System pressure is lower than expected. - WKB202630

SYMPTOMS

• Typical system pressure is low.
• Or typical system pressure is high.
• All leak tests pass.
• There are no visible leaks present in the flow path of the system.

ENVIRONMENT

• Acquity UPLC
• Acquity H-Class
• Acquity I-Class
• Acquity M-Class
• Alliance 2695
• Alliance 2795

CAUSE

The incorrect mobile phase was placed in the wrong bottle.

The mobile phase line was placed in the wrong mobile phase.

FIX or WORKAROUND

1. Replace the mobile phase with the correct mobile phase.
2. Place the mobile phase tubing into the correct mobile phase.  Prime for 5 minutes and initialize current initial conditions.

ADDITIONAL INFORMATION

Aqueous mobile phase tends to be more viscous than organic mobile phase and provides higher back pressure.  Ensuring that the correct lines are in the correct mobile phases will correct the pressure difference.