Metrohm 900 Touch Control Manual - Manual (Page 501)

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31 Troubleshooting
900 Touch Control
￭￭￭￭￭￭￭￭ 485
Problem Cause Remedy
The titration time is
too long. The control parameters are
unsuitable. Adjust the control parameters (see Chapter
29.3.2, page 310):
￭ Select Titration rate = optimal or fast.
￭ Define Titration rate = user and reduce
the control range.
￭ Define Titration rate = user and increase
the maximum rate (Max. rate).
￭ Define Titration rate = user and increase
the minimum rate (Min. rate).
The results are
spread widely. The minimum dosing rate
is too high. Define Titration rate = user and reduce the
minimum rate (Min. rate) (see Chapter
29.3.2, page 310).
The control range is too
small. Define Titration rate = user and increase the
control range.
The electrode responds too
slowly. Replace the electrode.
31.8 Karl Fischer titration
Problem Cause Remedy
The drift is very high
during conditioning. The titration cell is leaking. ￭ Check seals and septum. If necessary,
replace.
￭ Replace the molecular sieve.
The drift becomes
greater after each
titration. The sample releases water
very slowly. ￭ Adjust the method.
￭ Add solubility promoter.
￭ Increase the temperature (possibly using a
KF oven).
￭ See technical literature.
A side reaction is taking
place. ￭ Use special reagents.
￭ Adjust the method (increase/decrease the
temperature, external extraction).
￭ See technical literature.
The pH value is not in the
optimum range anymore. Add buffer, see technical literature.
The titration will not
be finished. The titration cell is leaking. ￭ Check seals and septum. If necessary,
replace.
￭ Replace the molecular sieve.