The high temperature of the furnace may be in the two operating states.

There is a hot run, the whole surface of the material layer of high temperature, or even fire, then the furnace temperature will also be increased, so the furnace temperature may be high heat run; there is a high temperature fire, and material Layer surface temperature is not high, then the furnace temperature is not necessarily high, but this time also in thermal operation.

So the furnace out of the high temperature must be caused by thermal operation, and thermal operation is not necessarily the furnace temperature is high.