ACQUITY pump unable to compress - WKB108550

SYMPTOMS

• Pump can prime—solvent comes out of the waste line
• No visible leaks at pump tubing or check valves
• When dynamic leak test starts, accumulator pump is unable to compress
• Replacing the high-pressure seals does not resolve the issue
• Low pressure (3 psi) is seen in the console when setting flow to 0.5 mL/min through the column

ENVIRONMENT

• ACQUITY UPLC I-Class BSM
• ACQUITY UPLC BSM
• ACQUITY UPLC H-Class QSM

CAUSE

Air in the pump head is preventing solvent from moving through the pump.

FIX or WORKAROUND

1. Remove the stainless steel fitting under the transducer on the primary pump. 
2.                                            
3. Set the flow to 0.5 mL/min. Eventually, solvent will flow through the bottom of the transducer: 
4. 
5. Rerun the leak test.

ADDITIONAL INFORMATION