another year another problem

[iceman]

i have a fireplace in my basement its 48 inches wide by 30?
i always seem to get a little smoke from the fireplace coming out into the room
i have tried cracking a outside door in the basement
i have installed one of those"bars" that lower the front end 4 inches
no matter what i try it always happens
you cant really see the the smoke you just smell it unless you go right up to it then you can see smoke coming out
the chim is on the interior wall and there is only one floor above it so it doesn't run more than 25 ft
it is however in a a chim that has 5 0r 6 seperate flues in it so no it does not share one
what can i do?

 

[stoveguy13]

What size is the flue?

 

[GVA]

It's in the basement and even though you open a window it's still competing for air with anything else down there.
Furnace
Gas hot water heater/ dryer
so what else you got in the basement?

 

[iceman]

What size is the flue?

i believe its 8

 

[iceman]

It's in the basement and even though you open a window it's still competing for air with anything else down there.
Furnace
Gas hot water heater/ dryer
so what else you got in the basement?

there is a furnace gas water heater but those are in another room
the room the fireplace in is is about24 x 36

 

[stoveguy13]

if you have a 8x8 it is the problem to small double check that

 

[iceman]

if you have a 8x8 it is the problem to small double check that

how can i measure and what size should it be

 

[stoveguy13]

the best way is to figure which one it is and get up on the roof

 

[BrotherBart]

It will be the same size as that brush you use to clean it every year. You DO clean it don't you?

 

[iceman]

It will be the same size as that brush you use to clean it every year. You DO clean it don't you?

lol no... are you crazy?????
why should i clean it????
lol
i don't but yes its cleaned

 

[jtp10181]

8" is not necessarily too small if its a pre-fab unit and that's what its tested to use.

I would have someone do a pressure differential test using magnahelic manometer. Someone (dealer) experienced with wood burning fireplaces should be able to do it. Most likely you do not have adequate makeup air coming in and the house gets negative the longer you run the fireplace. The basement is the lowest pressure zone in the house and is the hardest place to get natural draft appliances to draft. You also might not be getting good flu temps if the wood you burn does not have enough energy output (too wet or rotten wood). Before you say your wood is fine... do you really know what good wood is? I get people all the time tell me their wood is fine, and its not. I don't know your experience level so this may be trivial stuff you already know about but just tossing things out. From the info you gave it sounds like its an open face fireplace and not an efficient stove, correct?

Going back to the wood thing, I had a customer with a similarly sized fireplace on the main floor and they had the exact same problem. Their wood was sizzling it was so moist! They had to leave a window fully open all the time to balance the pressure in the house so it would work. I went there with some good wood and got a fire going, closed the window after a few minutes and it worked great. The pressure went down to about -7 Pascals but with nice hot flu gasses it would still work. With colder flu gasses anything under -2 Pascals or so is going to cause problems.

 

[webbie]

That is a large fireplace, and it should have min 12" square flue and probably bigger!

You can measure from the roof, or look up from the bottom and eyeball it - does it have a red clay tile (liner) in it?

It does sound like a case of the flue not being large enough, possibly combined with air pressure problems.

See: https://www.hearth.com/econtent/index.php/articles/chimney_and_fireplace_sizing/

30x48 = approx 1440 square inches - divided by 10 - means that the chimney should be 144 square inches, meaning a 12x12 would do that job. The problem is that some 12x12 tiles are as small as 10.5" ID, meaning they are only 110 or so sq. inches, which would still work in SOME cases, but in other (maybe yours) will not.

Solutions, assuming your chimney is already that size, include extending the chimney (www.extendaflue.com) or a chimney top fan (exhausto, etc.), as well as making the opening smaller in some way. A fireplace insert with a chimney liner would also solve this problem.

 

[begreen]

Sounds like it's begging for a nice stove or at least an insert to be installed in it.

 

[jtp10181]

Sounds like it's begging for a nice stove or at least an insert to be installed in it.

Yeah definitely I think installing a stove or an insert in there would really help a lot. It would also give you some real heat out of your wood instead of just wasting it.

 

[stoveguy13]

With 5-6 flues in the chimney there cloud also be some major off setts on the fireplace flue.assumeing that the flue is the correct size this may be anothe cause for the problem and also cloud make the installation of a stove a littel more difficult.

 

[elkimmeg]

Wrong flue size actually a 12 /12 is NFPA standard 96" cross-sectional area 40% smaller than required for that opening. Plus the negative pressure location
the basement and competing appliances for combustion air all probably in close vicinity . This spells a formular as you describe I hope your monoxide sensors are working, as one appliance can back draft another.. First correction would be suppling outsode air to the largest appliance probably your furnace. Meet its demand might allow enough combustion air for that fireplace

Posibly an outside air inlet to the fireplace as well . If you have a pull down attic stairs you need to seal that opening. This is a huge positive pressure valve making the negative pressure in the basement worse. Leaky windows in the floor above that fireplace, dose the same thing as the attic stairs or accces hatch

You have Three issues to deal with the pressure negative and combustion air and venting into too small a flue. Fix the other two might allow the smaller flue area to work

 

[stoveguy2esw]

im with BEGREEN and JTP , drop in a liner to an epa insert , problems solved , plus the added heating punch of an epa rated insert over a fireplace is HUGE if you want ambiance , find one with a large viewing window but why waste the heat.

