Home heating systems using gas boilers as a heat source are becoming commonplace and widespread.
Often homeowners refuse the services of centralized networks in favor of autonomous systems.
They prefer to independently regulate the heating mode and the start or end of the heating season.
The range of functions of modern gas boilers is much wider than before, new features and additions have appeared.
Let's consider a group of double-circuit boilers, the most popular gas units.
On smartphones, you can scroll the table right/left ↔
| Place | Name | Price |
| TOP 10 best gas double-circuit boilers | ||
| 1 | Buderus Logamax U072-24K | Find out the price |
| 2 | Federica Bugatti 24 Turbo | Find out the price |
| 3 | Bosch Gaz 6000 W WBN 6000-24 C | Find out the price |
| 4 | Leberg Flamme 24 ASD | Find out the price |
| 5 | Lemax PRIME-V32 | Find out the price |
| 6 | Navien DELUXE 24K | Find out the price |
| 7 | MORA-TOP Meteor PK24KT | Find out the price |
| 8 | Lemax PRIME-V20 | Find out the price |
| 9 | Kentatsu Nobby Smart 24–2CS | Find out the price |
| 10 | Oasis RT-20 | Find out the price |
Double-circuit gas boilers
Double-circuit boilers have two basic functions:
- House heating.
- Supply of hot water for domestic needs.
All other features are considered additional, contributing to a more successful and efficient performance of the main tasks. A special feature of this type of boiler is the need to operate throughout the year.
Single-circuit structures are stopped for the summer, which makes it possible to increase the service life of components and parts. Double-circuit units have to be operated in constant mode, turning off only the supply of coolant to the heating system.
This increases the load on the parts and components of the unit, reduces the life of the most loaded areas of the boiler.
As a rule, for such designs the power level is limited to 40-50 kW; more efficient units are already equipped with built-in storage devices or external boilers.
In terms of design, dual-circuit models are a basic option with an added secondary heat exchanger. However, there are other types of boilers that can demonstrate more stable and high performance.
These include:
- Designs with a combined heat exchanger. They provide more stable DHW heating, high performance and quick response to requests.
- Condensation models. These are boilers with the function of preheating the coolant using thermal energy from the condensation of water vapor from flue gases. Manufacturers claim an efficiency of 107-109% for them, which is completely absurd from a physics point of view. At the same time, condensing units are capable of working only with low-temperature systems. Under normal conditions, they lose additional capabilities and function as convection structures.
NOTE!
When choosing a boiler, you should make sure that its design can fully operate under the proposed conditions. Otherwise, expensive equipment will be used only partially, which is unacceptable.
Useful tips
- Be responsible when calculating power. If it is not enough, the room will heat up for a long time and cool down quickly. A powerful boiler, on the contrary, will lead to overheating - this is an unprofitable use of resources.
- If there is no separate, well-ventilated room and chimney, then a floor-standing boiler with natural draft will not suit you. It is better to opt for wall-mounted forced draft boilers.
- Do you already have hot water? Then you shouldn’t spend money on a double-circuit boiler.
- A biometric heat exchanger requires high-quality water without impurities. So if you do not have a water filter built into the water supply, then you will not save on such a boiler, because scale in the heat exchanger is guaranteed to lead to breakdown.
Kinds
Double-circuit gas boilers are distinguished according to certain characteristics.
By installation method:
- Wall mounted . For hanging installation, strong load-bearing walls are required. The dimensions and weight of such units are limited by permissible load conditions.
- Floor-standing . They can be installed directly on the floor, which expands the capabilities of boilers and allows them to be equipped with massive units of increased power and productivity.
By type of heat transfer:
- Convection . The coolant is heated by a gas burner.
- Condensation . A two-stage heating scheme is used, where the first stage is the heating of the return flow in the condensation chamber, and the second is the usual preparation process in the primary heat exchanger. For the process to proceed correctly, it is necessary to provide appropriate conditions, which is only possible in the southern regions.
By heat exchanger type:
- Separate . The heating of the coolant is carried out by the primary unit, and the secondary heat exchanger (usually plate type) is responsible for preparing hot water.
