Chromatography Forum

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Hi,

During routine maintenance I replaced a rotor seal on a six port Rheodyne valve.

Now I am not seeing any peaks when a sample is injected. As I am new to HPLC maintenance have I replaced the seal incorrectly? (HPLC was working correctly prior to this)!

Please help!

did you place the rotor correctly? you know, grooves on the surface should face the stator....

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Hi,

During routine maintenance I replaced a rotor seal on a six port Rheodyne valve.

Now I am not seeing any peaks when a sample is injected. As I am new to HPLC maintenance have I replaced the seal incorrectly? (HPLC was working correctly prior to this)!

Please help!

What else did you do during this maintenance? What model autosampler/injection valve. On the Rheodyne valves used on Agilent, not too easy to put together wrong due to hole spacings in the parts. Is your pressure steady, no leaks, same pressure as before???

It worked before, doesn't work now - so yes, you broke it.

Before pulling it apart again, I'd have another look at the connections, to make sure they are all on the correct valve locations, and also, if you are using PEEK tubing, ensure that every port tube end has a clear orifice.

Sometimes, the reconnection can squash the tubing end and provide a blockage. Also have a look to see if any liquid is appearing when you perform a large volume injection ( change loop size if fixed loop ).

If they all look OK, then reread the disassembly instructions BEFORE attempting to take it apart, and then closely observe what you find, and compare against the disassembly instructions - you should find what is wrong whilst pulling it apart. Then reassemble correctly. ...

There are some Rheodyne online resources, including a troubleshooting guide, manuals etc. available at:_
http://www.idex-hs.com/support/rheodyne ... tions.aspx
http://www.idex-hs.com/support/rheodyne ... guide.aspx

Bruce Hamilton

It worked before, doesn't work now - so yes, you broke it.

Bruce,

I'm still laughing

Been there, done that!