An attic fan draws hot air out of the top of a home and vents it outside. A broken fan belt stops the motor from engaging the fan blades and must be replaced if the attic fan is to continue being used. To replace a broken fan belt, remove the belt and substitute a functional one in its place. Fan belts are available at hardware stores, and a few household tools will take care of the disassembly/assembly procedure.
Pull the fuse or trip the circuit breaker supplying electrical power to the attic fan. If the attic fan has a power plug that is connected to an AC outlet, pull the plug instead.
Remove the screws surrounding the grille on the back side of the attic fan with a Phillips screwdriver. Wipe off the grill with a water-moistened paper towel to remove loose dirt and grime before placing it aside.
Pull one end of the old fan belt off from around the hub connected to the motor shaft. Pull the other end of the belt off the other hub inside the fan. Lift the belt out of the fan--if the fan belt is broken in half, pull the two sections off the hubs and lift them out of the fan. Dispose of the broken fan belt or pieces of the belt in the trash.
Spray the inside of the fan with bursts of compressed air. Shake a can of lubricating spray for five seconds. Spray a two-second burst of lubricating spray at the hub that the fan belt was wound around. Spray another two-second burst at the other hub.
Loop one end of the replacement fan belt around one of the hubs. Stretch the other end of the belt over to the other hub and loop it around this one as well.
Place the grille back on the fan and reattach the screws. Restore the electrical power,