A gas boiler designed for wall mounting is a combination of sensors and devices enclosed in one housing. It can be installed in the kitchen, thanks to its compactness it will not interfere. Choosing a wall-mounted gas boiler, you need to figure out what characteristics affect its performance, which companies produce the most reliable devices, since this is a potentially hazardous equipment.
The number of circuits of wall-mounted gas boilers
Models of gas boilers differ from each other in the complexity of the device, the principle of operation and cost. Of primary importance is the number of heating circuits. This characteristic determines the functionality of the boiler.
Single-circuit
Single-circuit wall-mounted gas boilers are intended only for heating. They have one heat exchanger. The heat carrier is heated due to the heat generated during gas combustion. Devices are made of steel, copper, cast iron. Copper heat exchangers are the most durable, as they are resistant to corrosion, but expensive. Pig-iron also will last a long time, but their disadvantage is fragility due to shock and sharp changes in temperature, significant weight. Steel heat exchangers are most popular due to the optimal price, weight and durability. Important disadvantages are external condensate corrosion and lower efficiency.
If equipment with steel elements is purchased, a boiler with a heat exchanger made of stainless or alloy steel should be preferred.
Double-circuit
In double-circuit boilers there are two heat exchangers, therefore they are used for heating and for providing a house or apartment with hot water. The devices are compact, a separate room for their installation is not required. When the secondary heat exchanger is operating, the heating circuit is switched off, i.e. DHW is a priority. If hot water is used in a standard volume, the coolant in the heating system does not have time to cool. Such a system is implemented due to the presence of a three-way valve.
Varieties by the principle of work
Gas wall-mounted boilers made in recent years are complex devices whose designers are trying to increase the efficiency in all possible ways. There are two varieties of wall-mounted gas boilers that differ from each other by the principle of operation.
Bithermal units
The design is represented by two metal tubes inserted one into the other. DHW water flows along the inner, smaller diameter, and the external circuit is designed for the coolant used in the heating system. A feature of such a device is that the internal circuit is heated from the external circuit.
Advantage: fast heating.
Disadvantages: maximum fuel consumption, excess traction.
Pre-thermal units
In pre-thermal boilers, the DHW heating circuit and the heating medium are separate, independent of each other. Tubes are usually copper, are located on different sides of the body, liquids are heated separately.
Advantages: rational energy consumption, work on natural traction.
Disadvantages: slow heating, the formation of limescale, the need for magnetic filters.
Specifications
The power range of wall-mounted equipment for thermal energy ranges from 4 to 60 kW.However, mounted boilers of low power are most in demand - from 4 to 25 kW.
Devices differ in the type of burners, which are closed (turbocharged) and open (atmospheric). In the latter, air from the room is used for combustion, exhaust gases are discharged through a chimney with natural draft. First, air is taken from the street, gases are taken to the street. A boiler with a closed burner can be equipped with two pipes or a coaxial pipe - a design of pipes of different diameters, where the smaller one is inserted into the larger one. They are brought out of the wall to the outside. Boilers of a closed type are noisy because their work is ensured by a supply fan, but they are considered safer.
In severe frost, the coaxial pipe can freeze, so its outer part is insulated with a protective casing.
Gas attachments are classified according to the principle of action on traditional and condensation. In traditional boilers, the thermal energy of residual gases is not used in any way. In the condensation for the extraction of heat from exhaust gases, another heat exchanger is installed. Combustion products are pumped by a fan. First, the coolant is heated due to the heat of the exhaust gases, then it enters the primary circuit, where it reaches the required temperature. The efficiency of condensing boilers is higher than traditional ones, but the price is higher as the device is more complex.
By type of energy consumed, boilers are:
- Non-volatile - less functional, but more reliable. Work in houses and rooms without electricity. Independent of power supply and power surges.
- Volatile - Electricity is used as an additional power source. When the power is turned off, the boiler does not work. It is recommended to connect them through a voltage regulator.
Volatile boilers are equipped with additional sensors and systems that increase operational safety.
Advantages and disadvantages
Each model has its own characteristics. The equipment is in high demand for a number of reasons:
- no separate boiler room needed;
- compactness;
- autonomy;
- high efficiency;
- profitability in comparison with the devices working on other types of fuel;
- the ability to connect to a gas cylinder and trunk;
- simple operation.
Disadvantages are also present:
- low power;
- dependence on electricity, sensitivity to power surges and the need to install an RCD for volatile models;
- installation clearance required.
