Lab Advisor Pressure too High Check Still Failing

Recently I noticed a larger pressure fluctuation during the injection process for my 1220 autosampler. I tested the system using Lab Advisor's Pressure too High test and it failed stating that there is a clog.  I switched out the needle, needle capillary, and the needle seat, but the issue is still persisting with a fluctuation of 15bar during the injection process. I believe the issue is during the mainpass-bypass switch.

Are there any actions I make take to reduce this fluctuation or is this okay? I am running water and methanol as my mobile phase.

Thank you.

  • Hi

    To identify which module is giving problem, you have to bypass autosapmler then see pressure..

    Remove column then see pressure..

    Like this you have to monitor to find exact location of blocking...

  • Hello,

    To identify where a clog is, I always suggest the same thing.

    1- Do you have a high pressure when you open the purge valve?

    2- close he purge valve and remove the capillary that goes into the column and get paper or beaker to take the mobile phase that will come out.

    3- Check what pressure you have at that moment and then right click on the sampler on your software and ''Switch valve to bypass'' and check the pressure. Pressure should drop slightly and not be above pressure limit in either case

    4- you can also disconnect the capillary from the valve (position 1 - that comes from the pump) and close the purge valve and see if pressure drops. If it did not drop significantly at 2 and 3 and drops at 4, I suspect the rotor seal of the injection valve is the issue.

    Let us know what you get.

  • Hello, 

    To answer your questions

    1- No, pressure is near 0 bar when the purge valve is open.

    2 & 3 - After following both steps, switching from mainpass to bypass decreased the pressure by roughly 1bar.

    4 Pressure did not drop. It is consistent with what is expected. 

    I ran IPA through the instrumentation and the Pressure too High test passed with it; however, the test does not pass with my mobile phase composition. 

  • What is your mobile phase? Normally, the pressure test needs to be run with Water or IPA.

  • hello  

    Would you be able to advise if you are still experiencing this higher fluctuation in pressure during injection? If yes, try connecting capillary to column inlet, use solvent composition and flowrate as in your method and switch your autosampler valve to mainpass. Wait for pressure to stabilise, note pressure.Then switch to bypass, wait for pressure to stabilise again, and note pressure. Compare and see the difference, bypass pressure should be lower than mainpass but not too much lower. 

  • Hello ,

    Since there has been no further reply to this post and the pressure too high test passes with IPA, it looks like you no longer have this issue, so I have marked the above reply as an answer. Please let us know if you still require assistance with this or contact your local Agilent Customer Support Team and share the serial number of your HPLC modules.

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