Fireplace odor

[Cinnaman]

I just had my masonry fireplace chimney & smoke chamber relined (several large cracks in terra cotta liner and smoke chamber) with a cement based poured liner (inflated tube to form liner). I also had a spring loaded chimney top damper installed to keep rain and drafts out when not burning. It looks great and I feel much safer.

Problem: After 4 or 5 fires, I'm already getting a strong smoke odor in the room when the fireplace isn't in use. I have the glass doors closed but there are small gaps in the glass panes that allow the odor through. I do not have a draft coming down the chimney but a general oozing of cool smelly air into the room. This isn't new....I had this odor before the repairs were done.

We also had a two zone air conditioning/heating system installed in the attic. I'm not sure if this is causing an air flow/exchange problem in the house by sucking air down through the chimney.

I know most people on this forum will tell me to get a stove or insert, but I like my wide open fireplace even though it isn't efficient.

Any suggestions? Are there tighter glass doors available? Is it a whole house air-flow issue?

Thanks

Dave

 

[kalevi]

You are getting air coming down the chimney. Get an insert. Your masonry fireplace is either breakeven or an energy loss. Once you have an insert, you will understand what wood heat is all about.

 

[gary]

We had a similar odor problem before and after the installation of a new chimney liner and insert. Turned out the tile chimney had creosote deposits on the outside of the tile from years of smoke that had leaked out through the joints and cracks. The smell was entering the house through holes in the firebox where it had deteriorated from heat and age. Our installer had failed to put in a blocker plate to seal off everything but the new liner. This has since been corrected. Check for openings in the firebox and around the area where your old damper was.

 

[jtp10181]

You said you have a lock top style damper? Are you closing it? If its closed air should not be able to come down the chimney.

The fact that air IS coming down the chimney means you have a negative pressure in the house and its using the chimney as a makeup air vent. Check your HVAC system for proper and functioning makeup air.

 

[Cinnaman]

The lock top damper is closed so the air coming down is minimal............it's more like the colder air inside the chimney is sinking down and oozing out through the cracks in the glass doors. I do not have any cracks between the firebox and the top of the chimney............it's all poured concrete now.

I think the HVAC might be the issue. If I have negative pressure in the house does it mean I need more return vents for the HVAC to suck through rather than sucking air through the chimney? When I open the lock top damper to start a fire I have a pretty strong downdraft to deal with before I warm the chimney and get it reversed.

 

[webbie]

Despite the sales pitches, it is my opinion that a top sealing damper is stupid. OK, I said it. When you install a damper on top of your chimney, the fireplace and chimney become a PART OF THE HEATED LIVING AREA. That means you have a LOT of smelly masonry inside your home.

Masonry is porous and top sealing dampers (or any damper) is not airtight.

If you want to check this, find a tight sealing metal plate or something else to experiment and close it off somewhere near the bottom.

 

[Cinnaman]

Maybe I need to buy a chimney balloon for when I'm not using the fireplace?

 

[jtp10181]

No you do not need more return vents, you need the HVAC system to have a better make-up air, which will draw air from outside into your ductwork when the house has a pressure less than outside.