System pressure on an Alliance drops and then recovers - WKB226020

SYMPTOMS

• System pressure drops, often to 0 psi, and then recovers 
• The pressure drops occur at high pressure
• RT shift is observed when running sample
• May also cause baseline issue

ENVIRONMENT

• Alliance HPLC System
• 2695 Separations Module
• 2695D Dissolution Separations Module
• 2795 Separations Module

CAUSE

Contaminated/bad check valve 

FIX or WORKAROUND

1. Clean or replace the check valves. Part number: 700000254 - PerformancePLUS™Check Valve Cartridges
2. Verify functionality by performing pressure test with stable delta

ADDITIONAL INFORMATION

Refer to WKB5864 for instructions on how to clean check valves.