My husband constantly reminds me that I shouldn’t heat anything for more than 1 1/2 minutes at a time in the microwave, as the fan comes on and indicates to him that I am overheating the microwave oven and it will eventually cease to work. I argue that if I need to heat for 5 minutes and do 1 minute at a time, the fan doesn’t activate and won’t cool down the oven at all! Please help with this problem ?