The oven is normally normal if it is used for the first time.

Because the factory, the oven heating tube is usually coated with a layer of grease, which is to prevent this component in the case of long-term non-use of the surface corrosion.

When you use it for the first time, the high-temperature heat pipe will ignite this layer of grease, so it will produce smoke, and accompanied by some unpleasant odors, the heat pipe is extended from the inner cavity all the way to the control part, that is, behind the knob, as you said, there is also a small section of the pipe, which also produces smoke, which will run out of the gap, and may be coming out from the knob.

Set the 200 degrees above the 20-minute timer, put it in a place where it can be ventilated or turn on the hood, rest assured that boldly open, the state of white smoke should be in 10 minutes or less will be the end of the state, if there has been white smoke, there must be other problems. If there is really a line problem, the machine is metal, even if the fire is also line fire melted inside, the home switch may be tripped, will not bring other security problems, in this case, find the seller, it should be unconditional solution.