Oven is a 220 volt three wire in cabinet oven. When first turned on say to 475 degrees, it will reach temperature and will maintain temperature for about 30 minutes maximum. After that it will start beeping and will show code F3. at this time oven will stop maintaining temperature. I go to turn it off and try to turn it on again and code F2 will show. At this point oven will continue to beep, continously showing code F2 even if I try shutting it off. This will continue until oven cools down. I also cannot find the manual on the web. I obviously do not know where my original manual is. Can you please tell me what part I need to replace and or tell me where I can download the manual. This is a year 1994 oven. Thanks, Enrique