Criteria for selection of double-circuit gas boilers, taking into account the characteristics

For heating of private houses and preparation of hot water, double-circuit gas boilers are suitable as well as possible. They work on the basis of the transfer of energy to the coolant that occurs when the most affordable and demanded type of fuel is burned. However, due to the extensive range of equipment is difficult to choose. Do you agree?

We will talk about how to determine the most appropriate model of a gas boiler. In the article proposed by us, all the guidelines for choosing a unit with the highest efficiency that can withstand intense operational load are given. Listed are market leading models and credible manufacturers.

The content of the article:

  • Structural features of the unit
  • What to consider when choosing?
  • Site classification
    • Floor type boilers
    • Features of the wall equipment
    • Parameters of parapet devices
  • Power Differences
  • Types of gas burners
  • Variety of ignition functions
  • Options for equipment
    • Modules with a natural bollard
    • Forced Equipment
  • Distinctive features of heat exchangers
  • Advantages and disadvantages of gas systems
    • Main advantages of devices
    • The disadvantages of double-circuit equipment
  • Overview of popular manufacturers and models
  • Conclusions and useful video on the topic

Structural features of the unit

A household gas appliance consists of a housing, two communication circuits, an integrated burner, heat exchanger, expansion tank, combustion product outlet unit, gas valve and control unit.

The main circuit is connected to a common heating system in a closed circuit. With the active operation of the unit in heating mode, the coolant circulates through the pipes of the primary circuit, and the hot water supply system (HWS) does not get into the system, since the way there is blocked by a special valve.

Installation of a double-circuit gas boiler

When installing equipment with two contour elements, it is necessary to remember that the length of the communication pipe connecting the boiler to the farthest point of the water intake should not exceed 7 meters. Otherwise, mineral elements deposited in the form of scale in the area of ​​the heat exchanger will begin to impede the movement of the working fluid and the productivity of the water heater will decrease significantly

When the user turns on a hot tap in the kitchen or bathroom, the valve is activated, closes the entrance to the heating pipes and directs the heat carrier to the DHW circuit for heating located in the heat exchanger water.

From there, the liquid enters the valve and is used for its intended purpose. When the need for hot water disappears and the valve closes, a reverse switch occurs and the valve redirects the heating medium to the heating circuit again.

What to consider when choosing?

All gas boilers of double-circuit type perform the same set of basic tasks, but differ from each other in such parameters as:

  • location;
  • power level;
  • type of burner;
  • ignition principle;
  • thrust type;
  • heat exchanger material.

All the above criteria are equivalent in importance and require mandatory consideration when choosing and purchasing heating equipment.

Site classification

By the principle of installation, boilers serving two communication circuits are floor, wall and parapet. Each option has its own special characteristics.

Focusing on them, the client can choose the most suitable method of installation, in which the equipment will be located conveniently, will not “eat” the usable area and will not cause problems in the process operation.

Floor type boilers

Outdoor units are high-power devices that can heat and provide hot water only a standard apartment or residential building, but also a large-sized production facility, a public building or construction

Double boiler connected to the system underfloor heating

If it is planned to use a double-circuit boiler not only for heating and domestic hot water supply, but also for feeding warm water floors, the basic unit is equipped with an additional circuit

Due to the large size and solid weight (up to 100 kg for some models) floor gas boilers they are not placed in the kitchen, but placed in a separate room directly on the foundation or on the floor.

Features of the wall equipment

Attachment is a progressive type of domestic heating equipment. Due to the compact size installation of a gas column can be made in the kitchen or in other small premises. It is combined with an interior solution of any type and organically fits into the overall design.

Gas boiler in the pantry

The double-hinged boiler can be placed not only in the kitchen, but also in the closet. It will occupy a minimum of space and will not interfere with any furniture or other household appliances.

Despite its small size, wall boiler has the same functionality as the floor device, but has less power. It consists of a burner, a surge tank, a pump for forcing the coolant to move, a pressure gauge and automatic sensors, giving the opportunity to use the fuel resource with maximum efficiency.

