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Any Chimney Experts In Here?


Northman

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I have two chimneys on my house.

One comes straigth up from my upstairs fireplace (cathedral ceilings), and through the roof - no bends.

The other comes out of the wood stove in the basement, rises 3 feet, makes a 90 out the wall, travels about 5 feet, then meets a "T" on the outside of the wall. Chimney goes straight up from there, with the bottom of the "T" used as a cleanout, so I have a 1ft section mounted on the bottom.

Problem is:

I have a bad downdraft in the woodstove chimney. To the point where I need to light paper on fire inside the horizontal pipe to get heat in the pipe. Otherwise, it fills the house with smoke before updrafting.

This happens every time the chimney cools off.

Both chimneys are the same diameter, both have the same rain caps, and both are approx. the same height.

Is there something I'm missing that I should be looking for?

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I got a fireplace that has a straight shot up, however downstairs I have a wood stove that does something similar like yours.

Comes up like 3ft take a 90 goes into a wall, takes another 90 to go out the chimney.

I don't know why you have "T"s in your piping :???:

Only thing I could recommend is to have the damper as free flowing as possible and allow as much air to get in thru the vents or whatever. Might help the smoke take the easiest route out. Get the fire going pretty good, and adjust to your normal settings.

I am mastering my woodstove downstairs.

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Where's your cleanout?

That's why I have a "T" on the outside wall, with the bottom part of it being the cleanout.

If I open the vents, I can actually feel cold air coming in from down the chimney. That's the whole problem. When I start a fire, the flow is reverse, until I get enough heat in the bastard, and choke it enough to force an upward flow.

By then I have a house full of smoke, smoke detectors going off (part of the alarm system), etc.

I just had an idea. I'm going to go switch caps and see if that makes a difference. Maybe one is defective, but I doubt it.

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I knew this was going to happen.....

It's drizzly here, and kinda cool, but I'm gonna have to climb up on the frickin' roof to investigate further....

The stove chimney is separate from the fireplace chimney, and they're about 8 feet apart.

Woodstove chimney, IIRC, is about 4 feet above the roof, but comes out below the peak, so may be less than 3 feet above the peak.

BRB, hopefully :sad:

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OK, you bastards :evil:

Now that I'm back off of the roof.....

The woodstove chimney is a full two sections above the roof (6ft), and about 4ft above the peak. Stove chimney is higher than the fireplace chimney, for sure.

I just removed the 1ft section at the bottom of the "T", and it was full of creosote flakes. Removed the section altogether, and capped the bottom of the T.

Went inside to try the fire, and it's still downdrafting. I couldn't switch the caps, because the pipes are a different type. I can feel warm air rushing up the fireplace chimney, but nothing coming up the woodstove chimney.

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This may sound stupid, but is the woodstove chimney on the side of the house that the wind hits or the opposite side? If it's on the opposite side, the wind flow over the house may be putting a positive pressure on the top of the woodstove chimney. you might have to move the woodstove chimney near the fireplace chimney to get it to draft. Also, is the "T" open on the bottom. If you don't get a good seal there, it will kill your draft. Insulated pipe even on the outside may help as well as it will hold the heat in better.

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The pipe is 2" insulated stainless steel, I forgot to mention that.

It's on the west side of the house, and any wind we get would come from the south, but I'm pretty well protected here.

The seal on the bottom of the T was questionable with the short section of pipe there, so that's why I removed it today, and just installed the plug.

Gonna try a few more times to check draft, as it may take some time to change.

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The pipe is 2" insulated stainless steel, I forgot to mention that.

It's on the west side of the house, and any wind we get would come from the south, but I'm pretty well protected here.

The seal on the bottom of the T was questionable with the short section of pipe there, so that's why I removed it today, and just installed the plug.

Gonna try a few more times to check draft, as it may take some time to change.

what's the differenance in height between the chimney's?

