The Variable Frequency Drive (VFD) varies the fan speed and allows for more efficient control of the air supply in modulating burners.
Speed reduction
At low loads, the fan can operate at a lower speed instead of being limited only by a damper.
Impact on pressure
Pressure and air supply change significantly with speed; therefore, the air-gas curve must be properly calibrated.
Energy benefit
Speed reduction can significantly limit the fan's electrical consumption at partial load.
Commissioning
Control is performed at multiple load points, measuring O₂, CO, and flame stability.
