système à deux tuyaux à retour inversé

CONT: [Chauffage à eau chaude]. (...) lorsque la température d'eau excède 100 °C il convient pour éviter toute vaporisation intempestive dans les vases d'expansion ouverts, de mettre ces derniers en circulation selon le système dit ""du retour inversé"".

CONT: Two-pipe reversed-return system ... The total pipe resistance is about the same for all radiators. Radiator No. 1 has the longest supply pipe and the shortest return pipe while radiator No. 3 has the longest supply pipe and the shortest return pipe.
OBS: For large installations the supply of hot water needs to be kept separate from that water which has been cooled by passing through a convector. To accomplish this, one pipe is used to supply the hot water, which then empties into another pipe used for return. ... The return may be classified as reverse return or direct return. The reverse return results in a more even flow of water because the supply and return are of equal length, resulting in equal friction losses. The direct return requires slightly less piping.