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- Posts: 8
- Joined: Thu Mar 19, 2020 10:48 pm
I have a Varian CP-3800/CP 2200 MS set up and I am having a bit of trouble with the flow rates. I calibrate the EFC and the Purge as directed by the manual. Split vent flow at the recommended 20mL/min, Purge vent flow at 4mL/min with a column head pressure of 10 PSI.
When the GC is on, to achieve the constant flow of 1.2mL/min as desired, the column pressure drops to -7.5 PSI. It will fluctuate from -7.5 PSI to around 0.1 PSI and the Column flow and total flow will also fluctuate.
Does anyone have any optimum setup conditions that I can follow so that this problem can be resolved?
*EDIT*
I changed the output pressure to Vacuum since it is attached to the Mass Spec. When I do this, the total flow fluctuates from around 56 mL/min to 8 mL/min. When the output pressure is at atm, these fluctuations are not present.