How Can You Tell if an HVAC Damper is Open or Closed?
TechXpert verified by Ken Kontra
An open damper plate will show a gap, and a closed damper has a plate that covers the duct to block air flow. A manual damper with a parallel damper lever means your damper is open, and an automatic damper will have an indicator on your damper motor to tell you if your damper is open or closed. Some damper motors have LED lights to indicate the damper position — green for open and red for a closed damper.
Checking if your damper is open or closed can seem tricky when you don’t have X-ray vision. Luckily, your damper gives signals to help you see its air flow status (that don’t require superpowers).
There are two main types of dampers: manual and automatic. Each damper opens and closes, but they show their status in different ways.
The air control plate in a manual damper is turned by a lever on the outside of your duct. If the damper handle is in a horizontal position, the damper plate has been set to open. If the damper handle is set vertically, the damper is closed to block air flow.
Automatic dampers regulate the airflow in your home with the help of an electrical damper motor. Controlled by your thermostat and zone panel, an automatic damper will tell you if it’s open or closed on the motor itself. Most automatic dampers have indicators that show if the damper is currently open or closed.
Be an HVAC Hero
If you’re noticing an open damper but no airflow, or else you feel airflow with a damper that indicates it's closed, it’s likely a problem with your damper motor.
Since automatic dampers are electrical items, they’re prone to short-circuiting. A broken damper motor needs to be replaced to get your zoning system back in action. Be the hero of your HVAC’s story, and call in a contractor to help you save the day.
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