Pressure issuee in Agilent HPLC 1100 series

[neo_009]

Hi we have a Agilent HPLC 1100 series and recently we have pressure issues. so i talked to the Agilent techanical department and they sugget to clean the valve, metering valve assembly, which i did but the pressure problem still persists. Then they asked me to change the needle and the sample loop, which i did.

but even after changing the needle, sample loop, cleaning the 6-port valve and the metering valve, the pressure problem still persists.

can anyone help me with what might be the reason for increased pressure without the column attached. I havent had pressure issuee when i test the autosampler in valve switch mode, but the pressure increases when i switched it to main valve.

Thanks in advance

Nishi

[Garlarg]

Hi!

What do you mean pressure issue?
The pressure is too high or too low?
Constant pressure change or abrupt changes (pressure spikes or drops)?
Did you perform the built-in Pressure and Leak Tests?
Are these issues occure in isocratic or gradient or both methods?

[Kimico]

Increased P seems to be upstream from the column. You have already changed the following: needle, sample loop etc etc. A strategy to localize the source which is causing high pressure when the switch is in main pass position is to bracket your issue. Keep the pump running with a flow sufficiently enough to create back pressure with out the column installed. Then start disconnecting capillaries that are part of the Flow patch (mainpass position) so that you can identify where you have flowand where you dont. in this manner you can pinpoint the source of your high pressure and it would not take you more than 10 min.

[neo_009]

Increased P seems to be upstream from the column. You have already changed the following: needle, sample loop etc etc. A strategy to localize the source which is causing high pressure when the switch is in main pass position is to bracket your issue. Keep the pump running with a flow sufficiently enough to create back pressure with out the column installed. Then start disconnecting capillaries that are part of the Flow patch (mainpass position) so that you can identify where you have flowand where you dont. in this manner you can pinpoint the source of your high pressure and it would not take you more than 10 min.

Thanks Kimico,
i did exactly what u told, and i sort out the problem already. Cheers mate.

thank you very much