Dear Penny,

I'm definitely not "the authority" on these things, but a similar problem
happened to me once.  Check the rubber o-ring around the oil wick in your
turbo to make sure that it hasn't been damaged or deformed during
installation.  Especially if this is one of the smaller turbos on the XP,
there is a very thin o-ring at the end of the wick that is often slightly
floppy and can become damaged or deformed if it isn't installed just-so.

Good luck!

Mike Kubo
NASA Ames Research Center
M/S 239-4
Moffett Field, CA 94035
(650) 604-6110

-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf
Of Penny Higgins
Sent: Thursday, January 11, 2007 2:46 PM
To: [log in to unmask]
Subject: [ISOGEOCHEM] Vacuum troubles

Hi all,

It's late and I'm tired and my Delta Plus XP is cheesing me off. I'm 
sure I've simply done something stupid, but I can't think of what it is.

We had to send our turbo pump back to Pfeiffer for repair (bad 
bearing). I just got it back and am putting everything back together. 
So far as I can tell, everything is tight and connected as it should be.

I turn on the pumps and get the normal gurgle from the rotary pump. 
No shock, it's been sitting idle for nearly a month. The turbos start 
up, as the gurgle continues. The turbos run quietly as they do when 
there is not a leak in the system, but the rotary is still gurgling 
away. The fail-safe finally shuts down the pumps when the turbos are 
unable to reach 70% (or whatever the cutoff is) of their operating speed.

Everything is tight, and the turbos don't howl like a jet engine as 
they do when there's a leak in the system, so I'm at a loss. I've 
checked to be sure the source is seated properly in the source 
housing, and it's OK. The one thing I'm not sure I have attached 
right is the down-to-air vent on the turbo. It looks right, but there 
are so many washers and rubber rings that I could have it wrong - 
could an incorrect installation be causing this problem? I suppose I 
could check that by simply removing it and inserting the plug to see 
what happens.

Is there anything else it could be? Could it be an artifact of the 
rotary sitting for so long (I don't think so)?

Yarrrgh!

Thanks all,

~Penny

*******************************************************************
                       Dr. Pennilyn Higgins
                        Research Associate

                             "SIREAL"
   Stable Isotope Ratios in the Environment Analytical Laboratory

         Department of Earth and Environmental Sciences
         University of Rochester
         227 Hutchison Hall
         Rochester, NY 14627

                    [log in to unmask]

Office: 209b Hutchison Hall               Lab: 209 Hutchison Hall
Voice : (585) 275-0601              Outer lab: (585) 273-1405
FAX   : (585) 244-5689              Inner lab: (585) 273-1397

           http://www.earth.rochester.edu/SIREAL/index.html
*******************************************************************