Most air vents have a small lever or dial on the side that allows you to open or close the fins just underneath the cover. When the fins are closed, air won't flow through the vent into the room. When they're open, air can move freely.
Airflow Check: Hold your hand in front of the vent to feel for airflow. If you feel air coming out, the vent is open. If there is no airflow, the vent is likely closed.
Once you access the trunkline, you will find the damper lever, which is attached directly to the duct. To adjust the damper lever, you will need to turn it to the left or right. If you want to close the damper, you will need to turn the damper lever in the opposite direction of the duct.
The task of removing a vent cover is straightforward, and any homeowner should be able to do it. Most of the time, the vent cover is held in place on the floor with two screws, one on each end. Use a screwdriver to twist the screws counter-clockwise and remove them, and just lift the vent cover up to remove it.
Most air vents have a small lever or dial on the side that allows you to open or close the fins just underneath the cover. When the fins are closed, air won't flow through the vent into the room. When they're open, air can move freely.
If the vent cover is stuck to the wall, use a box cutter to cut around the vent first. You should follow the edge of the vent cover at about a 30° to 45° angle and not cut perpendicular to the wall. Take the vents outdoors and soak them in water and a basic household cleaner. Rinse the vent covers thoroughly.
If you are looking at a duct that is coming off the furnace and going straight up like it is going to the upstairs, and the wing is in the same direction as the duct, it is open. If the wing is in the opposite or vertical position to the ductwork, then the damper is closed.
A professional will seal off the vents in each room of the home, and hook up the installation machine. Once turned on, the machine pumps an atomized polymer material into the vents, sealing the microscopic gaps and faulty connections.
The canister vent solenoid is normally open, and is closed only when the evap system is undergoing a leak check monitor. A vent valve that's stuck closed will cause refueling problems.
Open the air return vent panels by prying open the small metal levers holding the grill closed. These are usually on the top or side of the panel, depending on the location of the panel in a room. You may need to use a small flathead screwdriver to help open the levers if they're tight and difficult to open.
First up, locate the thumb screws on your return air grille. If it's hinged, gently swing it open. For fully removable grilles, carefully unscrew (usually two or more thumb screws) and lower it from the ceiling or wall. Once done, remove the filter and its frame from the grille.
Removing Vent Covers
While you can wipe and vacuum your vent covers without removing them, deeper cleaning required the cover to be removed. For floor vents this may be as simple as lifting the vent cover up. If it's in the wall or ceiling, you'll need a screwdriver to remove the screws first.
Turn the vacuum on to capture as much dust as possible that the fan is pushing through the ductwork. For how to clean AC vents, when finished vacuuming, use your brush to remove any built-up dust in the register. Reach down into the duct as far as you can with the microfiber cloth and wipe the interior clean.
Remove the existing vent by unscrewing it and gently wiggling the edges to remove the cover. You might need to run a straightedged razor between the cover and the wall in order to not pull paint from the wall. If the screws have paint over them, use an awl to dig out the paint and clear out the screw head.
Place the vents in your bucket of hot, lightly soapy water to soak. After they've soaked for a while (a half hour or so), use a microfiber cloth or sponge to remove any stubborn dust or dirt. Dry off the covers with a cloth and screw them back into place.