METHOD FOR OPERATING A WATER CONDUCTING HOUSEHOLD DEVICE

1 - 20 . (canceled)

21 . A method for operating a water-conducting household device, comprising:

determining a level of filter contamination of a filtration system connected in a hydraulic circuit of the household device; and

partially discharging wash liquid out of the household device in response to a determination that a predetermined threshold level of filter contamination has been undershot.

22 . The method of claim 21 for operating a dishwashing machine.

23 . The method of claim 21 , wherein a portion of the wash liquid remaining in the water-conducting household device after partial discharge is applied to the items to be cleaned.

24 . The method of claim 23 , wherein in a filling step an additional quantity of water is added to the portion of the wash liquid remaining in the water-conducting household device.

25 . The method of claim 21 , wherein the level of filter contamination of the filtration system is detected by means of a sensor device.

26 . The method of claim 21 , wherein the step of determining the level of filter contamination includes detecting at least one parameter selected from the group consisting of rotational speed and power consumption of a circulation pump connected in the hydraulic circuit.

27 . The method of claim 26 , wherein the step of determining the level of filter contamination includes evaluating at least a rotational speed profile of the circulation pump.

28 . The method of claim 27 , wherein a measure for rotational speed fluctuations of the circulation pump is determined from the rotational speed profile.

29 . The method of claim 28 , wherein the measure for rotational speed fluctuations is compared with at least one predetermined threshold value, and it is concluded that the predetermined threshold level of filter contamination has been undershot when the value of the determined measure for rotational speed fluctuations is lower than the predetermined threshold value.

30 . The method of claim 21 , further comprising driving a circulation pump by a brushless DC motor for applying wash liquid to items to be cleaned.

31 . The method of claim 30 , further comprising detecting an induced back electromotive force and/or a phase shift between an electrical voltage applied to the DC motor and a motor current for determining the rotational speed of the brushless DC motor.

32 . A water-conducting household device, comprising a hydraulic circuit with a filtration system whose level of filter contamination is detectable, wherein wash liquid is dischargeable only partially from the household device when it is detected that the predetermined threshold level of filter contamination has been undershot.

33 . The water-conducting household device of claim 32 , constructed in the form of a dishwashing machine.

34 . The water-conducting household device of claim 32 , wherein a portion of wash liquid remaining in the water-conducting household device after partial pumping-out is applicable to items to be cleaned.

35 . The water-conducting household device of claim 34 , wherein in a filling step an additional quantity of water is added to the portion of wash liquid remaining in the water-conducting household device.

36 . The water-conducting household device of claim 32 , further comprising a sensor device constructed to detect the level of filter contamination of the filtration system.

37 . The water-conducting household device of claim 36 , further comprising a circulation pump connected in the hydraulic circuit, said sensor device detecting a rotational speed and/or power consumption of the circulation pump for determining the level of filter contamination.

38 . The water-conducting household device of claim 37 , further comprising a control device operably connected to the sensor device for evaluating at least one rotational speed profile of the circulation pump.

39 . The water-conducting household device of claim 38 , wherein the control device is embodied for determining a measure for rotational speed fluctuations of the circulation pump from the rotational speed profile.

40 . The water-conducting household device of claim 39 , wherein the control device is embodied for comparing the determined measure for rotational speed fluctuations with at least one predetermined threshold value and determining that the predetermined threshold level of filter contamination has been undershot when the value of the determined measure for rotational speed fluctuations is lower than the predetermined threshold value.

41 . The water-conducting household device of claim 37 , further comprising a brushless DC motor for driving the circulation pump.

42 . The water-conducting household device of claim 41 , further comprising a control device constructed to detect an induced back electromotive force and/or a phase shift between an electrical voltage applied to the DC motor and a motor current for determining the rotational speed of the brushless DC motor.