edmontondown 发表于 2013-1-2 23:56 4 p: O! K* B7 Pyes, may have something fell down on the other end of the hood vent
, }; n% g M9 B6 v( ~( Q7 l
At 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.