Cold Chimney Syndrome

Trying to make good on a bad set up is tough.

One problem which has not been addressed directly is to correct, or minimize, your DEPRESSURIZED basement.
This is a common problem with basement wood burners.
Opening windows adds to the problem (the 'stack effect') of depressurizing your basement since your whole house acts as a chimney;i.e.,
air flows from basement to higher levels. Upper levels thus develop higher pressure than lower levels.

I would try pressurizing your basement by placing a good sized fan on the main level floor directed down the stairs to the basement.
This will force cooler main floor air downstairs increasing the pressure in the basement, somewhat. Maybe just enough.
Close basement doors and windows to help maintainer a higher pressure (more Pascals).
Make sure any utility fans for H/W heater, bathroom exhausts, kitchen exhaust fans, etc are OFF on all levels of the house.
Light paper and fine kindling in the firebox with your chimney damper open. Keep the door open slightly.
You might be surprised at the results...

Aye,
Marty

yah "negative pressure" in my house too, since I have 2-story and insert on 1st floor I battled the stack effect. It comes down to this, if the air is coming down the chimney and INTO the house, it definitely has to be going OUT of the house somewhere. I had a whole house fan (upstairs), and gas fireplace and vents (upstairs), leaky attic doors (upstairs), all of which contributed to the air going OUT of my house. I simply sealed these air loses with vapor barriers and the stack effect was greatly diminished, and of course made a big difference on my ability to get the fire going. Sealing with vapor barriers consisted of painter's plastic over whole house louvers (now since insulated with batts in attic), plugged gas fireplace vents with towels, and sealed attic doors with more painters plastic and insulation...in the end, BIG difference in being able to start a fire, and of course now overall comfort of the house too.

jeffs said:

Nothing is open, no exhaust fans running, furnace is off, attic access is in a closet on 2nd floor and closed tight, no air coming in from other fireplaces, no air leaks, house is VERY tight.

I have no chimney damper, so flue is full open.
Draft reg. on stove is full open.

One thing I was thinking of is that the furnace had been running prior to lighting the fire.
Maybe it was on long enough to create negative pressure.
We have a stupid power-vent exhaust on the furnace, which draws extra air.
Furnace is in a room adjacent to room with wood stove.
So maybe I should open a basement window for a few minutes prior to lighting to equalize pressure?

FPX Dude– I wasn't trying to warm the baffles, was blowing heat up into the opening at the front of stove, this is where my outflow is.

I don't think I have a bypass that I can open. I can slide the baffles forward about 2-3 inches, I don't know if I can get to the flue that way or not, I'll have to check.
This is a Napoleon 1900, would anyone know if there's a way I can get direct access to the flue from inside the stove?

Click to expand...

The only thing you want 'open' in your basement before striking a fire is your stove door and flue.
Anything else open adds to basement depressurization.
You want basement air to go up your flue, nowhere else.
The more your basement is 'pressurized', the more air and smoke go up your flue.

Aye,
Marty

jeffs said:

Marty S said:

jeffs said:

Nothing is open, no exhaust fans running, furnace is off, attic access is in a closet on 2nd floor and closed tight, no air coming in from other fireplaces, no air leaks, house is VERY tight.

I have no chimney damper, so flue is full open.
Draft reg. on stove is full open.

One thing I was thinking of is that the furnace had been running prior to lighting the fire.
Maybe it was on long enough to create negative pressure.
We have a stupid power-vent exhaust on the furnace, which draws extra air.
Furnace is in a room adjacent to room with wood stove.
So maybe I should open a basement window for a few minutes prior to lighting to equalize pressure?

FPX Dude– I wasn't trying to warm the baffles, was blowing heat up into the opening at the front of stove, this is where my outflow is.

I don't think I have a bypass that I can open. I can slide the baffles forward about 2-3 inches, I don't know if I can get to the flue that way or not, I'll have to check.
This is a Napoleon 1900, would anyone know if there's a way I can get direct access to the flue from inside the stove?

Click to expand...

The only thing you want 'open' in your basement before striking a fire is your stove door and flue.
Anything else open adds to basement depressurization.
You want basement air to go up your flue, nowhere else.
The more your basement is 'pressurized', the more air and smoke go up your flue.