All communication elements "hide" under a beautiful, modern body and do not spoil the appearance of the product.

Gas boiler burner

Gas flow to the burner is controlled by an integrated security system. In the event of an unexpected termination of the supply of a resource, the aggregate stops functioning completely. When the fuel starts flowing again, the automation automatically activates the equipment and the boiler continues to work in standard mode.

The automatic control node allows you to set the instrument to any, most suitable for the user operating parameters. It is possible to set your own temperature regime for different times of the day, thus ensuring an economical consumption of the fuel resource.

Parameters of parapet devices

The parapet boiler is a cross between a floor and wall unit. It has a closed combustion chamber and does not create harmful emissions. Does not require the arrangement of an additional chimney. Removal of combustion products is carried out through coaxial chimneylaid in the outer wall.

Parapet type boiler

The parapet-type boiler is the best option for heating equipment for small-sized rooms with a weak ventilation system. The device is designed so that during operation it does not emit combustion products into the atmosphere of the room in which it is installed

The device is mainly used to provide hot water and full heating for small houses and apartments in high-rise buildings, where it is not possible to mount a classic vertical chimney. Base power varies in the range from 7 to 15 kW, but, despite such low rates, the unit successfully copes with the tasks.

The main advantages of parapet equipment are the ability to connect heating and water supply communications to the central gas system and pipelines from any side convenient for the user.

Power Differences

Coppers of double-circuit type on power share on one-stage and two-stage. Single-stage devices always operate at a constant power level and use the same amount of fuel resource year-round.

This is not effective and entails gas overspending, because high-quality heating is required for a house or apartment no more than 5 months a year. At all other times, “driving” equipment at full power is not reasonable and not economically profitable.

Double boiler in the home boiler room

When installing equipment with a base power of 30 kW, you should be aware that these types of devices should not be located in residential rooms, and in separate rooms, equipped with high-quality ventilation system, individual access to the street and full chimney

The functionality of two-stage devices is wider.

With it you can:

  • regulate the mode of gas supply and rationally use fuel;
  • reduce the number of on / off, thus reducing equipment wear and extend its service life;
  • reduce to a minimum the amount of harmful emissions into the air.

Additionally, the device is equipped with a soft switching module, which reduces consumption energy resource and allows you to simultaneously operate the boiler and boiler of any capacity, installed by separately.

Types of gas burners

Gas burner can be atmospheric or pressurized. The first type has an elementary structure and does not produce any noise in the process. The module is cheap and, as a rule, is included in the basic configuration of the boiler.

Atmospheric burner

Despite the simplicity, the atmospheric burner is very reliable and works well for a long time. It can be applied both on budget devices, and on expensive, "heaped up" luxury products

The principle of operation of the atmospheric burner resembles the work of industrial bottom models. Fuel resource is supplied through the ejector and due to the thrust absorbs air from the surrounding atmosphere. Through a special hole the mixture enters the combustion chamber and immediately ignites.

As a result, fiery flames with a very low actual temperature appear above the outlet openings, the task of which is to heat the coolant to the desired level.

Supercharged (mounted) burners demonstrate a high level of efficiency, in a constant mode they maintain the installed the temperature in the coolant itself and in the hot water supply system, but they are much more expensive than atmospheric analogues.

However, these costs are justified, since the modules have advanced functionality and make it possible to spend the fuel resource as reasonably as possible without reducing the level of comfort in the home.

Pressurized burner

The burner of the supercharged (mounted) type is not included in the basic set of the double-circuit gas boiler. It is purchased separately, and then installed on the heating equipment.

During full operation in the supercharged burners, the air supply is forced, and its volume is very clearly controlled by the internal automation. The module is placed in devices equipped with a closed combustion chamber operating with supercharging.

Fuel and air are mixed not inside the system, but at the outlet. The process of the device is almost completely automated and does not require human control.

Atmospheric burners are placed in heating bypass devices with a capacity of up to 80 kW. Supercharged (mounted) modules are being introduced into large-sized units with a capacity of up to several thousand.

