on 4/26/2000 12:34 PM, Andrea Lini at [log in to unmask] wrote:

> I have very annoying problem with the diff pump on my VG SIRA II, it
> keeps turning off and on by itself with no apparent reason (backing
> pressure and cooling water are fine).
> Can anybody help please?
> Thanks!
>
> Andrea
>
> ==================================================
> |    Dr. Andrea Lini                    |  Stable Isotope Laboratory      |
> |    Department of Geology              |  Phone: (802) 656 02 45      |
> |    University of Vermont              |  Fax:   (802) 656 00 45        |
> |    Burlington, VT 05405               |  E-mail:[log in to unmask]     |
> |    U.S.A.                                     |  ISOGEOCHEM
> list-owner       |
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> | ISOGEOCHEM URL: http://geology.uvm.edu/geowww/isogeochem.html |
> ==================================================
>

We experienced intermittent behavior on one diffusion pump of our VG Prism
prior to the complete failure of that heater.  It's an Edwards pump.  The
heater element developed a "hot spot" with visible surface irregularity on
the ceramic insulation.  The heater wire within eventually became open
circuit.
-HB

--
Howard Berg
Development Engineer
UCSB Department of Geological Sciences
Santa Barbara, CA  93106-9630
Voice:  805.893.3487     Fax:  805.893.2314
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