The operating principle of a condensing heating boiler: an overview of the main manufacturers. Connection diagrams for a heated floor to a condensing boiler Connection diagram for a condensing boiler

To understand how beneficial condensing heating boilers are to use, you must first consider their operating principle. One of the features in this case is the receipt of additional heat, which is the result of condensation of combustion products. This phenomenon occurs due to a decrease in temperatures in the combustion chamber to 100-110 degrees, which cannot happen in a conventional chimney due to a strong decrease in draft.

Therefore, to achieve maximum use of fuel energy, hidden resources should be activated. Latent heat is that part of it that is released outside along with water vapor and smoke. Such heat losses may seem insignificant, but in fact their preservation can significantly increase the efficiency of the heating structure.

The efficiency of a condensing boiler is higher due to the fact that, compared to a unit of traditional design, condensation occurs in it of the steam released during the combustion process. This steam is then mixed with smoke, and the energy released is used to provide additional heating of the coolant.

Important! In order for condensation to occur, it is necessary to ensure a temperature difference between the steam and the surface with which it comes into contact. Thus, upon cooling, the steam turns into a liquid state, reaching the dew point. To ensure an effective condensation process, it is necessary to reduce the temperature to 60 degrees Celsius.

Design features

The operation of a conventional gas boiler is as follows: when fuel is burned, the coolant is heated and combustion products are released into the atmosphere through a chimney. Any long-burning unit in practice proves the low efficiency of such a scheme. Therefore, to increase efficiency, there are several significant changes in the design of condensing-type units:

• To effectively cool the smoke, the design provides another chamber. It is supplied to it after the fuel burns out in the firebox.
• Adjustable flame intensity thanks to the installed modular burner.
• The system has an additional heat exchanger, thanks to which water circulates from the return pipe. The temperature difference promotes steam condensation, which actively releases heat, heating the coolant.
• The cooled smoke is removed through the external circuit of the coaxial cable. The system also contains an internal circuit used to supply oxygen.
• Condensate is collected in a specially designed container.
• A fan is installed in front of the burner, thanks to which the gas is better saturated with oxygen.

The operating principle of such boilers on video

Advice! To save money, the chimney for such a boiler can be made of plastic. Since, due to the design features, the temperature of the exhaust air does not exceed 40 degrees, the plastic pipe will cope with the task perfectly.

Advantages and disadvantages

Now let's take a closer look at the pros and cons of condensing boilers. The design has several obvious advantages:

• Both floor-mounted and wall-mounted condensing gas boilers have higher power compared to conventional units.
• Significant fuel savings, achievable due to the original burner design. Thanks to it, it is possible to precisely regulate the operation of the unit.
• Minimum amount of harmful emissions into the atmosphere.
• Heat loss in a volume of no more than 2% of the total heat volume.
• Highly compact. Even a floor-mounted condenser will be significantly more compact than its counterpart of a traditional design.
• A double-circuit boiler of this type is perfect for houses with a “warm floor” system.

• Durability due to the high quality of the materials used and proper adjustment of the operating mode.

Important! Such units are most effective when used in houses with an area exceeding 200 m2. In this case, a large difference in return and supply temperatures occurs, and the efficiency of the device increases significantly when the low-temperature coolant return branch is heated. In addition, the larger the heated area, the more obvious the savings when using such equipment.

The disadvantages of boilers of this type include the following:

• A sealed chimney equipped with forced ventilation is required.
• A high level of efficiency is achievable only in low-temperature heating systems.
• Energy dependence.
• High cost compared to traditional designs.

Installation features

Installing a condensing unit involves several important nuances. And the first of them is the choice of location. The best option in this case would be a specially designated room, but if there is none, then installation can be done in the kitchen.

Advice! The walls of the room in which the unit will be installed must have a tiled finish. The floor must also have a non-combustible coating. There must be a hood in the room.

Hanging structures are fixed to the wall using dowels. The correct location of the boiler is achieved if its lower part has a slightly larger distance from the wall than the upper part.

