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.

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.

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,

If assume everything okay but still pressure not zero then doubt will go on Damping unit of pump because damping give pressure signal to LPM board of pump.

I will suggest to call your local agilent suppprt to check this because pump need to open to see exact root cause.

Thanks

THANKS ISHITIYAK!  Good to learn about this damper part.  Also of note, the pumps still work and the flow rate can be controlled --- just the pressure reading stays wrong.  Perhaps it is tolerated somewhat and we can use it temporarily before a thorough fix... Thanks again for your suggestions and prompt replies!