The aim of the invention is to optimize the analysis of substances separated by gas chromatography with a gas chromatograph, comprising a separating device and a mass spectrometer situated down there from. While the second device is in the power-saving mode, the first device may grant bandwidth to the second device during one or more predetermined timeslots. A motorized transfer device is configured to transfer the cleaning unit from the location of a first smelt spout to the location of a second smelt spout. The helix shaped contacts having first and second portions being in mirror image relationship to each other.