Refrigerant compressor installation comprising at least three compressors which are arranged in parallel between an intake conduit and a pressure conduit and which each comprise a lubricant sump unit, wherein the compressors, when in operation, work in such a way that the respective pressures in the respective lubricant sump units of the respective compressors form a pressure cascade according to which the compressors have a successively slightly decreasing pressure in the respective lubricant sump unit in a defined cascade sequence, and wherein the lubricant sump units are connected to each other in a manner corresponding to the cascade sequence by way of a lubricant conduit system for lubricant transport, and wherein each lubricant sump unit comprises a port to which is connected an insert element which on the one hand establishes communication with the lubricant conduit system and on the other hand is configured such that it predetermines, for the respective lubricant sump unit, a lubricant level from which lubricant is transported to the lubricant sump unit that follows next in the cascade sequence.