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
2. Verify functionality by performing pressure test with stable delta

ADDITIONAL INFORMATION

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