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Everything you need to know from A to D

AB  – CD

Also known as a circulation pump or circulator, the accelerator circulates the heating water between the boiler and the rooms that need to be heated. Very old installations do not have accelerators; they function using the thermosiphon process.

Accumulation or semi-accumulation
A domestic hot water reserve is heated in advance and stored in a tank or an accumulation tank. This process is essential where hot water is required in significant quantities, with a constant temperature.

Ambient thermostat
This complements the action of the boiler thermostat, by measuring the temperature of the room in which it is located. When the room temperature reaches the preset temperature on the ambient thermostat, the boiler thermostat shuts down the burner or the accelerator.

Atmospheric burner
Atmostpheric burner boilers account for almost all domestic floor-standing gas boilers. The flow of the pressurised gas draws in all or part of the air necessary for combustion. In atmospheric burners with "total premixing", all the primary air is premixed with the gas inside the burner. The mix is very uniform and produces an excellent level of combustion cleanliness, with excellent efficiency and low polluting emissions. 


Bleed device
An expansion vessel installation has a separate vessel to collect excess water that is created during heating. This vessel must have at least one bleed device, generally positioned at the highest point of the installation, which is used for releasing the displaced air from the vessel. The bleed device can be manual or automatic.

Boiler tank
With a capacity ranging from 50 to 250 litres, the boiler tank can be "incorporated", or "juxtaposed", to the boiler. It is "incorporated" when it is housed in the same casing as the boiler’s body. It is "juxtaposed" when, built separately, it is positioned beside the boiler.

Boiler thermostat (or aquastat)
This device is used to control the boiler to meet heating requirements. This can consist of a simple thermostat positioned on the boiler or an ambient thermostat which also measures the temperature of the room. Modern installations, however, increasingly rely on automatic or even programmable control systems.


A  – B  – CD 

Condensing boiler
Smoke has a high steam content. In a condensing boiler, the smoke is cooled by the return of heating water. The steam condenses and its latent condensation heat is transferred to the return water, adding to the combustion heat. With this process, we can reach an efficiency level (NCV) above 100 % and can make significant energy savings.

Control system
A control system is used to control the boiler for the following functions : regulation of the boiler’s temperature taking into account outdoor temperatures and weekly programming with three operating modes (automatic, permanent comfort, holiday period). The DIEMATIC Delta’s programmable control system is highly evolved, easy to use and can be controlled remotely.

A  – B  – C  – D

Domestic hot water priority
Domestic hot water boilers are generally fitted with a domestic hot water (d.h.w.) priority device. Upon request from the d.h.w. sensor, the priority device shuts down the heating pump and starts up the d.h.w. load pump. All the boiler’s power is directed towards the d.h.w. tank for fast refilling. The tank’s capacity must correspond to the power of the boiler. For a domestic boiler (from 18 to 40 kW), a 130 to 150 litre tank provides an excellent level of comfort.

Dual function boiler
The dual function boiler (or mixed boiler) integrates an instant domestic hot water production process. This is suitable for 1-room or 2-room apartments, with a maximum of three water supply points (kitchen sink, washbasin, shower).