Metrohm 807 Dosing Unit - Manual (Page 45)

￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
5 Troubleshooting
807 Dosing Unit
￭￭￭￭￭￭￭￭ 37
5 Troubleshooting
5.1 Problems
Problem Cause Remedy
Adsorber tube is
jammed Using your thumb or the balls of your hand,
apply forceful pressure to the center of rota-
tion of the adsorber tube, while at the same
time carefully rotating it counterclockwise until
the screw nipple releases.
Air bubbles in the
cylinder or in the
dosing tubing Leaking connection ￭ Check the ends of the tubing, in particular
that of the aspiration tubing.
￭ Tighten all of the tubing connections with
the wrench 6.2739.000.
￭ Check the locking mechanism of the hous-
ing. Suggestion: Remove the housing and
then reattach it.
The reagent degasses
excessively, e.g. released
air forms bubbles. ￭ Carry out [PREP] / [Preparing]
￭ Reduce the filling rate.
￭ Suggestion: Degas the reagent with ultra-
sound, nitrogen or in a vacuum.
Wear Replacing piston and cylinder.
[PREP] / [Preparing] is
not carried out or false
parameters- ￭ Carry out [PREP] / [Preparing]
￭ Correct tubing length and diameter.
An incorrect volume
is dosed Dosing unit either mounted
or assembled incorrectly. ￭ Remove the dosing unit and then reattach
it.
￭ Check whether the nominal volume on the
housing and the effective cylinder volume
match one another.
Data of the dosing
unit cannot be read. Data chip of the dosing
unit mechanically dam-
aged or impaired by chem-
icals. ￭ Remove the dosing drive and then reattach
it.
￭ Clean the data chip and the contact sur-
faces.
￭ Have the data chip replaced by the
Metrohm Service Dept.