Today the market offers over a hundred different boilers foreign and domestic manufacturers. Which one is preferred? How not to make the wrong choice? Do not miscalculate with the cost? Best choice to charge boiler specialist who will design for you heating system and domestic hot water. He will be able to provide an optimal combination of elements of the system, choose the boiler allowed to operate in the room where he provided his installation in your home, and will orient you on how to obtain numerous permits for the installation. However, the final word rests with the developer, however, after hearing the arguments of the designer, you have to make the final decision himself.
Of what should be used in selecting a boiler? Primarily from the fuel, which will be the most accessible for the long term in the area of construction of your home. Note that modern boilers fired with liquid or gaseous fuels will run throughout the heating season in the automatic mode and does not require additional time on your part, except for seasonal maintenance work that can produce customer service. But with solid fuel boilers hassle more: they must constantly load fuel. Determine the type of fuel, start choosing the boiler design:
Single-loop – designed for heating the coolant heating system only, or only for the hot water system or a bypass – it is suitable both for the heating system, and hot water system.
Next come from the thermal capacity of the boiler, which should identify the designer, the required parameters of the coolant system, the necessary quality control boiler output depending on the outdoor temperature (single-stage, two-stage, continuously modulating control), the material from which manufactured the boiler, its weight, size , cost, and other characteristics and parameters.
Choosing the type of fuel for its future boiler, it is advisable to consult the district or regional officials. It is necessary to find out what types of fuel used in this area to date, as carried out the order and delivery, as well as to find out development plans for the near and long-term .
Better if the boiler is designed to burn any one type of fuel. In this case, the design of the boiler and furnace fuel will be perfectly balanced and the boiler will run at maximum efficiency.
The ideal option is a gas – the most economical fuel. It contains less sulfur compounds, so the gas is burning more efficiently, ie the combustion of a unit mass of gas is obtained more useful heat for heating and hot water, and combustion products contain less polluting substances. Boilers not corrode as the combustion of other fuels, less soot overgrow.
Gas boilers easier to clean soot and do it less often. Gas-fired boilers are more durable, is not required to store the fuel for the future, and therefore does not require additional fuel storage area under the house or near it. When using gas as fuel, no smells. (The presence of gas odor indicates an alarm condition of the boiler.)
However, gas is not available everywhere. In the new cottages, which occur away from the existing building, it does not come immediately. If gasification of the village in which the house is built, there is no hope, you can install the boiler on liquid fuel. In this case, additional areas for special steel or plastic container for diesel fuel at an average of 4-10 m depending on the volume level of the house and its thermal protection. Fuel capacity creates the owner of the boiler confidence in an unstable economy and the market, but long-term (over a year) fuel storage in transparent plastic containers may lead to physical and chemical “aging.” Of course, the capacity of which are double-walled and have almost one hundred percent reliable, safe, but will be present in the house, even a faint, but still noticeable odor.
The containers can be placed outside the building and buried in the ground, but it is better if it will produce a specialized organization, mounted boiler; this is done, if the hydrogeological conditions allow. The close proximity of groundwater to the spring half-empty containers may “float”. Buried in the ground containers should be checked annually for leaks and examine. The rest of the operation of the liquid fuel boiler is not much different from the operation of the gas boiler. Modern liquid fuel burner blowing heated fuel prior to combustion in efficiency are not inferior to the gas. Liquid fuel is vaporized when it is burned, and the mixture of fuel vapor and air.
If your location will be difficulties with the acquisition of diesel or confuses you its value, then you can stop the choice on boilers for combustion of solid fuels: stone or brown coal, wood, peat or slate. Combustion efficiency in this case will be much lower, and harmful emissions is significantly larger than that of the gas and liquid fuel boilers. Furthermore, additional fuel storage area under constant and time-consuming to load fuel into the boiler. What we can do if you found out that gasification of the village, which is your house, there will be a few years? Set the boiler to another type of fuel, and then replace it with a gas – too expensive. The best option in this case – combi boiler installation. Of course, any combination will cost a bit more expensive than the boiler for one type of fuel, increase size, will require additional space to accommodate both reduce the efficiency. This is especially noticeable in universal boilers for combustion of solid, liquid and gaseous fuels, the thermal efficiency of which the combustion of solid fuel is 58-60%, and liquid and gaseous 70-80%, while in gas and oil boilers – 90-95 %.
