We have a Kenmore electric oven. It has started beeping and showing the letter and number F1 after use. It keeps beeping for sometime (flashing F1 the entire time) and doesn't stop after hitting the stop button. Finally after sometime it stops. We have misplaced our owners manual. Can you help us to find another owners manual, and tell us what F1 means. It says on our oven that the model # is 911. The serial # is 4L6962400. Thank you