kyle.ryan@LIGO.ORG - posted 15:22, Monday 28 November 2016 - last comment - 12:02, Tuesday 29 November 2016(31925)
Manually overfilled CP3
Significant exhaust temperature response (<-30C) 47 seconds after changing the manual mode %open value of the LLCV (liquid level control valve) from its as-found valve of 17 to 50 -> restored this value back to 17 following this exercise.
Comments related to this report
chandra.romel@LIGO.ORG - 15:59, Monday 28 November 2016 (31930)
I trended CP3 exhaust TC temp gauges over 30 days to see if the dips noted above have always been there. Looks like it started on Nov. 15th. The only change to CP3 noted was a Dewar fill while LLCV was set high to 21%. LN2 was coming out the exhaust so I lowered to 16% while the LN2 truck was still filling Dewar. The previous day on the 14th I had filled CP3 by setting LLCV to 100% and noted this was too much flow. Is this an instability in pump reservoir where it burps every 20-40 minutes? Note that from Nov. 19-21 signal was smoother. Could be a function of LLCV setting and how full exhaust line is. Fills lately have been really fast.
Images attached to this comment
chandra.romel@LIGO.ORG - 12:02, Tuesday 29 November 2016 (31969)
Here is the temp trend (in seconds). Not sure why the dip prior to fill. First I've seen that.
I trended CP3 exhaust TC temp gauges over 30 days to see if the dips noted above have always been there. Looks like it started on Nov. 15th. The only change to CP3 noted was a Dewar fill while LLCV was set high to 21%. LN2 was coming out the exhaust so I lowered to 16% while the LN2 truck was still filling Dewar. The previous day on the 14th I had filled CP3 by setting LLCV to 100% and noted this was too much flow. Is this an instability in pump reservoir where it burps every 20-40 minutes? Note that from Nov. 19-21 signal was smoother. Could be a function of LLCV setting and how full exhaust line is. Fills lately have been really fast.
CP3 exhaust is also noisy since Nov. 21st.