If you look at some of the IOM's for larger, 2 stage Carrier units, they will spec that you use a double suction riser with traps. Trane and Lennox may have something similar as well ( I can't really remember right now). I did a changeout on a resi condo setup once (2 ton) that had an oil trap on it at the AHU. To my surprise, when I pulled the trap off the lineset it didn't have a drop of oil in it and this unit was about 3 floors below the CU on the roof. I think technically there should be one in all installs where the CU is above the AHU but most people don't bother with it now, especially a double suction riser. It doubles the install labor and adds a significant amount to the materials cost plus the installers actually have to know how to pipe it in correctly. I would have to study a piping guide pretty good to get a handle on it since I've never had to install one before. I doubt you would see any contractor installing one without the engineer standing over him to watch it go in or at least threatening them with a redo. :)
Proper piping practice is all I was saying, and a reverse trap at the top of your vertical rise so all the oil you get there stays there would be proper practice, plus if you have over 20 vertical feet you need to think about oil traps at all points in the system. That said oil trap practice is changing due to the increasing use of Poly oils, but still check with the manufacturer cause I had to cut open the wall on the second floor of nice new building to install an oil trap cause LG wanted one on their ductless split. The rough-in tech did not read the instructions where it mentioned this so I had to weld in a very tight enclosed space. If I didn't do this and we started to eat compressors then what are we going to do, most likely no one would know there wasn't a trap if I didn't take the extra time to find out for sure.
Last I checked trane didn't require a trap until after 60ft or so on that size of unit. But that was a few years ago.
Also surprised to see a 6ton in that cabinet I thought they changed to the commercial cabinets at that point.
Would of liked to see a better support for the disconnect, i have a feeling it'll be kissing the ground soon.
It looks like a builders model, also shouldn’t the sight glass be "after" the drier? Maybe secure the whip also. :anyone: