We bought a used russell range (gas) and the oven heats over the temperature it is set at. I set the convection oven at 250 degrees and when I went to put in the food to bake the temperature, according to a thermometer in the oven, read 350 dregrees and when the food was removed the reading was 450. We had ther gas company come out to look at it but they were unable to help and told us to call Sears. Help