In the case described, a conformity assessment procedure is carried out in accordance with the Machinery Directive.
The pressure equipment must then have its own CE mark in accordance with the Pressure Equipment Directive.
Background information:
Extract from the 2nd Edition of the Guide to Application of the Machinery Directive 20006/42/EC
Directive 97/23/EC on pressure equipment (PED)
In accordance with Article 3, the PED is applicable, for the pressure hazards, to pressure equipment within its scope that is incorporated into or connected to machinery. If pressure equipment that has already been placed on the market is incorporated into machinery, the machinery manufacturer's technical file must include the EC Declaration of Conformity of that pressure equipment – see § 392: comments on Annex VII A 1 a.
Pressure equipment classified as no higher than Category 1 that is incorporated into machinery in the scope of the Machinery Directive is excluded from the scope of the PED. The Machinery Directive is thus fully applicable to such equipment. It should be noted that the Machinery Directive covers the risk of break-up during operation – see § 207: comments on section 1.3.2 of Annex I.