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

Question

Hello community,

I set up an Agilent 6890 (Software: ChemStation A08.03).

A few seconds after I start the GC, the error message "Shutdown ( # 6 ): Back Inlet Flow Shutdown" is shown on the display. The settings of the Back Inlet shows that the pressure is set to 0.29 but the actual pressure is 0.00. I already checked the helium inlet to the GC: It is set to 6 bar and the gas pipe are clean and nice. I also changed the septum. But the problem is still present. The inlet is connected to a 30 m x 0.250 mm column and the FID is used as detector.

Has anybody an idea how I can fix this problem?

Thank you!

shawntravis · Accepted Answer

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.

garyb007 · Answer

I suggest you call in to support and set up a service call if they can't give you any more help than what you got here.

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

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