HACH LANGE ORBISPHERE 3654, Руководство пользователя, Страница: 44 / 58

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Maintenance and Troubleshooting
8.2.3 Testing the sensor condition
Periodically, visually inspect the sensor head for any deposits. Rinse it under clean tap water,
and dry with a clean tissue.
To verify the sensor, check measurements vs. a known standard sample value:
•
If reading deviation is ±1% of the expected value, no action needs to be taken.
•
If deviation exceeds ± 1%, perform a new calibration.
•
If deviation exceeds 10% of the original values, replace the membrane.
CAUTION
Carry out the maintenance in a clean dry place in order to avoid damaging the sensor's
precision components, and also to prevent water or humidity from getting into the
sensor.
8.3 Membrane replacement
Note:
After replacing a membrane, the sensor must always be re-calibrated. Allow the sensor to settle for
30 minutes in measurement phase to allow measurements to stabilize, before performing the sensor
calibration.
8.3.1 Removing the membrane
It is recommended to leave the sensor in place in the instrument when changing the membrane.
It is not necessary to remove it.
To remove the membrane, follow the steps below:
First remove the flow chamber from the sensor by turning the flow chamber locking pin (see
position in
Figure 1 on page 11 ) counter-clockwise and gently lifting the flow chamber off the
sensor.
CAUTION
A thermistor at the top of the sensor (illustrated
right) is used to measure the sample temperature.
Do not bend or damage this component by trying to
twist the flow chamber off the sensor.
Unscrew the protection cap, using the tool provided in the
maintenance kit.
CAUTION
Never remove the protection cap, unless you plan to
replace the membrane.
Pull up the membrane holding ring with the tool provided in
the maintenance kit.
Remove the old membrane and discard it.