Shutdown (#6): Back Inlet Flow Shutdown - Agilent 6890

As james_jenkins mentions, assuming that the back inlet is a Split / Splitless inlet, in a general sense, an inlet pressure less than about 2 psi will be difficult for the GC to attain and maintain.  Increase the pressure setpoint as garyb007 mentions to see if the back inlet will increase in pressure at all.  If the inlet pressure does not increase by much or not at all, as @dheyaaldeen mentions, it may be a leak.  The picture of the column and column nut have a measurement of about 24mm of column exposed, unless you are using some specialized liner like a direct inject liner or similar, the correct column length should be 4mm to 6mm of column exposed past the tip of the ferrule.

As james_jenkins mentions, assuming that the back inlet is a Split / Splitless inlet, in a general sense, an inlet pressure less than about 2 psi will be difficult for the GC to attain and maintain.  Increase the pressure setpoint as garyb007 mentions to see if the back inlet will increase in pressure at all.  If the inlet pressure does not increase by much or not at all, as @dheyaaldeen mentions, it may be a leak.  The picture of the column and column nut have a measurement of about 24mm of column exposed, unless you are using some specialized liner like a direct inject liner or similar, the correct column length should be 4mm to 6mm of column exposed past the tip of the ferrule.

Thank you for your great support!

The actual pressure is still at 0.00 bar. I just looked it up: the pressure unit is bar. So 0.29 bar is the setpoint.

I replaced the folling parts:

• Septum
• O-Ring (at the top of the liner)
• Gold Seal
• Column Nut together with the Graphit Seal

In this step I also reduced the column length to 6 mm.

At the end, I checked the Inlet for leaks with Leak Detector Spray: No leaks found.

garyb007 I'm not sure what you mean. Where do I find the carbon filter?