Features of chimney installation

Today there are a number of options for connecting a chimney to a heating boiler. But no matter which one is ultimately chosen, it is important to maintain high tightness. The design of chimneys for condensing units does not differ significantly from the chimney connection diagrams in traditional models.

The basic requirements are as follows:

• Material of manufacture. The chimney of such a unit must be made of plastic or stainless steel. The main parameter here is not resistance to elevated temperatures, but acid resistance. The fact is that condensate has the same effect as light acid, so it is very important that the material is not afraid of corrosion.

• Chimney angle should be such that condensate can flow back into the boiler, but precipitation should not get into it, since this may result in damage to the unit due to a short circuit.

How to organize proper condensate drainage and avoid installation errors

As mentioned above, the basis for the operation of condensing boilers is the formation of condensate.

Important! The amount of condensate formed directly depends on the power of the equipment. So, during the day the unit can accumulate up to 50 liters of condensate, which has low acidity. Therefore, this liquid can be drained directly into the household waste siphon, which will not cause any harm to the environment.

Let's look at the main mistakes that can be made when installing such equipment:

• One of the most serious mistakes is the absence of a container in the system designed to drain condensate, or its inappropriate size. Unfortunately, this mistake is made even by experienced specialists.
• A wall-mounted boiler is installed on a wall that has a coating that is not protected from fire. This may cause a fire.
• The condensate is discharged outside. This is unacceptable, since at sub-zero temperatures the tube may freeze. As a result, the unit may simply become blocked and fail.
• Lack of gas filters in the system.
• The boiler is equipped with a gas meter that does not correspond to its power.
• During installation, the correct slope of the equipment is not observed.

During installation, it is necessary to take into account all the above points. Only in this case will the installed unit function correctly for a long time.

Most popular manufacturers

On the modern market of heating devices there is a number of condensing units produced by various companies. Let's consider the most popular manufacturers, whose products have proven themselves due to their high productivity and uninterrupted operation:

• Wisman ( Viessmann). The company is one of the world leaders in heating and refrigeration systems. Its products are distinguished by the introduction of new technologies and high performance. The Visman company provides excellent warranty service for its equipment and carefully cares about the quality of its products. Truly Italian quality at relatively affordable prices.
• Vaillant ( Vaillant) is a German manufacturer of heating equipment that has gained significant popularity in more than 60 countries around the world. The high quality of Vaillant products is emphasized by compliance with international standards. The company annually invests a lot of money in upgrading its technologies, producing premium equipment.

• Baxi ( Baxi). Another Italian company specializing in the production of heating equipment. It is one of the European leaders, having been present on the market for more than a decade. A large range of models and high reliability of the equipment produced by the company are the distinctive features of this manufacturer.
• Buderus. A well-known German company, which is one of the oldest in Germany. It has been producing heating equipment and components for it for almost 300 years. Today it is one of the undisputed leaders of the world market.

Conclusion

Condensing boilers are an excellent option for heating your home. This is reliable and productive equipment with high efficiency and enviable efficiency. Such units are best suited for heating large private houses, since in this case the level of efficiency increases significantly.

From the design instructions for condensing boilers Buderus (Germany).
Compliant SNiP 41-01-2003 clause 6.4.1 PIPELINES : "...Polymer pipes used in heating systems together with metal pipes (including in external heat supply systems) or with instruments and equipment that have restrictions on the content of dissolved oxygen in the coolant, must have an oxygen permeability of no more than 0.1 g/(m3 ∙day)..."

VITODENS Gas condensing boilers
Design instructions

Bosch Condens 3000W
- Possibility of direct connection to the underfloor heating system

Other model
BoschCondens 5000 W Maxx
Possibility of direct connection to the underfloor heating system
Without the required minimum circulation water flow

High-quality components such as a plasma-cured aluminum heat exchanger and robust construction make the Condens 5000 W Maxx not only extremely reliable, but also extremely durable. Thanks to innovative Flow Plus technology there is no minimum value of water pressure through the heat exchanger . For this reason, a full hydraulic system is not required.

