Chromatography Forum

Hi. I am working with an Agilent 1100 HPLC system.
I noticed that the pressure reading was > 10 bar (16 bar) with 5 mL/min water flow, while the purge valve was open. I changed the purge valve frit and the used frit was dark. After changing the purge valve frit, the pressure reading dropped from 16 to 10 bar.

Is somewhere still dirty or partially clogged? If yes, where could it be?

The other weird phenomenon is that there were a lot of bubbles coming out of the purge valve waste line when the purge valve was open.

I can still run my analysis method. I am just curious what was going on with my system.

Thanks a lot!

What is pressure during stopped flow and opened purge valve? If not about zero, it should be set but now I'm not able to say you where. I'll update my answer.

Bubbles coming out of the purge valve may be caused with untightness of valve body when opened (stupid answer I see ). When all pressure tests are OK, it is not problem.

Sadilek. Thanks. This is the right test. Pressure reading is 9 bar with 0 mL/min flow.
How to set the pressure reading for the damper?

So I have more informations (thanks to my friend Vaclav ).

We don't know procedure how to reset pressure on 1100 series pump. There is an allowed range approximatelly from -7 to +25 bars. If exceeded then is necessary to exchange pressure damper or mainboard (A/D convertor).

Maybe there is an Agilent specialist in forum who helps us.

Regards
Jan

Hi All,
The setting of presure unit is a Customer Engineer job firs of all.
But...
You have only chance for setting the pressure zero up if you have a Rev.K type of damper. The earlier version does not have the zero set potmeter. You can find a label on the side-rim of the damper. This contains the part no. and the version and the serial, If you have luck and your pump manufactured after 2002 an engineer can set the zero. If you have Rev:I the engineer have to replace the whole damper unit.
The positive difference is the better side then negative. If the damper leaks and the pressure signal drops below zero, the pump stops with "Pressure signal missing" error and red status. So don't worry about 9 bar.
Attila