The invention relates to a liquid cleaning device that is intended for purifying liquid from pollutants, which liquid cleaning device includes a vessel, having a lower chamber and an upper chamber, which lower chamber is connected to a heating member arranged to heat the liquid in said lower chamber, as well as further including a riser and liquid-distributor member, which riser is arranged to transport heated liquid from said lower chamber up to the upper part of said upper chamber, where the liquid-distributor member is arranged to impart the heated liquid an increased area of exposure to surrounding air, the liquid then, by means of the gravity, running back downward outside the riser and being collected in the lower part of the upper chamber of the vessel, said upper chamber and lower chamber being in at least conditioned communication with each other in order to allow transfer of the liquid from the upper chamber to the lower chamber. According to the invention, the heating member is arranged to be capable of assuming at least two power levels and that a change-over member is arranged to automatically reduce the power level of the heating member.