Opinions please. M.E. is proposing installing two 4.5 ton split systems to cool electrical rooms. There is no way to get OSA to these rooms and I do not have chilled water below 47 degrees OSA. My concern is that the condensing units will be on the roof and be aprox 100' above the fan coils. Am I looking at potential oil return or other problems even with increased line sizes and traps. Any advise here is much appreciated.