The optimum combination is for the combustion of liquid and gaseous fuels, as modern burners allow to burn both fuel almost equally. They modulate round a horizontal flame torch, so combi boilers for combustion of liquid and gaseous fuels have a cylindrical combustion chamber formed by the walls of iron or bimetallic (iron / steel) channels, which receive radiant heat, flame and convective heat their hot gases surrounding the transmission and its flowing transfer fluid on them. In the front end removable wall or door has a hole with a fixing device, which is mounted on (depending on what is supposed to fuel currently used) oil or gas burner of the blow, the corresponding output of the boiler.
Burner installation is easy. The burner is inserted into the hole, is adjusted to the depth of the combustion chamber, and then screwed onto the flange. Gas or oil-fired burner attached to the line with the union nut, from which pre-cap is removed. In reinforcing the burner block you want to insert two plugs. After this leak check gas valve and remove air from the pipeline or oil lines. Electrical wires are connected using connectors. Start the burner, especially the first one, a specialist should be made, as while the burner is regulated in accordance with the emission of polluting substances listed in the table in the installation manual of the burner, using a gas analyzer, which sensors are installed in the pipe for the flue. When switching to another type of fuel burner is dismantled and mounted torch for other fuels. Heating load of the building depends on the outside temperature, and with the design or close to load the boiler will run a relatively short period (5-20 days during the heating season). All the rest – with a load not exceeding half of the rated capacity of the current.
Logically it would be during the elevated temperature of the outer air reduce the capacity of the boiler, and hence the fuel consumption. However, the reduction of fuel consumption can lead to a change in the conditions of combustion, flame size in the combustion chamber and, as a consequence, reduces the efficiency. In this connection, by design, and liquid fuel gas burners can be single stage, two stage, designed for burning less fuel, and also modulating. Modulating burners allow power continuously adjusted depending on the heat demand by quantitative change fuel / air ratio, ie depending on when the amount of supplied air and the drag in the combustion chamber is changed fuel feed. This provides a stable boiler efficiency and minimum concentration of pollutants in the flue gas at a variable heat load.
Recently appeared on the world market combined burners for liquid and gaseous fuels. In this case, one set of the boiler burner, which is fed to the gas pipe and the fuel consumption of the liquid. There is no need to change the burner, it is only switch from one fuel to another. Naturally, such a burner device more complicated and the cost is much higher than with the two burners at different fuels. In this regard, such burner-still a rarity in the market.
For oil burner fuel from the tank is fed by the fuel pump pressure nozzle and sprayed in the form of tiny droplets. This droplet nuclei in the form of a mist mixed with air being blown into the fan blow necessary for combustion ratio and fed into the combustion zone. When ignition fuel mixture is ignited ignition device, and then the combustion process is supported independently. Flame will have in this case a yellow color. For blue flame used preheating fuel or electric heater flue gas stream. In this fuel droplets vaporize, turning into a vapor and mixes with air to burn more efficiently. Emissions of carbon monoxide CO, nitrogen oxides NOx and SOx sulfur will be far below the values of the most demanding European environmental standards. These oil burners are sometimes called blue-flame burners. Despite the fact that they are now more expensive than traditional, given that the regulatory requirements for combustion efficiency and ecology will grow for modulating burners with fuel preheating – the future.
Since gas burners for boilers have combined supercharging fan, they are more resistant to fluctuations in gas pressure in the pipeline network than atmospheric burner gas-fired boilers, and work even when the pressure of gas in the network to 70-80 mm. In order to improve energy conservation and efficiency in the combustion burner ignition, equipped with an air valve actuator (marked L in the model designation), which prevents the cooling of the combustion chamber at a time when the burner is not working. Gradually opening while firing boiler valve prevents pulsation and facilitate a smoother output boiler operating parameters. Today, the market are mainly the following burner manufacturers for gaseous and liquid fuels suitable for use in low-power boilers intended for heating houses: Hirsch (Giersch), Viessmann (Unit, Rotrix, Matrix, etc.), Weishaupt, Elko Kltsckner (all Germany), Hansa, Intercal, Bentone (Sweden), Oilon (Finland), etc.
