A method for emptying a system filled with a liquid product is provided. The system comprises an inlet, a tank, a first pipe connecting said inlet to said tank forming a first flow path, a second pipe connecting said tank to said inlet forming a second flow path, such that said first flow path and said second flow path provide a circulation flow path. The said second pipe is provided with a diversion valve such that at least part of said second flow path is diverted or that said second flow path is not diverted, for example to a filling machine. The second pipe is further provided with a second valve placed between said tank and said diversion valve, and a connection pipe connecting said second valve and a connection point of said second pipe placed between said diversion valve and said inlet. The method comprises feeding in sterile air into said tank such that liquid product in said tank and/or between said tank and said diversion valve is pushed out from said second pipe via said diversion valve, changing said second valve such that sterile air fed via said tank is directed to said connection point via said connection pipe, and feeding in sterile air into said tank such that liquid product in said tank and/or between said tank and said second valve and/or in said connection pipe and/or between said connection point and said diversion valve is pushed out from said second pipe via said diversion valve.
