This Information Applies To: Agilent G1311A/B/C, G7111A/B, Quaternary Pumps, and G1310A/B, G7110B Isocratic Pumps, G1312A/B/C, G7112B Binary Pumps
How to diagnose no flow or no pressure issues on binary, quaternary, or isocratic pumps.
The following information should help you find what part of the pump is causing a flow or pressure problem.
The most common places for a no flow/no pressure issue in a pump are:
Warning: Put on suitable gloves and other PPE for the solvents contained in your LC solvent bottles before starting this procedure.
Opening fittings while the solvent filters are submerged in solvent will lead to solvents leaks. Ensure that enough lab wipes or other absorbent material is used to soak up any spills. Dispose of lab waste appropriately.
In a quaternary pump, it may be the Multichannel Gradient Valve (MCGV) that has a blockage limiting your pump flow. Please bypass the MCGV.
To bypass it, connect a solvent bottle of HPLC-grade IPA (with a clean solvent filter installed) to the active inlet valve on the bottom of the pump head using the Adapter Part Number 0100-1847 (see Figure 4). Attach this adapter to the Active Inlet Valve (AIV) shown by the red arrow in Figure 5, then attach the solvent inlet tube from the bottle of IPA to this adapter.
If your pump has a passive inlet valve (PIV) installed, then you can connect the solvent inlet line from the IPA bottle to the PIV without the adapter, as shown in Figure 3.
Figure 4. Adapter, PEEK, female 1/4-28 to male 10-32
Figure 5. AIV Fitting
Do you see liquid filling up the well when the OBV was removed?
If yes, sonicate the OBV in methanol or IPA as it may be sticking. (see Tip)
If no, the inlet valve is the issue. PIVs and AIV cartridges (not the active inlet valve itself, Figure 6) can be sonicated in HPLC-Grade methanol or IPA (see Tip).
Caution: Only sonicate the AIV cartridge if sonication of an AIV is required. Do not sonicate the body of the AIV as it will damage the electrical components of the valve.
Tips: Note: The solvent used for sonicating depends on the mobile phase. If your mobile phase contains a salt buffer, or old acetonitrile being used in the organic phase then use warm (Less than 60 °C) HPLC grade water for sonication.
It is recommended to have replacement parts on hand to fix the pump issue. If sonicating the valve fixes the issue it is likely to stick again, so users should prepare to replace the valve soon.
Learn more on how to effectively troubleshoot your Agilent LC Pump pump:
HPLC-0GEN-2201e - Chromatographic Troubleshooting for HPLC e-learning course available from Agilent Education