Since the combustion of the liquid fuel to produce more sulfur compounds, which can condense on the surface of the walls of the boiler, especially at low water temperatures, combined surfaces boiler for liquid and gaseous fuels are made of cast iron, which is less subject to corrosion than the steel. This increases the weight of the boiler. In this regard, all combi boilers are produced in outdoor performance. Recently developed by Veissmann biometallicheskie boilers with double walls. This example model Vitola 100; Vitola 111; Vitola 200; Vitola 222. Biferralnaya mating surface heating of two materials – iron and steel consists of a steel cylinder and inserted into it elements of cast iron with radial ribs. The inner layer made of cast iron faces the flue gases, and when the calculated perceived performance at a higher temperature than the water facing the steel cylinder. This prevents condensation in the flue gases contained water vapor, the precipitation of condensate on the heating surface, and thus prevents its corrosion. “Cold start” this does not harm the boiler. The weight of the boiler is somewhat reduced.
Some models have built-in combi boiler capacity hot water cylinder. Those models that do not have them, can be attached to individual tanks, batteries of the same manufacturers that are installed near the boiler or under it to save living space. It should be noted that from January 1, 2000 came into effect new regulations for thermal protection of buildings, which provide for building envelopes in 3.5-3.7 times greater thermal resistance compared to 1995 levels. This means that the calculated thermal power boiler will decrease compared to the same area of the building, built on the old standards, as in 3.5-3.7 times. Of course, it will be real savings in the costs of boiler and heating system, and annual fuel costs. However, if the boiler serves both heating and hot water system, its capacity may not be enough for a comfortable hot water. Indeed, for a comfortable shower required flow 8 l / min of water at 40 ° C, and for filling the bath, which should occur at rates over 10 minutes, you will need hot water consumption of 15 liters / min. This will require 18-30 kW boiler output. Same power boiler at the present level of thermal insulation will be about 2-3 times less. Application of accumulator tank will increase the comfort of a large volume of hot water, but can simultaneously reduce thermal comfort in the house, because for heating larger volume of the accumulator tank hot water boiler with a smaller thermal capacity required a longer time – 40 minutes or more, and it is on this while the boiler is disconnected from the heating circuit. In this case it is necessary to do a feasibility study: or make selections based on the capacity of the boiler needs hot water, but use boilers with modulating burners that provide high efficiency at low power load, or use a separate storage tank hot water independent heating gas or oil burner.
When installing combi boiler will have to provide a separate room for placement of containers for liquid fuels. They can be plastic manufacturing firms Dehoust, Schutz, Roth (Germany) or steel produced by Roth. Plastic containers is cheaper and lighter than metal. Schutz firm produces tanks of 1050; 1600; 1850 and 2200 liters and a width of 78 cm and a height of from 195 to 199 cm, which provides the most economical use of the useful volume of the space and allows you to carry them through virtually any door. Double walls and reliable control system leak allow install them directly on the floor without a metal tray. A fuel tanks connected to a piping system to the battery required volume. Tanks are equipped with a special valve SMP protected from the spread of odor. On the fuel at the burner must install a fuel filter, for example, by Oventrop (Germany). The containers may be located outside the building and be buried deep in the ground freezing. It should be borne in mind that at low temperatures, the viscosity increases fuel, and the fuel pump will expend more energy to pump the fuel. Moreover, the water often present in diesel fuel, may freeze and clog the fuel lines.
Boilers have a connection for the flue to which shall be attached the chimney. Chimneys are made of stainless steel, because Flue gas temperature is low and loss may occur aggressive condensation in the chimney. Within chimney building, usually not Insulate.