Aye,
Marty

Click to expand...

You don't think there's a chance that my furnace/power-vent has pushed so much air out of the basement, that I've got lower-pressure in the basement than outside?

There is a slight draft into the furnace room of the basement when the furnace is on.
After it shuts off, wouldn't I have lower-pressure in the basement than the rest of the house?
So I can see how that would be pulling air down the flue to equalize air pressure.
I'm just thinking about opening a window for a few minutes to equalize pressure, not leaving it open when I start the fire.

Are you saying the air inside the house (overall) is still a higher pressure than outside because it's warmer?

Click to expand...

Read this to correct some of your incorrect ideas: "opening a window for a few minutes to equalize pressure".

http://woodheat.org/the-outdoor-air-myth-exposed.html

Aye,
Marty

rayg said:

I use one of those plumbers MAPP Gas canisters from Home Depot or lowes. You know the ones. Looks like a 14" high Oxy/Acetelene bottle with a pistol grip nozzel. I've learnt that if I have a cold chimney I am going to have smoke rolling out of all orifices of the stove. So I fire up my little Creme brulee Bottle and fire it for 60seconds through the opened damper in the stove and into the stove pipe. The 60seconds was trial and error over the course of several weeks a few winters ago. yet warming up that stove pipe does wonders for the draw. Top down is a good way to light yet take me a while to set up, so I don't do it. I uses this GAS/Propane bottle (they are about $20 from Home Despot)

Ray

Click to expand...

I tried starting my fire using this method today... All the smoke rolled right out the front of the stove :s Any other method and it will draft like a champ immediately.
Maybe because it's about... Oh geeze, I just looked up the temp and it's 55 out haha.

[quote author="Marty S" date="1324500048"
...

Read this to correct some of your incorrect ideas: "opening a window for a few minutes to equalize pressure".

http://woodheat.org/the-outdoor-air-myth-exposed.html

Aye,
Marty[/quote]

This article says that if a window is opened below the neutral pressure level in a house, air will flow into the house. In other words, it is possible to reduce negative pressure by opening windows, it just isn't guaranteed. To try to figure out if negative pressure is a problem, I'd go whole hog and do everything you can to eliminate the possible negative pressure. First I'd close doors between the basement and upstairs, second I'd turn off the furnace or anything else that sucks air, and third I'd open windows on at least two sides of the house (windows that open into the basement) until you can feel the breeze inside. Open them all! This should guarantee that you don't have negative pressure in the basement. If this doesn't help then I think you can move on to another solution.

If you do have a negative pressure problem Marty is right- just opening a window somewhere isn't necessarily going to fix the problem.

Just to add to a few good previous comments, from experience...

- Holding the lighter flame up to the baffle is the first thing I do everytime I plan to light the stove.
- I had to build an extension to the hairdryer to get the air movement into the flue; above the baffle. (Photo attached...hopefully)
- I can not possibly close that stove door before it gets burning hot and violent. No matter what the outdoor temp. Else I get the same result reported by OP. But must admit, never had flames lick the doorway. (Doesn't sound too good)

I have tried many drafting methods, and the hairdryer is what really works. My chimney is short and exterior. My stove is not, however, in the basement.

The good news is that all this bother became routine and easy.

Wood Duck said:

[quote author="Marty S" date="1324500048"
...

Read this to correct some of your incorrect ideas: "opening a window for a few minutes to equalize pressure".

http://woodheat.org/the-outdoor-air-myth-exposed.html

Aye,
Marty

Click to expand...

This article says that if a window is opened below the neutral pressure level in a house, air will flow into the house. In other words, it is possible to reduce negative pressure by opening windows, it just isn't guaranteed. To try to figure out if negative pressure is a problem, I'd go whole hog and do everything you can to eliminate the possible negative pressure. First I'd close doors between the basement and upstairs, second I'd turn off the furnace or anything else that sucks air, and third I'd open windows on at least two sides of the house (windows that open into the basement) until you can feel the breeze inside. Open them all! This should guarantee that you don't have negative pressure in the basement. If this doesn't help then I think you can move on to another solution.

