UV Lamp hours keep  increasing when HPLC system is at standby mode


Can you please provide me reason Why UV lamp hours of G1315A detector keep increasing even if 1100 HPLC system is at standby mode and instrument part i.e pump, lamp, thermostat and auto sampler is off after last sequence run ?




Thank you



  • Hello,


    I moved this post to the LC section of the Community where it is most likely that someone with the expertise to answer your question will see it. 

  • Where are you looking at hours?  Chemstation?  Lab advisor? Handheld?  What revision?

    What firmware revision is on the DAD? 

  • Hi,

    Please see attached pictures to find hours info, detector type, system at standby and ChemStation version in use.


    Thank you



  • I am the PSE for all LC detectors, except ELSD, but I have not heard about such issue before. Furthermore your G1315A is 22 years old and fully out of support since end of 2011! The Chemstation used is out of support as well and the FW on the DAD is outdated and too low. You then also sent almost 20 MB data of not much value. Usually we tell all CEs to collect at least a full LabAdvisor system report and the diagnostic buffers, which would be a fraction of the size of the four photos. In your case I also have my doubts about the D2 lamp. Is it an Agilent one? You didn't mention any part or serial number.

  • Hello


    I think software is showing “detector powered on time”. Please click DAD icon and find “Show module details”. (Not a right-click!) Then you can see detailed picture.  Next ,please find UV lamp icon that is longer oval like upside-downed egg plant, (I think the egg plant is long oval ,,,,, at least in my nearest supermarket,,,,, ) and click it. You can find “update variables display“, that will update numeric information of it on lower screen. You will find Lamp used hours.

    Right now, the “LabAdvisor” software does diagnostics function. So my suggestion is very old way . I can’t remember all detailed all procedure so please try clicking, “show module display” and “update variables display” , and arrow icon to getting back.


    Happy weekend for everyone!

  • On this old software- did you tell it that you replaced the lamp? and then it will ask you if you want to reset the hours to zero. There is no RFID tag so nothing to read. I haven't seen this before either.

  • Hi,

    I know system is very old and I start using it from 2016 . This system don’t have Lab Advisor install on it and after looking into maintenance logbook for this HPLC detector, all it say UV lamp replaced in 2011 and visible lamp changed in 2012. I think I have to take lamp out to see if it’s from Agilent or from any other supplier .

  • Hello,

    thanks for update (I wonder if my memories were incorrect,,,


    Your question is classed "difficult" ......


    Let me start easier one!  The visible lamp is not required replacing.  It seems working without error. that is typical "bulb" , if id is out the software tells you "current error" or something , (not like ignition error)


    The UV lamps age ,in general, the lifetime is around 2000h as you know,

    The 8100h is surprise! (Or someone missed to reset lamp hours! So today's DAD lamps have RFID tag recording correct "ITS" hours, as jhagel wrote , RFID information is reliable.)


    Your test result tells us "the light intensity is low", possible causes are:

    - aged lamp

    - something in the cell (UV absorbing solvent, bubbles or everything to hide beam!)

    - dirty flow cell windows

    - dirty or aged windows/lens of optical unit

    - other malfunction


    And your detector is old model (as sschombu wrote)

    Replacing to new genuine lamp is good idea in many cases :-) but sometimes  NOT for aged detector, If lens/windows/cell/windows/grating are dirty or burnt and you replace NEW-lamp, the light intensity will not recover and intensity test will fail. In this case you need to ask to repair of DAD. (and you can't return new-lamp... )

    I have no idea for repair parts availability (some are already gone...), so I recommend to ask local Agilent's service..., 

    possibility ,price, parts availability and risk of costs.


    In some cases you have no need to replace UV lamp:

    - you can do your analysis without any problem.

    - your chromatogram's noise is within YOUR specification

    - your chromatogram have now explicit drift or hiccup

    - your boss/customer/regulations permits use of old lamp.


    Sorry for complicated advices ,




    ps : If it's mine I will try to wipe two window in cell compartment with a clean wipe and non-metal toothpick..... only two window in cell room ! and leave it half day. I can't give you guarantee...

  • Hello everyone,


    Are there any "correct" comments ???



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