Sector 30 ID

E-Log:

12/18/2024 -- Heater vessel settings change upon power shutdown

Dave Cyl recommended to use a power adapter cable to switch the cryocooler power from E-power to regular power. Although the cryocooler is designed to start back up normal in the occurrence of a power shutdown, he has witnessed problems during this. His sector and sector 19 saw that upon powering back up of power shutdown, the cryocooler setting for the heater vessel levels were deleted and replaced with”####”.

For sector 3, we switched the cable to regular power (so did not experience this) : First switch to bypass mode, then power off cryocooler, then switch the cable, then power back on, and switch back to EPS (or keep on bypass if desired).

For sector 30, we did not use the cable and stood watch during the scheduled power shutdown. We switched to bypass mode, and it was then that I checked the heater vessel settings before the shutdown occurred. The settings already changed to #### before the cryocooler was shutoff, right after we switched to bypass mode. I then checked this again, by switching back to EPS, then back to bypass mode, and this problem did not repeat. The only difference was that I was on the heater vessel settings page while I did the bypass switch, so maybe that was why it remained. We then proceeded with the power shutdown (after also removing the screen from power) and upon powering back up, the cryocooler was functioning in the same/correct settings. The shutdown itself did not change the heater vessel level settings, it was only when we switched to bypass that first time that those settings changed.

We kept both cryocoolers in bypass mode during the January shutdown, in case any problems with the EPS occurred.