Double-circuit gas boilers have long been in demand in the heating equipment market. This is reasonable, because the equipment is designed simultaneously for space heating and water heating for domestic hot water. The assortment of popular manufacturers has models for every taste. Before buying, you need to study all the pros, cons and features in order to further ensure maximum comfort for yourself.
We have compiled a list of the main parameters that are usually of interest to future buyers. In our article you will find the best models from the brands Bosch, Vaillant, Ariston, user reviews and a description of technical specifications.
Structure
The main elements due to which the gas boiler operates: control unit, heat exchanger and burner. The heat exchanger is installed above the combustion chamber, inside it is the process of heating the coolant. The operation of the device is fully automated - this ensures complete safety and allows you to control temperature conditions.
Types of heat exchangers
Double
The dual heat exchanger has two modules, which are considered a single part. The primary module is responsible for heating the coolant for heating, the plate heats the water. The primary element looks like a curved finned tube, the plate - a set of compactly arranged plates.
Bithermal
The bithermal heat exchanger has two tubes - internal and external. The inner one is responsible for heating water for domestic hot water, and the outer one is for heating.
Experts say that the dual heat exchanger is much more reliable than the bithermic one. In the heating system, the coolant circulates continuously in a circle, so the scale is practically not formed. Running water is used for water supply, therefore a large amount of scale occurs, due to which this part of the heat exchanger often breaks down and requires replacement.
In the dual heat exchanger, only the part responsible for the hot water supply can be replaced. In the case of bithermic, you will have to change the entire module as a whole, and this is much more expensive. We also note that the construction of the bithermal type is much more complicated, the part is practically not repaired and most often requires replacement.
Material
- Stainless steel. The material is durable, but impractical. Due to insufficient heat transfer, efficiency is reduced. Despite this factor, the part is quite expensive.
- Galvanized steel. Galvanized steel heat exchangers break more often than others. It costs much less than the others, but it also does not last long.
- Copper. All high-quality gas boilers are equipped with a copper heat exchanger. Thanks to good heat transfer, efficiency is increased and gas consumption is reduced. For all the benefits you have to pay a decent amount, but such a detail will justify the high cost.
If you choose a technique by this criterion, it’s easy to decide. Copper will be the best option. Of course, everywhere has its drawbacks. Copper has a low melting point, but automation clearly monitors the general condition of the device and does not allow overheating.
Types of burners
All dual-circuit models are equipped with atmospheric burners, they can be:
- Single stage. To maintain the set temperature, the burner may go out and ignite; it does not have an intermediate position. Such a principle of operation can hardly be called reliable.
- Two-stage. The burner can operate at 100% and 50-60% power. Automation independently supports the specified mode and controls the power.
- Modulated. These are the most economical and reliable burners that can independently maintain the required power. Another plus - fuel consumption is reduced by 10-15%.
Automation and control modes
Automation is an important and indispensable element, without which the control and management of equipment is impossible. For security, the device constantly monitors three main parameters:
- flame control;
- pressure
- the presence of stable draft in the chimney.
These functions must be monitored first. In addition to the main, there are additional functions for which automation is responsible:
- Summer mode. In the summer, there is no need to use heating, so the device only works for domestic hot water. To prevent blockages in the heating system, the device periodically starts the coolant circuit.
- Post-circulation. After turning off the burner, the heat exchanger maintains a high temperature. The water will boil and the device will stop working if the circulation pump shuts off immediately. To prevent malfunctions, the pump drives the coolant for a while and turns off after setting the permissible temperature.
- Anti-frost. If the boiler is used for a private house or a summer residence in which you are periodically - the saving mode is started.
Type of combustion chamber
Open
Models with an open combustion chamber work according to a simple scheme - they take oxygen for work from the room. The device itself takes the amount of air that is necessary for stable operation.
This type of chamber requires the installation of a chimney through which combustion products and processed gases will be discharged. For such a boiler, the room must have good ventilation, otherwise you may suffer from suffocation or lack of air.
Closed
When installing a boiler with a closed combustion chamber, there is no need to free the whole room. This option is suitable if you are limited in area - installation will require only a few square meters. The air for operation is supplied with the help of a special fan, which works due to electricity - this factor can be attributed to the minuses.
If you decide to purchase just such equipment, you need to install a coaxial chimney. The device has a fairly simple design - one pipe is installed in another. Thus, air does not come from the room, but from the street, thanks to the installed outer pipe. All waste products are discharged through the outer pipe.
Mounting
According to the type of installation, the models are divided into two - wall and floor. What equipment is better to buy in a small apartment? If you are a fan of simplicity and compactness, stop at the wall-mounted version. Wall-mounted models do not require a special room; they can be installed in any room. Despite the size, the device can heat a room with an area of 250 to 350 square meters. m
Floor gas boilers must be installed in non-residential premises. The main rule that must be observed is good ventilation. Each manufacturer includes in the manual a list of requirements for a safe installation. Connection and adjustment of equipment must be carried out by a specialist.
