This invention concerns a method of improving kidney function, whereby a negative pressure is induced in the kidney. To this end, the rinsing program run is adapted if there is insufficient salt, if the softening device is switched off, and if the dishwasher machine is on. According to the methods, the coil is not damaged and a resin molding is formed with a uniform thickness. The front face of the support plate is further provided with at least one intermediate front layer made of a thermally conducting material extending at least partly below the chip. The transmission is operable in a plurality of operating modes, including at least mode in which the variator is utilized to provide a transmission ratio varying within a defined range and at least one mode in which the variator is bypassed to provide a fixed transmission ratio. This approach improves over the conventional distributed security model by centralizing security in one multi-level management structure.