Thermo Scientific thermoscientific Vanquish Pumps C, Operating Manual

Page: 210 / 296

8 • Troubleshooting
Page 210 Pumps C, Pumps F ( VC-Pxx, VF-Pxx)
Operating Manual
8.5 Pressure Issues or Shifts in Retention Time
When you observe pressure issues or shifts in retention time, the
following sections help you to identify and eliminate the source for the
problem:
• The pressure is not down to zero when the purge valve is open
See Pressure Not Zero with Open Purge Valve (
}
page 210) .
• Pressure pulsation
See
Checking the Compression Values ( } page 210) and Testing the
Static Mixer for Permeability ( } page 168) .
• Shift in retention time
See
Checking the Compression Values ( } page 210) .
• Inconstant pressure or high backpressure at the column and pump
See
Testing the Static Mixer for Permeability ( } page 168) .
8.5.1 Pressure Not Zero with Open Purge Valve
When
The pressure is not down to zero when the purge valve is open.
Follow these steps
1. For the pressure sensor for which the pressure is not down to zero,
check the pressure sensor cable and connector for proper contact.
a) Unplug the pressure sensor cable.
b) Reconnect the cable. To ensure proper contact push the cable
firmly into the connector.
2. Perform a self-test.
3. If the self-test produces a message, follow the remedial actions
recommended for the message.
8.5.2 Checking the Compression Values
The compression values of the pump heads can provide valuable
information for troubleshooting.
When
You observe pressure pulsation or shifts in retention time.