How to Release a Stuck Inlet Valve in a G7120A High Speed Pump

This Information Applies To: Agilent G7120A Infinity II High Speed pump modules

Issue:

The inlet valve is stuck if there is no flow when purging, or if the pump is not generating pressure after being turned off for an extended time period.

Steps to follow

Warning:  This procedure risks exposure to hazardous, toxic, or flammable solvents and reagents. Wear appropriate PPE as described in the material handling and safety data sheet supplied by the chemical vendor, and always follow good laboratory practice.

Tip: Before the LC system is turned off for an extended time period, it should be flushed with at least 10% isopropanol to prevent inlet valves from getting stuck.

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 tool kit (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: If old or aged Acetonitrile is left in the outlet ball valve, then the ball inside the valve can stick open or closed causing pressure and flow issues. Always flush pumps after use according to instructions given in the pump user manual. See Agilent Technical Note 01200–90090 for further details.

Learn more on how to effectively troubleshoot your Agilent 1290 Infinity II High-Speed Pump see the User Manual