I've only used it twice but the second time I used it was the other day, all day. About after 6 hours it just stopped. I don't know why. Maybe it was already programmed to stop after a certain amount of hours. I was way too busy to get the manual and check it out so I just turned it off and unplugged it, waited a minute or two, replugged it and it came back on. I have another GE AC which I've had for over ten years and it's 9900 BTUs and it's still working great so that's why I bought another GE. What I can say is that my new 5000 BTU AC is quiet enough, let's out a lot of cold air in my small bedroom and I didn't have to close the door and it was really cool just blowing on low/cool.  I installed it all by myself which is amazing LOL  Great buy!