seal, valve tests pass, not compression, what does this mean

Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.

18 posts Page 2 of 2
hplctroubleshooting wrote:
Hollow wrote:
hplctroubleshooting wrote:

-I figure that when the sample is being drawn, if there isn't a good seal, the drawing of the sample wouldn't be as efficient.
there is only one opening of the needle at this is in your sample. The seals just seal the flow path to the column. It's like a cross-road.
But if V3 doesn't seal properly, there will no vacuum and to few sample would be taken up...


-The valves seem fine, but I'll test them again today.
if we suspect V3, there is no need to re-do it, cause it's not beeing tested.

-There supposedly is a test for valve 3 in the waters manual, page 157, the fourth test from the top. edit: nevermind, it's not really test for valve 3 but rather a test for "needle port too high in seal".
That's what I've realized too. There is no test for V3, but there is a section for the Waters service people for special valve tests (page155).
Maybe you can get them to assist you on the phone?


Thanks for your help, will be trying out your suggestions either today or tommorrow.


experimental idea:
maybe you can build yourself some diagnostic setup for V3.
I'm thinking of kind a translucent peace of tubing attached to the waste line of V3. Then immerse this into some (coloured) liquid.
Then watch if liquid will be drawn into this tubing just the same time when your sample is taken up. If so, your V3 is faulty.
Depending on your tubing, test with large sample volumes, so not to oversee effect.


I don't believe this would realy help, but:
if there is "only" some dirt/buffer crystals within V3, try to thoroughly flush the waste line with 100% water, and maybe consecutevly even with IPA or mixtures of it, then back to MeOH.
I don't speak of only "purge inj", but configure the valves manually like during the purge cycle (V3 open, V2 open(?), V1 open, column/restrictor installed) and set a flow of about 1 ml/min and let it flow for some time (don't exceed 1000psi)
Repeat some purge cycles and then compr. check
...depending on your time vs. money budget...


well, in summary for today....and needless to say I am very confused and frustrated right now

1)I repeated all of the valve tests, the tests for the needle position relative to the injector seal (whether it was too high or too low so as to cause a leak), valve 2 and valve 1 checked out just fine. In that respect, I take back my emphasis on the seals, it doesn't seem to be an issue at this point.

2)repeated the compression test but this time noted a bubble after changing the compression parameters so that the syringe draws a lot of sample. I got excited over this and changed out the syringe, but unfortunately I wasn't able to get the syringe filled even manually drawing the syringe in and out while purging the autosampler. So, I got desparate, and perhaps a bit on the ridiculous side, and actually filled the syringe itself with some methanol, attached it to the autosampler, and then injected it into the system while it was purging so that all of the gaps could be filled so that I could draw some sample with the syringe and actually have it filled.

But overall the compression test never passed. And I could never get the system to draw some sample in the vial via a needle.

I tried to close V3, open V2, close V1 and try drawing some sample manually with the syringe, but for some strange reason my waters 717 plus autosampler wouldn't allow me (on the valve motion page-where you can adjust the valves one by one manually) to to have V2 open while V3 was closed, via any order in which it was applied i.e. opening V3, opening V2, then closing V3.

In any case, the compressibility test doesn't pass, even if I change out the syringe. At this point your assertions about having to focus on V3 seem valid. I may try out your test using some indicators tommorrow. At this moment, I can't think of anything else other then V3, I've purged the sample many times and it didn't change anything.

We've got a Waters guy coming soon, better that I tell him to bring with him a V3-waste valve.


Unique issue in Waters Alliance just like Waters 717 Autoosampler is that the needle at STREAM never leaks once we closes V3,V2 manually and then we checked it at WET and SEAL positions too. This means Valve 1 is okay
However when we test V1 by the procedure it hangs on with Restrictor Missing. with small amount of leak probably Needle Wash solution on vial found.
Seal Pack ADJUST test also hampered with Restrictor Missing message.

