A furnace assembly comprising a non-condensing furnace with a draft inducer. The draft inducer includes a permanent magnet electrically commutated motor and a draft inducer blower fan. The motor includes a stator, a rotor, a motor cooling fan, and a controller. The rotor being rotatable relative to the stator, the fan being operatively coupled to the rotor such that rotation of the rotor causes rotation of the fan, the controller being configured to selectively operate the motor in first and second different torque ranges of the rotor, with the first and second torque range operating within a fixed percentage and within a fixed percentage of each other. The controller being configured such during normal operation, the motor is not operable at any torques between the first torque range and the second torque range except during transitionary periods.