GE AKTApure, User Manual, Page: 363 / 522

Possible cause and action Problem
• Flow restrictor in off-line position
Use the Flow restrictor. Use the pH valve instruction to manually
set the Flow restrictor inline (Flow path:pH valve:Restrictor in-
line), or select the Flow restrictor in the Method Settings phase
of a method.
• Air in the UV flow cell
Use the Flow restrictor.
Remove the air by flushing the cell with water or buffer.
If persistent, clean the UV cell. See Section 7.5.1 Clean the UV flow
cell, on page 273.
• Air in buffers
De-gas if necessary.
• Make sure that both the instrument and the buffers have reached
the ambient temperature.
• Impure buffers
Check if the signal is noisy with water.
• Unclean optical fiber connectors
Clean the connectors. See Section 7.8.5 Replace the UV monitor
U9-M flow cell, on page 325.
• Dirt in the UV flow cell
Perform a System CIP. See Section 7.6.2 Perform System CIP, on
page 278.
If necessary, manually clean the UV cell. See Section 7.5.1 Clean
the UV flow cell, on page 273.
• Wrong type of UV cell is used
If a UV cell with 2 mm path length is to be used, use only cells
marked U9-2.
Baseline drift or noisy signal
ÄKTA pure User Manual 29119969 AB 363
8 Troubleshooting
8.3 Troubleshooting: Monitors