Checking The Compression Values (Loading Pump) - Thermo Scientific Dionex UltiMate 3000 Series Operating Instructions Manual

UltiMate 3000 Series:
NCS-3500RS and NCP-3200RS

6.7 Checking the Compression Values (Loading Pump)

Relevant only for the loading pump
Tip: The following applies only when the loading pump has backpressure.
The compression value of the pump head can provide valuable information for
troubleshooting. If you observe pump pulsation and/or shifts in retention times, check the
compression values:
On the pump display, select the Diagnostics menu and Compression.
•
In Chromeleon, open the Commands dialog box for the loading pump and select
•
LoadingPump_Wellness_RightBlock and Compression.
The values are indicated in percent; they show the compression of the last stroke. The
compression value should be lower than 100% and remain stable. If the value is close to
100%, the required precompression may not be reached and pulsation may occur.
The table shows guides values for some solvents:
Solvent
Acetonitrile
Methanol
Water
* with 100 % of degassed solvent delivered at 40 MPa, pump purged and stable for some time The values
are linear to the pressure.
• If the compression value is lower than indicated in the table, the valve cartridge (outlet
check valve) may be defective. Replace the cartridge (→ page 182).
• If the compression value is higher than indicated in the table
♦ The piston seals may be defective. Replace the piston seals (→ page 194).
♦ The valve cartridge (inlet check valve) may be defective. Replace the cartridge
(→ page 182).
• If the compression is very high and the pressure is low, there may be air bubbles in the
system. Purge the loading pump (→ page 76).
Page 174
Compression*
70 % ± 10 %
75 % ± 10 %
50 % ± 10 %
Operating Instructions