- Bouncing or fluctuating pressure
- Little to no flow observed during and after priming
- Alliance 2695
Switching from a buffered mobile phase using a higher composition of organic than the original buffer causes the check valve to stick.
FIX or WORKAROUND
- Use a higher aqueous wash.
- Sonicate check valves. To avoid solvent leakage, first close the GPV. From the main screen, select Diagnostics > Other Tests > Turn Off GPV.
- Sonicate check valves in water for 15 minutes.
- Sonicate in methanol or acetonitrile for an additional 15 minutes.
- Reinstall check valves.
- Reset GPV and select OK.
- Prime unit at 7.5 ml for 3-5 minutes.
- Monitor flow and pressure. If resolved, continue with analysis.