Turbidity Sensor And Thermistor - Haier GE GDF510P M4 Series Service Manual

Turbidity Sensor and Thermistor

Operation
The turbidity sensor measures the amount of
suspended particles in the filtered wash water.
The thermistor is also located within the turbidity
sensor. The sensor assembly contains a LED
transmitter which emits light and a receptor
(similar to a photo-cell) which receives light. The
wash water passes between the transmitter and
receptor, the control interprets these readings
to determine the soil level and if any prewash or
rinse cycles may be skipped. The cycle design
sets parameters to a maximum cycle length; and
the turbidity response will shorten the overall
cycle length if the soil level is below the cycle
preset specifications. By measuring several
times during a cycle to monitor soil levels, energy
can be saved by removing unneeded rinses, thus
shortening the overall cycle time.
If the turbidity sensor fails open or shorted, the
control will default to the maximum fills and
circulation time that the control is programmed for.
Turbidity Sensor Calibration
Calibration occurs every 100 cycles. After the
final rinse but before dry, the control will add three
extra rinse cycles. The first cycle will fill, circulate
two minutes and drain. The second cycle will
be a fill and drain. The third cycle will be a fill,
circulate, calibrate and drain. The cycle will now
advance to dry and complete.
Replacement controls will enter a calibration
at the end of the first cycle that the control
completes, as mentioned above. If the first cycle
is interrupted and calibration does not occur,
calibration will retry on the next cycle, until it is
completed. Calibration will not occur on demand.
Turbidity Sensor Diagnostics
If the turbidity sensor fails open or shorted, the
control will default to the maximum fills and
circulation time that the control is programmed for.
Use Consumer Error Mode to look for turbidity
sensor faults.
Turbidity Sensor Removal
1. Turn the sensor counter-clockwise (CCW).
2. Pull the sensor out of the sump.
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