I want to know how to set a vacuum pressure switch on a ZK2 series product.

Regarding the setting of a vacuum pressure switch, in the case of a vacuum pressure switch, refer to the operation manual for the ZSE10(F), and in the case of a vacuum pressure switch with an energy saving function, refer to the operation manual for the ZK2-ZSV□.
Operation manuals are here.ZSE10(F) ZK2-ZSV□