Abstract: A fan assembly particularly adaptable for use with an induced draft heat exchanger having a fan with a plurality of variable pitch blades, a drive mechanism and a pitch control mechanism, wherein the drive mechanism and the pitch control mechanism are designed to be located upstream of the heating element on the cool-air side of the heat exchanger. The pitch control mechanism is coupled directly to the rotating fan shaft, separate from the frame member for the heat exchanger to prevent problems in the alignment of the bearings for supporting the fan assembly. A fail safe mechanism is also provided in the rotating assembly of the fan to insure maximum pitch of the fan blades if the pitch control mechanism fails.