Hi,
We have just installed a new Viking range hood and vented it out side. There are two flappers, one on the outside wall of the house and the butterfly-type flapper that sit on top of the hood. This one keeps opening on its own, it seems like there a draft or something. The noise is driving me insane. I tried to weigh the wings down, but only solved the problem partially.
Why is this happening and how can this be fixed? I would appreciate anyone's input on this.
Thanks!