Outside the building, due to the aforementioned reasons, it is necessary to carry out the chimney of stainless pipes with double walls between which is laid insulation. If the insulation is not provided, the condensate drain is arranged in a special tank that it should be followed by neutralization before descending into the sewer. These chimneys have a standard range of sizes and are produced by both domestic and foreign firms. For example, by Bertrams (Germany). Chimney section, its installation in the building and height depending on the capacity and combustion parameters must define and develop a project specialist for smoke removal. From the flue draft in the boiler depends on, and therefore, the reliability and stability of the combustion process. Error in laying the chimney may not only lead to improper operation of the boiler, but also to the accident, so this problem must be taken seriously.
Combination boilers have built-in device of automatic control work, which can be equipped with electronic units, for example, to program the boiler to operate in different modes of operation of the heating system, automatic temperature control of heated water in accordance with the ambient temperature, etc.
It should be noted that the combined boilers for liquid and gaseous fuels have increased reliability compared to gas-fired boilers, since shortages of gas, which can be on distribution networks, especially during periods of extreme cold, when possible freezing of gas condensate, the landlord can go to another type of fuel. Single point of failure in the circuit reliability combi boiler on liquid and gaseous fuels can be power outages, which ceased operation at the fuel pump, the fan, igniter and automatic control unit and the boiler automatically shuts down. With the resumption of power supply ignite automatically. However, if the electricity is not fed for a long time – a day or more, which often happens in small towns, there is a danger to “freeze” the heating system and the boiler itself. In this case it may be advisable to establish in-house backup generator power at the same diesel power which must comply with the total capacity of electrical equipment including electric boiler in a cottage or provide backup furnace heating, as is often the developers make individual houses abroad.
Most often, the choice in favor of an electric boiler affected by what electricity is almost everywhere now. But that’s just what we have electricity? More precisely, what do we have electricity? About as it is to talk too much. We live, as we know, not in the West, where for two or three-hour interruption in the power supply to the consumer the right to demand a penalty electricity company. We have the same electricity even in the Moscow suburbs sometimes disappears for a few hours and sometimes days. And during that period to do with heating? Uninterruptible power supply (UPS), capable of providing electric boiler energy for such a long period, of course, exist, but they occupy a volume of space and have such a huge cost that their installation in your own home can not be considered. So escape from the scourge is only powerful diesel generator. It is this feature of our electricity is simply impossible not to consider when choosing equipment. One should also consider that the cost of electricity in our country increases fairly regularly. Electricity has ceased to be the cheapest carrier (40 cents per kilowatt – a lot of it), what will happen next, predict, in general, is not difficult.
There is another nuance of domestic electricity. With supply voltages of 220 V power boiler will be limited to five kilowatts (boiler greater power supply is simply not allowed). This is barely enough power for heating the cabin 6×6 m And who is now building these homes? Now the most common house – is 250-300 square meters. A more powerful boilers are designed for three-phase voltage of 380 V. And you need to consider where to take these same three phases, the costs to laying power cables and for permission to leave electricity. After all, according to existing norms on every house put power of 10 kW / hour. Everything above this figure can only be obtained for an additional fee.
And this additional fee may be such that it is easier and cheaper to bring gas to the house. It is safe to say that virtually the entire Moscow region currently lacks electricity. Add to this the high depreciation grids. Energy often offer to solve these problems as follows: “Let us pave the high voltage cable to you, and you put your own substation and then do what you want.” Everything seems to be just, but the cost of its own substation may be such Even if such a problem to solve together the whole cottage village residents, and even then it manages to suck every homeowner is not cheap.
Choosing an electric boiler must take into account the fact that not any coolant in it can be used. TANS – a zone of intense heat, so there is always a “surface” layer of coolant, which overheats. From the “rigid” water begins to precipitate lime, ethylene glycol (antifreeze) starts to be burnt surface of the salt brines fall. What are the risks? Fraught is primarily that precipitated material (salt, soot, etc.) change the working conditions at the interface “TEN – coolant.” As a result, in order to heat up the old coolant temperature, the surface temperature of the heating element will have to increase that immediately affect its lifespan. Electricity consumption also increases. In general, problems immediately arise much. So before you fill in some new coolant, you need to think very hard.