Xylem MULTI 3500i HANDHELD MULTIPARAMETER METERS - Manual (Page 86)

What to do if... Multi 3500i
84
No stable measured
value
Obviously incorrect
measured values
Sensor symbol flashes
Cause Remedy
pH electrode:
– Diaphragm contaminated – Clean diaphragm
– Membrane contaminated – Clean membrane
Test sample
– pH value not stable – Measure with air excluded if
necessary
– Temperature not stable – Adjust temperature if
necessary
Electrode + test sample:
– Conductivity too low – Use suitable electrode
– Temperature too high – Use suitable electrode
– Organic liquids – Use suitable electrode
Cause Remedy
pH electrode:
– Not connected – Connect electrode
– Cable broken – Replace electrode
– pH electrode unsuitable – Use suitable electrode
– Temperature difference
between buffer and test
sample too high
– Adjust temperature of buffer
or sample solutions
– Measurement procedure not
suitable
– Follow special procedure
Cause Remedy
– Calibration interval expired – Recalibrate the measuring
system