R. Short, J. Oberling

Today we swapped the in-service PSL chiller for the spare, so we can do required regular maintenance on the in-service chiller, and changed the system filter.

The PSL was shut down and the chiller lines swapped over to the new chiller.  At this point we swapped the system filter with a new one.  The filter cup was pre-filled with coolant (10% mix of OptiShield in lab water) and the chiller reservoir was filled.  We turned the new chiller on and set the flow to ~4 lpm to help push out air bubbles; the system ran in this configuration for ~90 minutes.  Interestingly, we are back to having small collections of air pockets around the filter cup.  We'll monitor this and bleed air from the filter cup as necessary, but there are no more visible air bubblles moving through the chiller lines that we can see.  I'm wondering if chiller position in the rack has something to do with this?  The old chiller sat ~2 feet lower than the new one, maybe that's contributing to the air pockets (total WAG on my part)?  We're thinking that next time we swap chillers we'll move everything down a shelf and see if/how things change.

The chiller flow was set to ~2.8 lpm, as this is where the old chiller was operating, and the PSL restarted.  Everything came back up without issue and the PSL is running and ready for IFO recovery.  The old chiller was moved to the mechanical room, where we will flush it out and start going through its regular maintenance checks.  This closes LHO WP 12290.