<!-- Title: 05:50:31  Tue Sep 21 2004 -->
<!-- Crewchief: Bill Noe -->
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Shutdown Continues


<!-- Date: Tue Sep 21 05:52:22 2004 -->
Dewar still has 22% and pressure is still high. Will ask Steve and/or Jim to check this out this morning.<p> Everything else looks ok.
<!-- Author: Bill Noe -->


<!-- Date: Tue Sep 21 06:02:59 2004 -->
Storage dewar was ~22%, but at high pressures the AMI  probe may not be reading correctly. Jim adjusted wet engine valves. 
<!-- Author: Steve -->
<!-- Comment: Tue Sep 21 06;16;17 comment by...Steve -->
The dry back pressure also was causing control dewar pressure to remain high. It was running full out and cold.


<!-- Date: Tue Sep 21 07:42:17 2004 -->
<pre>So here's what I've done to get the plant back: 
Slowed down the dry engine. It was making liquid and pressure spikes were 15 psig, stalling out magnet flow. Need to work on this loop. 
Established 18 g/s when dewar pressures stabilized. 
Had to run PVBP by hand. 
Once the valves were adjusted, slowly increased wet engine speed until net liquifaction saw a gain. 
Will optimize w.e. speed so as not to overwhelm the plant (pressure-wise).</pre>
<!-- Author: Steve -->


<!-- Date: Tue Sep 21 08:28:53 2004 -->
<pre>With the help of Jamie Grado and Dervin the O2 sensors have been changed, zeroed and calibrated, in the ODH heads under the detector East and West sides. Note: It is not necessary to move mini skirts to access heads as they are on removable brackets.  
 
 
</pre>
<!-- Author: George Wyatt -->


<!-- Date: Tue Sep 21 08:49:43 2004 -->
SVX chiller shut down to wire in the "new" high pressure switch.  Alarms silenced.
<!-- Author: Andy H. -->
<!-- Comment: Tue Sep 21 09;04;34 comment by...Bill Noe -->
ISL chiller was checked and is running fine but with no load to speak of it is running colder than normal on the receiver...hence the ice.


<!-- Comment: Tue Sep 21 11;11;34 comment by...Andy H. -->
SVX chiller work complete.  System up and running again.
<!-- Date: Tue Sep 21 10:05:40 2004 -->
I have been fighting the cryo plant all morning. The major contributing factor in stability is storage dewar pressure. I have been making large changes to PVBP to keep the pressure at 7 psig. The pressure spikes affect magnet flow, control dewar pressue, and wet engine inlet temp. 20% valve position changes in a five minute period were not uncommon. 
<!-- Author: Steve -->


<!-- Date: Tue Sep 21 10:26:31 2004 -->
I now have PVBP regulating dewar pressure at 7 psig. I changed the TI in the PID (in 4Mation) from 10 to 0.1. This is no longer an electric actuator, so IMHO this valve can be allowed to control. We already have slow acting valves:  PVMF and EVCP. There may be a better way to accomplish this, but the results are in historical.
<!-- Author: Steve -->



<!-- Date: Tue Sep 21 13:38:08 2004 -->
We notice that net liquifaction reduced from 70 to 42 l/hr. The dry engine was running colder, causing some back pressue on the shell side. Bob Sanders has changed some engine loop parameters to see if it will regulate better.
<!-- Author: Steve (&Bob) -->


<!-- Date: Tue Sep 21 13:44:16 2004 -->
Dewar level at 37.6%; setpoint changed to 38 to see wet engine loop changes. 
<!-- Author: Steve -->


<!-- Date: Tue Sep 21 14:03:27 2004 -->
Cryo control loops:  changed Dry engine PG from 50.0 to 100.0,  TI from 45.0 to 20.0.  changed Wet engine PG fro 40.0 to 100.0,  TI from 120.0 to 60.0, DT from 3.0to 10.0
<!-- Author: Sanders -->


<!-- Date: Tue Sep 21 14:34:45 2004 -->
THE PLAN: Test wet engine loop 1st thing in the morning. Will add 2% to the setpoint and observe performance.
<!-- Author: Steve -->