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Thanks again to all who braved my long and overly-detailed posts asking
about the IRMS vac system. In case anyone was wondering, the reason I could
never diagnose a severe, underlying problem that was causing multiple
turbos to fail is that there never was one.

The first turbo, as I had initially determined (before deciding I must have
been wrong) likely died because of the missing o-ring on the vent valve.
The second turbo died, however...

... *because there was no oil wick in it.*

The end result was parts of the shaft that weren't supposed to spin
freely... spinning freely. So, let this be a lesson: unless you've got a
'warranty void if broken' sticker on the reservoir cover for your turbos,
you might want to take a look before installing and make sure someone
hasn't removed it for long term storage or to feed another turbo in need of
a wick, or that the rebuild company hasn't missed a step.

So, if anyone had become alarmed about 3-way valve positions on pump-down
due to all my ranting, well, I imagine you can relax. (As per the manual,
you're really NOT supposed to have it set to FV when pumping down a fully
vented machine/analyzer, but everyone does it to no apparent ill effect,
so, hey.)

Well, at least we've got a shiny new rough pump now.

Matthew Wolhowe
University of Washington
School of Oceanography