Chromatography Forum

Hi, I'm posting because I need some help

There is Shimadzu LC-20AD Prominenece which has two pump A and B

But Pump B can't purge at all since it got a high pressure error

When I push the button of purge, appear the word 'Purging Line' on the board of pump B just for a while but disappear and no react anymore

It works except for purging and I don't know the reason

If you know how to fix it, plz let me know

Thank you

It sounds like there is a clog somewhere in or down-line of pump B. Have you tried disconnecting the fittings from the outlet and running a purge? This would help to narrow down possibilities.

To purge , you must open the drain valve , otherwise it does not purge.
Is this the case ?

This sounds like a purge valve problem. I think if you keep turning the purge valve in the "open" direction, it will eventually come out altogether. You can then check for any problems, and back-flush the outlet. Don't lose any bits. You should be able to get it back in, and all behaving properly.
Edit: I just noticed yours is a prominence pump. I've only done this with a Nexera. I think they're similar.

I can confirm that Nexera and the Prominence are the same in that you can get the purge valve to come out by simply turning it until it does so.

I can also add a story of when I experienced issues with purging a Prominence system.
I tried purging and it didn't work, I think it showed an error message something about high pressure. I took out the purge valve and had a look, couldn't see anything stuck there. Eventually I disconnected the column and tried again, a thin stream of eluent hit the interior of the column oven as I held the PEEK in that direction. So the flow when purging apparently went straight on-column, I don't think that column was used anymore as my colleague had been doing this many times during about half an hour
Eventually it all came down to the waste tubing. It was bent so that no flow could pass, which meant that it didn't matter if the purge valve was open or not, it couldn't go to waste anyway.

Hi Perreman ,
Don't worry about your column , when the pumps sees more than 10-20 kg/cm2 pressure during purge mode, it automatically stops and gives a warning '' open drain valve ! '' , so it can not apply much pressure to your column.

Since you removed the column , then it pumps at 10 ml/min , so you see the stream of solvent coming out from tubing ( if the pressure is still below the threshold).

... yes, purging is very safe on Shimadzu systems. Incidentally, if you have two pumps configured to operate like a single binary pump, and anything goes wrong with the purge on one of them, usually both pumps will purge OK even with just the one purge valve, because if pump A's valve is closed, it will attempt to pump 10mL/min out its normal outlet, which can then go to the mixer, back in pump B's outlet, and to waste via pump B's purge valve!