New Top-Lock Damper- Smokey Smell

[NewbieHomeowner]

Good afternoon - just discovered this site and hoping I could get some advice. I'm a new homeowner. My house has a masonry fireplace in the den. Based on the recommendations of some friends, I installed last week a Lock-Top damper after I expressed some concern about heat loss through the old metal damper right above the firebox.

On Thursday morning, after having a nice fire going for a few hours Wednesday night, I noticed that there was a strong, old smokey smell coming out of the fireplace within seconds of closing the damper. I confirmed that there were no embers still burning from the previous night. But to play it safe I left the damper open for the rest of the day. Thursday night I close the damper again, same thing happens. Smokey smell slowly fills the room. If I open the damper, the smell goes away.

Does this make any sense? Is air somehow coming down the chimney when I close the damper? Isn't preventing that the whole point of a Lock-Top damper?

Background info - I had the fireplace and chimney inspected prior to purchasing the house, including a camera inspection. Nothing major turned up, just a few small cracks near the lintel that had to be patched up. Chimney was cleaned as well.

Any advice would be appreciated.

 

[pen]

It should certainly help a down draft, but can't deal with what might already be there.

Was the chimney well cleaned before installation? Was there a problem before this fire?

 

[velvetfoot]

I confirmed that there were no embers still burning from the previous night.

How did you actually do that? I would contend that if things aren't totally stone cold it's not out. Can you run your hand through it? If you can, and it's still warm, would that be enough to smell? Any CO detectors nearby, temporarily, to maybe indicate something or other?

 

[branchburner]

Welcome to the forums! My theory is that even though the fire is out, the masonry is warm, and so warm air is rising within the chimney. Since it can't escape, it cools and sinks back down, causing a circular convection current within the chimney that bring some odors down with it as it cycles.

Do you still have the old metal damper in place, and are you closing that, too? Perhaps in addition to the top damper you could use some sort of balloon or pillow system at the bottom, too, to prevent any circulation into the living space:
http://www.amazon.com/Fireplace-draft-stopper-large-plug/dp/B0001HA8MC

 

[kennyp2339]

My take, with the damper open the chimney drafts normal, has stronger draft than the house (positive flow) with the damper in the closed position the air currents shift perhaps from a bathroom fan, hot air furnace, dryer, range hood ect, this takes the smoke smell from the fireplace and brings it out into the living area, again when the the damper is open the natural draft of the chimney trumps any other the other appliances the user may have running. Just a theory atm with limited info.

 

[Ashful]

Embers don't give off "old smokey smell," but a used chimney does. This is why dampers are traditionally installed at the smoke shelf, not atop chimneys.

 

[NewbieHomeowner]

Just wanted to follow up on this. After some internal discussion, the company decided to remove the top lock damper and reinstall the bottom damper. They told me that they see this issue some time with stone fireplaces- somehow cold air from the outside seeping through the stones and creating a downward draft, causing the smokey smell. Let's hope this fixes the problem.

 

[NewbieHomeowner]

How did you actually do that? I would contend that if things aren't totally stone cold it's not out. Can you run your hand through it? If you can, and it's still warm, would that be enough to smell? Any CO detectors nearby, temporarily, to maybe indicate something or other?

Trusty infrared thermometer confirmed embers were out.

 

[NewbieHomeowner]

Welcome to the forums! My theory is that even though the fire is out, the masonry is warm, and so warm air is rising within the chimney. Since it can't escape, it cools and sinks back down, causing a circular convection current within the chimney that bring some odors down with it as it cycles.

Do you still have the old metal damper in place, and are you closing that, too? Perhaps in addition to the top damper you could use some sort of balloon or pillow system at the bottom, too, to prevent any circulation into the living space:
http://www.amazon.com/Fireplace-draft-stopper-large-plug/dp/B0001HA8MC

I actually ordered that inflatable plug last week while I was waiting for the company to put back in the top damper. It definitely helped. but it's rather annoying to take out and reinstall each time I want to use my fireplace. I think it's more useful for the end of the season.