Dionex GS50 pump won't hold prime

[chrisv]

Hey everyone,

I've been trying to diagnose and fix a problem with our Dionex instrument. Basically, the system doesn't hold prime.

So far I've replaced: the O-rings on both the waste and priming valves, the piston seals in both pump heads, and the inlet and outlet check valve assemblies.

Our system also has a vacuum degas assembly, which seems to be working according to the diagnostics screen. I'm somewhat of a novice at this, so I'm not sure what else I should do/look for.

Any advice would be appreciated.

Thanks,

-Chris

[bisnettrj2]

See page 113, etc. and 65, etc. in the following document:

http://www.dionex.com/en-us/webdocs/577 ... 03_V20.pdf

And this Chromforum post:

viewtopic.php?f=1&t=12187

[Mark Albertson]

Hi Chris,

Check you are not just loosing prime on on pump head, if you are you may have detached the piston from the magnetic coupler

Regards

Mark Albertson
Thermo Fisher Scientific
Sales Mgr ANZ.
IC, Sample Prep

[Mark Albertson]

Sorry Chris having a hectic day

Hi Chris,

Check you are not just loosing prime on one pump head, if you are you may have detached the piston from the magnetic coupler

Regards

Mark Albertson
Thermo Fisher Scientific
Sales Mgr ANZ.
IC, Sample Prep

[chrisv]

Mark,

It looks like I'm losing prime on the primary pump head (when I disconnect the line from the secondary pump head and place the end underwater, I get bubbles. Replacing the line also resulted in bubbles).

It doesn't look like the piston is being detached.

I also don't notice any leaks.

In the past, changing check valves resolved any loss of prime issues I've had with this instrument.

-Chris

[Mark Albertson]

Hi Chris,

If I read you correctly you may have air bubbles in the line from the proportioning valves to the primary pump head. If this is the case the proportioning valve may have failed due to a number of factors, the most likely in my experience is usually failure to have all the inlet lines on the proportioning valve primed with liquid. Try using a brown Dionex joiner to bypass the proportioning valve, this can be achieved by joining say inlet port A with the outlet port on the proportioning valve. Reconfigure the pump to normal operating mode with both pump heads operational. If your bubbles cease to appear then you have found the source of your priming issue.


Cheers

Mark