If you do have a negative pressure problem Marty is right- just opening a window somewhere isn't necessarily going to fix the problem.

Click to expand...

OMG. Simply, the above is wrong.
Most ALL basements are depressurized unless they have a forced air make up system.

We're talking about cold weather here. This is when you want a fire. Right?
In cold weather, your house acts like a chimney, sucking air in lower levels of
your house to equalize pressure as warm air escapes out the upper levels ('stack effect').
As air flows upward, the upper levels become more pressurized than the lower levels.
Given this (see previous reference), opening windows "until you can feel the breeze"
is a good way to increase the stack effect and further depressurize the basement, which
does not help (in the least) starting a fire down there.

Aye,
Marty

Jeffs,

From reading your experience of getting a roaring fire and still not getting a good draft sounds like your problem is worse than mine. So the depressurized basement may be an extra contributing factor.

But for what it is worth, I will tell you what my method is. I have a heat gun that I hook up to a small section of duct that is connected to the stove's air intake, where the "outdoor air kit" would be connected. I run the heat gun for about 2-5 mins. You may need to run it longer. This has the benefit of forcing hot air into the stove which heats the stove's firebox, but also forces air up over the baffle and back through the horizontal section of the flue ( I have a hearth installation with a rear discharge that goes about a foot into a tee). So I am pressurizing the stove and forcing air into the flue.

I usually turn off the heat gun before I start the fire. But there were a couple times that I was not sure I got the draft established and I was in a hurry and I started the fire and left the heat gun on. Of course I closed the fire box door to make sure I continued to force the air and combustion products up the flue. But the big caveat is that wood stoves are suppose to operated with the draft from the flue drawing through the stove such that there is a NEGATIVE pressure in the stove which pulls room air in. So the technique that I use to preheat the stove/flue is just the opposite, I am pushing air into the stove/flue to pressurize them. So this is not a good idea to operate the stove with a fire in it for more than a minute or two.

Once I run the heat gun for 2 - 5 minutes I get enough of a draft pulling air up the flue that the match light bends into the stove before I light the newspaper, and once I light the newspaper and kindling, or super cedar, I won't get smoke and the draft only pulls stronger as the fire gets going. So if you had a fire started and it was not causing smoke in the room, and when it went out, you then had a reversal of draft, I would say you definitely need to force air into your basement with a fan, at least until your draft is strong enough to overcome the negative room pressure.

Once your stove is cruising at 500F, do you ever have back pressure problems? Or is your draft good when the stove is hot?

granpajohn said:

Just to add to a few good previous comments, from experience...

- Holding the lighter flame up to the baffle is the first thing I do everytime I plan to light the stove.
- I had to build an extension to the hairdryer to get the air movement into the flue; above the baffle. (Photo attached...hopefully)
- I can not possibly close that stove door before it gets burning hot and violent. No matter what the outdoor temp. Else I get the same result reported by OP. But must admit, never had flames lick the doorway. (Doesn't sound too good)

I have tried many drafting methods, and the hairdryer is what really works. My chimney is short and exterior. My stove is not, however, in the basement.

The good news is that all this bother became routine and easy.

Click to expand...

+1 for grandpa...I was just thinking about how you could "MacGruber" something together to get it right into the flue...I dunno how much room you have to work with to get access to this but follow this arrow, and this is where you need to get the hairdryer flowing air to

jeffs said:

FPX Dude– I looked in the firebox last night. Not much room to get a hair dryer (with extension) under the flue. I have about a 2" gap at the front (where the arrow goes up in your diagram). The baffles are vermiculte, and don't appear very durable, so I don't want to bump them around very much. They are looking a little cracked already, and at $60 a set...

Click to expand...

I think you've just described my setup too. 2" sounds about right. That extension on my hairdryer is flexible. Was meant as a temporary test, but became permanent. If I stuff it up there and miss the flue hole, it doesn't really work and I have to start over. Hard to explain, but it does work when nothing else will.

