Flow - Thermo Scientific thermoscientific Vanquish UHPLC System Operating Manual

8.2.4

Flow

No flow
Possible Cause
Leak in system
Inlet and/or outlet
check valve
contaminated or
defective
Air trapped in pump
heads
Air trapped in
autosampler flow path
Column temperature
too high – eluent
evaporating
Flow fluctuations
Possible Cause
Pump inlet path
clogged
Air trapped in pump
inlet path
Inlet and/or outlet
check valve
contaminated or
defective
Piston seals not sealing
tightly
UHPLC System
Operating Manual
Remedial Action
Find and eliminate the leak.
Clean the inlet check valve or outlet check valve, and replace the check valve if
necessary (refer to Pump Operating Manual).
Purge the pump (refer to Pump Operating Manual) and check in the Chromeleon
software whether the degasser has reached the operating vacuum
(Degasser Vacuum = OK).
Perform a wash cycle (refer to Split Sampler Operating Manual).
Select a lower column temperature (refer to Column Compartment Operating
Manual).
Remedial Action
Check the solvent inlet lines, solvent line filters, and solvent selectors/proportioning
valve, for example, for signs of clogging.
• Purge the pump.
• Inspect the degasser for indications for leakage. Check in the Chromeleon
software whether the degasser has reached the operating vacuum
(Degasser Vacuum = OK). Degassing may not work properly if the flow rate is too
high.
• Inspect the capillary and solvent line connections for leakage; tighten loose fitting
connections.
Clean the inlet check valve or outlet check valve, and replace the check valve if
necessary (refer to Pump Operating Manual).
Replace the piston seals (refer to Pump Operating Manual).
8 • Troubleshooting
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