wtw inoLab Multi 9310 IDS, Operating Manual, Page: 99 / 114

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Multi 9310 IDS What to do if...
ba75937e10 08/2021
99
No stable measured
value
Obviously incorrect
measured values
15.2 Dissolved oxygen
Error message
OFL, UFL
The measured value is outside the measuring range.
Cause Remedy
IDS pH sensor:
– Junction contaminated – Clean junction
– Membrane contaminated – Clean membrane
Test sample:
– pH value not stable – Measure with air excluded if neces-
sary
– Temperature not stable – Adjust temperature if necessary
IDS pH test sample:
– Conductivity too low – Use suitable IDS pH sensor
– Temperature too high – Use suitable IDS pH sensor
– Organic liquids – Use suitable IDS pH sensor
Cause Remedy
IDS pH sensor:
– Sensor unsuitable – Use suitable IDS sensor
– Temperature difference
between buffer and test sample
too great
– Adjust temperature of buffer or sam-
ple solutions
– Measurement procedure not
suitable
– Follow special procedure
More information and instructions on cleaning and exchange of
sensors are given in the documentation of your sensor.
Cause Remedy
– Measured value outside the
measuring range
– Use a suitable IDS D.O. sensor