Thermo Scientific Dionex UltiMate 3000 Series Operating Instructions Manual page 177

Problem
No flow
NC pump with Classic flow
meter:
Flow fluctuation,
flow is too low
poor gradients
Loading pump:
Flow fluctuation
Operating Instructions
Probable Cause
The system is leaking.
The eluents are degraded, dirty or
of poor purity/quality.
Contamination occurs
somewhere in the system.
One or both valve cartridges are
not installed correctly (not in the
direction of flow) or are
defective.
There are air bubbles in the
eluent or in the pump head.
The filter frit in the inline filter
may be blocked.
There is an air bubble in the flow
path.
After a maintenance procedure
(replacement of pump head,
piston, or piston seal) the pistons
are not in the appropriate position
for normal operation.
The flow selector is clogged
(partially or completely).
The inlet path is blocked.
There is air in the inlet path.
The check valves are dirty or
defective.
UltiMate 3000 Series:
NCS-3500RS and NCP-3200RS
Remedial Action
Find and eliminate the leak.
Use fresh solvent. Use fresh
and appropriate solvents (MS-
grade).
Flush the system with an
appropriate solvent.
Install the cartridges in the
direction of flow or replace
the cartridges if necessary
(→ page 182).
Purge the pump (→ page 72)
and check the degasser.
Replace the filter frit in the
inline filter (→ page 209).
Perform a wash cycle. Non-
degassed wash solution is
used. Degas the wash solution
(→ Autosampler manual).
Remove and reinstall the
pistons (→ pages 188
and 190).
Purge the entire NC pump
(both channels) by using
water (→ page 73) and
perform the Viscosity
Measurement (→ page 114).
The result must be >95 % for
both solvent channels. If the
result is considerably higher
for one or both channels, the
flow selector is clogged.
Replace the flow selector
(→ page 204).
Check the inlet lines, filter of
the pump, proportioning
valve etc. for signs of
blockage.
Purge the pump (→ page 72)
and check the degasser.
Clean the check valves or
replace the valve cartridges
(→ page 182).
Page 169