Top Brands Rating
Most of the heating equipment on the market belongs to foreign manufacturers. Referring to the opinions of experts and users, we have compiled our list of the best double-circuit boilers, it includes manufacturers' models:
- Buderus;
- Bosch;
- Hotpoint-Ariston;
- Baxi;
- Vaillant.
Among the Russian brands can be distinguished brand "CONORD".
Description and specifications
Buderus Logamax U072-24 K
Buderus Logamax combines all the important parameters - true German quality, conciseness and style. The device is easily mounted on the wall, and takes up no more space than a conventional kitchen cabinet. Logamax U072 is not sensitive to gas pressure drops and power surges.
The system maintains stable operation even at a temperature of –35 degrees. The device has a flow sensor, a Hall sensor and a coarse filter - all elements are easily disassembled and cleaned. Additional security is provided by automation, which fully controls all processes.
Mounting type | Wall |
Dimensions | 700x300x400 |
Power | 24 kW |
The combustion chamber | Closed |
Expansion tank capacity | 8 l |
Heating area | 192 m² |
Gas consumption | 2.8 m³ / hour |
average price | 33 969 rubles |
Bosch Gaz 6000 WBN-18C RN
The model has a capacity of 18 kW and an efficiency of 93.2% - this allows you to heat rooms up to 144 m². The big plus of Bosch is its low gas consumption, which does not exceed 2.1 m³ per hour at maximum power. Automation controls the voltage in the network and maintains stable operation at voltage drops from 165 V to 255 V.
Note the compact dimensions that allow you to install the device even in small rooms.
Mounting type | Wall |
Dimensions | 700x400x499 |
Power | 18 kW |
The combustion chamber | Closed |
Expansion tank capacity | 8 l |
Heating area | 144 m² |
Gas consumption | 2.1 m³ / hour |
average price | 26 900 rubles |
Hotpoint-Ariston Atleas X24 Ff
Ariston is rightfully one of the first places on the heating equipment market. The entire line is famous for its advanced security system.
The Atleas X24 FF has a net power of 24 kW and an efficiency of 93.2%. For complete protection, the automation is triggered in the event of a drop in gas pressure, lack of traction, water overheating, flame extinction and liquid freezing in the circuit. The stylish display and the Ariston logo complement the picture.
Mounting type | Wall |
Dimensions | 770x400x315 |
Power | 24 kW |
The combustion chamber | Closed |
Expansion tank capacity | 8 l |
Heating area | 192 m² |
Gas consumption | 2.7 m³ / hour |
average price | 40 075 rubles |
BAXI Eco Four 24 F
The Baxi Eco Four 24 F is a fairly advanced model. In addition to heating and water heating, the boiler can be used for the “underfloor heating” system. Automation includes 7 protection systems, including anti-freeze mode. This mode can also be used during departure. The summer mode provides for the shutdown of the heating system during the summer season and the use of equipment only for domestic hot water.
Mounting type | Wall |
Dimensions | 730x400x499 |
Power | 24 kW |
The combustion chamber | Closed |
Expansion tank capacity | 6 l |
Heating area | 180 m² |
Gas consumption | 2.7 m³ |
average price | 39 540 rubles |
Vaillant atmo TEC pro VUW INT 200 / 5-3H
Vaillent atmo TEC pro is suitable for heating rooms up to 160 m². It is worth noting the presence of summer mode, thanks to which the device can only be used to heat water. Vaillant has several levels of protection: from overheating of water, disturbance of circulation, extinction of the flame and so on.
Mounting type | Wall |
Dimensions | 800x400x338 |
Power | 20 kW |
The combustion chamber | Closed |
Expansion tank capacity | 6 l |
Heating area | 160 m² |
Gas consumption | 2.8 m³ / hour |
average price | 41 870 rubles |
Reviews
Andrew, Stavropol
After the repair, I had to think about creating an independent heating system. Choose between Proterm and Navien. They wanted equipment with convenient controls, but they were confused by the high prices. After lengthy disputes, Proterm was purchased. With its help, we acquired not only our own heating, but also hot water. Most of all I like a quality protection system. When a gas outage occurred, the system drove water in emergency mode so that it did not freeze. It is a pity that a non-volatile boiler did not fit our requirements. And with this: no electricity - no heating.
Inna, Kirov
For a long time I did not know how to choose a technique and not make a mistake. After listening to acquaintances, I bought a model from Lemax - the price was fine and everything seemed to fit the characteristics. When the purchase was brought, the first question was, what is it and how to use it? Over time, I figured out the settings and controls - nothing complicated if you read the instructions. Although I still don’t know how some modes work. I would not say that my choice was the right one. In the spring, the burner itself began to go out, and then it could hardly be re-ignited.
The correct choice of a double-circuit boiler is a guarantee of a comfortable life with uninterrupted heating and hot water. We hope that our article will help you determine what you want to see in a future purchase. Do not forget about the rules of safe operation, and the equipment will last you more than a dozen years.