How to Release a Stuck Inlet Valve from a 1290 Infinity Flexible (Quaternary) Pump

Answer

This Information Applies To: Agilent 1290 Infinity Quaternary Pump G4204A, 1290 Infinity II Flexible Pumps G7104A/C, and G7131A/C.

Issue

If the flexible/quaternary pump does not generate flow or build up pressure, it could be due to a stuck inlet valve. One common solution is to manually release a stuck inlet valve by flushing the valve.

Items Required

• Syringe (p/n 9301-6474)
• Syringe Adapter (p/n 9301-1337)
• Mounting Tool for Tubing Connections (p/n 0100-1710)

   

  Tips: Before shutting down the system for a long time, it is recommended to flush the system with at least 10% isopropyl alcohol (IPA) to prevent the inlet and outlet valves from getting stuck. If using high salt buffers, flush your system with 100% water before the IPA flush. Follow this article to prepare the HPLC for a long-time shutdown.

   

  Caution: Never apply pressure to the degasser, multichannel gradient valve, or four-channel gradient valve as it can damage the components.

Steps to Follow

1. Remove tubing connections from degasser channels A, B, C, and D to the gradient valve using the mounting tool to access the inlet weaver (Figure 1).

   
   
   Figure 1. Remove degasser tubing from the MCGV or 4CGV
   
   

2. Open the fitting at the center of the gradient valve and remove the inlet weaver (Figure 2).

   
   
   Figure 2. Remove inlet weaver from the MCGV or 4CGV
   
   

3. Slightly open the black plastic screw at the bottom of the inlet valve, and rotate the inlet weaver to the front of the pump. Then, retighten the screw (Figure 3).

   
   
   Figure 3. Loosen and adjust inlet weaver
   
   

4. Disconnect the capillary from the pressure sensor inlet and place it into a small beaker to collect solvent (Figure 4).

   
   
   Figure 4. Disconnect pressure sensor inlet capillary 
   
   

5. Fill the syringe with a suitable wash solvent.

    

   Tips: If running buffers with high concentrations of salt, use warm water. For organic deposits, use ethanol, acetone, or IPA.

    

6. Connect the syringe and adapter to the inlet weaver (Figure 5).

   
   
   Figure 5. Connect syringe and adapter to the inlet weaver  
   
   

7. Push the syringe to flush the inlet valve and pump head with the wash solvent (Figure 6).

   
   
   Figure 6. Flush inlet valve by pushing solvent through with syringe
   
   

8. Restore the original pump connections. Flush the pump for several minutes. 

Learn how to effectively operate your Agilent Flexible/Quaternary Pump: Agilent 1290 Infinity LC Systems with OpenLab CDS Agilent 1290 Infinity LC Systems with OpenLab CDS ChemStation Edition eLearning paths available from Agilent education