The fact that a range hood (with an internal motor) is used in combination with a ventilation system or a central fan does not withdraw the functionality of the range hood which is defined by the Regulation (EU) 66/2014 as an appliance, operated by a motor which it controls, intended to collect contaminated air from above a hob.
If the function of the referred product is to collect contaminated air from above a hob, it cannot be considered as a ventilation unit but as a range hood covered by Regulation (EU) 66/2014.
Disclaimer: Please note that the European Commission cannot provide a legally binding interpretation of the EU legislation, as this is the sole competence of the European Court of Justice. Any remarks from the European Commission services are without prejudice to the position the Commission might take should related cases arise in a procedure before the Court of Justice.