Heat output
It is the maximum useful power of the boiler.
The ability of the device to heat a room of a particular area directly depends on this parameter; by power, you can approximately determine the heating area, if this parameter is not indicated in the specs. The most general rule says that for a dwelling with a ceiling height of 2.5 – 3 m, at least 100 W of heat power is needed to heat 1 m2 of area. There are also more detailed calculation methods that take into account specific factors: the climatic zone, heat gain from the outside, design features of the heating system, etc.; they are described in detail in special sources. Also note that in dual-circuit boilers (see "Type"), part of the heat generated is used to heat water for the hot water supply; this must be taken into account when evaluating the output power.
It is believed that boilers with a power of more than 30 kW must be installed in separate rooms (boiler rooms).
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.
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.
Max. gas consumption
Maximum gas consumption in the boiler with the corresponding energy source (see above). Achieved when the gas heater is operating at full capacity; with reduced power and consumption, respectively, will be lower.
Note that boilers of the same power may differ in gas consumption due to the difference in efficiency. While the more fuel-efficient models tend to cost more, the price difference pays off in gas savings.
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".
Central heating return
The diameter of the pipe for connecting the pipe through which the cooled water returns from the heating system to 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.
