ALS G1313A Leak


Working on a G1313A ALS Had a leak at needle seat when in mainpass. Changed needle, needle seat and needle loop. It has stopped leaking but if I do maintenance diagnostic and it comes to the last step where it lifts out the syringe from the needle seat. Liquid flows out of the tip of the needle and then you hear the valve clicking and it stops.

What would cause this?

  • Hello Georgina,

    What maintenance diagnostic are you doing after the changes you made and are you using Lab Advisor?

    Is the pump running at the time you are doing this diagnostic?  If yes, I suspect that you have what is called "cross-port" leaking due to a defective rotor seal in the injection valve.  What valve clicking you hear?

  • Hi,

    Thanks for replying.

    I am using the G4208A Agilent Instant Pilot and running the diagnosis injector steps for the Autosampler. 

    The second last step: the syringe is in the needleseat and it turns to mainpass.

    The next step: it lifts the syringe and you can hear the rotor move again. This is when the liquid flows from the syringe It sounds like the rotor tries again to move and succeeds on the second try and liquid stops flowing.

    We have run sequences with the ALS and it works but I feel this is going to only work for a while. You think I should change the rotor seal?


  • Hi Georgina,

    I would suggest taking a look at the rotor and see if it's worn.  Take a look also at the back of the stator [metal where all the capillaries are connected] and make sure it's not scratched.  If yes, replace as well.  Most of the time, the described issue is with  a worn rotor seal.

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