Pressure problem with UPLC Acquity BSM

<p>Hi,</p><p>somebody can help me about to risolve the problem that is showed in attached file?</p><p>1. I have changed all seals;</p><p>2. I have changed  pump head  of primary A with pump head  of primary B and I have seen the same problem on the primary A;</p><p>3. I have replaced pump head primary B with Head of accumulator and I have seen the problem to the accumulator, so I have understand that the problem probably is on the head.</p><p>As, with the channel B, I generally use MeOH:ACN + 0.1 % Acetic acid I have changed too the seal wash housing, but I have always the same problem.</p><p>4. I washed the pump head with methanol in the sonicator but the problem don't change.</p>


  • HI, I don't have much experience with waters instruments yet.. but with the Hitachi intruments I would repair when the pressure would fluctuate as shown I would either change or sonicate the flow valves before and after the pump head. hope this solves your problems.

  • Hi

    This looks as either an inlet check valve problem on the primary B pump head or a seal leaking on the same head. Please observe that you should not swap a primary pump head with an accumulator pump head since the check valves on these pump heads are not the same.

    I would start by changing the check valve. If you do not have a spare one take it off and put it in a sonication bath with first 100% water and the 100% organic for 20 minutes each.

    best regards


  • Thanks a lot for your answers.

    I have delete the possibility that the problem is the check valve because I changed the Chek Valve B with Check Valve A and the problem rested on B and no on A.

    When I changed the pump head from primary to accumulator I changed too the check valve. I changed only pump head.

    Best regards

  • Hi Again

    I would then try the accumulator check valve on the B pump.

    best regards

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