Structure and the main differences
The gas boiler consists of three main modules burner, heat exchanger, control automatics. The burner is located in the combustion chamber, above it there is a heat exchanger where the coolant is heated. Automation controls the whole process. It provides safety and changes the modes of the equipment.
Boiler with a closed combustion chamber (turbine)
Types of heat exchangers
Two-circuit boiler differs in that it can heat both water for heating and water supply. It is necessary to do it separately, that is why the heat exchangers are special. There are two types of them:
- Double heat exchanger. Consists of two separate modules, the primary and the platen. In the primary one the coolant from the heating system is heated, in the secondary one. the water for daily needs. The primary heat exchanger is a tube with fins, the secondary set of plates. They are located in different parts of the boiler at the top of the primary, lamellar at the bottom, but interconnected because read, a single part.
- Bithermal heat exchanger. It represents two metal tubes of different diameters, inserted one into the other. The inner tube heats the water for DHW, the outer tube for the heating system.
A system with a dual heat exchanger is more reliable. Since the heating system is closed and the coolant circulates in a circle, a little scaling is formed. When heating water for DHW the situation is reversed flowing water is heated, and therefore a lot of scaling. This part of the heat exchanger periodically requires repair or replacement. If a dual heat exchanger is possible to replace only the part that heats the water for domestic needs, the bithermal division is not provided, you have to change the device as a whole, and it is much more expensive. There is another point: dual-circuit gas boiler with a dual heat exchanger in this case normally works for heating, with the bi-thermal situation is different it does not work at all.
How to Install a Combination Boiler/Water Heater | Ask This Old House
Heat Exchanger Material
On the choice of a two-circuit gas boiler can also affect the material from which the heat exchanger is made. It can be:
- Stainless steel. Not a bad option for longevity, but it has a rather low heat output, which reduces the efficiency of the boiler. Nevertheless, the price of such a heat exchanger is high.
- Galvanized steel. It is the cheapest type of heat exchanger, but also the shortest lasting.
- Copper. An excellent option for heat transfer (boilers have a high efficiency) and durability, but the price is high. But this scares very few people outweighs the opportunity to pay less for gas in operation. It is for this reason that most of the good two-circuit gas boilers are equipped with copper heat exchanger.
Choosing a two-circuit gas boiler on this parameter is not so difficult. Copper seems to be the best option. Not without disadvantages high chemical activity and low melting point but they learned long ago to compensate. To ensure that the boiler automation does not overheat. Chemical activity is neutralized by using chemically neutral materials in the heating system polymeric pipes are used polypropylene or cross-linked polyethylene.
Types of burners for gas boilers
In the wall mounted double-circuit gas boilers are installed atmospheric gas burners. According to the method of flame control they come in:
- Single-stage. Burner either on or off. There are no intermediate positions. To maintain the desired mode of heating the burner fires up and then extinguishes. Not a good algorithm.
- Two-stage. There are two modes of operation: 100% power and 50-60%. Automation itself regulates the required power. Such burners are more economical, they allow you to maintain the temperature more accurately. By reducing the number of on/off cycles.
If we talk about the best choice, it is modulating burners. They allow you not only to maintain an accurate temperature of heating, but also heat water to the specified parameters. If you want to choose an economical two-circuit gas boiler, it must have a modulating burner.
Automation
Automatics in gas boilers is mandatory, it provides safety, switches modes of operation. There are three main parameters that are constantly monitored:
These are key points that just need to be controlled. If even one of these parameters is not normal, the boiler does not turn on. In addition there is an extensive list of additional functions:
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Maintaining a stable temperature. There are two types of automation: one controls the temperature of the coolant, the second the air in the room. comfortable conditions are created by controlling the air weather changes, but regardless of this in the room is maintained.
These are the functions that are common, but there are also specific: the ability to connect (and control) the solar panels, floor heating system. There is a weather-dependent automatic. In this case there are remote sensors, which are installed outside. According to their data the work of the boiler is adjusted.
Control panel of the gas boiler Ferroli Diva
All these functions are stored in the microprocessor that controls everything. The average user of the automation is faced only with remote thermostat that can be installed in any room and according to the readings of which the temperature can be regulated (another optional feature). In general, all interaction with the boiler and its automation is limited to a small panel. All the necessary information is displayed on the screen. There are also buttons that can be used to change the modes, set the temperature.
