This sounds like a component heat failure inside the unit on a circuit board. If it isn't in warranty, to figure out if that's what's going on, you can open it up and spray various components, one at a time, with Freon (Cool Spray at the Electronics Stores). When you hit the temperature sensitive part, the unit will work again. Go slow, and you should be able to pinpoint the bad part. Now the difficult part will be getting a replacement part, and if you're warranty's still good, better to let them fix it. I read where they're discontinued, so parts may be hard to get, and you might check Ebay for a replacement. Wish I had better news.