Testing The Loading Pump For Leakage - Thermo Scientific Dionex UltiMate 3000 Series Operating Instructions Manual

7.11 Testing the Loading Pump for Leakage

After you have carried out any maintenance or repair work on the fluid system of the
loading pump, test the pump for leakage.
Tips: As an alternative, you can test the loading pump for leakage also by running
the diagnostic functions in Chromeleon (→ page 134).
If leakage occurs for the NC pump, the message 'Cannot regulate flow' will
appear on the pump display (→ page 149).
1. Close the outlet of the loading pump with an appropriate fitting plug (for example,
Viper fitting plug, part no. 6040.2303).
2. In Chromeleon, in the Commands dialog box for the loading pump, set the upper
pressure limit to 50 MPa under Pressure > UpperLimit.
3. In Chromeleon, select a flow rate of, for example, 30 µL/min.
4. Decrease the flow as soon as the pressure builds up, typically between 20 and 30 MPa.
5. Have the pump deliver some µL/min until a pressure of 45 MPa has built up.
6. When this pressure has been built up and when the pump delivers a flow of 1 µL/min,
the pressure should increase or remain constant at least. If it does not, this indicates
possible leakage.
7. Find and eliminate the cause for the leak, and then perform the test described under
this list. Possible sources are:
♦ Capillary connections
Inspect them for signs of leakage and tighten leaking connections.
♦ Piston seals
♦ Inspect the piston seals for leakage (→ page 186).
♦ Replace the piston seals (→ page 194).
♦ If leakage is observed with new piston seals, operate the pump for at least
2 hours at 35 MPa to run in the seals. (In this case, tightening the pump head
screw does not help.)
♦ Check valves
♦ Tighten the valve nuts (→ page 182).
♦ Remove the valve cartridges (→ page 182) and clean them, for example, in an
ultrasonic bath.
♦ Purge valve
Inspect the purge screw and purge unit for indications of leakage.
Operating Instructions
UltiMate 3000 Series:
NCS-3500RS and NCP-3200RS
Page 211