extraordinary abilities of the owner, she quickly achieved success. Since 1894, the company began producing gas equipment, and today the Vaillant Group, which has factories in 7 countries, is known all over the world, including for its developments in the field of energy-saving equipment.

Bosch

The workshop, founded in 1886 by the German inventor-researcher Robert Bosch, for a long time had nothing to do with heating boilers. Only in 1929 did the founder of the company decide to restructure it and move to a broader field of activity. Since that time, many enterprises have joined the structure of the corporation, including companies producing household boiler equipment.

The history of the German company Buderus began in 1731, when its founder Johann Wilhelm Buderus rented a small metallurgical plant where cast iron parts for furnaces were produced. In 1898, the company received a patent for its own sectional boilers, and in 1981, it introduced cast-iron condensing equipment. Since 2003 trademark Buderus belongs to the Robert Bosch GmbH group of companies.

Baxi

The company appeared in 1866 in England. It was founded in partnership between Richard Baxendaal and Joseph Heald, and the Baxi trademark was used only in 1930 when producing one of the heating systems. Today, boilers made in Italy by Baxi S.p.A., which belongs to one of the enterprises of the Baxi Group holding, are entering the Russian market.

Vaillant ecoCOMPACT VSC INT

Gas condensing boilers are latest technology in the heating technology category. Their main advantage over traditional appliances is their high efficiency, which is 15–20% higher than that of conventional boilers. But high efficiency is observed only at low-temperature operating conditions of the heating system.

And that's not all.

Features of condensing boilers

Such units can provide heat to additional branches, for example, a “warm floor” system. Plus, their service life is 2 times longer than that of traditional models, and the range of power and configuration is wider. Such mounted boilers can have a power of up to 100 kilowatts, while conventional boilers can have a power of up to 35 kW.

Why do conventional boilers have low efficiency? To understand this, you need to understand the design of the device. In such units, thermal energy is collected in fairly large quantities, but not all of it is used to heat the coolant, since there are losses. In addition, under certain conditions, condensation forms on the heat exchanger. This leads to corrosion of the metal from which the heat exchanger is made. So the service life of such a boiler is several times shorter.

Why does condensation appear? It's all about the temperature inside the heat exchanger. It should not fall below a certain indicator. If this happens, the draft in the chimney weakens, and wet vapors begin to deposit on the metal parts of the boiler. With sufficient draft, wet vapors are promptly removed from the combustion chamber. This is the whole problem with conventional gas boilers.

In condensing boilers, a recovery process operates when latent thermal energy is extracted from condensing wet vapors generated during the combustion of natural gas. And this is a distinctive feature of such boilers.

If we consider the individual components of any boiler, its main element is the heat exchanger. In ordinary boilers there is one, but in condensing boilers there are two. Moreover, they can be separate or combined - two-stage. The primary heat exchanger in condensing boilers works the same as in conventional ones. That is, the heat from the combustion of fuel passes through it, heating its surface, and therefore the coolant that moves through the internal cavities. By the way, the primary coolant never cools down to the dew point temperature. The second heat exchanger is heated by the same gases, but coolant from the return line flows through it.

Boiler structure

Now notice that the water in the return line is much lower than in the supply line. This means that wet vapor will certainly condense on the surfaces of the heat exchanger. But at the same time, latent thermal energy from the condensation process will be added here. That is, when a substance transitions from a vapor state to a liquid state, heat is always released. This is a law of physics. This is why the efficiency of condensing boilers is several percent higher than that of conventional boilers.

But here comes one very important question- how to deal with negative impact moisture that will form on the walls of the secondary heat exchanger? Experts offer two options:

1. Make a heat exchanger from stainless steel.
2. Coat a cast iron or steel device with silumin, an alloy of aluminum and silicon.

Where does the condensate go?

This question is often asked by consumers who have decided to purchase a condensing boiler. The design of the heating device has a small reservoir where condensate is collected. From there it is discharged into the sewer. By the way, in Europe it is prohibited to pour such water into the sewer. Each consumer must dispose of condensation waste at his own expense. These are the strict requirements.

How much condensate is formed, for example, per day? If you take a 30-kilowatt floor-mounted condensing gas boiler, it will produce about 30 liters of condensate per day. The volume is considerable, which is why the Europeans do not give permission to dump all this into common system sewerage. True, today models have appeared on the market with a neutralizer built into their design. This is a new tank filled with magnesium and potassium granules, which are alkali metals. The acidic condensate passes through an alkaline environment, causing a chemical reaction. As a result, the final products are formed - carbon dioxide and water. This water can now be drained into the sewer.

