I had earlier returned an ASIAIR "Plus" that would not turn on, and received a replacement from Cloud Break Optics.
I was using a 14.1 volt power supply, based on this specs for the ASIAIR Plus at Highpoint:
The web page is here:
https://www.highpointscientific.com/zwo-asiair-plus-wifi-camera-controller-asiair-plus
When I opened up the box with the replacement unit, it still did not work (same symptoms, no red LED PWR light, no green SYS light activity), so I decided to dig further.
Turns out the 15V specs is false!
With a variable voltage supply (that can source 4A up to 30V), I found that the range that the ASIAIR Plus (at least the one I have in hand at the moment) is in the range of 7.50V to 13.85V.
Outside of that range, even the red LED does not turn on. (With 7.0V input, the red LED flashed for an instant).
(If you are in a rush to get an ASIAIR "Plus," perhaps Cloud Break still has the unit that I returned to them. "Never used" :-) :-).
FWIW, an ASIAIR "Pro" that I have in the lab booted up fine at 14.1V input.
Chen