Comment drytek2 SNF 2009-09-11 20:38:05: EH500 blower ... no joy!

shott at shott at
Fri Sep 11 20:38:06 PDT 2009

I tried to see if replacing the oil in both the EH500 blower helped with pump speed.  The oil in the coupling reservoir looked pretty nasty ... and I've left it in a nalgene container if anyone wants to look at it.
However, fresh oil did not seem to increase ability to handle gas load.
With no load, pumps to base quite nicely.  However, can't seem to control to 150 mtorr with an oxygen flow of more than about 25 sccm.  As soon as you hit about 30 sccm of flow the throttle valve is 100% open and pressure rises.  Pressure is about 300 mtorr by the time flow reaches 100 sccm.
This would seem to argue that the blower should be replaced.
If Cesar is in this evening or over the weekend, I'm hopeful that he can install a new blower. 

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