Chimney Smoke Smell

[Buckaroo5]

Recently removed gas burning logs from fireplace and went to wood burning. Have excellent draw - no odor or smoke when fire burning. When damper is closed, am experiencing smoke odor. I sealed where the throat damper housing meets the firebox to minimize cold downdraft as there were some voids. Still have smell. I think my next step is to install a Lymance Top Sealing Chimney Damper.

I suspect the real issue is a well sealed house with negative pressure caused by bathroom exhaust fans, clothes dryer exhaust fan and gas dryer/hot water heater burner make-up air. The gas furnace has outside air supply. Please save me... I am going down the rabbit hole. I have been investigating installing a Heat or Energy Recovery Ventilator like this which I would pursue if necessary after the top sealing damper install.

http://www.solerpalau-usa.com/products/erv-hrv/tr.html

What do you guys think?

Buckaroo

 

[rlitman]

The water heater make up air will be negligible. The dryer will move a lot of air, and can cause a chimney to reverse, but then the smell would be worse when you're running the dryer. Is it? The same goes for the bath exhaust.

What sort of chimney is this? Is it interior or exterior?

 

[ford33]

I think you are on the right track to look at providing make up air to the home.

Test your theory by running a bathroom fan and other air exiting devices to see if the smell is present.

I would go back to the gas fireplace logs. So much cleaner and easier to use.

 

[Jackfre]

Put a good quality glass door on the fireplace and close it when the fire is out. You are correct on the negative pressure in the home. We have taken the technology of the Thermos bottle and applied it to new construction.

 

[jenga70]

I have been tightening up a second house and when I asked the HVAC guy working on the furnaces about make up air, he recommended bringing in air from outside in an insulated flex duct and placing the end of the duct about two to three inches from the bottom a insulated box with an open top. The cold air pools in the box and when the air pressure changes in the house, such as dryer runner, the fresh air will come out the box as needed.

 

[Buckaroo5]

The water heater make up air will be negligible. The dryer will move a lot of air, and can cause a chimney to reverse, but then the smell would be worse when you're running the dryer. Is it? The same goes for the bath exhaust.

What sort of chimney is this? Is it interior or exterior?

Exterior chimney but at this point in the central Ohio season, don't think that is a major contributor. Can't say for certain on the dryer but I think the smell is worse when the upstairs master bath exhaust fan (new & powerful) is running.

Buckaroo

 

[Buckaroo5]

Should I install the top chimney damper or go straight to the make-up air solution?

Buckaroo

 

[rlitman]

Should I install the top chimney damper or go straight to the make-up air solution?

Buckaroo

If your bath fan is strong enough and your house is sealed well enough that it is causing air to reverse through the chimney, putting in a damper on your fireplace will just cause air to return from somewhere else. Like perhaps you water heater's vent.

 

[LS6 Tommy]

Glass doors on the face of the fireplace are not air tight. They won't completely stop a downdraft. I suggest also looking into getting the chimney cleaned or checked for a cleaning. The smell might be contributed from leftover buildup from before it was converted to gas.

Tommy

 

[Buckaroo5]

Glass doors on the face of the fireplace are not air tight. They won't completely stop a downdraft. I suggest also looking into getting the chimney cleaned or checked for a cleaning. The smell might be contributed from leftover buildup from before it was converted to gas.

Tommy

I have looked it over....chimney is squeaky clean. The gas logs have been in there since before we bought it (17 years ago - house was 2 years old).

Buckaroo

 

[TractorJeff]

If you seal the fireplace chimney from back drafting, then the water heater will backdraft pulling bad gasses into your house.
If and when you run the fireplace, then every available hole will back draft to feed the fire.
I would recommend an air make up system.

 

[Falcon67]

This is why we quit burning wood. After making the house leak a bunch less, we could never get a fire without smoke smell in the house unless one window was open pretty wide, which kinda negates the use of a fireplace LOL. We'll go back with gas logs at some later date, depending on what I do about propane supply.

