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["Hu, Yu" <yuhu AT bnl.gov>]

Dear Flemming,

Ziyue might be still busy in STAR now, and trying to solve the "yellow temperature alarm" which I mentioned in today's shift log. I apologize for the unclear shift log that I wrote, there are many tests for other systems going on at the same time, and sometime we couldn't get a chance to record all the details. 

Since I'm back, let me try to summarize what we did today during my shift. After Ziyue came back, he might give us more updates.

We did the following today:

1) After 10:00 meeting, Ziyue came to the control room, by the same time I met Bill and Prashanth, we explained the situation and which part (valve) needed to be checked. Bill called Bob to check what we could do (since he was following all the FST installation), after he and Prashanth went into STAR, they found the connectors (chill water fast connected to the cooling tube connected to patch panel plates) is unconnected can reach without open the pole tip. After discussion, they connected that connector. No water is leaking. They came back, and we turned the FST HV on and did a pedestal_tcd_only run with FST (24131052).

2) We did a couple of runs to warm up the whole electronics (24131052 to 24131054) to see if we still have an overheating problem. We found the yellow alarm which we identified yesterday on all the PPBs is gone, (to make sure it is gone, we run it multiple times), and seems the major problem we identified yesterday is fixed after connecting the cooling pipe.

3) But then we found 3 new problems happen: a) yellow temperature alarm on FST RDO 4,  Disk2, modules 8, 10, and 12. which are all from inner sensors on those modules after Ziyue checked from the online monitoring sheet. b) temperature alarm on rdo1 disk1 module 3,5 were also found with yellow alarm; c) HV trip on Disk 3, module 2 and 3 (see shift log). We decide to try to figure out and solve the problem a) and b) first.

4) Since the alarm might be due to the bubbles in some of the cooling loops. And to our last year's experience, rebooting the FST cooling system usually fix it. We did a couple of more tests.

5)To confirm the new yellow temperature alarm (items (a) and (b) as I mentioned in item (3)), we turn the pump off and on remotely a couple of times and followed by a test run to check the temperature, the yellow alarm is still there.

5) We went to STAR, turned off the cooling system, closed the nitrogen, opened the reservoir valve, rest for 2 mins and let the coolant flow back to the rack. And then closed the valve, and turned on the nitrogen. Rebooted the cooling system. After we came back to the control room from STAR, we switched on and off the pump multiple times, then turn on the chiller, FST HV, take a pedestal run for 15 mins, and then take another pedestal run, just to check the temperature after 15 mins. The alarm b) is cleared. But we still have the same yellow alarm a) which is on the same loop, for the same channels.

6) In total we did step 5) 3 times, 1st time I went there with Ziyue, to make sure the procedure is the same as we did in the last year. The next 2 times he went there with our DOs. But we still have the same yellow alarm on FST RDO 4,  Disk2, modules 8, 10, and 12 all the time after each time we reboot the systems.

Thank you.

Best,

Yu

---

From: Star-fst-l <star-fst-l-bounces AT lists.bnl.gov> on behalf of videbaek <videbaek AT bnl.gov>
Sent: Thursday, May 11, 2023 16:54
To: Star-fst L <star-fst-l AT lists.bnl.gov>
Subject: [Star-fst-l] overheating modules

 

Hi Ziyue Zhang

Could you send a more detailled report to the FST list on the heating
issue on FST and what you learned today.At the 10 o'clock meeting the
conjecture was that one of the patch panels were overheating. Is this
still true?
Whereas the shift entry today seems to point to a cooling loop issue on
the disk 2

"We still get the yellow alarm on FST RDO 4, disk 2, module 8, 10, 12.
We will stop this run and start a new run to test."

best regards
Flemming


--
Flemming Videbaek
senior scientist, emeritus
videbaek @ bnl.gov
Brookhaven National Lab
Physics Department
Bldg 510D
Upton, NY 11973

phone: 631-344-4106
cell     :  631-681-1596
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