JUMO 202610.0, Operating Instructions Manual, Page: 58 / 68

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12 Maintenance
12.1 Two-wire transmitter for dissolved oxygen
General In order to simplify maintenance, a change of the electrolyte and / or the
membrane is not envisaged. After the end of their operating life (usually after
the electrolyte has been exhausted), they are replaced altogether.
During measurement operation, the maintenance work described below has to
be carried out at regular intervals.
It is advisable to enter the maintenance schedule in a logbook or calendar in
advance.
The intervals are given by the degree of fouling or pollution.
Cleaning
✱
Clean the transmitter housing in a bucket with drinking water using a
suitable brush. Do not brush the membrane or the protective film!
✱
Clean the membrane, or the optional protective film, in a bucket with
drinking water using a soft sponge.
✱
Remove salt deposits (if necessary):
Immerse transmitter in drinking water or in a 1-5% hydrochloric acid
solution (only for up to 10 minutes). Then rinse thoroughly with drinking
water.
Simple testing
of the
measurement
function
✱
Clean membrane and dry it.
✱
Wait for about 45 minutes - the instrument should now indicate approx.
9.09 mg/liter at 20°C and 1013 hPa, or a saturation concentration of
approx. 100 %.
Values for additional temperatures can be taken from EN 25 814.
Recalibration
➩
Chapter 10 “Calibration”, page 42ff.
Do not touch the membrane or the (optional) protective film with
sharp or pointed objects! Do not damage the membrane or the
(optional) protective film!
The measurement signal may change during maintenance work!
Control devices or PLCs operated by the transmitter may react in
an undesirable manner!
Dirt deposits on the membrane may introduce measurement
errors.
In the course of normal operation, a grayish-white deposit may
form on the anode of the sensor module. This deposit does
not
affect the proper functioning of the measuring cell.