Mechanical Troubles With Fireplaces: Dampers

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Fireplace Dampers

Sometimes it is the little problems that make a fireplace seem unusable. Here we will cover some common mechanical difficulties, and how to solve them.

Stuck or Non-Working Fireplace Dampers


Corrosion and debris are the most common causes of stuck fireplace dampers. 

A good first step is to have the fireplace professionally cleaned. Your chimney professional will sweep the flue and remove the soot and debris that is piled up around the fireplace damper. At the same time, he/she can lubricate the moving parts and make adjustments, or recommend a new damper if yours is damaged beyond repair. If it has been a year or more since you have had the flue cleaned, have it done, anyway, for fire safety. 

For the do-it-yourselfers, here are some hints for fixing fireplace dampers. But this doesn’t take the place of a professional chimney cleaning. 

Safety Alert


Wear gloves and eye and ear protection any time you work on your fireplace. Damper edges are sharp, and will cut you. Debris in the flue could get into your eyes and ears, causing injury.

Fixing Fireplace Throat Dampers


fireplace damper -CHIMNEYS.COMIf your damper is a throat damper, the kind located just above the fireplace opening, it is operated either by a handle inside the fireplace, or by a small knob on the outside, somewhere between the mantel and the opening. 

Using a flashlight, take a look at the moving parts. If anything looks warped, rotten, or broken, call your chimney professional for a quote on a replacement damper. If the parts look rusty or corroded, first try oiling them. A spray penetrating oil works well. Put some newspaper down in the fireplace to catch run-off, and don’t get any oil on the brickwork. 

Take a look at how the handle assembly works. Some are simply a notched handle that pushes the damper blade up. (The damper blade is the plate, the thing that actually opens and closes.) 

Others (among the external-knob type) have a worm-gear on a shaft. When you turn the knob, the shaft turns the worm gear. A ring moves along the worm gear, and pushes a lever connected to the damper blade. It sounds complicated, but take a look, and you will see it is pretty simple. 

A third type incorporates a handle and a counter-weight. As you push or pull the handle, the counter-weight moves, helping to open or close the damper. 

Yours might also be a variation on these basic types. Try pushing (gently!) against the damper blade. See if the damper blade’s stuck, or if the handle mechanism seems to be the culprit. 

Safety Alert:  Watch out for falling debris!

You might find that there is a buildup of sand, soot, and debris behind the fireplace damper that is preventing the blade from moving. If so, have the chimney cleaned. 

Also, check along the bottom edge of the damper blade. Sometimes there are metal tabs or notches designed to fit into slots or holes in the housing. If the blade isn’t set in place properly, that could be your problem. Sometimes it is necessary to disassemble the handle mechanism to get the blade back where it goes. 

Fireplace Damper – A Good Time to Call a Professional

It is probably wise to call a professional at this point, or you may end up with a pile of parts and no idea how to put them back – especially if you have the external-knob style of damper. If you decide to try it, be careful not to drop any pieces. Cast-iron parts break easily, and you could hurt yourself, too. 

Fixing top-sealing fireplace dampers


top-sealing-damper-lyemanceAdjusting a top-sealing fireplace damper requires getting up on the roof, a job best left to a chimney professional. Although top-sealing fireplace dampers tend to be relatively trouble-free, sometimes the cables need to be replaced or adjusted, or debris interferes with the moving parts. 

If you think the fireplace damper is frozen shut (during or after an ice storm), check with the operating instructions or the installer. Sometimes there is a feature built into the damper that allows you to tug sharply on the cord, engaging a lever-type device on the fireplace damper that breaks the ice seal. 

Problems with dampers can also cause smokey fireplaces. If you have this problem, take a look at Smokey Fireplaces & Currier and Ives.

~ Todd Woofenden

~ Asking for Chimney Information ~

After reading an article, you can ask a question about that article. Replies will come from Chimney Professionals, and sometimes from homeowners, who are giving their answer based on the information you provide. Remember that they are providing answers SIGHT and SITE unseen! 

CHIMNEYS.COM recommends that you use these comments to better inform yourself to discuss your chimney and venting issues with a professional whom you call to your home to evaluate the issue.

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