air leakage through chimney damper
straightcuts
| Posted in Energy, Heating & Insulation on
advice and product information please. I know two ways to stop (minimize) air leakage through the chimney: 1)put an inflatable bladder in the chimney; and 2)install a spring-activated damper at the chimney cap (Mike Guertin did an article on this a couple of years ago). But what about a third way: improving the air seal at the original chimney damper. I’ve been searching for specialized gasket “kits” for this use, but haven’t found any. Am I looking for somehting that hasn’t been developed yet? Has anyone tried this?
Replies
what kind of chimney?
What kind of dampoer you have?
What kind of appliance you using?
I can think of a couple dozen combination of varibles to those questions
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I'm thinking in generic chimney terms. But let's assume we're dealing with a "modern" chimney equipped with a functional steel or cast iron damper. The homeowners want to be able to have a fire in the fireplace, but when the damper is closed, they want a more positive air seal.
Seams to me any gasket up in there would be a royal
pain to replace. I'd try for sealing the glass doors better.
new cast dampers do fit pretty god, but after a time, somebody will inevitably build too hot of a fire and warp it, so gasketing is not the solution anyways.
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I guess I am still missing something...Sounds like you mean the iron damper in a masonry fireplace there, but you don't say particul;arly and I don't know what you mean by a 'modern' chimney.But if it is designed and built with the right size and height of a flue, it won't downdraft cold air to leak in. The air flow would be UP, not down.If there is down flow of cold air, that tells me the house is built very tight and that some OTHER combustion appliance neeeds makeup air, causing a negative pressure in the house.
THAT is the correction that needs to be made.
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I think what you tend to get, out of a full masonry fireplace/chimney, is a cold draft simply from air entering the firebox from the room, chilling, then pouring out. The only way to address this is with some sort of a fireplace door or cover.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Hi, cuts, let me guess--- the fireplace is in the lower part of the house, it's that right ?
I'm following this thread closely.
For YEARS, we had a cold draft in the LR area. Was always cold. Only build a couple fires a year. But Mrs Scrapr wants to be sure that we aren't leaving any smoke in the house.
Was about to get a blower door test to figure out where the draft was. Sat down with the tech and started naming windows, doors, etc. Came to me then that the damper had been open all that time.
Much more comfy now. LOL
Advice is much appreciated. Sounds like the best solution is to outfit the FP with glass doors that can be tightly shut. I was trying to avoid this since the top of my FP is curved, which means an expensive custom door. Nuts.
I'm not sure why you threw the top-of-flue damper overboard. It's definitely going to be cheaper and it'll be pretty unobtrusive (the handle in the fireplace, that is). May take a little doing to remove the existing damper or figure out how to coordinate, but still...
I think it'd be hard to achieve as tight a seal w/ glass doors. That's just based on a much-longer length of seal and differential pressure.
"I'm thinking in generic chimney terms. But let's assume we're dealing with a "modern" chimney equipped with a functional steel or cast iron damper."" Sounds like the best solution is to outfit the FP with glass doors that can be tightly shut. I was trying to avoid this since the top of my FP is curved, which means an expensive custom door. Nuts."^You referred earlier to the homeowners as a third party, now to your own FP personally. This is confusing as to what it is you are having a problem with and ...shakes head
So you are NOT talking about a generic thing, but a specific house and fireplace. Some accurate information about that particular situation would go a long ways to finding the best solution. And don't dismiss the idea of a blower door test study because if you have other combustion sources robbing air from here, things are not well balanced and could someday pose a life threatening situation with the right combination of variables. a glas door set will not help in that situation if you are actively sucking air in thru this chimney
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