User Manual

Multi 3500i What to do if...
83
6 What to do if...
6.1 pH and ORP measurement
Error message,
OFL or UFL
(measuring range
exceeded or undercut)
Error message, Error
(calibration error)
Cause Remedy
Electrode:
– Air bubble in front of the
diaphragm
– Remove air bubble
– Air in the diaphragm – Extract air or
moisten diaphragm
– Gel electrolyte dried out – Replace electrode
Test sample
– The pH value lies outside the
measuring range
– not possible
Cause Remedy
Electrode:
– Diaphragm contaminated – Clean diaphragm
– Membrane contaminated – Clean membrane
– Moisture in the plug – Dry plug
– Not enough electrolyte – Top up electrolyte
– Electrode obsolete – Replace electrode
– Electrode broken – Replace electrode
– Socket damp – Dry socket
Calibration procedure:
– Incorrect solution temperature
(without temperature sensor)
– Set up correct temperature
– Incorrect buffer solutions – Select buffer solutions
suitable for the calibration
procedure
– Buffer solutions too old – Use only once.
Note the shelf life