Maintenance Schedule - Hach POLYMETRON 9240 Basic User Manual

4. The reactivation process is automatically followed by a rinsing of the overflow vessel and
measuring cell using the process sample. Upon completion of the rinsing step, the analyzer is
ready for the first manual step in the cycle.
5. Place the sample level detector on the side and pour approximately 200 mL of the solution into
the overflow vessel, as prompted on screen. Manual introduction is complete when the sample
overflows at the back of the overflow vessel.
6. Place the sample level detector back on top of the overflow vessel and select OK to start the
measurement. The display switches back to the main measurement screen and displays the
measurement value.
7. Once measurement of the solution is complete, the measured value and time will be displayed
against verif. s. This should be almost identical to the value entered in the VALID. SOL field
previously.
The value displayed in gap, will be the percentage difference between the concentration of the
verification solution entered in the VALID. SOL field, and the concentration measured by the
instrument. If this value is too high, then a calibration of the analyzer is recommended.
8. Once the cycle is complete, the analyzer automatically reverts back to standard measurement
mode.
9. Select Main to go back to the main measurement screen.
GRAB SAMPLE
Similar to the verification process, this option allows measurement of a sample of your choice. Before
starting this process, ensure you have a sample of approximately 200 mL to measure.
Note: It is recommended that the grab sample should have a concentration of > 10 ppb and should be at the same
temperature as during calibration for better accuracy. Under these conditions, measurement with manual
introduction gives 5% accuracy from 10 ppb to 10 ppm at a temperature which is within ± 5 °C of the temperature
during calibration.
1. The first step of this cycle allows the reactivation of the electrode. The message SENSOR
ACTIVATION is displayed. Select Yes to reactivate the sensor. Select No if time is more
important than accuracy.
2. The reactivation process is automatically followed by a rinsing of the overflow vessel and
measuring cell using the process sample. Upon completion of the rinsing step, the analyzer is
ready for the first manual step in the cycle.
3. Place the sample level detector on the side and pour approximately 200 mL of the solution into
the overflow vessel, as prompted on screen. Manual introduction is complete when the sample
overflows at the back of the overflow vessel.
4. Place the sample level detector back on top of the overflow vessel and select OK to start the
measurement. The display switches back to the main measurement screen and displays the
measurement value.
5. Once measurement of the solution is complete, the measured value and time will be displayed
against grab s.
6. Once the cycle is complete, the analyzer automatically reverts back to standard measurement
mode.
7. Select Main to go back to the main measurement screen.
MAINTENANCE/DIAG.

Maintenance schedule

Table 1 shows the recommended schedule of maintenance tasks. Facility requirements and
operating conditions can increase the frequency of some tasks.
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