Coolant min. T
The minimum operating temperature of the heat medium in the boiler system when operating in heating mode.
Coolant max. T
The maximum operating temperature of the heat medium in the boiler system when operating in heating mode.
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.
Efficiency
The efficiency of the boiler.
For electric models (see "Energy source"), this parameter is calculated as the ratio of net power to consumed; in such models, indicators of 98 – 99% are not uncommon. For other boilers, the efficiency is the ratio of the amount of heat directly transferred to the water to the total heat amount released during combustion. In such devices, the efficiency is lower than in electric ones; for them, a parameter of more than 90% is considered good. An exception is gas condensing boilers (see the relevant paragraph), where the efficiency can even be higher than 100%. There is no violation of the laws of physics here. It is a kind of advertising trick: when calculating the efficiency, an inaccurate method is used that does not take into account the energy spent on the formation of water vapour. Nevertheless, formally everything is correct: the boiler gives out more thermal energy to the water than is released during the combustion of fuel since condensation energy is added to the combustion energy.
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.
Safety systems
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Gas pressure drop. This protection system ensures that the boiler is switched off in the event of a critical drop in gas pressure, insufficient for the normal functioning of the burner. In the event of such a fall, the valve that supplies gas to the burner is closed and blocked. After the restoration of gas pressure, it also remains closed; it is necessary to open it and resume the gas supply manually.
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Water overheating. A temperature sensor automatically turns off the boiler when the temperature of the water in the system is critically exceeded.
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Flame loss. Flame loss protection is based on a sensor that monitors the combustion of gas and automatically stops its supply. It prevents the room from filling with gas and the possible tragic consequences of this.
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Draft control. In boilers with an open combustion chamber, to maintain normal conditions in the room where such a boiler is installed, constant removal of products of combustion into the atmosphere is necessary. The lack of a normal draft in the chimney can lead to the accumulation of combustion products in the room. The draft protection system prevents this by automatically turning off the boiler when it detects the release of combustion products outside the chimney.
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Power outage. Most modern boilers h
...ave an electronic control system; in addition, many structural elements (pumps, valves, fans, etc.) are also powered by electricity. Thus, a power outage during the operation of the boiler will inevitably lead to an abnormal mode of operation, which is fraught with breakdowns and even accidents. To prevent such cases, a power outage protection system is installed, which completely stops the operation of the boiler in the event of a power outage. When the power supply is restored, the boiler needs to be restarted manually.
— Water circulation failure. This protection system controls the normal movement of the water through the heating circuit. Water circulation failure can lead to overheating of some elements of the boiler and damage to it. To avoid this, if the circulation is disturbed, the system turns off the pump and shuts off the gas supply to the burner.
— Frost protection. A system that controls the temperature in the heating circuit. Freezing of the liquid in the circuit disrupts the normal operation of the heating, which may require heating of the pipes and lead to system damage. To avoid this, when the water temperature drops below 5 °C, the burner is ignited, the circulation pump is activated, and the circuit warms up to a temperature of about 35 °C — thus preventing the formation of ice in the pipes.
