1290 Infinity II Binary Pump Tuning/Conditioning


I am trying to determine whether or not my binary pump is working properly. I have heard three different opinions with respect to the tuning parameter. This post ( RE: Tuning A and Tuning B parameters in Binary Pump of 1290 LC ) indicates that +/-1 is acceptable. However, I have also heard +/-0.4 from an Agilent trainer, and +/-0.2 from my service technician.

For my system, the tuning parameter for Pump A  typically stays below 0.1, but pump B can vary from 0.05 to 0.2. However, lately the tuning parameters for both pumps have been drifting upward, sometimes as high as between 0.15 and 0.2. According to my service tech's opinion above, this is brushing against the upper limit for acceptability.

My questions for the community are:

  1. How do I interpret what is going on? I don't have any other indication of error (e.g., leak, pressure fluctuations)
  2. What at what point do I really need to worry about the pump tuning parameter? Is it even something that I should bother monitoring?
  3. Would running a conditioning routine for the binary pump have any effect?
  4. How is conditioning different from, say, running at a high flow rate for ~15 minutes? I ask this because I am experiencing difficulty executing a conditioning routine in MH Acquisition from the "prepare pump" menu (nothing happens).

Any insight would be greatly appreciated. Thank you!


  • 1. I created this table to explain what some of the values could mean:

    2. Yes, as I mentioned in the other post. Between plus and minus 1, you should still be in the specification for retention time precision. 

    3. Yes, conditioning is useful for removing micro air bubbles from the system. During conditioning (flow to the system, not ready state "conditioning"), the tuning value does not change. After conditioning, the pump will go back to its normal operation and then begin to update the tuning and you may see values closer to zero because micro air bubbles have been removed during the conditioning.

    4. Using higher flow rates and pressure is also helpful, but conditioning helps the primary chamber better remove air bubbles from the system. Do you have more information as to why it is not working? Conditioning is using the flow rate and composition from the loaded method in masshunter and then runs for the time set in the prepare pump context menu. This runs in a not ready state, but flows to the column.

  •  , thank you very much for this information!. Regarding difficulty conditioning the pumps, I think I was misunderstanding how the conditioning routine executes. Originally, I thought that the pump conditioning routine would work similarly to pump purging, where I'd just have to press start and the program would do its thing. But I see now that I need to have the solvent proportions and flow rate active prior to initiating the conditioning routine. I was able to condition my pumps this morning.

    As a tangent, sometimes I see a sawtooth pattern in the tuning parameter trace for one of my pumps. The pressure trace looks fine, and the tuning parameter trace for the other pump looks fine as well. The pattern usually doesn't stick around for too long, but it does seem odd. Any idea what this is indicating?

  • It could be indicating something like an air bubble/particle which has effected the defill step of the pump cycle. It basically could indicate that the one stroke was not ideal. If it is going away, the air is likely being removed.

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