About the anti-diffusion layer (oxygen barrier):
"... This result once again confirms the fallacy of the widespread statement: “Pipes of small diameters do not necessarily need to be reinforced or protected from the ingress of oxygen into the coolant, since the flow of oxygen through the wall of such pipes can be neglected.” Proponents of this point of view urge not to reinforce with aluminum and not to coat with an AVOH layer (anti-diffusion layer for PEX pipes). and small diameter PPR pipes. However, it is precisely these pipes that stand, for example, in front of steel panel radiators (steel wall thickness is 1.2 mm). Therefore, it is necessary to reinforce small and large diameter pipes with aluminum for heating systems. Moreover, for small-diameter pipes this rule is more important than for large-diameter pipes, where calculation and reference to a specific application scheme is necessary.
For example, with D = 2x10-11 m2/s (oxygen permeability of polypropylene) and ∆сО2 MAX = 270 g/m3 (approximate oxygen content in the atmosphere)
Q/V=1.9٠10-8/DN2 (g/s٠m3) or 1.6٠10-3/DN2 (g/day٠m3)
for DN20mm, we get 4 g/m3 of oxygen per day - in other words, the formation of 30 g of rust is possible. One meter of pipe DN20 PN20 (SDR=6) contains 2.2x10-4 m3; accordingly, through this linear meter of pipe a maximum of 8.8x10-4 g/day will pass into the coolant. oxygen.
For example, if the heating system is made of polypropylene pipe PN20 (unreinforced or fiberglass reinforced), the volume of the heating system is 100 liters, there is a wall-mounted boiler with an aluminum-copper heat exchanger and a heating temperature of 80 C° and steel panel radiators, and the pipe capacity is 50 liters, then per day for a typical set of pipes of different diameters with SDR=6, about 0.1 g of oxygen will pass into the coolant; converted per year, this amounts to 37 g of oxygen, or 250 g of rust produced in steel panel radiators (which will very likely leak after a year or two of use).
The scope of this article does not include an exact quantitative analysis of oxygen permeability, but the example given allows us to resolve the frequently asked question: “How much oxygen does a plastic pipe allow through? Is it a lot or a little? I think we have given a very specific answer. In conclusion, we note that many informative works have been written on this topic, but the conclusions of readers or companies supplying similar products to the market do not always correspond to the analysis carried out in these articles..."

In European countries, traditional (Convection) boilers have long been abandoned. What is the reason for this approach? Europeans are thorough people and know how to calculate benefits, but if they use condensing boilers, then there is a benefit. What can it be expressed in?

Pros and cons of condensing boilers

1. The high efficiency of boilers is ensured by the combustion gas, which releases a large amount of water vapor and has a very high temperature. The boiler equipment supplies this “additional heat” to the boiler heat exchanger, which provides additional heat removal.
2. Unlike a traditional boiler, a condensing boiler has a modulation range of 6 kW, resulting in a reduction in its consumption (20-30% depending on the average winter temperature).
3. Thanks to the closed combustion chamber, it is safer and more environmentally friendly.
4. Low weight and dimensions of the boiler.
5. Low noise and vibration levels.

From these indicators it is clear why practical Europeans choose condensing boilers, although they are somewhat more expensive than usual. In Russia, according to the owners of such boilers, their payback due to gas savings occurs at 2 – 4 year of operation.

Installation of condensing heating boilers

The use of a condensing boiler in the heating system must be included in the design. Since it differs significantly from the usual one in the wiring, pipe diameter and chimney feature.

As a rule, wall-mounted boilers are used for heating private houses. Their power is enough to heat a house, and their compact dimensions allow them to be located in any convenient place; there is no need to build a separate boiler room. For example, a boiler with dimensions of only 589x368x364 is able to heat a house with an area of ​​up to 240 m².

Installation of condensing heating boilers is possible on any reliable foundation. To do this, either the fasteners that come with the kit are used, or a mounting frame is made. The use of such a frame allows this boiler to fit organically into any interior.

