Blade dampers generate less sound and are available in two varieties: parallel and opposed dampers. Parallel blade dampers: Their blades shift in precisely the same path and maintain the airflow. Guide dampers are modified by hand and are typically used in more mature HVAC programs. They are less popular currently https://air-control-dampers-for-h90112.blogunok.com/36812688/detailed-notes-on-air-control-dampers-for-hot-climates