The Function of Chimney Flues & Fireplace Dampers

A chimney/fireplace system has a lot of parts, components and areas – and plenty of terminology to describe each. The chimney flue and fireplace damper sometimes are thought to be basically the same thing, since both have to do with drafting and venting a fireplace.

The fact is, these two parts of your system are quite different in terms of function and necessary maintenance and upkeep. Let’s look at the specs of flues and dampers.

The chimney flue

The flue is the inside passageway of your chimney through which smoke and combustion gases are carried up and away from your home out the top of your chimney. Most flues in homes today include a flue liner (or chimney liner), which is designed to provide smooth drafting and protect the chimney’s interior masonry from heat, fire and damage from acidic compounds.

Flue liners are typically built from stainless steel, clay tiles or a cast-in-place material. Each style of liner is durable and long-lasting – but no liner will last forever. Chimney liners should be inspected regularly to spot early signs of damage or malfunction.

Flue issues

The most common problems flues experience are:

• Damage due to cracks (and therefore leaks) in the masonry
• Excess flammable creosote, which is responsible for most chimney fires
• Drafting obstructions such as tree debris and small-animal nests
• Damaged chimney liners

Maintaining your flue

Annual chimney sweeping is recommended for flues connected with wood-burning fireplaces. A CSIA-certified chimney sweep uses specialized tools to remove creosote and obstructions, thereby keeping your chimney safe and efficient.

As noted, chimney liner inspections are important as are inspections of your masonry structure and components such as the chimney crown, chimney cap and chimney flashing.

The fireplace damper

Your damper is a plated device that sits above the firebox. Its function is to regulate the volume of air that travels through the fireplace/chimney system. When fully open, the damper allows for sufficient air to start fires easily and keep them burning aggressively. It also gives smoke and toxins such as dangerous carbon monoxide a pathway to exit the fireplace.

When you aren’t using your fireplace, the damper should be tightly closed to prevent an unwanted exchange of air between your home and the outside world. A closed damper also keeps bugs, squirrels, birds and other critters out of your house.

Damper issues

A damaged fireplace damper may not fully open or close. Rust can cause this. So can warping and general old age. After an inspection, your chimney technician will tell you the extent of any damage present and will advise either repair or replacement of the damper.

While dampers are pretty simple devices, they do a very important job. If there’s an issue with your damper, it’s one that needs to be addressed right away.

As you can see, fireplace dampers and chimney flues both work to help smoke and combustion gases vent properly out of your fireplace. Beyond this similarity, each component has unique functions that must be maintained in order for it to work safely and correctly.

Do you have a problem with your damper or flue? A-1 Chimney Specialist of Winchester, TN, and Huntsville, AL, is ready to help. We provide licensed fireplace and chimney inspections, chimney sweeping and all types of chimney repairs to keep your home and family safe.

Get your questions answered or schedule an appointment at (931) 967-3595 in the Winchester area or (256) 285-4895 in and around Huntsville.