VWR International MU 6100 H, Instruction Manual

Page: 80 / 96

What to do if... MU 6100 H
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No stable measured
value
Obviously incorrect
measured values
14.2 Dissolved oxygen
Error message
OFL, UFL
The measured value is outside the measuring range.
Cause Remedy
Electrode:
– Junction contaminated – Clean the junction
– Membrane contaminated – Clean membrane
Test sample:
– pH value not stable – Measure with air excluded if
necessary
– Temperature not stable – Temper if necessary
Ele test sample:
– Conductivity too low – Use a suitable electrode
– Temperature too high – Use a suitable electrode
– Organic liquids – Use a suitable electrode
Cause Remedy
Electrode:
– Electrode unsuitable – Use a suitable electrode
– Temperature difference between
buffer and test sample too great
– Adjust temperature of buffer or
sample solutions
– Measurement procedure not suit-
able
– Follow special procedure
More information and instructions on cleaning and exchange of
sensors are given in the documentation of your sensor.
Cause Remedy
– The measured value is outside
the measuring range of the meter
– Use a suitable D.O. sensor