Which expansion vessels must have the CE mark?

According to the European Directive PED 2014/68/EU, the “CE” mark must be affixed to all the vessels in which the product of the maximum working pressure (PS) indicated in the vessel’s label, and the volume (V) is more than 50 liters per bar. Vessels for which the product PSxV is equal to or less than 50 liters per bar are included in the category of vessels ruled by Article 4 par.3 of the Directive, which does not need the “CE” mark.