Yep, post pics or put them somewhere we can see them. If you have a YouTube account a video there.
Without a visual we can only guess
If it had, or was set up to add, a roof top Air Conditioning unit it could be a simple drain line for condensate from an evaporator.
We've done so much, for so long, with so little, that we can now do the impossible, overnight, with nothing.
The United States Marines, America's 911 force -- 6531, 3521 '79-'99
Retired mech (auto/aviation), Extra Class HAM, NAUI/PADI OpenWater