- Combined (bithermic) . It is a coil made of a pipe of a specific cross-section, where two streams can flow simultaneously without mixing. Allows you to increase DHW productivity, but is difficult to clean from lime deposits.
By type of combustion chamber:
- Atmospheric (open) . The traditional way of boiler operation, where smoke is removed naturally through a standard chimney, and air is taken directly from the room.
- Turbocharged (closed) . Air is taken from the outside using a coaxial chimney (pipe-in-pipe design). The turbocharger fan provides fresh flow. It also displaces flue gases, providing a stable and adjustable smoke removal mode.
IMPORTANT!
Turbocharged models are much more efficient and stable in operation; they are optimally suited for use in residential areas.
What is important to do before installation work begins?
Before purchasing a gas boiler for an apartment, there are requirements that must be met:
- obtain permission from the gas service to install heating equipment;
- select the room and location where the unit will be located;
- take care of the availability of high-quality ventilation;
- choose a coaxial chimney and think about how it will be laid.
You cannot install gas equipment in apartments:
- multi-storey buildings not connected to the main gas pipeline;
- where there are false ceilings and capital mezzanines.
To carry out installation, it is better to call specialists who have the right to perform such work.
What parameters should you pay attention to when purchasing?
When choosing a suitable model of a gas double-circuit boiler, you should pay attention to the main technical parameters of the units:
Combustion chamber type
The most popular are boilers with a closed combustion chamber. The entire process of fuel combustion and smoke removal occurs in a system isolated from the room atmosphere, which increases safety for people.
In addition, the controlled smoke removal process is much more effective than unstable natural draft.
Power
The boiler power level is the main indicator demonstrating the ability of the unit to provide thermal energy to rooms of different sizes.
Usually the desired model is selected based on 1 kW of power per 10 m2 of area.
It is necessary to take into account that you should not make a large reserve, since the boiler operating mode should be close to the nominal one.
Heat exchanger material
For the manufacture of heat exchangers they use:
- Stainless steel . This is the most affordable option, which is used in boilers in the middle and budget price range. The heat transfer and service life of such units are quite high, there is the possibility of repair or restoration.
- Copper . Heat exchangers of this type are installed in the most expensive and productive series of gas boilers. The performance of copper heat exchangers is considered the highest.
- Cast iron . Typically used in powerful floor-standing units. The heating mode is stabilized due to the high thermal inertia of the material.
Boiler type
There are two types:
- Convection . Conventional design of a gas unit.
- Condensation . In addition to the traditional method, these models are equipped with a coolant preheating function, which reduces fuel consumption and the load on the heat exchanger.
When choosing the type of boiler, it is necessary to take into account that the operation of condensing devices is possible only when the difference between external and internal temperatures is no more than 21°, which in Russia cannot be ensured due to climatic conditions.
Energy independence
There are volatile and independent installations. The former have the maximum range of functions, but in the event of a sudden power outage they become useless.
The latter do not use electricity, which expands the geography of their use. At the same time, non-volatile models have minimal capabilities and a complex ignition method.
TOP 10 rating
Let's consider the most popular models of double-circuit gas boilers, recognized by specialists and ordinary users as the most successful in design and operational terms:
Buderus Logamax U072-24K
Gas double-circuit boiler designed for wall mounting. Equipped with a closed combustion chamber and a separate heat exchanger - the primary one is made of copper, the secondary one is stainless.
Heating area - 200-240 m2. Has several degrees of protection.
Models with the “K” index heat hot water in flow-through mode. It is possible to connect a room temperature controller.
Federica Bugatti 24 Turbo
Representative of Italian heating technology, wall-mounted double-circuit gas boiler. Designed to work in a cottage or public space with an area of up to 240 m2.
Separate heat exchanger - copper primary and steel secondary. The manufacturer provides a 5-year warranty, which indicates confidence in the quality and operational capabilities of the boiler.
Bosch Gaz 6000 W WBN 6000-24 C
The German company Bosch is known all over the world, so it doesn’t need any additional introductions. The Gaz 6000 W series is represented by wall-mounted models designed for use in private homes.
