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Alliance pressure fluctuation or no flow - WKB7030

Article number: 7030


  • Pressure fluctuations observed after changing mobile phase
    • Pressure fluctuations between 100 psi and 700 psi at 0.3 mL/min in 100% water
  • Several wet prime cycles, no air bubbles
  • V3 purge outlet clear waste line does not have a steady stream of flow during prime
  • Water in line A and B
  • Acetonitrile in lines C and D
  • Early retention times


  • 2695 Separations Module
  • 2795 Separations Module


Air bubbles in lines, loss of prime in solvent manager.


Priming the solvent manager:

  1. Perform a manual dry prime using a syringe to draw mobile phase from each line.
  2. Perform a wet prime on each solvent management mobile phase line.
  3. Operate flow rate and confirm pressure stability.
  4. If pressure fluctuations continue:
    • Repeat steps using methanol to remove all air in the lines.
    • Consider wet priming one additional step using 25%A, 25%B, 25%C, 25%D composition each line.


For more information, refer to the Waters Alliance e2695 Separations Module Operators Guide.

eluent, pressure ripple

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