You may need to go a big higher if your getting a draft. I can't remember heights forsure, but I'll talk to a friend that works on them for you.

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Just a thought. When you are trying to light the woodstove, do you have a gasfired furnace in the house? If you do, and the blower is running, maybe there is some "leakage" and it is sucking air, instead of all of the air returning to your furnace through the return air vents. If that would be the case, and the furnace blower is running, it would suck air down through your woodstove vent? Just a thought.

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I have a furnace, but it's forced air electric.

Never thought of it pulling in through a leak, but it would have to be a pretty big issue to create a vacuum in the basement enough to downdraft.

Worth looking into, though.

Dwayne, the chimney with the downdraft is about a foot taller than the other one. The difference is the fireplace chimney is protected all the way up, except for the last section.

The stove chimney runs outside the house, exposed more to outside air, and wind turbulence, I guess.

If nothing else, I may have to add another section of chimney. That'll mean adding a brace, as well, cause I'll be 9ft above the roof :shock:

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Are the chimneys on the same wall, and if they are is that wall an end (ie flat) of the house? You could always put in a couple 45's and move the woodstove chimney beside the fireplace and it should draft well. All you'd need would be a couple 45's and a couple sections of pipe.

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Nope. The stove chimney comes up the outside wall, but the fireplace chimney comes out through the roof, above the living room.

I have a two-sided fireplace that divides my living room & dining room. It has it's own "wall" from floor to ceiling, but you can walk right around it.

The chimneys are approx. 8ft apart on the roof, but would be impossible to join, or pair up.

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I have had some tough times mastering the art of getting the chimney to draw since I installed the Englander stove. The first thing I tried was to extend the chimney above the roof line. It didn't help that much. What does work is to almost close the damper and stick a propane torch through the remaining crack and heat up the chimney. You can check to see if it's hot enough to draw by burning some rolled up newspaper while the torch is still heating things up. It's a pain in the ass but with practice you can tell about when to light the kindling.

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Awesome, Nik! :worship:

Gives me a few things to try. My house is a raised bungalow, and it would make sense that the heat rising to upstairs, coupled with the fireplace chimney, can be causing a negative pressure in the basement.

I can also try the window trick.

Cool!

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OK.... just saw this,

Your Downdraft as you call it, is caused by the heat in your whole house rising.

I Have the same problem.

It's easy for poeple with basement fireplaces to encounter this problem.

Didn't read the links.... so this might be a rerun for you, but...

The heat in your house rises and escapes through your roof and any other cracks up high.

So the cold from outside wants to come in and replace the heated air and lay on the floor. Or in yours and my case, the basement.

The lower the opening in to your house is, the faster and easier the cold draft will rush in. The cold air will come in threw the bottom of a cracked door while the hot air will escape out the top of the same door. :wink:

You know all this so far and you already have your answer...

In order to change the flow in the basement chimney...YOU have to reverse the flow.

So... instead of the paper trick which doesn't always work real well, go to your local hardware store and buy yourself one of these...

149711_3.jpg

You need the rubber hose one.... so you can stick it up your pipe, without holding a bottle upside down.

http://www.homedepot.com/prel80/HDUS/EN_US...dgmj.0&MID=9876

Then blast the cold air up your chimney in seconds without the chance of smoking yourself out. :wink:

This is the only thing that continues to work for me.

:grin:

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So what do you do, Eric?

Just light the torch up the pipe for a given amount of time, then light the stove?

How long to you keep it going for, and how far up the pipe do you stick it?

Problem is I have a fairly new stove, so it has a big baffle on top of it, before you get to the chimney. I'd have to undo the chimney (not a big deal, just disconnect it at the first 90) to put the torch up.

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If I'm understanding right the stove chimney is on the outside of the house while the fireplace one is inside? The outside one will be colder and always harder to get a updraft going. The cold, heavier air drops down the pipe. The "stack effect" from air escaping upstairs and the stove chimney being in the basement makes it worse.

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