And now a few words about the maximum efficiency of the condensing unit. If you purchase this model, but leave the old heating system, where there is no radial piping, do not complain that there will be no savings. After all, such a boiler will work effectively only during the warm-up period, and then everything will go according to the old scheme. Therefore, my advice is to immediately change the wiring diagram. This is the first one.

Secondly, the temperature difference at the boiler outlet and inlet must be at least 55 degrees. In this case, the optimal temperature of the coolant at the outlet should be +82C. And this is with natural circulation of hot water inside the heating system.

History of devices

These boilers appeared back in the 50s of the last century. The first models were unreliable because they quickly failed under the influence of acid condensate. In addition, in different European countries there was no uniform standard for gas mixtures used to heat the coolant. That is, there was a problem on top of a problem. Everything changed in the 70s, when stainless steel began to be used for the production of secondary heat exchangers.

Today, in almost all European countries the state supports the installation of condensing boilers. For example, banks issue loans with the lowest interest rates for its purchase.

Alternative point of view

One hundred percent efficiency is a bluff of advertisers. But manufacturers of heating equipment, including gas boilers, are trying to achieve maximum efficiency. It should be remembered that this indicator depends on many factors:

• From the age of the heating unit.
• The relationship between the power of the boiler and the volume of the room it heats.
• Using a modern type of ignition or old options.

Currently, manufacturers offer two types of condensing boilers - with wet and dry heat transfer. Units with dry heat transfer are boilers that are used in residential premises, that is, they are ordinary condensing devices. Units with wet heat transfer are used mainly in commercial boiler houses and are still under development. They are more effective, but much more expensive.

Benefits from condensation

All boilers that are installed in small private houses have the ability to change power by regulating the gas supply to the burner. In this regard, condensing boilers are in no way inferior to their conventional counterparts, but their maximum operating efficiency is observed at lower temperatures. That's the whole difference. But not only that.

What is the relationship between boiler power and coolant temperature? The more powerful the boiler, the more fuel it consumes, and the higher the coolant temperature. And vice versa. Most often, the efficiency, and therefore the operating efficiency of the heating unit, depends on the fuel supply. The more of it, the better.

In condensing boilers everything is different. Their maximum efficiency is observed when the boiler is loaded at only 30%. In this case, there is no point in choosing from a low-power or more powerful unit, since this indicator does not matter.

By the way, experts believe that a “warm floor” system works well with a condensing boiler:

• The temperature of the coolant in both the supply and return of the heated floor is always below the condensation level of wet vapors. This barrier is +56C.
• An underfloor heating system contains a fairly large volume of water, which must be long time warm up. That is, the burner operating cycle at low temperatures with minimum power increases. This means that more time is spent on the condensation process.

If we compare it with a simple boiler, the coolant quickly heats up, the burner turns off, and vapor condensation does not occur. The decrease in efficiency is obvious.

Chimney for boiler

It is clear that condensing boilers release combustion products at a low temperature, which means that the draft in the chimney will be weak. Combustion products cannot rise up the chimney naturally, so in such models the combustion chamber is closed, and fans are installed on the chimney. By the way, it is for such boilers that a coaxial chimney is installed - a pipe in a pipe. The internal fan removes fuel combustion products, and the external fan draws air from outside into the combustion chamber.

Please note that condensation will certainly form in the chimney itself, whether you like it or not. Therefore, it is made of acid-resistant steel. And if the house has a brick chimney, then its internal walls must be lined with the same steel. This prerequisite proper operation of condensing boilers.

Advantages and Disadvantages

The advantages of such units include the fact that during a long winter, when the average temperature is -20C, they work much more efficiently than their conventional counterparts. In addition, with proper operation, natural gas savings occur by at least 15%. And if you compare it with old models, then by 30%. In addition, these models are least harmful environment, because they emit a minimum of CO and other gases.

But they have only one drawback - this high price. And if we compare again, the difference with conventional units will be no less than 2 times. If we consider the situation from an economic point of view, then such heating units will pay for themselves faster where the need for heat is greatest. Therefore, the deficiency can be transferred to another category. We will assume that this is direct investment, because the increase in gas prices is obvious. And no one knows what its price will be in 5 or 6 years. And savings are constant, so there is no need to skimp when choosing the latest technologies.

Conclusion on the topic

New heating technologies are gradually entering our lives. And it is clear that the winner will be the manufacturer who supplies the market with highly efficient units at an affordable price. We will not say yet that gas condensing boilers have an acceptable price, but this is just the beginning. A few years ago, few people knew about these boilers, but now they are quite popular. And most importantly, consumers are looking less and less at price, realizing that savings of even 15% are a good indicator.