This document specifies general performance requirements and general requirements and procedures for testing and calculation of the energy efficiency index (EEI) for glandless circulators having a rated hydraulic output power of between 1 W and 2500 W designed for use in heating systems or cooling distribution systems. This document also applies to pump heads designed for these types of circulators. All known hazards which are likely to occur at normal installation and operation are covered by the European Standards EN 809 and EN 60335-2-51. As regards safety for electro-technical parts of circulators, EN 60335-2-51 applies.