Summary: WP11663 & WP11664 Today Camilla, Jason, Chris S, and I confirmed the leak location in the TCSX supply line on the rubber portion of the expansion joint. We then replaced all 4 expansion joints and then pressurized the lines with air to test for leaks overnight.

Longer version: Last week while swapping the TCSX laser we sprang a leak in the TCSX supply line (alog75550). After regrouping and planning how to proceed, we planned to first confirm that the leak was actually coming from the expansion joint, replace all of these joints if necessary since the rubber has a lifespan of ~5-10 years and it was installed in 2013/2014, then retest before adding water to the system to ensure no leaks. Today, we did a gravity drain of all of the lines and disconnected the lines from both tables, then bagged the expansion joint where the suspected leak was, and then with Chris S's help, added a bit of air to the system. We started with a low 20psi injected with a blow gun attachment pushed onto the quick connect at the chiller end of the line. We couldn't see, hear, or feel any air so we started upping the pressure in steps. We added some soapy water to the joint in hopes of making bubbles. Eventually at ~80psi I was able to see a brief bubble form before the soap was then sucked into the crack that we suspected the leak came from, presumably from a Bernoulli effect with the air flowing through the pipe. We did it again and got the same results. Leak confirmed Attachment 1

We then replaced the 4 expansion joints with new ones (Spear mfg EJ21-010SR). One of the four was slightly shorter, maybe 8mm, but we were able to find slack in the system to make up for it. Previously the joints were at a slight angle, so we added some pool noodle in the wall feedthrough tube to raise the pipe on the mechanical room side of the joint slightly (Attachment 2). This seemed to help straighten the lines and hopefully put less strain on the lines or joint (Attachment 3 Attachment 4). There is still some sagging over the pipe bridge, but we will find a solution for that another day (Attachment 5).

With the four joints replaced we needed to test them. After conferring with Richard, we rewrapped the joints with a thick plastic and secured with Kapton tape (Attachment 6), then fired the compressor up again at 50psi output and added a bit of air to one line with the dry connect still connected. Once we confirmed that it would hold the bit of air we put in, we put in the full 50psi. We did this for all 4 sections - X & Y supply and return. We let it sit for 30 minutes and then confirmed that the lines were still pressurized. While the lines all felt equally pressurized when we release the pressure, we noticed a single drop of water in the plastic that was wrapped around the joints. We were not sure if this was coming out of the line, or just a spot we missed while replacing them. Seeing through the for water residue is challenging. So, we repressurized the lines and will leave them overnight like this. On our way out Jason and I saw a drop of water in the bag but in a different place. And again, we aren't sure if this is new water or just from a hidden spot we didn't dry. The pressure test overnight might give us some more clues.