What do the instructions say? What does the vendor say? They
usually have to check with a tech and get back to you. If it doesn't
work properly, they'll usually refund your money ...

Larry, you seem to have a different customer service experience than me with Chinese Ebay sellers. There are never any instructions, and when you write them they write back with some nonsense which is completely irrelevant to your question. Sometimes they give a refund. Sometimes they even try to bargain when you get something totally defective. "Is it OK to refund half? After all, we did pay the shipping..." Anyway, for ten bucks it's not worth getting into it with them. In this case I would say that the unit does work, but just not as I had hoped. I would have to run my compressor continuously to supply the needed air, and I would fill my shop with fog in a short time.