An improved burning system for automatically controllably charging a wood-waste burning steam boiler utilizes a fuel bin unloader having a gravity fed screw metering device for feeding fuel into the system in response to steam demand and pollution output feedback signals. The metering device deposits fuel through a rotary air lock into an air stream of a fuel injection fan having a vortex controller on the inlet side to modulate and maintain a proper fuel-air ratio for wood firing. The fan injects the fuel and air into the boiler through a controlled proportioning valve. All controls and recording devices are contained in one control unit for operating each component of the system to achieve and maintain a proper fuel-air ratio according to received steam demand and pollution output feedback signals.
