Just changed the needle and seat on an Agilent 1100, the pressure went down when equilibrating, but now drops to nothing on injection

24 April 2013 1 8K Report

The instrument is old, I changed a lot of the other plumbing. The pressure is fine and steady when equilibrating, then when it goes to make the injection, it just starts flowing from the needle and not through the brand new needle seat...

Jonathan Decenzi

Thanks, it ended up being the rheodyne valve, it was sticking so I had to take it apart, clean it and replace the stator.

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Science method

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