How Do You Tell If Dampers Are Open or Closed?

Kellan Jansen
by Kellan Jansen
There’s nothing like a cozy evening spent by the fire. It’s why so many of us prioritize purchasing homes with fireplaces in them. However, before you use your fireplace, it’s

There’s nothing like a cozy evening spent by the fire. It’s why so many of us prioritize purchasing homes with fireplaces in them.

However, before you use your fireplace, it’s important that you understand how to operate it properly. One key aspect of this is understanding when your dampers are open and when they’re closed.

You can perform a visual check to see whether your dampers are open or closed. Stick your head in the fireplace and look up to do this. You can also feel for a draft by moving your hand or face into the fireplace. Or, check the current position of chimney controls like the cable, rod, and handle.

What is a Damper?

A damper is a valve or plate that’s used to regulate the flow of air inside a variety of systems. They’re most commonly found in ducts, chimneys, VAV boxes, and other types of air handling equipment.

Dampers can be used for many different things. In HVAC systems, they’re used to regulate the temperature of each room in a home. In chimneys, dampers are used to close off the flue. This keeps the weather (and animals) out of a home and warm or cool air in it.

Dampers can have both automatic and manual controls. Automatic dampers usually open when you need them to with the press of a button. Manual ones can be a bit more difficult to operate if you aren’t familiar with them.

What Are the Different Types of Dampers?

Your HVAC system may have one of several different types of dampers. Understanding the damper that you have can make it much easier to verify whether it’s open or closed at any given time.

First, you may have butterfly dampers. These use a blade on a hinge that’s designed to fill the duct as needed in order to restrict airflow. These are capable of completely cutting off all airflow and can be used to prevent backdraft.

Your HVAC system may also have louver dampers. These have ultra-fast response times and strong air blocking properties. They use flat blades on hinges to regulate airflow.

Guillotine and inlet vane dampers are two other types of dampers that your HVAC system may feature. Guillotine dampers offer the best seal possible. Inlet vane dampers are commonly used in applications where precise airflow control is needed.

How to Tell if an HVAC Damper is Open or Closed

If you aren’t very familiar with HVAC systems, it can be difficult to figure out whether a damper is open or closed. However, once you learn what you should be looking for, the process isn’t all that challenging.

You simply need to locate the damper and look at the position it’s in. If the damper is angled down, then that means it’s closed. If the damper is in a horizontal position, then it’s almost definitely open.

How to Adjust an HVAC Damper

Learning how to adjust your HVAC dampers is an excellent way to gain more control over your home’s climate. The amount of air that each of your rooms receives is based on your damper settings.

These plates are located within your air ducts and can be adjusted based on your needs. You can do this by following this step-by-step guide for adjusting HVAC dampers.

  • Open all air conditioning vents in your house. Find the duct trunks that lead out from the furnace and locate the damper level on each duct. There should be a metal level on the side of each duct. Move these levers in the direction the duct travels, not across it.
  • Close any dampers that lead to rooms that need less air conditioning. Do this by turning the metal levels so they point across the ducts. You can shut off all airflow to these rooms by closing the dampers completely. Or, close the dampers slightly to restrict airflow slightly.
  • Wait and a few days and take notes of the temperatures in each room. Figure out which of your rooms are too warm, which are too cold, and which are just right.
  • Return to the air conditioning dampers and make adjustments as needed. If you’d like for a room to be cooler, then open the damper that’s leading to that room more. If you’d like for a room to be warmer, then close the damper that’s leading to that room more.
  • Repeat this process as needed until each room in your home has the right temperature.

How to Tell if Damper is Open or Closed on Wood Stove

Wood stoves are another appliance that utilizes dampers. They use a damper system that’s very similar to the ones used by chimneys. Dampers control airflow into the firebox and give you some control over how fast and hot the fire burns.

The first thing you need to identify is where the damper handle is located. These are typically either on the outside of your flue pipe or on the exterior of your stove.

Once you’ve identified where your damper handle is, the next step is to learn how to operate it. Some handles push in and pull out while others turn clockwise or counterclockwise. Some handles also slide from side to side.

After you’ve figured out how to operate your damper, try placing fully in one position. Then, stick your hand into the unlit wood stove. If the damper is open, you should feel some air circulating within it. If the damper is closed, you won’t feel anything at all.

Once you’ve figured out which position is open and which is closed, you can manipulate the damper to meet your needs. Keep it open when you want to operate the wood stove and closed when you don’t.

How to Open a Chimney Damper

All chimneys have dampers. Knowing how to operate these is an important part of making sure that you’re using your chimney in the correct way. This will depend on the type of damper you have.

For example, you might have a throat damper. These usually have a rod control inside of the fireplace itself. You can operate this by pushing or lifting the rod further than it currently sits.

You may also have a knob control on the fireplace exterior that you can simply turn to operate the damper.

Or, you might have a top-mount damper. These typically have a chain that you can pull down to either close or open the damper. You’ll need to secure the chain when you pull it down. Otherwise, the damper will immediately spring back up into its previous position.

How to Tell If an HVAC Damper is Broken

Broken HVAC dampers can lead to serious issues that could cost you thousands in repair charges. That’s why it’s important to be able to ascertain quickly whether your damper is broken or not.

First, determine whether your system is displaying some of the common signs of a broken damper. This typically looks like extra air noise or over-conditioning in your home. If either is occurring, consider contacting an HVAC professional to come out and take a look at your dampers.

You can also attempt to open or close your HVAC dampers if you know how to do so. As you attempt the operate the dampers, you should be able to see visually whether they’re actually changing their position.

Finally, if you still aren’t sure, you can try to turn on your A/C system after attempting to close or open a damper. Go into the room that the damper led to and see whether you feel a corresponding change in the amount of air that’s entering the room.

Related Questions

Which way is a damper open?

If your damper has a rotary control, then typically clockwise is the direction you’d turn the knob to open your damper. If you have a top-mount damper, pull on the chain. If you can pull down on the chain and it doesn’t spring back up, then the damper is open.

When should I close the damper on my fireplace?

You should always keep your damper open while your fireplace is burning. Additionally, keep the damper open until all of the embers within the fireplace have stopped burning after you put a fire out. Keep your damper closed in all but these two scenarios.

Kellan Jansen
Kellan Jansen

Kellan is a content writer who specializes in everything DIY. When he's not behind the keyboard, he enjoys spending time with his pets, playing music, and geeking out about basketball. He hopes to make your home improvement projects a little bit easier to accomplish.

More by Kellan Jansen