Boiler ID Fan vs FD Fan: Key Differences
A boiler ID fan draws flue gas from the boiler and helps maintain furnace negative pressure. A boiler FD fan supplies combustion air into the furnace. Both are important for stable combustion, but they work on different sides of the boiler system.
What Is a Boiler ID Fan?
An induced draft fan is installed on the flue gas side. It moves hot flue gas through dust collectors, desulfurization equipment, ducts, and chimneys. It may need high temperature, dust, wear, or corrosion-resistant design.
What Is a Boiler FD Fan?
A forced draft fan supplies fresh air for combustion. It helps control air volume, furnace pressure balance, and boiler efficiency. FD fans usually handle cleaner air but may require higher pressure depending on system resistance.
Comparison
| Item | ID Fan | FD Fan |
|---|---|---|
| Function | Exhaust flue gas | Supply combustion air |
| Location | Flue gas side | Air supply side |
| Gas | Hot flue gas | Fresh air |
| Main challenge | Temperature, dust, corrosion | Pressure, airflow, control |
Zhichengfans Support
Zhichengfans can supply boiler ID fans, FD fans, primary air fans, secondary air fans, biomass boiler fans, and heavy-duty process fans according to airflow, pressure, gas temperature, dust, fuel type, and installation layout.
FAQ
Can one fan replace both ID and FD fans?
Usually no. ID fans and FD fans have different functions and installation positions.
Which fan handles hot flue gas?
The ID fan usually handles boiler flue gas.
