Chromatography Forum

Hello!

I am trying to troubleshoot Back Inlet Pressure Shutdown on my Agilent 7890B.

I removed the septa and do not see a liner. We purchased some liners online but it appears they are too large even though it was the model specified. It was working previously.

The gas pressure looks good on the back of the unit. Trying to figure out where I would like for pressure leaks.

Sorry, having problems following this. Are you new to GC? It was working fine, without a liner? Does the new liner you bought not fit because there IS a liner present, and you're trying to insert another one?

What type of inlet are you using? A standard 7890B S/SL? What liners did you buy, from who, and what were they ones you were previously using? I don't get this.

If there's no liner, there's no liner seal ("O-ring"). Put a correct liner and correct liner seal on the liner.

Hey Jake. Sorry for delay in reply. Yes, I'm pretty new to GC maintenance / troubleshooting.

It's a purged pack inlet liner. We ordered these inlet liners from Agilent via the manual and they appear to be too big.

5080-8732
https://www.agilent.com/store/productDe ... =5080-8732

It was calibrated and verified recently by someone else and got some good runs but then our CRM and LCS started failing and I went to check the septa and liner and did not find a liner.

Picture of injection port after removing weldment

Ah, OK. Thanks. Sorry, lots of experience with 7890B's, but I have no experience at all with that inlet, so can't really help much.

Ah, OK. Thanks. Sorry, lots of experience with 7890B's, but I have no experience at all with that inlet, so can't really help much.

Appreciate you looking into.

Helium is getting to the instrument. We think it might be a bad column. I have someone here taking a look at.