22 does just fine with POE. R22 as a low temp is a different animal and requires a demand cooling module to keep discharge temperatures down. As far as issues with oil return, I have 2 condensers (1 freezer) that are low temp 22 that I take care of. I haven't noticed any problems with it.
JP will be along here soon to tell me I'm wrong. :grin:
What type of oil the system was in the original compressor? If mineral I would drain the poe from the new comp and replace with mineral then install. I will not deliberately mix those oils in large quantities.