Dishwasher operation time is jumping

Symptom:

The running time that shows on the display is jumping, e.g. from 180 jumped to 130. Unit doesn't drain after prewash but continues with the main wash.

Background (Dishwasher Auto Clean Function):

All of the Samsung dishwashers are equipped with a "Turbidity" sensor.

This sensor is mounted at the very bottom of the dishwasher where it is sure to always be in contact with water.

The turbidity sensor detects the amount of dirt in the water by measuring the amount of transmitted light between the emitter and receiver to determine the cleanliness of the wash water. These turbidity measurements are supplied to the dishwasher PCB main (control board), which makes decisions on how long to wash in all the cycles.

The dirtier the water, the less chance for the light to reach the other side and therefore the longer the wash time.

Reason & Solution:

The time that shows on the display is an estimated time. The dirtier the water, the longer the wash time. On the other hand, the cleaner the water, the shorter the wash time.

** Normal Cycle **

Normal Cycle is a special cycle on the dishwasher. It's designed as an economic cycle. After the prewash, if the turbidity of the wash water, measured by the turbidity sensor is clean, the PCB will skip the water exchange and use the same water to continue with the main wash for energy saving purposes.