Incorrect Primary pump leak rate profile during Dynamic leak test - WKB204323

SYMPTOMS

• During "monitoring leak rate" step, leak rate ramps down quickly from about 1000 nL/min to <150 nL/min
• Dynamic leak test still passes
• Accumulator check valve is new (see article WKB12203)
• Primary check valve is new

ENVIRONMENT

• ACQUITY UPLC H-Class

CAUSE

Faulty Primary pump head seals and plunger

FIX or WORKAROUND

1. Rebuilt Primary pump head seals and plunger ( 700004747)
2. Confirm Primary pump leak rate profile during Dynamic leak test is as expected: 

ADDITIONAL INFORMATION