Agilent 8890 Front Inlet: Pressure not ready at run time

[msk4]

Hi, I'm new to Gas Chromatography.
So I'm trying my best to learn and know about this.

But unfortunately, I got a problem when using the machine.
First of all, I'm using Agilent GC 8890 model.

Here's the issue:
Agilent 8890 Front Inlet: Pressure Not Ready at Run Time
When runnuing my sequence, this issues happened all the time.

But it didn't make machine shut down. Just occurred when it starts every single time. I think the injection process didn't work well. I'm afraid I could not fix it for now.

So could you help me to find out what's the matter?

[MSCHemist]

Could be a leak. I recently had a leaky Merlin Microseal that was causing pressure problems before I removed it and put a septum/nut on.

[Travisdog2]

Hi MSK4,

As MSCHemist said, this is most likely to be related to a leak.

The 8890 has a leak and restriction test which you can find in either the maintenance or diagnostics section of the touchscreen (I don't remember which off-hand). If you run this it will give you some idea of whether there is a leak or not and if so, how much of a leak.

The most common culprits are likely to be the septum, septum nut and column nut, although we have had a valve issue in the past which caused a fairly large leak. Personally, I would run a septum change (or whatever it's called) from the maintenance menu, swap out for a new septum and tighten down the nut. The septum change protocol includes a leak and restriction test as part of the protocol - Green is OK, red is bad. If you still have a leak, then you might consider tightening down the septum nut a little further to see if that changes anything, but don't go too far.

If the leak is large, it may be worth checking the weldment, taking it off and re-attaching - These can be quite fiddly and don't always align correctly. If this doesn't fix things, then the next candidate is the column nut. The septum change protocol should bring the oven down to ambient temperature, so it should be safe to open up the oven (check temperature first) and see if the column nut is loose or not. If loose tighten it.

Personally, I have had a lot of issues with the standard nuts and so moved over to self-tightening nuts which are amazing...

Hope this helps.

R