sample pressure low

<p>After the injection, system ran for a minute and the error message came on and systerm stoped running. the error message was "sample pressure low(-0.8): possible no wash solvent or needle damage.</p><p>Please advise,</p><p>thanks,</p><p>Chi</p>


  • DavDag

    The most common reason for this error is low or empty Wash Solvents. Ensure all Wash Solvents are full and well primed. Additionally some other things that could lead to this error are a damaged Sample Needle, O-ring, or Wash Syringes.


  • Liage

    did you solve your problem? I had the same problem three weeks ago  and could not run the samples overnight. I changed the needle, the weak wash and strong wash syringes, but the problem was the  same. Even the Waters Engineers could not fix the problem. Finally they exchanged the  whole fluidics drawer. Since then the problem doesn't appear anymore.


  • SamP


    the problem is also known to me.

    It appears occasionaly, mostly after the system was not running/no injection for some time e.g. over weekend, even if the system was refreshed with "startup system".

    I'm able to "solve" this issue by conducting some extended cylces of "wash needle" from the console's menu.

    Something it needs one or two tries.

    It seems to me, that the system wants to reach and hold some pressure on the needle for some short time (look at the sample pressre chart).

    Maybe there is some air trapped somewhere which prevents the test to pass. With only system startup, only the fluid path from reservoir to syringe is purged, not the needle wash itself (if I remember it correct)

    In my case, once the wash cylce passes in the "manual mode" (with the same volumes as in the instrument method) I don't have any problems in running some sample sets.

    Another guess would be that one wash syringe has a bit too much clearance on the piston, so the pressure build up isn't that immediately as needed (but if so, I would expect the test to fail everytime, which it doesn't in my case)