This Information Applies To: Agilent G7120A Infinity II High Speed pump modules.
If you are getting no flow when purging, if the inlet valve is stuck, or if the pump is not generating pressure after being turned off for an extended period of time.
Before the system is turned off for an extended period of time, it should be flushed with at least 10% isopropanol to prevent inlet valves from getting stuck.
Steps to follow
1. Remove the capillary connection from the outlet of the secondary pump head.
2. Unscrew the tubing at the inlet valve.
3. Attach a Luer lock syringe with an adapter to the tubing and fill it with solvent. A syringe and Luer lock adapter are provided as part of the HPLC toolkit (Agilent Part No G7120-68708)
4. Reconnect tubing to the inlet valve.
5. Unscrew tubing at the degassing unit and attach the syringe to it.
6. Push solvent with a syringe until it comes out at the top of the High Pressure Filter Assembly.
7. Detach the syringe and reconnect the tubing into the degassing unit.
8. Reinstall the capillary connection to the High Pressure Filter Assembly.
9. Purge the LC system to remove air.
10. Re-equilibrate your LC system with your initial solvent composition and wait for the baseline to stabilize.
Cause: Inlet valve can wear over time and start to leak. Also, polymerization of solvent, (especially aged Acetonitrile) on the ball of the Inlet valve can cause it to be stuck open or closed. Always flush your system with an appropriate storage solvent. See Agilent Technical Note 01200-90090 for further details.