The FD fan, also known as the primary fan, is responsible for supplying the air required for the normal combustion of the boiler. It draws in outside air and forces it into the boiler furnace, providing the necessary oxygen to support the combustion of the fuel.

  The FD fan helps create a positive pressure zone within the furnace, ensuring a controlled and efficient combustion process. On the other hand, induced draft fans are responsible for removing flue gases from the boiler system. It creates a negative pressure zone within the furnace that helps remove exhaust gases and maintain proper ventilation within the system. ID fans help increase the overall efficiency of the boiler by removing combustion by-products and enabling better heat transfer. The FD fan and ID fan work together to maintain proper combustion and ensure efficient operation of the boiler system. They are usually controlled by a control system that monitors and adjusts the airflow to meet the desired operating conditions and maintain the desired combustion efficiency. Proper sizing, maintenance of FD fans and induced draft fans must be ensured for performance, efficient combustion and proper draft control in the boiler system. Regular inspection and maintenance by qualified personnel is necessary to ensure the fan is functioning properly and to resolve any problems that may arise.