GE GDWT668V Technical Service Manual

Also see for Cafe CDWT280V: Dimension Guide Service manual

– 31 –Turbidity SensorThe turbidity sensor measures the amount ofsuspended particles in the wash water in the sump.The sump water lays within the 1/4- to 3/8-in. gapbetween the LED transmitter and the receptorduring the designated fills. Successive turbiditymeasurements are supplied to the control moduleand used to determine whether to add or skip anyprewash or rinse cycles and whether to adjust thewash or heat times. By measuring the turbidity level,the control module can conserve energy on lightlysoiled loads by skipping unnecessary cycles. If thesoil level is high, the control module adds one ormore rinse cycles and increases the wash and heattimes as necessary.Note: If the turbidity sensor fails, the unit operatesfor the maximum amount of time, using themaximum number of wash and rinse fills for theselected cycle.The turbidity sensor can be tested by checking theresistance across the wires on the control board atJ3, pin 1 (yellow/black wire), and J3, pin 4 (orangewire). (See Control Board Connect Locator View.) Thethermistor's resistance has a negative temperaturecoefficient.• At 75°F, the resistance is approximately 9.9 K.• At 140°F, the resistance is approximately 2.8 K(Continued next page)1234TURBIDITY/TEMPERATURESENSOR J31234NTCRECEIVER EMITTERTRANSMITTERCATHODEVccYBNXSXOXFloat SwitchThe float switch activates if water reaches thefloat stem inside the dishwasher. The switch onlyterminates the voltage to the water valve.To remove the fl oat switch:1. Remove the two 1/4-in. hex-head screws andthe access panel.Disconnect4. Pull the float switch out of the bracket.2. Disconnect the float switch wire harness.3. Remove the 2 Phillips-head screws holding theswitch to the dishwasher.Control Board Turbidity Sensor