Just after I posted this my search on generac site came up with the manuals. Turns out it is a liquid cooled unit, not air cooled. I see no way to edit the title or delete this post.
Still have the same questions though.
Saw a 22kw unit QT02224ANAN offered "for parts/repair". About 300 hours on meter. Sitting on a pallet.
Worth looking at? What to look for? The Generac site did not seem to respond to my search efforts.
I assume it is propane/NG powered, could it be test run on a portable tank?