Chromatography Forum

Hello, everyone. I am asking possible causes for a problem of our Agilent 1200 HPLC equipped with a G1311A quaternary pump. This system works fine for over 3 years, then suddenly one day pressure gradually increased within one minute into over 400 bars, which is the upper pressure limit and the system automatically shuts down.

To troubleshot this problem, first, I checked the cloggage on solvent inline filters which are fine, then columns, lines by disconnecting them from downstream direction, but the pressure still increased at over 400 bars even I disconnected everything downstream from the pump head and let the purge valve open.

Does anyone experience this same issue before and can someone give suggestions what are the possible causes? Thanks a lot!

Have you cleaned check valves on the pump heads? Most likely dying seal parts have clogged the outlet check valves. Consult the manual for dismantling the check valves. They can be cleaned by sonication.

Hello

Have you checked/replaced PTFE frit in purge valve?

Regards

Tomasz Kubowicz

The outlet tubing of pressure sensor clogged.