Help finding vacuum pump oil

[miboss]

I'm having a difficult time finding the recommended oil for my Airtech pump. The manual states ATO-4000 and I've always been able to buy from my dealer. Unfortunately, that seems to be a manufacturer number, and not tied to any real specs. Because of the pandemic, I'm told there are some supply chain issues and airtech may be shutdown for a while. My dealer is out of the oil. They were able to tell me it should be vac oil #22, but I'm not able to find a product that meets these specs.

Anyone have any ideas or can point me toward the right oil?

Thanks!

[maple flats]

I use (different pump) TSC vacuum pump oil without issue. It is a synthetic oil.

[wiam]

I have a Busch that is very similar to airtech and have used the tractor supply oil for a few years.

[Shaun]

I just did a google search for "ISO 22 Vacuum Pump Oil" and seemed to get quite a few hits. ISO 22 refers to viscosity as far as I know.