Quaternary pump pressure reading wrong

Hi 

https://community.agilent.com/technical/lc/w/wiki/7687/troubleshooting-high-pressure-issues-in-agilent-lc-systems

Follow above link to check where is problem.

First, u should see frit of purge valve.

Did any PM done after one year or not?

Thanks for your suggestion!  No PM was done in the past year due to software problem.  Now there is no computer issue, but pump showed a pressure 200+ bar even if it does not run and no flow at all.  And the pressure does not change AT ALL after turning on the pump and flow is increased from 0 to 1 ml per min.  Could the pump sensor problematic?

I don't think sensor problem.

Follow the link i shared in above reply.

You have to isolate one by one to know where is problem.

Like without column, pressure there or not.

Purge valve is open then pressure is there or not.

In the link, i shared in my prevoius reply, all steps are mentioned there.

If opening purge valve pressure down then replace frit of purge valve.

Follow all steps, to resolve this..

If any doubt then let us know.

Hi andrew3025

What solvent/buffers were in the system when it was last used?

Andy

Thank you for your detailed answer and guidance.  The issue may be clearer to you experts --- even if without column, with purge valve open, the showed pressure number is still there, looks like a NOMINAL pressure but actually should be zero...

Thanks,

I believe it is regular case:  two solvents --less polar one is ACN with 0.1% TFA, more polar one is water with 0.1% TFA.  Thanks for your suggestion,

I believe it is regular case:  two solvents --less polar one is ACN with 0.1% TFA, more polar one is water with 0.1% TFA.  Thanks for your suggestion,

Hi andrew3025

Not sure how well a pump would react to being left with TFA in it.  I would definitely give the system a good long flush with water (possibly hot water), and maybe then isopropanol, to see if there is some residue causing the faulty readings.  

Other than that, it looks like a repair job is needed

Andy

Thanks Andy for your suggestions!   I will try to do more flush.