The circuit has a single stage or multistage compressor unit with at least one collecting container (S), at least one bypass container and at least one suction separator with a pump preventative control function. The function of the bypass container and the function of the suction separator are implemented in a separator (D). A vertical separating wall is located in the lower region of the inner chamber of the separator. The wall has at least one opening, preferably in its lower region.
