Any domestic solid fuel appliance i.e wood burning stove,multi fuel stove will only work efficiently when connected to a chimney system capable of generating adequate up draught to induce sufficient air for efficient combustion and to overcome any frictional resistance associated with the system.The natural (up) draught on the chimney will depend on a number of factors.
The use of a mechanical extractor fan in any room will creat a depression,if this depression is greater than the up draught generated by an open flued appliance installed in the same room the products of combustion will be drawn into the room
Long time experience confirms the above risks
Additional research has also indicated that the "natural ventilation" created by a continuous burning open flued appliance will greatly reduce the risk of condensation occurring within the room inwhich the appliance is installed
THEREFORE THE USE OF MECHANICAL VENTILATION IN THE SAME ROOM AS ANY OPEN FLUED APPLIANCE MUST BE AVOIDED