Pressure fluctuates only when running pump A on an ACQUITY BSM - WKB62121

SYMPTOMS

• Pressure fluctuations occur only when running BSM pump A
• The fluctuations occur after the system sits idle over a weekend
• Pump A lines are in water; pump B lines are in methanol
• When using pump B only, there are no pressure issues

ENVIRONMENT

• ACQUITY Binary Solvent Manager (BSM)

CAUSE

Air in the mobile phase A (water)

FIX or WORKAROUND

Change the mobile phase on pump A. Sonicate the mobile phase and prime pump A thoroughly.

ADDITIONAL INFORMATION

One suggestion is to change the solvent to 50:50 methanol/water for pump A, to limit the introduction of air and microbial growth.