I too had the exact same issue MarsG76 describes but did not have the same outcome after going through the steps he outlines. I did everything that was listed but found the temperature still did not reach the correct level. Instead, everything is connected via a Pegasus Ultimate Powerbox, I disconnected all the USB plugs whilst the AstroPC was off, switched it on again and, one by one, reconnected everything. Each time I reconnected, I then went into NINA and connected there too. This has so far appeared to solve the problem. What happens now is that I select -10c and it reaches this temperature but shoots past it to around -11.3c to -11.5c but then springs back and settles at -10c. All works so far, touch wood. Hope this helps somebody else.