edmontondown 发表于 2013-1-2 23:56 3 E$ X' S+ h4 b/ m- E5 |; @; _% |yes, may have something fell down on the other end of the hood vent
8 K: c9 O$ k* c t! p' ]5 dAt 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.