Pressure fluctuation, high delta psi on Alliance HPLC system- WKB54901

SYMPTOMS

• Delta psi is 400 bar at 1 mL/minute
• Wet prime does not resolve the issue
• Check valve replacement does not resolve the issue
• Presence of rust on accumulator pump head assembly, seal wash assembly, and plunger
• Rebuilding the primary and accumulator pumps does not resolve the issue
• The static leak test fails

ENVIRONMENT

• 2695 Separations Module
• 2795 Separations Module

CAUSE

Defective pump head assembly and seal wash assembly on the accumulator pump. Etching on the pump head.

FIX or WORKAROUND

1. Replace the pump head assembly (WAT270961) and the seal wash assembly (WAT270962) on the accumulator pump.
2. Rebuild the accumulator pump with a new pump head assembly and seal wash assembly.
3. Pressurize seals to 3000 psi.

ADDITIONAL INFORMATION

With etched pump head, delta psi was 35 psi at 1 mL/min. After replacing the etched pump head, delta psi is 10.