The oven has a pre-set temperature, so you don't need to adjust it.

pre-set 是由前缀 pre-（表示"预先"）和动词 set（设置）组成的复合词，意思是"预先设置好的"。 pre-set temperature 指"预设温度"，即设备出厂时或使用前已经设定好的温度值。