With 2695 Separations Module, “system over pressure” occurs frequently; pressure is low when sending the mobile phase without a column - WKB106823

SYMPTOMS

• “System over pressure” occurred twice successively, but the system pressure was about 160 psi when flowing 100% methanol at 1 mL/min without a column

ENVIRONMENT

• 2695 Separations Module
• The first “system over pressure” is because of the pre-column blockage, and the pre-column is replaced with a new one
• Compression check successful

CAUSE

Because the pre-column is blocked, there is a possibility that the PEEK tube in front of the pre-column is also clogged, which may be the cause.
When the column is removed, no pressure is applied to the head, so the pressure drops, but when the column is connected, pressure is applied to the head, so the pressure may increase during injection.

FIX or WORKAROUND

Replace the tube in front of the column with a new one (usually 0.005-inch ID PEEK tube).

ADDITIONAL INFORMATION