This Information Applies To: Agilent G1311B/C, G7110B, G7111A/B, G7112B, and G7120A Pumps and Agilent G7122A, G4225A, G1379A/B, and G1322A Degassers
The error message "Vacuum Limit Not Reached" will appear if the degasser does not reach a preset limit (default value is 100 mbar) in a predefined time window (default 8 minutes after powering on the module). This may happen for many reasons.
One reason may be due to the condensation of vapors from volatile organic solvents. The vapors can condense in any part of the degasser and not restricted to any component. As such, the vacuum chamber, vacuum tube or the vacuum pump may all experience vapor buildup. If this occurs in the vacuum pump, it makes it less efficient to remove the air and achieve the 100 mbar level in time. It doesn’t happen often but the vacuum pump can totally fail and not turn on at all. This is easy to determine as no sound will be heard when the module is powered on.
The vapor can also cause cracks or fissures to develop in the vacuum tubing thus making it impossible to ever achieve the preset vacuum level.
The vacuum chamber may also develop condensate buildup, which will require a longer time to evacuate thus giving the error. In some rare cases, the chamber may even develop a crack.
In addition, other internal components can fail in rare cases, but in this case it is better to contact an Agilent Support representative.
The external degassers will not give "Vacuum Limit Not Reached" messages as they aren’t connected to Controlling software or Lab Advisor. The red error light will go on to indicate a problem. In addition, if a remote cable is connected to the pump, it will also turn all the modules red. Whether this cable is connected or not is optional.
Steps to follow
If you cannot resolve the issue, contact your local Agilent Support representative for more help.
Learn how to effectively troubleshoot your Agilent LC System:
HPLC-0GEN-2201e - Chromatographic Troubleshooting for HPLC e-learning course available from Agilent education