Same happens in V2 test . The Waste Valve 3 open upon PURGE mode but again when it performs compressibility test hangs on with restrictor failure error.

I cant believe all my Waters Alliance have same issue and 1 717 autosampler. Something is really wrong.

I noted and did the battery replacement too.

Plz guide

Thanks
If you systematically have the same issue on multiple instruments, then the root cause is most likely the same. Were they all serviced by the same person in the same way?





fareedtayyeb wrote:
hplctroubleshooting wrote:
Hollow wrote:

experimental idea:
maybe you can build yourself some diagnostic setup for V3.
I'm thinking of kind a translucent peace of tubing attached to the waste line of V3. Then immerse this into some (coloured) liquid.
Then watch if liquid will be drawn into this tubing just the same time when your sample is taken up. If so, your V3 is faulty.
Depending on your tubing, test with large sample volumes, so not to oversee effect.


I don't believe this would realy help, but:
if there is "only" some dirt/buffer crystals within V3, try to thoroughly flush the waste line with 100% water, and maybe consecutevly even with IPA or mixtures of it, then back to MeOH.
I don't speak of only "purge inj", but configure the valves manually like during the purge cycle (V3 open, V2 open(?), V1 open, column/restrictor installed) and set a flow of about 1 ml/min and let it flow for some time (don't exceed 1000psi)
Repeat some purge cycles and then compr. check
...depending on your time vs. money budget...


well, in summary for today....and needless to say I am very confused and frustrated right now

1)I repeated all of the valve tests, the tests for the needle position relative to the injector seal (whether it was too high or too low so as to cause a leak), valve 2 and valve 1 checked out just fine. In that respect, I take back my emphasis on the seals, it doesn't seem to be an issue at this point.

2)repeated the compression test but this time noted a bubble after changing the compression parameters so that the syringe draws a lot of sample. I got excited over this and changed out the syringe, but unfortunately I wasn't able to get the syringe filled even manually drawing the syringe in and out while purging the autosampler. So, I got desparate, and perhaps a bit on the ridiculous side, and actually filled the syringe itself with some methanol, attached it to the autosampler, and then injected it into the system while it was purging so that all of the gaps could be filled so that I could draw some sample with the syringe and actually have it filled.

But overall the compression test never passed. And I could never get the system to draw some sample in the vial via a needle.

I tried to close V3, open V2, close V1 and try drawing some sample manually with the syringe, but for some strange reason my waters 717 plus autosampler wouldn't allow me (on the valve motion page-where you can adjust the valves one by one manually) to to have V2 open while V3 was closed, via any order in which it was applied i.e. opening V3, opening V2, then closing V3.

In any case, the compressibility test doesn't pass, even if I change out the syringe. At this point your assertions about having to focus on V3 seem valid. I may try out your test using some indicators tommorrow. At this moment, I can't think of anything else other then V3, I've purged the sample many times and it didn't change anything.

We've got a Waters guy coming soon, better that I tell him to bring with him a V3-waste valve.


Unique issue in Waters Alliance just like Waters 717 Autoosampler is that the needle at STREAM never leaks once we closes V3,V2 manually and then we checked it at WET and SEAL positions too. This means Valve 1 is okay
However when we test V1 by the procedure it hangs on with Restrictor Missing. with small amount of leak probably Needle Wash solution on vial found.
Seal Pack ADJUST test also hampered with Restrictor Missing message.

Same happens in V2 test . The Waste Valve 3 open upon PURGE mode but again when it performs compressibility test hangs on with restrictor failure error.

I cant believe all my Waters Alliance have same issue and 1 717 autosampler. Something is really wrong.

I noted and did the battery replacement too.

Plz guide

Thanks
Scott Allison
HawkEye Analytical, LLC
www.hawkeye-analytical.com
"Restrictor Missing" message may mean you need a column that will provide more back pressure installed.
Thanks,
DR
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