Variety of ignition functions

Starting a domestic bypass boiler is carried out manually (by means of matches or a lighter) or by means of built-in elements (electric ignition or piezo ignition). The first method is the simplest and most accessible. The second makes it possible to save blue fuel, not leaving the wick in the igniter in a constant mode.

There is only one disadvantage of this option - dependence on the availability of electricity in the network. If the energy for some reason ceases to flow, the equipment is immediately turned off and automatically activated again when the supply of electrics resumes.

Piezo firing is absolutely safe and allows you to turn on the boiler by pressing just one button. The element does not depend on the supply of current and it is possible to use the equipment even in the absence of electricity.

Options for equipment

During operation of the unit, the fuel burns and flue gases are generated. To remove them from the dwelling, you must have natural or forced traction. It will ensure timely removal from the apartment or house of all products of combustion and released harmful substances.

Modules with a natural bollard

Natural-fired boilers have a simple construction and take the necessary air for full combustion from the room in which they are located. When intensively exploited emit some amount of steam and various chemicals. Removal of emissions produced through vertical chimney.

Double-circuit gas boiler

Among the main advantages of units with a natural burden is a reasonable cost, energy independence and the absence of noise effects during operation

In general, devices with natural paving are convenient and good; however, when the pressure in a gas pipeline drops, the quality of their work is significantly reduced. At the same time, the risk of rapid burnout of the burner increases, as the fire at a reduced pressure level diminishes or goes inside the burner.

Uneven pressure in backbone networks provokes serious fuel overspending, which entails an increase in the size of utility bills.

Forced Equipment

Boilers with forced type are sometimes called supercharged or ventilatory ones. The air they take is not from the room where they are located, but from the street. The modules are equipped with closed combustion chambers, and the release of waste substances is carried out through a coaxial horizontal discharge with the help of a powerful fan built into the system.

Coaxial gas boiler outlet

A coaxial tap consists of two pipe elements of different diameters inserted one into the other. Combustion products leave the room at a smaller pipe, and the space between the small and large pipes enters the room from the street with fresh air necessary for the full functioning of the boiler.

Products with a forced pitch are easily mounted, do not make claims to the location, do not "eat up" oxygen in residential areas, stably and They work well even with reduced gas pressure in central trunk networks and do not need an additional vertical chimney arrangement.

Instruments are blamed for the noisy operation of fan elements, higher cost, and dependence on power supply.

Distinctive features of heat exchangers

The heat exchange unit of the heating device can be cast iron, steel or copper. The cast-iron version retains heat for a long time, is almost not exposed to corrosion due to the high wall thickness, and is resistant to aggressive heat carriers. It has a lot of weight and therefore mainly integrates into floor boilers.

It requires great care during installation, since any blows violate the structural integrity of the material and lead to the formation of microcracks.

The steel structure weighs little, is not afraid of mechanical impact, calmly transfers temperature drops of the coolant, is easily transported and mounted. Has a certain tendency to corrosion. The boiler control system helps to avoid it, which does not allow the coolant temperature to fall below the critical point.

Copper elements are much more expensive than iron and steel counterparts, but compensate for the solid cost of a large number of advantages. Inside the heat exchanger of copper sediment and scale are formed at a minimum and do not interfere with the normal circulation of the working fluid. The walls of the device are heated uniformly and do not cause local overheating of the coolant.

Advantages and disadvantages of gas systems

In places where central gas communications are laid, double-circuit boilers are very popular. They are bought for heating and uninterrupted provision of hot water for apartments, houses and country cottages.

Main advantages of devices

The gas system demonstrates a high level of efficiency, gives several times more energy than it consumes, serves for a long time and runs smoothly. In constant observation by the person does not need.

