Too high and fluctuating chimney draught has a negative effect on combustion in the stove. The consequences are black glasses, increased fuel consumption, significantly higher emissions, energy losses and a possible overloading of the stove. Draft regulators react to pressure changes in the chimney and regulate the chimney draft to the optimum value for the fireplace. The supplied air volume increases the volume flow and thus limits the negative pressure. This process ensures even combustion – you save measurable energy and consequently fuel, and in addition, part of the fine dust is burnt off even before it enters the chimney.
The DraftBox is a draught regulator, in technical terms a secondary air device, for room air-dependent stoves with a NW 150 flue pipe connection. The stove must offer the possibility of connecting the flue pipe vertically and horizontally. The horizontal flue pipe connection must be used for the DraftBox. The second smoke pipe socket that may be required for the stove is not included in the scope of delivery.
Technical solution
The DraftBox is a draft regulator that is mounted behind the single fireplace in a visually inconspicuous way. The space-saving, matt black design blends in with the look of the fireplace. The DraftBox can be used for room air-dependent supply air routing.
- Quick and easy to retrofit on the additional horizontal smoke pipe connection NW 150 (must be provided by the customer)
- Draught optimisation at the nozzle of the fireplace
- Energy savings potential of approx. 20 %
- no overheating of the fireplace
- Energy and thus fuel savings
- over 50 % emission reduction due to constant draught conditions
- Pressure stabilisation of the flame pattern
- Optimisation of combustion
- Clean glass, as there is no breakage of the glass flushing system
- Connection to room air dependent stoves
- Room air dependent: Combustion air from the installation room
- External air supply: combustion air from supply air duct, ventilation shaft/chimney (must be present), thus optimised room climate, separate calculation by specialist company or chimney sweeper necessary.
- Space-saving, matt black design, thus visually inconspicuous
Proven efficiency
Independent study by the Fraunhofer Institute for Building Physics (IBP)
Emission assessment by Fraunhofer-Institut
The study found that emissions in the areas of CnHm, NOx, CO and dust were reduced by more than 50%.
Experimental set-up:
tested on a modern single room fireplace 3.0-6.1 kW
Results:
- up to 21 % increase in combustion efficiency
- up to 83 % reduction in chimney draught
- up to 45 % reduction in fuel consumption
- up to 45 % longer burn time with the same fuel quantity
DraftBox in three versions
The DraftBox is available in the versions: DraftBox light, DraftBox short and DraftBox long. The versions short or long differ only in length, not in function.
DraftBox light
The DraftBox light can be used with stoves with and without a supply air nozzle. It can be retrofitted to the horizontal smoke pipe nozzle without much effort.
DraftBox short/long
The DraftBox short/long is used for stoves with a supply air nozzle. These two models connect the supply air nozzle with the smoke pipe nozzle and can be adjusted by the individually adjustable distance between the nozzles. The DraftBox short/long is used on approved standard single fireplaces that are tested for room air dependency (RLA) (for example: wood-burning stoves in living areas).
The supply air is fed directly from the room during room-air-dependent operation; during operation on an external supply air inlet, it is fed to the stove via a supply air pipe. This supply air pipe must be provided by the customer. The dimensioning of the supply air duct of fireplaces must be carried out by a specialist company or by the chimney sweeper by means of a separate calculation.
