Closes WP11368.
We've been seeing the CO2X laser regularly unlocking (alog71594) which takes us out of observing, today we swapped CO2X and CO2Y chillers to see if this issue followed the chiller. Previously, swapping CO2Y with the spare stopped CO2Y from unlocking, alog54980.
The old CO2X (S/N ...822) chiller seems to be reporting a unsteady flow at the LVEA flow meter, see attached, suggesting the S/N ...822 chiller isn't working too well. This is the chiller TJ and I rebuilt in Febuary 67265.
Swap. Following some of the procedure listed in alog#61325: turned off both lasers via medm, turned off and unplugged (electrical and water connections) both chillers, swapped the chillers, replugged in, turned chillers back on (one needed to be turned on via medm), checked water level (nothing added), turned on CO2 lasers via medm and chassis. Post-stick notes have been added to the chillers. Both lasers relocked with ~45W power.
- Before Aug-15 16:00UTC
- TCSX: S/N ...822 (full S/N in 60547)
- TCSY: S/N ...617
- After Aug-15 16:00UTC
- TCSX: S/N ...617
- TCSY: S/N ...822
Jason, TJ, Camilla
The worse chiller (S/N 822) flow rate dropped low enough for the CO2Y laser to trip off so swapped CO2Y back to it’s original chiller (S/N 617) and installed the spare chiller (S/N 813) for CO2X. We flushed the spare (instructions in 60792) as it hadn’t been used since February 67265. Both lasers are now running again and flow rates so far look good.
The first set of water we ran though the spare (S/N 813) chiller has small brass or metal pieces in the water (caught in the filter), see attached. Once we drained this and added clean water there was no evidence of metal so we connected it to the main CO2X circuit.
Looking at the removed CO2X chiller (rebuilt in February 67265), it had some black gunk in it, see attached. This is worrying as has been running though the CO2X lines since Feb and was running in the COO2Y system for ~5 hours. I should have checked the reservoir water before swapping the chillers.
Overnight they seem stable as well, but the new TCSX chiller (617) looks very slightly noisier and perhaps has a slight downward trend to its flow. We'll keep watching this and see if it continues.
I spoke too soon. Looks like TCSX relocked at 08:27UTC last night.
On Tuesday evening, the removed chiller (S/N 822) drained slowly. No water came out of the drain valve, only the outlet, which was strange. Today I took the cover off the chiller but couldn't see any issues with the drainage. I left th chiller with all values and the reservoir open so the last of the water can dry out of it.