A fan assembly comprising a casing having an inlet and an outlet for fluid circulation through the casing, and a closeable opening to allow access to an interior of the casing. A rotor induces fluid circulation in the casing. A motor is connected to the rotor so as to actuate the rotor. A carriage supports the motor and the rotor, the carriage being operatively mounted to a track so as to be displaceable between an operating position of the fan assembly, in which the rotor is positioned in the casing for inducing fluid circulation in the casing, and a maintenance position of the fan assembly, in which the rotor is out of the casing for maintenance, wherein the rotor is displaced between the operating position and the maintenance position through the closeable opening.