After replacement of the electrolytic solution and/or of the membrane, insert the probe con-
nector in the measuring instrument and wait 15 minutes before taking the measurement of
the dissolved oxygen (this time is necessary to use up the oxygen that has remained impri-
soned in the electrolytic solution during replacement).
Checking the state of the probe.
The glass body that covers the cathode and the membrane in the head of the probe must not be
damaged.
If there are any cracks in the glass body that covers the cathode the probe must be replaced.
If the oxygen-permeable membrane is damaged or dirty it must be replaced.
When the head of the probe is unscrewed the probe is not sufficiently protected. Handle it with care
so as to avoid knocks which could cause irreparable damage.
Checking the probe offset.
The probe offset is already compensated in the factory.
1. The user can check the probe offset by immersing it in the 0.0% dissolved Oxygen solution
(DO 9700).
2. Pour the zero solution in the phial supplied with the probe into a small container, cleaned with
distilled water.
3. Insert the probe in the zero solution and wait at least 5 minutes.
4. The instrument must indicate a saturation index of less than 0.3%.
Calibrating the probe.
1. Wet the sponge contained in the calibrator DO 9709/20 with 2 ml of distilled water;
2. insert the probe in the calibrator;
3. wait a few minutes until the system has become thermally stable;
4. select the dissolved oxygen display in %;
5. press the CAL key for at least 2 seconds;
6. when the indications %, °C and SAL are flashing, press the key mg/l %.
The value indicated by the top display will gradually go to the value 101.7%
Storage of the dissolved Oxygen probe.
When the electrode is not being used it must be disconnected from the instrument to avoid need-
less consumption of the electrolytic solution in the probe.
Always keep the electrode damp using the special cap supplied with the probe, filled with distilled
water.
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