Backdraft dampers are made to reduce backdrafts in HVAC devices. These are put in in exhaust ducts to avoid the reverse movement of air. Backdraft dampers tend to be put in in spots in which unfavorable pressure might come about, for example loos and kitchens. Though various damper styles exist, https://aircontroldampersforengin91123.bloggerswise.com/44379779/getting-my-air-control-dampers-for-hot-climates-to-work