edmontondown 发表于 2013-1-2 23:56 ! b- p9 s4 S" v; Nyes, may have something fell down on the other end of the hood vent
8 q5 q7 g! N* l' s" z* M$ yAt 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.