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Done.</div>
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<a href="https://logbooks.jlab.org/entry/4009546" id="LPlnk847381">https://logbooks.jlab.org/entry/4009546</a><br>
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Note that this change won't survive a power cycle of the controller.</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Morgan Cook IV <mcookiv@jlab.org><br>
<b>Sent:</b> Friday, July 1, 2022 1:57 PM<br>
<b>To:</b> Brian Eng <beng@jlab.org>; Marc Mcmullen <mcmullen@jlab.org><br>
<b>Subject:</b> Re: DC CO2 mix 2?</font>
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Yeah, I think it's a pressure differential issue. It looks like the pressure differential between the CO2 tank and the mix 2 buffer tank isn't enough. For some reason the CO2 tank isn't building pressure as it should.
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Can you lower the fill mix 2 fill points from 80-100 psi to 70-90 psi?<br>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Brian Eng <beng@jlab.org><br>
<b>Sent:</b> Thursday, June 30, 2022 12:52 PM<br>
<b>To:</b> Morgan Cook IV <mcookiv@jlab.org>; Marc Mcmullen <mcmullen@jlab.org><br>
<b>Subject:</b> Re: DC CO2 mix 2?</font>
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If I had to guess there was probably an issue with the zeroing. Best is if you can valve off both up and downstream of the MFC prior to zeroing, but at a minimum one of the sides needs to be valved off. Since I don't have the PI&D in front of me I don't know
what's possible offhand.</div>
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These don't normally have such high flow when the valve is closed.</div>
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<div id="x_x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Brian Eng <beng@jlab.org><br>
<b>Sent:</b> Thursday, June 30, 2022 12:39 PM<br>
<b>To:</b> Morgan Cook IV <mcookiv@jlab.org>; Marc Mcmullen <mcmullen@jlab.org><br>
<b>Subject:</b> Re: DC CO2 mix 2?</font>
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Right now Mix 2 seems fine.</div>
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There seems to be issues with the mix 1 CO2 MFC. The valve is all the way closed but it still thinks there is ~6 l/min flow.</div>
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<div id="x_x_x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Morgan Cook IV <mcookiv@jlab.org><br>
<b>Sent:</b> Thursday, June 30, 2022 12:15 PM<br>
<b>To:</b> Brian Eng <beng@jlab.org>; Marc Mcmullen <mcmullen@jlab.org><br>
<b>Subject:</b> DC CO2 mix 2?</font>
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Hey Y'all,<br>
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When y'all get a minute, can you take a look at the DC mix 2 system? There is some new, strange behavior with the Mix 2 CO2 flow. It seems that when both Mix 1 and Mix 2 are calling for full flow, i.e filling the buffer tanks, there doesn't seem to be enough
flow through the Mix 2 CO2 mfc.<br>
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This morning when I came in, the Mix 2 CO2 mfc was at 100% open with a zero/negative flow. They only way I got Mix2 CO2 to flow was to turn off Mix 1 completely, then Mix 2 seemed to work correctly. Reducing both the Mix 1 set pt and HTCC rotameter seemed to
allow some CO2 to flow through Mix 2, but even then, then mfc creeps open to 100% to try and maintain the required flow.
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The CO2 was filled a couple of days ago, and the tank and line pressure are a bit low but I can't quite figure out why only Mix 2 CO2 is affected. I did re-zero all the Mix mfcs but I don't think it changed anything.</div>
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Thanks,</div>
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Morgan<br>
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