Main varieties of solid fuel boilers
The main unifying point is that a solid fuel boiler with a water circuit can only be installed on the floor. As fuel can be used various materials. wood, coal, coke and special fuel briquettes.
The peculiarity of double-circuit boilers is that they not only heat the room, but also provide an opportunity to get any amount of hot water. In order to choose the right solid fuel boiler you should consult a specialist in advance, who will help you choose the right model. It depends on how well the room will be heated.
What are the gas boilers for a private home
A wide choice of boilers can confuse the buyer. Therefore, it is necessary to understand what types exist and what their differences are. For the consumer it greatly saves time, nerves and money. You won’t have to listen to a sales assistant. You will not suffer inconvenience if you choose incorrectly. You will not have to spend money for a second boiler in case of an unsuccessful purchase. The difference between the boilers, for example, with open or closed combustion chamber is not so complicated. And we’ll help you figure it out.
One- and two-circuit boilers
The two large groups of boilers are single and double-circuit. In the second case, there is no need for an additional boiler. The boiler heats water not only for heating, but also for domestic.
Two-circuit gas boilers receive cold water from the central water supply. It is then heated and goes where it is needed at that moment. A special valve is responsible for water distribution. Heating systems provide hot water if there are no taps connected in the house. When the user wants to wash the dishes or take a shower, the design of the boiler directs the flow exactly to the domestic system. In this case, the water access to the radiators is blocked.
Important clarification: If you like to take a bath and want to put a two-circuit boiler, its required power should not be less than 28 kW. You can refine the value by considering the size of the rooms in the house and the number of occupants who regularly need hot water. The more these figures, the more powerful the boiler must be to provide all needs at once.
In some cases, it is possible to heat water for household needs and single-circuit boiler. Versions sold today can be designed for such a variant. But you still need to buy a boiler. Boiler for such a system is connected to the boiler, and only a specialist should deal with such installations and connections. He should also help in selecting models of devices. Most people do not want to get involved with such complexities and simply buy an electric boiler for household needs.
For example, to quickly connect an additional boiler, you can consider a boilerplex module from GIBAX. This model is used to connect both vertical and horizontal water heaters. The latter should be water heater and run on electricity. The diameter of the pipe connection to the water supply. 1/2 “. The module has the following modes: shutting off the water heater to the water supply system; drain water with air suction, in order to perform preventive maintenance.

Another way to divide stakes into varieties is open or closed combustion chamber. In the first option, the air is taken directly from the room, so a quality ventilation system is simply necessary.
And there is still a risk of lack of oxygen. In Europe, this type of boilers has already been abandoned, it does not pass today’s safety criteria, which in the EU are very strict.
But with some risks and possible additional costs boilers with an open combustion chamber have a very simple. They are relatively cheap. They rarely break down and shut down when compared to other models in the same price range. They are much easier to install and easier to find a specialist for that.
Boilers for heating the house with a closed combustion chamber are more relevant. They meet all modern safety requirements. At the same time require a separate installation of the chimney. But sometimes it is better to spend once and not worry, than to be afraid that the oxygen level in the house will go down. And as with such boilers, the risk of poisoning by combustion products, which is also present in the boilers of the open type, is excluded.
The disadvantages of the model with a closed chamber include the installation of a special ventilation system, which will consume electricity. This makes the boiler dependent on the voltage in the network, and means additional costs for the installation of the entire heating complex.
Today it is better to choose a boiler with a closed combustion chamber and the installation of a separate chimney. This is a safer option. But sometimes there are obstacles for installing this variant. For example, it is impossible to make a hole in the wall for the combustion products outlet. Therefore, in this matter, the main role played by the technical characteristics of the housing, which should be the basis for selection.
Choice criteria
Let’s first look at what parameters are selected for such equipment, and then let’s take a closer look at the features of each type.
So, first you need to analyze the initial data: the type and area of the living space, the presence of the main pipeline in its immediate vicinity. And also choose how to heat water for domestic needs.
- You can put any boiler in the country house, especially if it is equipped with a separate room and there is a possibility to install the chimney. But in the apartment instructions allow the installation of only one type of gas equipment. with forced draught. They have a closed combustion chamber and a special chimney, which at the same time exhausted gases and fresh air needed for combustion.
