Xylem WTW TriOxmatic 690, Operating Manual, Page: 32 / 40

What to do if... TriOxmatic
®
690
32 ba25314e05 09/2020
6 What to do if...
The sensor is in the air
and the display shows
0.0 mg/l or 0% O
2
The sensor cannot be
calibrated
If the sensor still cannot
be calibrated after
changing the electrolyte
and membrane cap
Measured values too low
Measured values too
high
Cause Remedy
– No electrolyte in the membrane
cap
– Change the WP 600
membrane cap (see section
5.3)
Cause Remedy
– Contaminated membrane cap – Clean the outside of the
sensor (according to
operating manual), wait at
least 15 minutes and
recalibrate.
– In the case of contamination
that cannot be removed:
Exchange the membrane
cap and electrolyte.
Cause Remedy
– Contaminated electrodes or
sensor toxification
– Clean the electrodes (see
section 5.4)
Cause Remedy
– Membrane contaminated
– Sensor has not been calibrated
for a long time
– Clean the outside of the
sensor, then recalibrate (see
section 5.2 and section 4.2)
– Membrane does not fit snugly on
the gold working electrode
– Change the membrane cap,
then recalibrate (see section
5.3 and section 4.2)
Cause Remedy
– Sensor not yet completely
polarized
– Wait for complete
polarization (at least 1 hour)