I dug some pictures out of some very old archives and that thing looks very similar to something called a “Union” brand. It seemed to have been a local lable on a unit that was mass produced for “store-name” marketing. It was difficult to get certain parts for them when they were new. Circa 50’s and 60’s around this neck of the woods.
Looks like an old Singer Condenser to me. Not sure if Singer was sold/marketed in your part of the country. I can’t even remember who distributed the equipment in our area, but was considered a Track Res./Multi-Family Builder Budget grade unit.
As I recall, the compressor had some kind of ID within its model number, that ID’d the equipment manuf… Not sure, but may be worth checking out, if you’re really interested.
That was easy my client was a realtor looking to buy a Repo for her grandson she had not made an offer on the home at the time of inspection and was wanting to know exactly how much money was going to have to be spent to make it liveable so I exceeded my SOP by troubleshooting that old piece of junk.
I put my gages on the unit and it only had 10 PSIG of Freon with the unit not running. The condenser fan motor had bad bearings and would not come up to speed. So basically she would be looking at the cost of motor replacement finding and repairing the freon leak re-charging the unit. Due to age I recommended not spending any money on the unit just replacement.
Just like RR I gave her choices Repair a junk unit or replace it with new.