- Boiler power is chosen based on many parameters, the main ones. the heated area and ceiling height. According to a simplified formula, it is calculated by multiplying the area by 0.2 kW, assuming a ceiling height of 2.5 meters.
To keep the house warm, it is important to correctly determine the necessary capacity of the equipment
Please note! You also need to consider the region of residence, the quality of insulation of the house, the number of windows and doors, and other individual data. In addition, if you use gas boilers for hot water, you need to add to the calculated power of another 40-50%.
- If the house can not be connected to the centralized gas supply, the boiler can be powered by cylinder liquefied gas. But the cost of heating and water heating in this case will be much higher, and convenience of operation is lower. In such cases, it is better to consider alternative heat sources.
Heating with propane is allowed only in a private home with a separate room for the installation of cylinders
- Equipment functionality. You can choose whether it will only work for heating, or provide you with hot water on a permanent basis. In the first case, you need a single-circuit boiler, in the second. a two-circuit.
Differences in the scheme of heating and hot water between one-and two-circuit boilers
Features of gas heating
Despite the presence of a large number of alternatives (electricity, diesel, diesel fuel, fuel oil, wood, coal), it is still the gas heating that leads the world. And there are good reasons for this:
- Economy. Compared to other options, gas is relatively cheap and characterized by high efficiency. It takes into account not only the cost of fuel itself, but also the additional costs for its storage (for the consumer), maintenance of the entire system, etc. For example, parts for rare types of boilers can be hard to come by, and sometimes you have to overpay. This is also taken into account.
- Minimum human involvement. Heating with wood or coal requires the mechanical addition of fuel. Everything is automated here, including gas supply and flame control.
- Cleanliness, no soot, smoke and other things. Boilers can be safely installed in the kitchen.
- Large rooms can be heated. One powerful boiler is quite able to cope with a building of several floors.
At the same time the gas heating has its disadvantages. Or rather, the specifics.
In particular, the installation of the boiler requires approval of the gas inspection. Installation can be done only by the organization with the license to provide such services.
Do not forget that gas is explosive. That is why it is extremely undesirable to save on automation: it monitors, among other things, its leakage (we are talking about modern technology).
In addition, it is necessary to take care of ventilation. Combustion products can escape from the building naturally. But if you have problems with the draft, you need to change the place of installation of the boiler (which is not always possible) or to ensure that it is forced.
Heating boilers
Company “MTK Group” offers a wide range of gas, solid fuel and electric boilers from leading manufacturers.
Heating boilers are in high demand among residents of private homes and cottages, owners of small businesses. Since not every private building can have a central heating, boilers for the home are the most effective solution. Many owners of country property install heating boilers, which allow you to maintain a comfortable temperature in the house throughout the cold season. Boiler for home heating can be gas, electric or solid fuel. The principle of action of these units is to transfer the heat to the carrier which can be water, a non-freezing liquid or air.
Competently selected and installed, such a heating device will significantly reduce the cost of utility bills.
Gas boilers, despite the existing alternatives for heating suburban and private homes, are very popular. This is due to a lot of advantages of the equipment. a reasonable price, high efficiency, economy and ease of operation. The range of two-circuit gas boilers is incredibly large, which sometimes causes difficulties in choosing. Today’s article will talk about the models presented in the rating of the best two-circuit gas boilers in 2022.

The best compactness have 2-circuit models of units. All that is required for efficient operation, is placed in the body of the boiler. For it remains only to choose a place for installation in accordance with the technical requirements. 1-circuit models, equipped with a boiler, need more space, and therefore may require additional expense to arrange a separate room.
Principle of operation of the two-circuit gas heating boiler and features of its connection
All issues related to the organization of autonomous heating and hot water preparation are solved by purchasing a single boiler that can serve both systems. Not knowing the principle of operation of two-circuit gas boiler heating, it would be illogical not only to make a purchase, but also to operate the unit. Agree?
We will tell you about the scheme of operation of the heating device, consider all its weaknesses and strengths. Understanding the basis of operation of the equipment, you can easily enjoy all its benefits. And if necessary, you will be able to detect malfunctions in time, to understand and eliminate the causes of their origin.