 

[larry_g]

Recently removed gas burning logs from fireplace and went to wood burning. Have excellent draw - no odor or smoke when fire burning. When damper is closed, am experiencing smoke odor. I sealed where the throat damper housing meets the firebox to minimize cold downdraft as there were some voids. Still have smell. I think my next step is to install a Lymance Top Sealing Chimney Damper.

I suspect the real issue is a well sealed house with negative pressure caused by bathroom exhaust fans, clothes dryer exhaust fan and gas dryer/hot water heater burner make-up air. The gas furnace has outside air supply. Please save me... I am going down the rabbit hole. I have been investigating installing a Heat or Energy Recovery Ventilator like this which I would pursue if necessary after the top sealing damper install.

http://www.solerpalau-usa.com/products/erv-hrv/tr.html

What do you guys think?

Buckaroo

Might I suggest an experiment. Block off ~90% of the the fireplace opening with some cardboard or something. Leave a vertical slot opening in the middle and in this opening hang a streamer that will bend in the breeze if there is one going through the slot. Now go through the house turning on fans or other devises that draw air out of the house. Bathrooms, kitchens, even a window or door on the low pressure side of the house.

It should be perty obvious by the wiggling streamer if one or more things are causing back draft. You also state that the fireplace draws well. Have you considered where that air comes from?

lg
no neat sig line

 

[rlitman]

Might I suggest an experiment. Block off ~90% of the the fireplace opening with some cardboard or something. Leave a vertical slot opening in the middle and in this opening hang a streamer that will bend in the breeze if there is one going through the slot. Now go through the house turning on fans or other devises that draw air out of the house. Bathrooms, kitchens, even a window or door on the low pressure side of the house.

It should be perty obvious by the wiggling streamer if one or more things are causing back draft. You also state that the fireplace draws well. Have you considered where that air comes from?

lg
no neat sig line

Smoke from a match will highlight air currents better than a streamer.

 

[Buckaroo5]

fd

Might I suggest an experiment. Block off ~90% of the the fireplace opening with some cardboard or something. Leave a vertical slot opening in the middle and in this opening hang a streamer that will bend in the breeze if there is one going through the slot. Now go through the house turning on fans or other devises that draw air out of the house. Bathrooms, kitchens, even a window or door on the low pressure side of the house.

It should be perty obvious by the wiggling streamer if one or more things are causing back draft. You also state that the fireplace draws well. Have you considered where that air comes from?

Thank you everyone. These are all great comments.

I did put plastic across the firebox opening for about 24 hours after I sealed the voids between the damper housing & firebox - was very pleased to see no movement/billowing and thought I was done. Unfortunately, I didn't do that test before I sealed the voids (I know....bad scientific method) and I had not come up with the theory about the exhaust fan yet so didn't test their effect.....will do so and report results.

Where is the air coming from to provide the draw? Great question....don't know. Maybe through the bathroom fan vents? Absolutely no smoke or odor - I do have an NG log lighter which gets things heated up & burning pretty quick....

Buckaroo

 

[Falcon67]

Between the two bath exhaust fans and the 400+ CFM kitchen vent hood, I can do my own "blower door tests".

 

[HoosierMark]

Friend had a wood stove that would draw poorly and also had smoky smell when not burning.. Then he admitted they left the bathroom vent fan on 24-7. Turned it off and problem solved. That was the cause of the negative air draw.

 

[FTG-05]

This might help: http://www.chimneysweeponline.com/hoglazeodor.htm

Also, look into adding an Outdoor Air Kit: https://www.hearth.com/talk/threads/pros-and-cons-to-an-outside-air-kit.53128

 

[Buckaroo5]

I installed a Lymance Top Sealing Damper and it reduced the smoke smell a lot. I kept the throat damper as well and drilled a hole in the housing to route the cable for the top damper. Nice unit and easy install other than the silicone they sent me was hard so I used the silicone I had on hand. Got it from WoodlandDirect.com and was happy with them. I'm sure it will save me some BTU's and I think I'm done with this for the moment. I am still thinking long term,however, that I may want to install an energy recovery ventilator if I could control it to maintain a slight positive pressure....

http://www.solerpalau-usa.com/products/erv-hrv/tr.html

Thank you all for your help.

Buckaroo