The coolant for gas wall-mounted boilers must be of high quality.
Features of connection and operation
A simple wall-mounted boiler can be installed independently if the manufacturer in the technical documentation notes this possibility. In any case, the connection to the gas line and verification of the installation should be carried out by an authorized person. It is allowed to independently connect the device to the heating system, water supply. After checking the correct installation, the gas service specialist issues a permit for the operation of the boiler. It is impossible to use the boiler without this document, otherwise fines await the owner.
Before installing the boiler, it is necessary to develop and approve the project for laying gas pipes and connecting equipment. After the approval of the project, the boiler is installed, strictly observing all the requirements of the project documentation. A meter and a stopcock must be installed on the supply pipe.
In the room where the device is installed, there should be a window with a window. The wall on which the installation is carried out must be finished with non-combustible materials.You should also take measures to increase the efficiency of the ventilation system in order to ensure sufficient air exchange and minimize gas contamination of the room. It is recommended to make a hole in the kitchen door with an area of at least 0.02 m2 and close it with a grill.
Boiler selection criteria
The power of the device is the main characteristic that you should focus on when choosing equipment. It is indicated in the technical documentation. If you do not make accurate calculations, it takes 1 kW to heat 10 m2 of space. These values are very approximate. By default, the ceilings in the room should be no more than 3 m high, the outer wall is only one - the one with the window.
The buyer should pay attention to the characteristics of the boiler, its additional functionality in the form of built-in control and safety systems, as well as to the initial conditions in which the equipment will operate:
- the presence of a chimney;
- the need to install a water boiler;
- quality of double-glazed windows and wall insulation;
- place of installation;
- budget;
- climatic zone;
- the location of the premises, relative to the cardinal points.
All selection criteria are interconnected and interdependent.
With more accurate calculations, it usually turns out that the boiler capacity should be 20-30% higher. In addition, it is necessary to provide a power reserve in case of large frosts of approximately 20%. If an indirect heating boiler is connected to the device, it is necessary to add about 30%.
High power does not mean that gas consumption will be significant. This only suggests that the heated area warms up faster. The fuel consumption in this case will be approximately the same as when using less powerful models.
Double-circuit boilers are more suitable for heating rooms of a relatively small area - up to 250 square meters. If the total heated area is larger, there is a risk that the equipment will not cope with its task. In this case, it is recommended to choose a single-circuit mounted boiler, and to install an additional boiler to heat the water.
When purchasing a double-circuit boiler, it is necessary to focus on the performance of heating water. The fluid is heated by flowing method, therefore this characteristic is fundamental. The manufacturer indicates the number of liters per minute when heating the water at 25 or 35 degrees (Δt °). The norm with the simultaneous operation of one or two water points is considered indicators Δt °:
- 25 ° C - 11 l / min;
- 35 ° C - 7-8 l / min.
In summer, cold water is much warmer, therefore, it does not need to be heated very much, in winter, heating should be more intense.
Popular wall gas boiler manufacturers
The range of wall-mounted gas boilers is represented by products of foreign and domestic production, markedly different in price, quality, reliability. The most high-quality models of boilers of German companies are considered:
- Vaillant;
- Bosch;
- Buderus;
- Wolf.
More affordable, but also reliable boilers of Italian manufacturers:
- Ariston;
- Beretta;
- Baxi.
Of the brands of domestic production are popular "Neva", "ZHMZ". In any case, you should give preference to the products of those companies that have long existed in the market, provide a long warranty and have an developed network of service centers.
Reliability Rating
In the first place is the rating of gas boilers brand Ariston. The company's products are represented by four lines, of which two - Alteas X and Ariaton Genus - belong to the premium segment, and two - Ariston Clas and Ariston Egis - to the middle one. The boiler can be purchased at a price of 25 thousand rubles.
In second place is BAXI.The compact models Baxi Main 4 and Main 5, Baxi Eco 4 and Baxi Eco Compact with an additional stainless steel heat exchanger and budget Baxi 4 Tech and Baxi Eco 4S stand out especially.
In third place are the expensive, but high-quality Vaillant units. Vaillant turboFIT VUW 242 / 5-2 is popular - it is a relatively inexpensive model from the dual-circuit gas boilers declared in the rating with a copper primary heat exchanger.
The wall-mounted gas boiler is convenient in that for all its functionality it does not require a separate room for installation. Its rather modest characteristics are enough for heating and providing hot water to an apartment or a small house. Such equipment should be selected taking into account operating conditions by performing the necessary calculations.