Double boiler in the interior of the kitchen

Double boiler looks neat and modern. In contrast to the units operating on solid or liquid fuels, in the process of work practically does not emit unpleasant odors and creates a minimum of soot and soot

The fuel resource is fed to the plant continuously, and the built-in controller independently monitors the presence of fire on the burner. If the flame is extinguished, the sensor sends a signal to the ignition unit and the automatic spark supply instantly restores the fire. The control of the boiler is elementary and does not pose any difficulty

The disadvantages of double-circuit equipment

The main disadvantages are associated not so much with the device itself, as with the process of its legitimization and installation. You can’t just buy a boiler, bring it home and install it yourself according to wiring diagram. First, it is necessary to observe a lot of technical nuances, draw up documentation and coordinate all subsequent actions with the local gas supply company.

There will be required to provide:

  • project equipment installation, issued in accordance with the norms adopted in the law;
  • contract for installation with a specialized organization;
  • copy of the license of the profile organization, confirming the right to conduct work.

In addition, you will need to organize the removal of exhaust gas from the dwelling, to build an additional chimney for this or use the old one, and to control a potential gas leakage, install additional equipment.

Master repairs gas boiler

If the boiler smokes, it is possible that the pressure in the system has decreased or the operating burner has worn out and started to burn through. A professional with proper experience can help you quickly fix problems.

The main installation activities can be started only when the project documentation for gas heating organization It will pass all the stages of coordination and the client will receive a stamped permit for the arrangement of the system.

Overview of popular manufacturers and models

The market of modern gas equipment offers customers a large number of high-quality appliances for residential heating and hot water.

Among mounted units the most popular are:

  • Navien DELUXE 24K (South Korea) - efficiency, good functionality and reasonable cost;
  • Baxi MAIN 5 24 F (Italy) - low cost, high efficiency, long service life;
  • Vaillant turboTEC pro VUW 242 / 5-3 (Germany) - reliability, high-quality heat dissipation.

In addition to the qualities listed above, the models are notable for their attractive appearance, compact dimensions, fit into a variety of interiors and freely placed even in small rooms difficult layouts.

Gas device with two circuits Vaillant

The gas device with two contours of the German company Vaillant has a convenient control knob and a display on which you can see the level of heating medium at the moment

Of the outdoor units, the most demanded high-power (30 kW) ATON Atmo 30E, practical Lemax Premium-25B and more expensive, but very functional Navien GA 17KN.

Boiler Navien GA 35KN

Navien GA 35KN despite the high power, reasonably consumes fuel and allows owners to save on utility bills without compromising personal comfort

Baxi SLIM 2.300 Fi and Protherm Bear 40 KLZ are included in the line of premium technology. Have advanced functionality and reliably serve for many years. For all parameters and physical characteristics correspond to the strictest European standards (confirmed by the certification certificate CSQ and UNI EN ISO 9001).

Wall mounted double boiler

For small-sized premises (up to 50 sq. M) suitable boiler with a base power from 7 to 12 kW. If the area of ​​real estate is larger (for example, 150-200 sq.m.) it is better to purchase a 23-25 ​​kilowatt unit

Weak units simply cannot provide a large apartment or a house with full heating.

Buy floor gas boilers and wall models it is necessary only in company stores or official representative offices of manufacturing companies. There, the client will be told in detail about the principles of operation of this or that unit and will help to make the best choice.

Conclusions and useful video on the topic

A simple and clear description of the basic principles of the operation of domestic gas bypass boilers. Overview of the "quick start" and "run out of the pump":

Expert opinion and a few interesting moments that should be paid attention to when choosing a boiler:

How are wall-mounted boilers and how they work:

Purposeful choice of a double-circuit domestic gas boiler for heating and hot water supply is an important, crucial moment. No need to hurry here. It is better to think over everything in advance, to decide on the brand and type of equipment, to calculate short-term costs.

It is necessary to take into account the cost of the purchase and installation activities, and then make a purchase in a specialized store. The manager will issue guarantee papers and at the same time advise the client in detail on the principle of operation of the device and the rules for safe operation.

Please write comments in the block below, ask questions, post a photo on the subject of the article. Tell us about how you selected the model of a gas boiler for installation in your own home or in the country. Share useful information and guidelines of choice that will be useful to site visitors.

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