Thermo Scientific thermoscientific Vanquish Pumps C, Руководство по эксплуатации

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8 • Troubleshooting
Pumps C, Pumps F ( VC-Pxx, VF-Pxx)
Operating Manual Page 211
Follow these steps
1. In the Chromeleon software, check the Compression value for the
pump heads (= CompressionDrv1 ).
The values indicate the compression of the last stroke in percent.
The compression value should be less than 100%.
¨
With isocratic conditions, the compression value should remain
stable.
¨
When running a gradient, the compression value changes
roughly proportional to the pressure curve.
If the value is close to 100%, the required precompression may not
be reached and pulsation may occur.
The table shows guide values for some solvents (pure solvent,
degassed, delivered at 40 MPa) with the pump being purged and the
pressure being stable for some time. The values are linear to the
pressure.
Solvent Compression in %
Water 25 % ± 10 %
Methanol 50 % ± 10 %
Acetonitrile 45 % ± 10 %
2. Take remedial action if required.
Compression Remedial Action
Lower than indicated in the table The outlet check valve may be defective.
Replace the valve cartridge. See
Replacing the
Outlet Check Valves (
}
page 164) .
Higher than indicated in the table • The piston seal may be defective. Replace
the piston seal. See
Replacing the Piston
Seals or Support Ring (
}
page 147) .
• The inlet check valve may be defective.
Replace the valve cartridge. See
Replacing
the Inlet Check Valves ( } page 162) .
Very high (message " Compression
limit reached " and low pressure)
• Air bubbles may be present in the pump.
Make sure that no air bubbles are present in
the solvent lines and then, purge the pump.
• If solvent shut off valves are installed: Verify
that the valves are open.
• Excessive leakage may be present on the
inlet check valve. Remove the solvent line
from the solvent reservoir and the solvent
line filter from the solvent line. While the
pump is running, observe the liquid in the
solvent line. If the liquid moves also against
the direction of flow during the stroke, the
inlet check valve may be defective. Replace
the valve cartridge. See
Replacing the Inlet
Check Valves ( } page 162) .