Oven will not heat to desired temperature. Share Share Share Most likely the calibration needs to be adjusted on the thermostat. Many times the manufacturer can assist in re-calibrating over the phone, depending on the type of unit. Note: A 10-20 degree variance is normal per some manufacturers. Topics Cooktop/Oven Range Related Posts Oven will not open (locked). Self-clean feature will not turn on. Right rear burner becomes warm when oven is on.