SCHOTT Instruments ProLab 2000, Operating Manual, Page: 101 / 125

ProLab 2000 What to do if...
101 ba75577e03 11/2009
Error message, OFL
Error message, Error
(invalid
calibration)
Error message, LEAK
Measured value flashes
for a long time
(No stable measured
value)
Measured value too low
Measured value too
high
Cause Remedy
– Measuring range exceeded – not possible
Cause Remedy
D.O. sensor:
– Electrolyte solution depleted – Regenerate probe
– Membrane contaminated – Clean membrane
– Electrode system poisoned – Regenerate probe
Cause Remedy
D.O. sensor:
– Membrane damaged – Exchange the membrane cap
– Membrane head screwed on
not tight enough
– Screw membrane head tight
Cause Remedy
D.O. sensor:
– Membrane contaminated – Clean membrane
Cause Remedy
D.O. sensor:
– Insufficient flow – Provide flow to the probe
Cause Remedy
– High amount of dissolved
substances
– Correct solubility function
using the salinity equivalent
– Air bubbles bump on the
membrane with high velocity
– Avoid direct flow to the
membrane