Article 7
1. Member States shall deem that boilers which comply with the harmonized standards, the reference numbers of which have been published in the Official Journal of the European Communities and for which the Member States have published the reference numbers of the national standards transposing those harmonized standards, to be in conformity with the essential efficiency requirements stipulated in Article 5 (1). Such boilers must bear the CE mark referred to in Annex 1, section 1, and be accompanied by the EC declaration of conformity. 2. The conformity of series-produced boilers shall be certified by: - examination of the efficiency of a boiler type in accordance with module B as described in Annex III, - a declaration of conformity to the approved type in accordance with module C, D or E as described in Annex IV. For boilers burning gaseous fuels, the procedures for assessing the conformity of their efficiency shall be those used to assess conformity to the safety requirements laid down in Directive 90/396/EEC on the approximation of the laws of the Member States relating to appliances burning gaseous fuels. 3. When appliances marketed separately are placed on the market, they must bear the CE mark and be accompanied by the EC declaration of conformity, which defines the parameters enabling them after assembly to achieve the useful efficiency levels laid down in Article 5 (1). 4. The CE mark of conformity to the requirements of this Directive and to the other provisions concerning the granting of the CE mark, and also the inscriptions specified in Annex I, shall be affixed on boilers in a visible, easily legible and indelible manner. The affixing on such products of any other mark, sign or indication liable to create confusion with the CE mark both as regards its significance or in its appearance shall be prohibited.