Heating area
The maximum area of the building that the boiler can effectively heat. However, it is worth considering that different buildings have different thermal insulation properties and modern buildings are much “warmer” than 30-year-old and even more so 50-year-old houses. Accordingly, this paragraph is more of a reference nature and does not allow a full assessment of the actual heated area. There is a formula by which you can derive the maximum heating area, knowing the useful power of the boiler and the climatic conditions in which it will be used; see Heat output for more details. In our case, the heating area is calculated according to the formula "boiler power multiplied by 8", which is approximately equivalent to use in houses that are more than a dozen years old.
Power supply
The type of electrical supply required for normal operation of the boiler. Power supply may be required not only for electric models but also for other types of boilers (see "Power supply") — in particular, for the operation of control automation. Connection options can be:
—
230 V. Work from a household system with a voltage of 230 V. At the same time, models with a power consumption of up to 3.5 kW can be connected to a standard outlet, but for high consumption devices, you need to connect directly to the distribution board. Many of the electric boilers with this connection also allow operation from 400 V (see below).
—
400 V. Operation from a three-phase system with a voltage of 400 V. This power supply is suitable for boilers with any power consumption. However, it is not as common as 230 V: in particular, it may be difficult to use it in a residential area. Therefore, this option is provided mainly in high-power devices for which a 230 V power supply is not suitable.
— Autonomous work. Work in completely autonomous mode, without an electricity connection. This format of operation is found in all boilers that do not use electrical heating (see "Energy source"), except for purely liquid fuel ones — in them, electricity is necessary for the operation of the fuel supply systems.
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.
Coolant min. T
The minimum operating temperature of the heat medium in the boiler system when operating in heating mode.
Heating circuit max. pressure
The maximum pressure in the heating circuit of the boiler, at which it remains operational, and there is no risk of physical damage to the structure. For a heating system, the maximum pressure is usually about 3 bar, and for a domestic hot water circuit up to 10 bar. When the maximum pressure is exceeded, a safety valve is activated, and part of the water is discharged from the system until a normal pressure level is reached.
"Summer" mode
It is an operating mode designed for the warm season. In this mode, it works only to provide domestic hot water, and the heating is turned off. If the boiler is equipped with an outside temperature sensor, this sensor is also switched off in
summer mode so that the heating does not turn on at night when the outside temperature drops.
Circulation pump
The presence in the boiler of
circulation pump.
Such a pump ensures the movement of the coolant along the heating circuit, due to which the heat is evenly and efficiently distributed over the radiators. Similar devices are also available as separate devices; however, buying a boiler with a circulation pump eliminates the need to purchase additional equipment and simplifies the heating system. The disadvantages of such models include the complex design: if a separate pump fails, it is enough to replace only it, and the module built into the boiler may require complex and expensive repairs, and the heating system becomes unavailable.
Also note that it is theoretically possible to build a heating system without a pump, based on natural circulation; however, such systems have several disadvantages, so it is still preferable to use forced circulation.
Flue diameter
The diameter of the pipe through which combustion products are discharged from the combustion chamber.
In boilers with a closed combustion chamber often used the coaxial flue, consisting of two pipes nested one inside the other. At the same time, products of combustion are discharged from the combustion chamber through the inner pipe, and the air is supplied through the gap between the inner and outer ones. For such flues, the diameter is usually shown in the form of two numbers — the diameter of the inner and outer pipes, respectively. The most popular values are
60/100,
80/80 and
80/125. Non-coaxial flues can be
100,
110,
125,
130,
140,
150,
160,
180 and
200 mm.
Inlet gas pressure
It is the optimum gas pressure supplied to the inlet of the boiler system. Most often indicated for natural gas and is about 15-20 mbar. This parameter must match the specs of the gas supply system. However, the pressure in the latter may be higher, which may require the installation of a special gas regulator.
