We've been using our stove for almost two weeks now, reading the manual and watching the dvd that came with it to learn more about it. The dvd says that if the hopper lid or door is left open, an icon will appear on the remote and that it will shut down the stove after a certain amount of time for safety reasons. My question is how long does it take for this icon to show up and for the stove to shut off? We had the hopper open for seven minutes and no icon, no shutoff. I want to make sure the stove is operating properly. Thanks!