Xylem 201570, Operating Manual

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DurOx 325 Maintenance, cleaning, replacement
13 ba25400e04 10/2020
5.5 Checking the sensor for freedom from zero-current
The sensor is zero-current free. Checking the module for freedom from zero-
current is only necessary in the case of malfunctions that cannot be remedied
by exchanging the electrolyte solution and membrane cap or by cleaning the
electrodes.
There are 2 possibilities to check the sensor for freedom from zero-current:

Measurement in a nitrogen atmosphere (recommended method)

Measurement in a sodium sulfite solution according to DIN EN 25814/
ISO 5814.
CAUTION
If you check the sensor according to DIN EN 25814/ISO 5814, do not
leave the sensor in the sodium sulfite solution for more than 2 minutes.
Danger of sensor poisoning!
Test criterion The sensor is OK if the measuring instrument displays < 1 % D.O. saturation
after 2 minutes.
5.6 Disposal
CAUTION
The ELY/G electrolyte solution irritates the eyes and skin. When dealing
with the ELY/G electrolyte solution, observe the following points:

During working activities, always wear suitable protective gloves
and protective goggles/face shield.

If it comes into contact with the skin, rinse thoroughly with water and
immediately change contaminated clothing.

If it comes into contact with the eyes, rinse thoroughly with water
and consult a doctor.

Follow the safety datasheet.
Note
For measurements under high pressure the filling must be
completely free of air bubbles.
Readiness to measure After approx. 30 to 50 minutes, the sensor is ready for operation.
Subsequently calibrate the sensor.
Note
If you want to measure very low oxygen concentrations (< 0.5 %
saturation), we recommend to let the sensor rest overnight and
then calibrate it.