Having secured the boiler to the wall, proceed to connecting communications according to the appropriate diagrams. Carbon monoxide is removed through the chimney; the pipe must be insulated and there should be no flammable surfaces nearby.

It makes more sense to use such a highly efficient boiler with systems that also have high performance. For example, with Kermi radiators, which have the highest level of heat transfer and a heating system known as the Tichelmann loop.

Installing heating loops has a number of advantages:
Balance of the system. No additional regulators required.
High efficiency due to equal water flow throughout the system.
Uniform heating of radiators.

These effects are achieved due to the fact that the return heating line starts from the first radiator, reaches the final one, and from there is supplied to the boiler. As a result, all radiators function as one and, regardless of the distance from the boiler, heat up equally.

It includes not only heating equipment, but also a set of specific measures for its installation and installation. Correct and high-quality installation will certainly affect the operation of the boiler in the future.

There are a number of standards and regulations for the installation of gas condensing boilers. First of all, you need to know that installing a condensing boiler requires permission from the gas inspectorate. When connecting the boiler, you must comply with the technical rules for connecting gas and the necessary safety measures.
This is a prerequisite to prevent boiler damage and possible injury to people.

It’s even better if the installation and installation of the condensing boiler is carried out by qualified specialists.

How to choose a boiler installation location

The best place to install is a non-residential premises. If the house does not have such a separate room, then the boiler can be installed in the kitchen. Ideally, the walls of the room where the boiler will be installed should be tiled, but in no case with fire hazardous materials. The floor must be covered with a non-flammable coating; it is advisable that there is a sewerage system in the room. Condensing heating boilers require an exhaust hood in the room where they are installed.

The wall-hung condensing boiler is fixed to the wall with special hooks using dowels. It is correct if the condensing boiler is located in such a way that its lower part recedes from the wall more than the upper part.

If, on the contrary, it means that the boiler is not secured correctly. The installation of the condensing boiler is done in such a way that there is no tilt, otherwise this may lead to a short circuit.

Therefore, when attaching the boiler to the hooks, you need to carefully check the verticality of the boiler so that it is not tilted forward or sideways.

Chimneys of condensing boilers

There are many options for connecting a chimney to a condensing boiler. The main requirement for condensing boilers is the tightness of the joints of the chimney elements.

In general, the design of the chimneys of condensing boilers is not very different from the design of the chimney of conventional gas boilers.

Features of chimneys for condensing boilers:

• the material from which they are made. The chimney for a condensing boiler must be made of acid-resistant materials, for example, stainless steel or plastic. This is due to the fact that the condensate that passes through the chimney is a light acid, so the chimney material must be protected from corrosion.
• The chimney for a condensing boiler must be located at such an angle that the resulting condensate flows back into the boiler, but no precipitation gets there. The entry of atmospheric precipitation into the boiler can lead to a short circuit or breakdown of the boiler.

Condensate drainage and main mistakes when installing condensing boilers

A condensing boiler provides an operating system in which condensate is formed from water vapor contained in combustion products.

Depending on the power and temperature conditions, up to 50 liters of low acidity condensate can be formed per day. This allows you to drain it into the household waste siphon and not harm the environment.

However, there are some errors when:

1. Lack of condensate drainage or installation of an unsuitable container for this purpose. Experts can also make this mistake due to inexperience. They may either not install a condensate drain at all or install some kind of container, for example, an ordinary bucket, as a drain. This should not be allowed, because it is a grave mistake.
2. The condensate drain is led outside, which, of course, in sub-zero temperatures will lead to icing and freezing of the pipe. This will block the boiler and may cause it to break.
3. Installation of boilers on walls with flammable coating.
4. The use of a gas meter that does not correspond to the boiler power.
5. No gas filters.
6. Failure to maintain the correct slope angle of the boiler.

A condensing boiler requires the presence of all of the above points, and also requires compliance with all technical rules and standards for installation and assembly.

Often private houses do not have access to centralized systems, so owners have to independently decide how to implement...