MRC Update ....

John Shott shott at
Tue Apr 6 17:08:11 PDT 2010

MRC Community:

This afternoon we received our spare Santovac diffusion fluid and 
checked both the level and color (which is normally clear) of the 
fluid.  We found it to be significantly low but otherwise looked pretty 
good.  As a result, rather than dropping the diffusion pump, it seems 
more reasonable to fill it to the proper level.  We have added about 300 
cc of Santovac5 ... the full charge amount is only 500 cc so we were 
well down.

The only trouble .... I can't seem to get the diffusion pump back on.  
Because I didn't turn it off, I don't know if there are any tricks.
Hopefully, Jim Kruger or someone else will be able to figure this out 
and get the heater back on again.  It is roughed down .... but needs the 
pump heater to come on.  I did check the overtemp switch and it 
initially seemed to be an open circuit.  After a bit of fiddling, to 
read 0 ohms.  However, even after that, I measured no voltage at the 
plug, so wonder whether there is some sort of upstream interlock on the 

Of course the heater will need to be on before pumping can be tested.  
Beccause the heater is not on, I don't want to clear the shutdown ... I 
will be out for 2-3 hours, but if anyone (Jim Kruger, Cesar, or Eric, 
for example) can get the heater back on, the shutdown can be cleared for 
vacuum testing.



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