5973N Diff not pumping down

[MSCHemist]

Hi all I am off to troubleshoot our new (to us) 6890+-5973N system. It is not pumping down and is timing out. Apparently Chemstation (E02.02) is just closing with no error messages.

The foreline pump an E2M1.5 seems to be doing what it is supposed to being noisy at first then silencing down as it proceeds.

-My only guess is not enough oil in the diff pump and that is the first thing I'll check
- maybe the Side plate o-ring needs some TLC (wipe it off with methanol and apply Apiezon L) the vent valve o-ring as well.

Any other possibilities?

(after my 5975 gave me six months of $#% I have a whole new system to make me crazy).

[carras]

Hi MSChemist,

Check if the oil inside the pump is hot, in my 5972 you can tell by touching the upper part of the pump casing. Do you get any error message such as "diffusion pump oil too cold" or words to that effect during pump down?

[MSCHemist]

No error messages and chemstation just shuts down. It came close once and was almost to operating range when it suddenly started talking about venting and chemstation crashed.

[MSCHemist]

Scratch my last post I am confused. I am reaching <100 mtorr and the diff pump is not activating. I believe 300 is the threshold.

I got a 448 error message?

[MSCHemist]

I think I see the issue Chemstation and the MSD are not on the same units.

On the MSD pannel it says to foreline pressure is 70 mtor which is great
On Chemstation it says pressure 70 Torr too high.

How do I resolve the difference in units?

[MSCHemist]

OK after 3 hours with agilent and being completely perturbed we got it to work. Basically like I said the MSD tells chemstation the foreline pressure is 70mtor and Chemstation thinks it is 70 Torr and won't turn on the diff pump. I was able to pump it down from the instrument keys and though chemstation still thinks the foreline pressure is 70 Torr it isn't doing anything about it so it works.

Agilent is looking into a solution. It is Chemstation MSD E02.02SP1

[James_Ball]

I have an older 5973 HPIB/Diff unit we upgraded to LAN and E.02.01 and I had a similar problem the other day. We had a shutdown of power on a weekend and I came in on Saturday to start things back up. Came back Monday and the unit was in vent mode. I sat and watched it a couple times and noticed the pressure dropped to where it should be but still got the Diff Pump error of not being hot yet. After a few tries it finally took and kept running. I noticed it does read the foreline pressure but calls it Turbo Pump Speed instead, even though all the units are set correctly.

[MSCHemist]

Well I'll post a solution if Agilent comes up with one. I tried reinstalling the firmware on an unrelated issue (temp fault 2048 800) and it didn't resolve it. It seems to be working OK now. Pressure is really good 2E-05 torr better than my 5975b Turbo unit which is 4.2E-5 Torr. The GC might need some more insulation arround the injector. The front inlet temp went down to 235 from setpoint 250 because the oven was at only 40 and the fan was blowing so hard. It had a good tune.

I don't know why everyone says the E2M1.5 is a whimpy pump it got the instrument down to 70 mTor in only a few minutes.

[MSCHemist]

Agilent says the issue has been documented and will be fixed with the next Chemstation service pack

I have verified that we have this issue documented and it is on the list of fixes to be done with the next patch. There is no need to do the experiment I suggested. The service request number is in the subject line if you need more help with this, call back and reference the SR number.

[Yama001]

We have found it difficult to use Agilent's E.XX series to pump down the MS. We have much better luck by just using the intrument panel commands to pump down. We only start the software after the instrument panel says the MS is ready.