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Section 9 Troubleshooting
Keep the probe clean and in the recommended storage solution when not in use for the best
accuracy, stabilization time and life of the probe.
Problem
Decreased probe performance
causes slow stabilization and
prevents accurate calibrations or
measurements.
Sample properties cause slow
stabilization or inaccurate
measurements.
Procedure problem causes slow
stabilization and prevents
accurate calibrations or
measurements.
16 English
Possible cause
The glass sensor is dirty.
The reference junction is
clogged.
The filling solution has
contamination.
The probe is not conditioned
to the sample sufficiently.
The glass sensor has become
dry.
The calibration slope of the
probe has changed.
The sample absorbs carbon
dioxide (CO
) from the air,
2
which causes the pH value to
slowly decrease in low ionic
strength (LIS) or high purity
samples.
The sample temperature is
low, or there is a large
temperature difference
between samples.
The filling hole is closed.
Air bubbles are around or
below the probe tip.
The electrical connection
through the reference junction
is not sufficient.
The stir speed is too slow or
too fast.
An incorrect buffer solution
was used or the buffer
solution has contamination.
The protective tape was not
removed from the filling hole.
Solution
Clean and condition the probe.
Refer to
Clean the probe
on page 11.
Clean and condition the probe.
Refer to
Clean the probe
on page 11.
Replace the filling solution.
Refer to
Replace the filling
solution
on page 14.
Condition the probe. Refer to
Preparation for use
on page 5.
Soak the probe tip in buffer
solutions. Refer to
Soak
procedure for dry probes
on page 15.
Increase the accepted slope
limit settings if possible, or
contact technical support.
Use the LIS chamber for
LIS/high purity samples to
prevent CO
absorption.
2
Increase the sample
temperature or adjust the
temperature of different
samples to be the same (within
2 °C (3.6 °F)).
Open the filling hole during
use.
Carefully tap or shake the
probe to remove air bubbles.
Shake the probe in the solution
from side to side to refresh the
reference junction.
Try a different stir speed.
Use the specified buffer
solutions of good quality.
Remove the tape from the
filling hole. Refer to
Preparation for use
on page 5.
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