The heat from the oven comes from the bottom I just placed my vac onto the bottom and set oven at 40c I would hit the vac when I noticed the oil had liquified do you think cause the chamber was sitting on the heat source for quite a while this could of burned the oil as even no the oven is set at 40c im unsure if this is accurate as the bottom of my chamber was getting quite hot where I could only touch it for a couple of seconds