Chromatography Forum

Hi,

I changed the seal pack from my 2695 about 1 month ago and its been working fine for less then 3 weeks. Now I can see from the sample compartment that liquid is dripping again from the lower spacer..

I thought that the seal pack would work properly after replacement since the adjust seal values are in the acceptable range. By the way, the instrument didn't show me whether it passed or failed the seal adjustment.

I made sure the orientation of the needle is correct but I could be wrong. Could the misalignment cause the leaking again?

Or is it because the pressure during the seal adjustment was only around 1300psi.

This is very frustrating because I thought I could fix the seal pack leaking problem. Could anyone give me some valuable suggestions please?

Thank you very much!

You may want to check the tubing fittings that plug into the injector. If one of them is leaking you may get liquid coming down through the foam and down through the injector port.

thank you very much! I will look into it tomorrow and hopefully find out something.

Worse comes to worse, will needle disorientation cause leaking too?

Thanks so much again!

The needle orientation should not affect whether or not the instrument leaks. Your peak shapes will be poor, but your instrument should not leak.

First, verify that all of the fittings you undid are not leaking and verify that the leak is indeed your seal pack. Did you rebuild the seal pack yourself or did you acquire a new seal pack and install it? Also, pressure during seal adjustment is supposed to be around 1000-psi with a flow rate of 0.3-1.5 ml/min and too high a flow rate can damage seals. You saw no results when the instrument completed the seal adjustment? That's odd. According to information that I have, you actually have to press the "Accept Results" key in the "Adjust Seals dialog box to proceed.


CJ

Hello and thanks for the valuable suggestions.

I re-tightened the needle a bit inside the injector today and there was no more leaking for the rest of the day... I am still worried because now I am afraid that I have overtightened the needle, maybe it will start to leak again after a few weeks. And also somehow the pressure is still 10-20psi lower than it supposed to be although no leaking sign has been found at the moment.

I ordered the seal pack rebuild kit with needle from Waters and replaced all the high pressure seals, spacers, filters and needle etcs by myself. I also purged the injector twice and generated a pressure of around 1300psi before I started adjusting the seal.

When I performed the seal adjustment, the instrument only showed the top, bottom and width seal data values at the end, and in my cases they all are in the acceptable range, so I accepted the results. However, apart from the seal data values I was expecting that the instrument would also show a pass or fail status on the screen...

I just started to do maintenance and troubleshooting this year so maybe lots of stuffs that I did might not make sense. Hope people here can understand...

Thanks so much!

I doubt that you've overtightened the compression screw on the needle because they require one full turn to seat the ferrule, unlike most other SS compression fittings on LC's. If it's not leaking and the needle is aligned, I think you'll be OK.

Does it pass a compression test after purging? How's your injection volume accuracy? If they're both OK and you have no leaks, then I'd say you're done.

Hi, this morning I also found that the restrictor loop was not tightened enough so I retightened it. No more leaking so far and pressure is back to what it supposed to be normally.

To be honest I did not perform the compression check after the seal adjustment... Even if the pressure seems to be normal and the retention time is consistent with the what it used to be, is it important to perform a comp check? Would it be still okay if I do it after such a long time?

Thanks for your continuous suggestions!