Top Down Fire– I watched the video suggested by Be Green http://www.woodheat.org/wood-heat-videos.html
I'm really interested in trying the top-down fire as they do it in the video. I tried a TD last weekend, but not exactly the way they do in the video. I was surprised to see them do this with the door closed, and wondering if that would help me by keeping more heat in the stove, and forcing it up. I've always heard to start the fire with the door open. Could it be this is the simplest solution I haven't tried????

Click to expand...

Just wanna say that the small amount of heat from TDF probably won't help if 5 mins from your heat gun didn't. I have tried TD and find it to be OK, but does little for back drafting. And I could not even dream of fire starting with the door closed. Avoid the temptation and keep that door ajar for 15-20 mins.
This will become routine...you'll look back at this and laugh. (I think/hope/pray)
ETA: "door open" means about an inch. Fully open doors on EPA stoves tend to let (some) smoke into the room. I would close it a bit more if the latch didn't bump in the way. (I decided to add this after rereading about the flames licking the doorway)

I have this problem also. I have found that some news paper with smokless clear lampoil from walmart works well to get it going. I put some news paper in and put the smokless oil (liquid pariffin ive heard) on the paper an light. It pushes out pipe seems and door but a lot less smoke for me. A propane torch works for me too if i aim it in the chamber above the ceramic board on my nc13 if it is not extremly cold out.

even a newspaper "torch" wouldn't work for me, that blast of cold air rushing down the chimney was like the jet stream and would still force smoke in the house and I didn't want any.

Jeffs, I was thinking about maybe a 3 ft. 2" flexible plastic tube (like the kind you would use for a beer bong! ), duct tape to hairdryer, then kinda slip it around the baffles and up the flue.

Marty S said:

Wood Duck said:

[quote author="Marty S" date="1324500048"
...

Read this to correct some of your incorrect ideas: "opening a window for a few minutes to equalize pressure".

http://woodheat.org/the-outdoor-air-myth-exposed.html

Aye,
Marty

Click to expand...

This article says that if a window is opened below the neutral pressure level in a house, air will flow into the house. In other words, it is possible to reduce negative pressure by opening windows, it just isn't guaranteed. To try to figure out if negative pressure is a problem, I'd go whole hog and do everything you can to eliminate the possible negative pressure. First I'd close doors between the basement and upstairs, second I'd turn off the furnace or anything else that sucks air, and third I'd open windows on at least two sides of the house (windows that open into the basement) until you can feel the breeze inside. Open them all! This should guarantee that you don't have negative pressure in the basement. If this doesn't help then I think you can move on to another solution.

If you do have a negative pressure problem Marty is right- just opening a window somewhere isn't necessarily going to fix the problem.

Click to expand...

OMG. Simply, the above is wrong.
Most ALL basements are depressurized unless they have a forced air make up system.

We're talking about cold weather here. This is when you want a fire. Right?
In cold weather, your house acts like a chimney, sucking air in lower levels of
your house to equalize pressure as warm air escapes out the upper levels ('stack effect').
As air flows upward, the upper levels become more pressurized than the lower levels.
Given this (see previous reference), opening windows "until you can feel the breeze"
is a good way to increase the stack effect and further depressurize the basement, which
does not help (in the least) starting a fire down there.

Aye,
Marty

Click to expand...

If you close the doors between the basement and the upper floors, assuming the doors are reasonably airtight, then why would the basement remain depressurized with windows open?

FPX Dude said:

even a newspaper "torch" wouldn't work for me, that blast of cold air rushing down the chimney was like the jet stream and would still force smoke in the house and I didn't want any.

Jeffs, I was thinking about maybe a 3 ft. 2" flexible plastic tube (like the kind you would use for a beer bong! ), duct tape to hairdryer, then kinda slip it around the baffles and up the flue.

Click to expand...

Ditto here. Good desciption FPX.
I have always planned to use an air tube from a VW beetle, (if you're familiar with those things), but just kept using the old cracker wrapper.
Ah heck...here's a link to the heater tube ($9): http://www.chircoestore.com/catalog/product_info.php?cPath=109_115_525&products_id=3209

Hi, I too am a new wood burner struggling with cold stove down draft problems. We don't run stove overnight so each morning we wake up to cold stove.

I've given up on stoves full of newspaper, newspaper and kindling, top down lighting..etc. All good technicques for some, but just didn't work for the downdraft we were dealing with as the temps got very cold.

