Metrohm 870 KF Titrino plus Manual - Manual (Page 78)

9.2 Miscellaneous
￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
68 ￭￭￭￭￭￭￭￭
870 KF Titrino plus
Problem Cause Remedy
The sample is over-
titrated. The increments at the end
of the titration are too
high. ￭ Define Titration rate = user and reduce
dosing rate (Max. rate) (see Chapter
7.1.3, page 53).
The following experiment provides a clue
for the optimum dosing rate: During condi-
tioning, display the drift and add sample
without starting the titration. Select a value
below the highest drift as dosing rate.
￭ Stir faster.
The amount of methanol in
the working medium is too
low. ￭ Replace the working medium.
￭ Reduce the amount of solubilizer, if work-
ing with solvent mixtures, see technical lit-
erature.
The electrode may be cov-
ered. Wipe off the electrode with ethanol or a suita-
ble solvent.
The solution
becomes darker
after each titration. Replace the working medium.
The electrode may be cov-
ered. Wipe off the electrode with ethanol or a suita-
ble solvent.
The electrode has a short
circuit. 1. Check the Pt wires.
2. Switch on the electrode test.
The endpoint is
reached too quickly. The dosing rate outside the
control range is too high. Define Titration rate = user and reduce the
dosing rate (Max. rate) (see Chapter 7.1.3,
page 53).
The titration times
with volumetric
titration are con-
stantly longer. With two-component
reagents the buffer
capacity of the solvent can
be exhausted. Replace the working medium.
9.2 Miscellaneous
Problem Cause Remedy
No report is printed. The printer is not recog-
nized by the instrument. ￭ Switch the 870 KF Titrino plus off and on
again.
￭ Use a hub on the USB connector and con-
nect the printer to the hub.