Smoke not going up flue.....

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arborman

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Hello everyone,

New to the forum, thanks for reading this.

I am not new to burning. I had a Lopi Revere insert installed in my house in Nor Cal on the coast about 9 years ago. I have most likely burned in this stove over 1000 times, with no problems at all.

About 3 weeks ago, I went to light a fire, in my usual manner. A minute later, I came back into a smoke filled room. Eventually, the fire took and it cleared the flue, and smoke poured out the chimney like normal.

This episode spurred a call to my local sweep, who came out and inspected everything. Said I had some heavy build up, nothing crazy, and everything else looked great. No problems...

Last night, I went to light a fire for the first time since he came out. Boom, same problem... only this time I could not get the smoke to clear. I tried to light crumpled paper to see if that would clear, but no go... I called my wood stove shop this morning, and hes stumped.. was talking about negative pressure, but I am not buying that. Why, in 10 years and over a 1000 fires, would this occur back to back?

Anyone have any advice for me? Thanks
 
Things to check:

Is the bypass damper actually working? Did the sweep actually clean the cap?
 
The negative pressure thing is a valid point. Were you, per chance, running any exhaust fans in the kitchen, bathroom, laundry at the time?
Even outside atmospheric conditions vs interior pressures could cause a problem, I would think.
Have you tried cracking a window an inch or so, then lighting newspaper to see if you can establish a positive draft?
 
We do not have any exhaust fans in the house at all, and our house is sealed about as well as a Hooker..

I did have some windows open at the time..

If it makes any difference, the stove is on the bottom floor of the house. I just find the atmospheric pressure thing hard to believe, just because I never had this happen before in 10 years, now it happens twice in less then a month.

Thanks for the replies...
 
arborman said:
We do not have any exhaust fans in the house at all, and our house is sealed about as well as a Hooker..

I did have some windows open at the time..

If it makes any difference, the stove is on the bottom floor of the house. I just find the atmospheric pressure thing hard to believe, just because I never had this happen before in 10 years, now it happens twice in less then a month.

Thanks for the replies...


When you open the by-pass feel if there is cold air coming down, if there is grab the old hair dryer then plug it in stick it up the by-pass and turn it on for about one minute then turn it off when it is up the by-pass then start your fire.



Zap
 
oldspark said:
Maybe your pipe came apart.

That is actually a thought I had. I just figured Mr. Chimney sweep would have caught that.

Our chimney guy is also a Fireman, so I figured he would be pretty trustworthy when saying he checked everything and tagged it as being "safe and clean".
 
Are you experiencing unusually cold weather? Very cold air pouring down the pipe could cause it. Open windows might exacerbate it.
 
What are the outdoor temps? How tall is the flue on the stove?
 
10 years and a 1000 fires and it happens back to back, sounds fishy to me.
 
Just curious if you had a heavy fog? Stirred up a memory from my youth on the central coast. Heavy fog would cause that on a cold start-up, but this was an ancient cast iron stove in a ranch house. A cold ranch house.
 
Weather wise, it has been pretty mild. Most of you will laugh at the thought of even starting a fire. It was about 50 degrees out when I started the stove. As for fog, there has been zero fog. We get heavy fog all summer, and that is when most of the burning happens, and that has never, ever happend. Im talking THICK fog.. 40' vis, and dripping wet.

I am guessing that the flue is around 25-30' tall? I am guessing there is a bend or two in it, because it is a duel stack chimney. There is another open hearth fireplace directly above this one..
 
Was the fireplace burning when you tried to light the stove? If not, was the damper in the fireplaced closed?
 
We never use the open hearth..... well, maybe for ambience a few times a year..

As for the damper being open, yes, it is open. My kids made me open it before Christmas so Santa could get down.

On a lighter note, my youngest told me to check the flue because Santa may have gotten his boot stuck inside.
 
50 degree outdoor temps, a fireplace damper open on the same chimney, and perhaps a bit of wind from the 'wrong' quarter? Might just be a recipe for errant downdrafts.

Three weeks ago makes the first incident only a couple of weeks or so after Christmas... when the fireplace damper was opened.

Hmmm.

Peter B.

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Peter B. said:
50 degree outdoor temps, a fireplace damper open on the same chimney, and perhaps a bit of wind from the 'wrong' quarter? Might just be a recipe for errant downdrafts.

Three weeks ago makes the first incident only a couple of weeks or so after Christmas... when the fireplace damper was opened.

Hmmm.

Peter B.

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Well, I just closed the upper damper. Did a test light on some newspaper, and my house is yet again filled with smoke.

I am sure that upper damper has been open MANY times before when I have lit fires downstairs.

My conclusion here is the sweep guy overlooked something, and I either have a broken flue or a major block in it. There is a bunch of creosote in the box from when the sweep was done, so it did make it down the flu into the stove...
 
Give it a couple of hours for your interior air to normalize, now that the upper damper is closed. Then try it.
 
Occasionaly when the sweep comes over he pushes the cresote down the flue and then removes the debris from the thimble area. Some times the packed cresote is sort of undermined and a layer is left still in the flue sort of a bridge. It has happened to me several times in the early years, always try and use a mirror from the bottom when done sweeping.
 
Against my better judgment, I'll take another few shots in the dark...

You say the chimney cap was cleaned... have you actually confirmed that visually?

You have a masonry chimney. Is there a cleanout somewhere? Could it be missing its cap, or sealed improperly?

Is there a 'nether' region at the top of the insert where creosote can gather and not be readily noticed?

Okay, I'm done.

Peter B.

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arborman, while you're waiting for the next few hours to try the re-light, see if you can stick a 500watt shop light in the stove. leave the door open a bit, and let the heat from the light pre-heat the flue slowly. Later, if you still get the smoke rolling out, then you've got a problem.
 
A possibility that the chimney was partially clogged before you had it swept and either he compacted the creosote and completely plugged it or perhaps he negelected to properly clean above the baffles and the flue outlet is plugged with everything he brushed down.
 
I think it has a lot to do with outside conditions. The same thing happened to me last year damp outside and a front moving into the area. Sure enough smoke filled room twice in two weeks through some newspaper in good to go after a minute or two. I have had my stove 4 years and that is the only 2 times it has happened. Think about this when you first light your stove the firebox fills with smoke because the draft is poor and the pipe is cold hampering draft add in not so great air conditions outside and the smoke has no where to go but down into ash tray into your house.
 
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