The grill seems to be OK (its not open curcuit) but doesn't work. However the element seems to work if you turn on the Top Oven. There is a warning in the handbook about not switching the Grill & the Top Oven on at the same time and I think that is what has probably happened. But there is no info in the handbook about the consequences of the Top Oven & Grill being turned on at the same time. What happens? How can I get the grill working properly again?