Wood Smoke smell in second floor


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Old 02-14-16, 06:54 AM
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Wood Smoke smell in second floor

Hi

Been in the house around 6 years or so. Used the wood fire place every winter. The chimney is generally swept every 2 years.

Ever since our gas furnaces and gas hot water was replaced there has been a strong smell of wood smoke in our second floor and basement when we have a fire lit. Its an open fire place (ie no insert). We have 1 clean out for the fire in the basement. It does have some significant ash volume in it - the sweeper guy said I could clean it out with a shop vac but its not really a worry at this point. I remove the ashes from the fireplace directly rather than push it into the basement. The chimney runs thru the house mostly. Our Den has a cathedral ceiling and the chimney is attached to side of the house above the den. ie the last 10ft or so are outside.

What I've found is that by opening a small window in the basement about an inch the wood smoke smell upstairs disappears. There is a very strong flow of air through that window when I open it. It takes around 30 mins or so and the smell is gone on the second floor.

The old furnaces vented (along with the water heater) thru one of the vents in the chimney (two total). The furnaces heat the first and second floor each plus there are some vents in the finished part of the basement. All of the HVAC equipment is in the basement next to the fireplace structure (brick). The new furnaces are direct vented outside but pull air in from the basement. The new water heater is direct vented outside as well. The chimney vent for the old furnaces is capped in the basement but not at the top of the chimney. We decided to replace the water heater at the same time to avoid having to put a smaller liner in the chimney vent. Both vents at the top of the chimney are at the same height.

So I'm trying to work out a permanent solution and avoid opening the basement window when we use the fireplace. There is alot of water pipes near the window (within 5ft or so) and I don't want them to freeze if we leave the window open.

Any thoughts on the next steps ?

Thanks

Mick
 
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Old 02-14-16, 07:54 AM
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Clearly you aren't getting enough makeup air to account for the combustion air the furnace and WH are using. This is causing your fireplace to not draft properly.

This can be a dangerous situation and needs to be addressed.

Most newer furnaces have the option of connecting an outside air supply. I would ask the dealer that installed it if that can be added.

Another option is to run a fresh (outside) air supply duct over close to the area where the furnace and WH are located. It can even be equipped with a damper so it is only open when the equipment is operating. This is more typically done when the equipment is in an enclosed room, but doesn't have to be.

Probably your best and cheapest option is to add outside air connections to both appliances if they allow that. But get a competent HVAC co in right away.

The pro's here may have some other suggestions.

If you intend to use the fireplace, I'd open that window. You can wrap the pipes with insulation to help keep them from freezing, but it's a short term solution.
 
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Old 02-14-16, 09:55 AM
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I probably missed it, but assuming the fireplace is on the first floor with furnace and water heater in basement. It takes me awhile to digest problems like this, but here is my thinking.
An open fireplace requires A LOT of air and when in use, the replacement air has to come from somewhere. With the old flue not in use it may be drawing that air down the chimney and pulling wood smoke from the top of the other chimney. If the liner inside the brick chimney is not perfectly sealed the smoke then enters the gap between the two and finds leaks into the house.

When you open the window in the basement you reduce the negative pressure inside the building by giving it a new source of air.

Not a nice time of year to be doing this, but in case you are up there shoveling snow, you could add a cover to that abandoned flue.

Reviewing the makeup air for both the furnace and water heater is a good idea as CT suggested.

Bud
 
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Old 02-14-16, 10:15 AM
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Bud9051 - Yes Fireplace on the first floor with the HVAC all in the basement.

Thanks guys - confirmed what I thought - I was wondering if the best course of action was to add an external air source for the furnace(s). Will look into that approach.

I'll get my HVAC guys in to add the external source and when the sweep is here in the spring I'll get him to seal the other flue.

My other theory (more expensive) was to add an insert into the fireplace with a blower. I still might to that from a efficiency standpoint anyway.
 
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Old 02-14-16, 10:34 AM
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A fireplace is terribly inefficient anyway and a blower is usually used to keep them from backdrafting. I think the abandoned flue is getting filled with cold air. A bit of science here, but the natural air flow through a house (stack effect), especially in the winter, is "in" through the lower leaks and "out" through the upper leaks. But, when that chimney is filled with cold air, it acts like a lower leak despite originating well above the roof line. Thus it becomes a source of replacement air.

I have enjoyed burning wood all of my life. My last open fireplace was in Brick. I now use a glass door wood stove (Regency) and love it. It offers the same view of the fire without the concern as to where the sparks may fly and it produces a lot of heat. Up here in Maine it is our backup when the power goes out. We can even cook on it and did so during the ice storm of 98.

Rather than a blower, I'll spend some of your money, check out a wood insert that uses outside air for combustion.

Best,
Bud
 
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Old 02-14-16, 02:53 PM
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Thus it becomes a source of replacement air.

And that air is from the flue from the fireplace right ? I think I get it.

Will get that covered off in the spring.

Thanks for the insert lesson - i needed it!
 
 

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