OT- Chimney problem/advice?

[Anonymous-0]

Recently bought different house- has fireplace on main floor and one in basement. Getting smoke in basement even with damper closed when burning on the main floor. Not always, sometimes worse than others- I have been looking for a pattern but can't figure it out. Have tried to get hot fire started right away but sometimes still getting smoke downstairs. Advice?

 

[Greg_Ky]

Furnace in the basement? could be cold air return open and no warm air register open in basement pulling air from fireplace. Any smoke from the main floor fireplace back into the room? Need as much info as posssible.

 

[onefarmer]

Do the flues from the two fireplaces exit next to each other?
I'll bet the house is air tight enough that you start a fire in the one fireplace, that negative pressure occurs, pulling smoke down the flue of the second fireplace. I'm sure the damper isn't completely air tight since it is letting smoke in.

 

[Heyseed]

Could be several things. check out this link for chimmney guys. I have nothing to do with them but their site has lots of good info.
http://www.safesidechimney.com/smokeprob.htm

 

[Janicholson]

A cold chimney will down draft air into the house causing issues with convection draft. There should not be a fireplace connected to any other combustion device (including another fireplace). That is the reason for multiple chimney pipes common in Europe.
If they are distinct chimney flues, one may be down drafting as the other is convecting, sucking smoke into the house from the smoke at the top. A sealed damper may cure this, or the discharge "pot" of the fire place raised to a foot above the other "pot".
Power chimney systems are commonly used on troublesome combustion systems (forced draft fans)
Their primary issue is that they do not work when the electricity is off, and they can be a source of restriction in a convection only application.
As stated in the other answer, supply (makeup) combustion air can also cause reverse flow. The best solution is to pipe in cold combustion air to the fire box area of any combustion device. (this can be a massive improvement in efficiency by not burning heated room air.
Fix it before use, carbon monoxide is as deadly as a train wreck with a baby carriage. Keep us informed, JimN

 

[muleman51]

I would suspect that if you open a window slightly the problem will go away. Your house is tight enough that when you get a fire going it needs to pull in air from somewhereand your basement damper is the place it draws from,so you get smoke back down. Ithink you just need combustion air from an easier source ( open window or fresh air vent in furnace room). Hope this helps, this is not an uncommon problem.

 

[Mattias]

Some more ventilation in the basement would probably do good in more than one way if it's that tight.

JimN, Do you mean that only one channel are common even in relatively modern houses over there? We have both kinds at our house and the newer twochanneled one is from 1900 and the older one is from before 1840 but could be from 18th or 17th century as well.

Mattias in Sweden

 

[Anonymous-0]

Flues exit next to each other. Basement has good door and windows that are tight but main floor has very loose front door and draft. There is a furnace in the basement and in the attic. I tried to see a pattern by turning the furnace off or making sure the blower wasn't running until I had a hot fire in the fireplace. Never use the lower fireplace and thought about sealing it. Looks like best bet is to get a sealing damper for the top of the flue.

 

[Janicholson]

Putting a sealing damper on the top of the unused chimney is good (with a sure method of letting all know it is there if they were thinking of starting a fire in the lower hearth.
Extending the outlet point of the user hearth would do about the same thing.
The external air supply will also be well worth the effort. I do not know the age of the house, but fireplaces have, in many cases, become decoration and no effort was made to have them provide any actual heat. They have radical excessive draft, and suck heat out instead of making nice warm. Best of luck, JimN

 

[GeneMO]

No one has mentioned this, but the first thing I would do is clean the flu. Clean it real good. Can you get a mirror in at the bottom cleanout? I used to look up mine with a mirror to see if it needed cleaning.

Also, Is the flu tall enough? Does it extend above the highest point of the house?

A good clean flue, dry wood, and a good hot fire and it should be ok, again, supposing it is tall enough.


Gene

 

[CJ3b_jeep]

Mine does the same thing. I have a fireplace on the 1st floor, and a wood burner in the basement. Two separate pipes going up and out the roof, except I do not get smoke coming down mine, just cold air. When I start a fire in the basement on, I have to reverse the shop vac and blow air up it to break the negative flow. The flue does not seal enough to stop cold air from coming down it.