 

[iceman]

Wrong flue size actually a 12 /12 is NFPA standard 96" cross-sectional area 40% smaller than required for that opening. Plus the negative pressure location
the basement and competing appliances for combustion air all probably in close vicinity . This spells a formular as you describe I hope your monoxide sensors are working, as one appliance can back draft another.. First correction would be suppling outsode air to the largest appliance probably your furnace. Meet its demand might allow enough combustion air for that fireplace

Posibly an outside air inlet to the fireplace as well . If you have a pull down attic stairs you need to seal that opening. This is a huge positive pressure valve making the negative pressure in the basement worse. Leaky windows in the floor above that fireplace, dose the same thing as the attic stairs or accces hatch

You have Three issues to deal with the pressure negative and combustion air and venting into too small a flue. Fix the other two might allow the smaller flue area to work

in the other room there is a outside air inlet for the furnance a window was taken out damper put in with a duct running to about 2-3 inches off the ground
there is no attic hatch but a door to get up there.... however there is a whole house fan
the house is complete with new windows and the basement is a walkout kinda

 

[iceman]

im with BEGREEN and JTP , drop in a liner to an epa insert , problems solved , plus the added heating punch of an epa rated insert over a fireplace is HUGE if you want ambiance , find one with a large viewing window but why waste the heat.

i love fire
the basement is heated and doesn't get that cold so to say but i have a nice bar there so the ambience is perfect
plus the wall its in is about 15-18 feet long a strange kind of stone brick thing so i don't want to take away from the wall
when that thing is going it looks great
plus i don't want to drop 3000+ for a really nice insert right now

 

[iceman]

That is a large fireplace, and it should have min 12" square flue and probably bigger!

You can measure from the roof, or look up from the bottom and eyeball it - does it have a red clay tile (liner) in it?

It does sound like a case of the flue not being large enough, possibly combined with air pressure problems.

See: https://www.hearth.com/econtent/index.php/articles/chimney_and_fireplace_sizing/

30x48 = approx 1440 square inches - divided by 10 - means that the chimney should be 144 square inches, meaning a 12x12 would do that job. The problem is that some 12x12 tiles are as small as 10.5" ID, meaning they are only 110 or so sq. inches, which would still work in SOME cases, but in other (maybe yours) will not.

Solutions, assuming your chimney is already that size, include extending the chimney (www.extendaflue.com) or a chimney top fan (exhausto, etc.), as well as making the opening smaller in some way. A fireplace insert with a chimney liner would also solve this problem.

i had to special order a cap because with six flues most people don't stock something that big so if i get an extenda cap i would be in another boat because i would have 5 more to go lol

 

[stoveguy2esw]

does that outside intake connect directly to the furnace? if not the furnace is still in play , the "tight house" and whole house (attic?) fan is not helping when running as far as backdrafting is concerned, pulls massive positive pressure in the top of the house , raising the zero pressure line higher in the house which causes increased negative pressure in the basement (which is already a negative pressure environment anyway) basement fireplaces in a tight house will generally be sluggish at best bacause of this, outside air may be needed in close , i mean close proximity to the fireplace to equalize the situation.

 

[iceman]

does that outside intake connect directly to the furnace? if not the furnace is still in play , the "tight house" and whole house (attic?) fan is not helping when running as far as backdrafting is concerned, pulls massive positive pressure in the top of the house , raising the zero pressure line higher in the house which causes increased negative pressure in the basement (which is already a negative pressure environment anyway) basement fireplaces in a tight house will generally be sluggish at best bacause of this, outside air may be needed in close , i mean close proximity to the fireplace to equalize the situation.

no it doesn't connect but imagine a not having a basement window. so much air comes in that window there is a door to close in that room away from the rest of the basement. the duct runs to the ground for fire code purposes i believe

 

[iceman]

i just checked the flue from inside the firplace its not 8 inches it might be 8 inches wide but its rectangle and looks more than a foot long maybe 14- 18 long 8-10 wide
i also added about 30-40 fire bricks to make the opening a little smaller and that never helped

 

[stoveguy13]

that would most likely be the cause of your problems the flue is to small for the size of the FP. what do the rest of the flues serve? you said there was six of them.

 

[iceman]

that would most likely be the cause of your problems the flue is to small for the size of the FP. what do the rest of the flues serve? you said there was six of them.

well... one was closed and sealed at the top so we could change the heating sys... one has the boiler and gas heater ... one is a gas firplace ... one is another wood firplace that has never been used the other is for a gas grill that has never been used and the last is the fire place we are talking about