Pressure fluctuations on ACQUITY H-Class QSM - WKB19400

SYMPTOMS

• Pressure fluctuates on both Accumulator and System pressure traces
• Delta still within 1% of system pressure but higher than usual and unstable
• Can increase baseline noise on UV detectors
• Dynamic leak test passes
• Replacing check valves doesn't solve the problem

ENVIRONMENT

• ACQUITY H-Class Quaternary Solvent Manager (QSM)

CAUSE

Blockage in gradient proportioning valve (GPV).

Affects either A/B solvent lines or C/D solvent lines

When closing GPV from Acquity Console, some solvent is still flowing through the affected line

FIX or WORKAROUND

Replace the dual-channel GPV (700005161) for the affected solvent lines.

ADDITIONAL INFORMATION