Chromatography Forum

Hi there!
I had a problem with the quaternary pump on my LC system. The system was shut down for almost 4 months and was last closed with MetOH 50%.
I wanted to turn it on but the pumps were blocked. Reading the manual I thought I should remove the LDA and clean the check valve.
Would this be a solution?

Thanks.

won't hurt... Also, make sure your proportioning valve works - that all of the solenoids are opening when they should.