The 24 kW model is the most common; it is optimal for most residential and public premises.
There is multi-stage protection, the copper primary heat exchanger is designed for 15 years of service.
Leberg Flamme 24 ASD
Leberg boilers are usually classified as budget models, although there is no noticeable difference in cost with products from other companies.
The Flamme 24 ASD model has a power of 20 kW, which is optimal for houses with an area of 200 m2 . A special feature of this boiler is its high efficiency - 96.1%, which is noticeably superior to alternative options.
It runs on natural gas, but can be converted to liquefied gas (replacement of burner nozzles is required).
Lemax PRIME-V32
A wall-mounted double-circuit boiler, the power of which allows you to heat 300 m2 of area. This is suitable for two-story cottages, shops, public or office premises.
Produced in Taganrog, the basic technological principles of assembly were developed by German engineers . The boiler is equipped with a copper heat exchanger that ensures high heat transfer.
Designed for operation in difficult technical conditions.
Navien DELUXE 24K
Korean boiler, the brainchild of the famous company Navien. It belongs to the budget group of equipment, although it demonstrates high performance .
Equipped with all the necessary functions, has a self-diagnosis system and frost protection. The boiler power is designed to operate in houses up to 240 m2 with ceiling heights up to 2.7 m.
Installation method: wall-mounted, there is a separate heat exchanger made of stainless steel.
MORA-TOP Meteor PK24KT
Czech double-circuit gas boiler designed for wall-mounted installation. Designed for heating 220 m2 . It has several degrees of protection, blocking in the absence of liquid movement.
It is possible to additionally connect an external water heater, which significantly expands the possibilities of DHW supply.
Adapted to unstable power supply voltage (permissible fluctuation range is 155-250 V).
Lemax PRIME-V20
Another representative of domestic heating engineering. Wall-mounted double-circuit gas boiler, designed to serve 200 m2.
A modulating burner allows you to distribute fuel more economically by changing the gas combustion mode depending on the intensity of coolant circulation. It has a separate stainless heat exchanger and can be connected to a room thermostat.
There is a possibility of remote control.
Kentatsu Nobby Smart 24–2CS
Japanese wall-mounted gas boiler providing heating of 240 m2 and hot water supply. Model 2CS is equipped with a separate heat exchanger (primary copper, secondary stainless).
The main type of fuel is natural gas, but when changing jets it can be switched to using liquefied gas. Most of the performance characteristics correspond to European boilers of similar power and functionality.
It is possible to use several design options for the chimney.
Oasis RT-20
Wall-mounted double-circuit gas boiler made in Russia. Designed to work in rooms of about 200 m2. Equipped with an efficient copper heat exchanger and a stainless secondary unit.
The combustion chamber is turbocharged, there is a built-in expansion tank and a condensate drain.
With an optimal set of functions and high build quality, the model has a relatively low price, which ensures its relevance and popularity.
How does price influence choice?
Price is critical. Market conditions matter. People had more money, they invested in something more reliable, when there was less money, there was a crisis, people began to cut corners on everything. They choose what is cheaper. This is the paradox of the market. A person builds a house for at least 20 years, but at the same time does not think in terms of 20 years. The choice is made based on price.
This is a choice not only of boilers, but also of radiators, pipelines, fittings. If there is a crisis, then they put on frankly cheap bullshit. Forgetting that bricked-up pipes will be difficult and expensive to replace. Even if the crisis is already over and there is money.
Spare parts for wall-mounted gas boilers
Before purchasing a boiler, find out the cost and delivery time of spare parts for it. Ask Gorgaz which boilers they service.
You need to heat your home. You agreed with them that they will build your heating system, and most likely, they will also purchase all the materials. Many installers have discounts, and they make a little money by supplying materials, and you save a little.
Most likely, you will ask them the same questions that customers most often ask me:
- Can you tell me which gas boiler to buy for a private home?
- Which pipes are better and why?
- Can you tell me which heating radiators are better?
- How long will delivery of goods and installation take?
- Why so long?
- Why is it so expensive?
What materials do you think installers recommend in 90% of cases? Most installers recommend those materials on which they get the biggest discount!
