edmontondown 发表于 2013-1-2 23:56 * u+ y% U' }3 _- E, F; Syes, may have something fell down on the other end of the hood vent
. ]. A& q @: V q& L4 GAt the other end(outside) of the vent duct, there is usually a metal cover for the opening, it can swing up and down and if it is a windy day, it will be blown swinging, thus making a kind of banging noise.