But, I have found a combination of tricks that work for us.

Put Vent in the full open Position. Then hand break a small piece (about 2" x 3") of fire "Starter Logg". We put that in the cold stove (by itself), light it , close the door, and leave it alone until it is mostly all flaming (10 minutes). Then we open the door and use our hands to check to see if the stove chamber feels warmer and the cold drafts have subsided. Sometimes it takes a few more minutes. Once warm, i put a EnV Brick (similar to BioBrick) tight on each side of the firestarter, 4-6 pieces of kindling across the top of the bricks/starter, a few smaller pieces of hardwood across the top of kindling and then leave it alone for 15 minutes. Vent still fully open. It usually flames up quite well and definately gets the draft working. From then on we just operate the stove as conditions warrant.

Every time this works to establish the air flow up the exterior stainless steel chimney. And no smoke in the house !

My set up is a H300 Hampton stove. Double wall interior pipe goes up 2 feet, turns 90 degrees, connects to selkirk insulated stainless steel chimney pipe, 18 inches near horizontal run thru wall,clean out piece/90 degree on outside bracket that turns pipe up, then up ~25 feet run to above roof line.

Good Luck to you ! Hope this helps.

I have a back drafting basement stove too. Here's my bullet-proof trick for getting it going.

If your stove has a pedestal with a front access door and draws air from the bottom (inside the pedestal), you could try pressurizing the firebox. Get a 6" AC fan and wire up a cord with an inline switch. Build a cardboard (or wood/metal if you want to get fancy) shroud to fit the pedestal opening with a cutout for the fan. Put the shroud in place and the fan in frint, blowing into the pedestal.

Build your fire (I like top down) but do not light. Close the door, open the draft and turn on the fan for a minute or two. Open the door, quickly light the fire and close the door. Let the fire slowly catch - and it will be real slow sometimes. When you see the flames and smoke starting to curl over the baffle, the backdraft has been reversed and you can open the door and remove the fan.

Wood Duck said:

Marty S said:

Wood Duck said:

[quote author="Marty S" date="1324500048"
...

Read this to correct some of your incorrect ideas: "opening a window for a few minutes to equalize pressure".

http://woodheat.org/the-outdoor-air-myth-exposed.html

Aye,
Marty

Click to expand...

This article says that if a window is opened below the neutral pressure level in a house, air will flow into the house. In other words, it is possible to reduce negative pressure by opening windows, it just isn't guaranteed. To try to figure out if negative pressure is a problem, I'd go whole hog and do everything you can to eliminate the possible negative pressure. First I'd close doors between the basement and upstairs, second I'd turn off the furnace or anything else that sucks air, and third I'd open windows on at least two sides of the house (windows that open into the basement) until you can feel the breeze inside. Open them all! This should guarantee that you don't have negative pressure in the basement. If this doesn't help then I think you can move on to another solution.

If you do have a negative pressure problem Marty is right- just opening a window somewhere isn't necessarily going to fix the problem.

Click to expand...

OMG. Simply, the above is wrong.
Most ALL basements are depressurized unless they have a forced air make up system.

We're talking about cold weather here. This is when you want a fire. Right?
In cold weather, your house acts like a chimney, sucking air in lower levels of
your house to equalize pressure as warm air escapes out the upper levels ('stack effect').
As air flows upward, the upper levels become more pressurized than the lower levels.
Given this (see previous reference), opening windows "until you can feel the breeze"
is a good way to increase the stack effect and further depressurize the basement, which
does not help (in the least) starting a fire down there.

Aye,
Marty

Click to expand...

If you close the doors between the basement and the upper floors, assuming the doors are reasonably airtight,
then why would the basement remain depressurized with windows open?

Click to expand...

It is illogical to use an incorrect assumption (..."the doors are reasonably airtight") in asking a question
which has already been answered.

First, if the doors are only "reasonably" airtight, they are not airtight.

Second, doors between floors are not made airtight.

Third, leakage between floors of a house occurs in places besides doorways.

Fourth, if the basement were not depressurized, air would not come into the basement through
an open window in the first place.

Aye,
Marty