Tomorrow, we finish piping in a new construction combination walk-in-cooler/freezer system. The evaporators for both systems are on a first floor and the condensing units are on a roof, approximately 8' above the evaporator coils.
The line sets penetrate through the top of each box where they 90 over and run horizontally for approximately 25' and 15', respectively. Once the lines penetrate the back wall of the building, they 90 over 3' and up 6' to the top ledge of an adjacent wall. Once over the wall, the lines will be 90'ed back down about a foot so they are parallel with the connections on each condensing unit. Then, it's just a matter of finishing the run horizontally to each condensing unit.
We have installed traps at each evaporator coil inside each box. My question is this. Considering the piping up over the roof and back down, will this situation cause any oil return problems and, if so, what can I do to alleviate this problem?