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User name mckee
Log entry time 12:49:54 on September 8,2001
Entry number 40072
keyword=Cryo problem
At about 12:00 I noticed the buffer dewar was overfull, with a level of about 95%. The cold return temp was 4.4K, and the PID settings for EV9180 showed a minimum valve position of 50 and a maximum of 48!
I verified that the EV9180 and EV9180A PID settings had not been tampered with, and then did some tests. First, by putting EV9180A in manual mode, I could not get the minimum valve position of EV9180 to change. This explains why the valve was open so much. I tried toggling between manual and auto mode with no success.
Currently, EV9180 is in manual mode, set to a position of 35%. I reached this by slowly changing the valve position in increments of 2% each.
EV9180 should be left in manual mode until the buffer dewar level lowers to 65%. It may take more than one magnet fill to consume this quantity of helium.