Power consumption
The maximum electrical power consumed by the boiler during operation. For non-electric models (see Energy source), this power is usually low, as it is required mainly for control circuits and it can be ignored. Regarding electric boilers, it is worth noting that the power consumption in them is most often somewhat higher than the useful one since part of the energy is inevitably dissipated and not used for heating. Accordingly, the ratio of useful and consumed power can be used to evaluate the efficiency of such a boiler.
Expansion vessel capacity
The capacity of the expansion tank supplied with the boiler.
The expansion tank is designed to drain excess water from the heating system when the total volume of liquid increases as a result of heating. It consists of two parts connected by a flexible membrane: in one, hermetically closed, there is air under pressure; in the other, excess water enters, compressing the membrane. In this way, a catastrophic increase in pressure in the heating circuit is avoided. The optimal volume of the expansion tank depends on several system parameters, primarily the volume and composition of the coolant; detailed recommendations for calculations can be found in special sources.
Expansion vessel pressure
It is a pressure in the hermetically sealed part of the expansion vessel (for details on the design, see Expansion vessel capacity). The required pressure in the expansion vessel must be approximately 0.3 bar higher than the initial pressure in the system. The initial pressure, in turn, directly depends on the total height of the heating system or, rather on the difference between the height of the highest and lowest points of the heating system. It can be derived using the approximate formula P=H/10, where P is the initial pressure in the bar, and H is the height difference between the highest and lowest point of the system in metres. Thus, if the height difference is 2 m, the initial pressure in the system is 0.2 bar, and the pressure in the expansion tank must be at least 0.5 bar.
Heat exchanger
The material of the primary heat exchanger, in which thermal energy from hot combustion products is transferred to the heat medium. The efficiency of the boiler, the heating rate and the service life of the unit directly depend on the material of the heat exchanger.
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Copper. Copper is a material with the best heat dissipation specs and high corrosion resistance. It heats up quickly, which allows you to save energy during the operation of the heating boiler, has a low roughness coefficient, and has a long service life. The only drawback of this metal is its high cost. Copper heat exchangers are installed in heavy mid-range and premium grade equipment.
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Aluminium. Aluminium as a heat exchanger material is characterized by excellent thermal conductivity and long service life. Moreover, it is cheaper than
copper. To reduce the cost of production in copper heat exchangers, they try to reduce the wall thickness. You don't need to do this with aluminium.
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Cast iron. Boilers with a cast-iron heat exchanger heat up for a long time and cool down slowly, retaining heat for a long time after heating stops. Cast iron is also notable for its high heat capacity and low susceptibility to corrosion. The service life of a cast iron unit can be 30 or 50 years. The reverse side of the coin is the huge weight and
...size of heating equipment, which is why boilers with cast-iron heat exchangers are produced mainly in floor-standing boilers. In addition, cast iron does not tolerate sudden temperature changes — they can cause cracks.
— Steel. Steel heat exchangers in heating boilers are the most widely used. Steel has a combination of high ductility and strength when exposed to high temperatures, is inexpensive, and can be easily processed at production stages. However, steel heat exchangers are susceptible to corrosion. As a result, they are not as durable.
— Stainless steel. Stainless steel heat exchangers are rare in heating boilers, which is explained by the high cost of using this material. But they combine the advantages of both cast iron and steel. Stainless steel exhibits high corrosion resistance, resistance to thermal shocks, low inertia, and long service life.Central heating flow
The diameter of the pipe for connecting the pipe through which the heated water enters the heating system from the boiler.
Diameters are indicated in inches. In some cases, it is allowed to connect a pipe of a different diameter through an adapter, but the best option is still a match in size. Among which models stand out for
3/4",
1",
1 1/4" and
1 1/2".
