Boiler induced draft fan and high temperature ventilator calculate the required power and selected motor according to the maximum temperature of gas medium. When the temperature of gas medium is high, the density is small, the pressure is low, and the power required is small. The motor power of boiler induced draft fan or high temperature fan is much smaller than that of normal temperature fan. Special attention should be paid to the starting of this kind of ventilator. Because before the ventilator starts, the temperature of the gas medium is difficult to meet the requirements of the working temperature, sometimes even after the ventilator rotates at room temperature, the furnace can be heated. In this case, the centrifugal fan will shut the gate to start, but also pay attention to the overload of the motor. If the gas temperature of the ventilator is very different from the gas temperature of the ventilator when it starts, whether it can start directly depends on the actual situation at that time. If you don't take it seriously, the motor is in danger of burning down.