Thermo Scientific Dionex UltiMate 3000 Series Operating Instructions Manual page 174

UltiMate 3000 Series:
NCS-3500RS and NCP-3200RS
Problem
Pressure pulsation or
inconstant pressure
(Cont'd)
Peak tailing
Peak Broadening,
increased dead time
Page 166
Probable Cause
After a maintenance procedure
(replacement of pump head,
piston, or piston seal) the pistons
are not in the appropriate position
for normal operation.
Loading pump
The filter frit on the high-
pressure side of the pump is dirty.
Too large extra column volume.
There are poor capillary
connections.
The inner diameter of the
capillary to the detector is too
large.
The filter frits on the solvent
supply lines are clogged.
The capillaries are clogged or
there a poor capillary
connections.
The sample loop is clogged.
The column is overloaded or
contaminated.
The eluent has changed.
A fused silica capillary with
poorly installed peek sleeve is
used.
Remedial Action
Remove and reinstall the
pistons (→ pages 188
and 190).
Replace the filter frit
(→ page 209).
Use short capillaries with an
appropriate inner diameter
(Nano LC: 20 µm;
Cap LC: 50 µm;
Micro LC: 75µm).
Replace the capillaries.
Consider using Viper
capillaries.
Use a capillary with an
appropriate inner diameter.
Check the filter for
permeability. Replace the
filter frit if necessary
(→ page 62).
With the NC pump, the
message 'Cannot regulate
flow' appears on the pump
display.
Replace the capillaries.
Consider using Viper
capillaries.
Replace the sample loop
(→ Autosampler manual).
Clean or replace the column.
Use fresh solvent.
Use an appropriate Viper
capillary instead.
Operating Instructions