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Everything you need to know from E to O

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Efficiency
The efficiency is the ratio between the energy consumed (power input) and the energy available for heating (useful output). 100 % efficiency means that 100 % of the power input is returned in the form of heat. A boiler’s efficiency depends on a number of factors : the quality of materials used for the boiler’s heating body, the design of the burner, and the control system. Modern boilers have high efficiency rates ranging from 92 % to 95 %; these rates exceed 100 % with condensing boilers.

Eutectic cast iron
A eutectic heating body is made of cast iron, produced using De Dietrich’s technological expertise. The technology enables the boiler to durably withstand variations in temperature, and corrosion. The eutectic cast iron’s components (iron, carbon, silicon, etc.) are measured in very precise proportions to obtain their fusion at a very constant temperature. The cast iron produced using this process is as an excellent uniformity, with no inherent weak points. This results in an excellent resistance to corrosion.

Expansion vessel
Water expands when it is heated. A vessel capable of absorbing the expansion therefore needs to be positioned on the circuit. In installations fitted with an accelerator, the expansion vessel is "closed" and contains air or a gas which is separated from the water by a membrane. In thermosiphon installations, the expansion vessel is positioned at the highest point, and is "open" to the air.


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Floor-standing boiler
A floor-standing boiler is positioned on the floor and is usually associated with a high-quality domestic hot water production system.
 

Forced flue boiler
A forced flue boiler has no installation restrictions. It can be installed in a home without a chimney or with an inoperative chimney. It simply requires an opening in an external wall, of approximately ten centimetres in diameter, for the horizontal or vertical forced flue to pass through. This consists of a double concentric tube : one brings in the new air, the other discharges the combustion products.



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GCV (Gross Calorific Value)
This is equal to the sum of the NCV and of the latent heat in the steam produced by the combustion. By condensing this steam, we can recuperate additional heat (from 10 to 15 %), which can result in an efficiency of over 100%.

Gentle heat
Good insulation (walls, windows, roof, pipes) and the ability of modern boilers to operate at a low temperature means that radiators can be supplied with heating water at 50°C, as opposed to the former 70 or 80°C. To use this process, "Gentle heat" radiators are requiered which supply a more regular, more uniform heat. Using this method, the temperature differences between floor and ceiling are virtually eliminated.


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Heating circuit
Heat is produced in a boiler, which is then sent to a water circuit and is propelled by a pipe network to the rooms that need to be heated. The accelerator accelerates the circulation of the water.



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Immersion heater / Bath-water heater
An immersion heater or a bath-water heater is a fully independant device, which separates heating functions from domestic hot water functions.

Independent tank
An independent domestic hot water tank is a tank which is connected to the boiler, but that can be positioned at a distance. Its capacity ranges from 150 to 950 litres.

Instant domestic hot water
Domestic hot water is “instant” when it is produced simultaneously to its use. In order to do this, a boiler needs to have a high enough power to meet this requirement. The process is therefore limited to relatively moderate flows in order to prevent the installation of very large equipment.


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Low temperature boiler
Modern "low temperature" boilers function by keeping average temperatures between 30 and 60°C. This has three advantages: provision of the required quantity of heat when it is needed, reduction of the boiler’s losses to ambient air and reduction in energy consumption.


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Mixing valve

The function of a mixing valve is to mix the water at the heating outlet with the return water, in variable proportions, in order to:

  • permanently adapt the temperature of the water that is sent into the heating body to a level lower than the boiler’s temperature (in floor heating installations, a 3-way valve is required to avoid damaging the panel with water that is too hot)
  • raise the temperature of the return water, to avoid the formation of condensation inside the boiler which reduces the risk of corrosion
  • render the circuits fully autonomous (temperature, programming).

 

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NCV (Net Calorific Value of combustibles)
This is the total quantity of heat produced by the combustion of an energy source. For example, the combustion of 1 litre of fuel oil or of 1m3 of natural gas produces approximately 10 kWh. This enables us to compare the cost of different energy sources.


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Outdoor sensor
The regulator has an outdoor sensor which measures the outdoor temperature. The regulator adjusts the heating temperature automatically according to variations in the climate.