Smoke in home

[shoe]

Good morning,
I am having an issue with smoke in the house. The stove a Jotul F 500 BP came with the house, unfortunately the house and I must assume the stove itself had very little maintenance done on it, I purchased a gasket kit for the stove from Rocky Mountain Stove and replaced all the gaskets last fall, cleaning it out very well in the process. I had no problems last winter. This year the smoke smell started right off the bat it.

I first suspected my gasket job, so I placed a large wad of newpaper in the cold stove and lit it, of course it got smoky inside the stove using a strong flash light I didn't see any smoke escaping into the house.

I know everyone will point to wood not dry enough, but last year I purchased a moisture meter and all the wood I've used this year is between 12-16% moisture (Jotul recommends 20% or less.) The chimney has been thoroughly cleaned and I was able to see the stainless steel on the inside. Wood is a mixture of oak (white and red), shaggy bark, walnut and hickory. I've been checking the moisture of every piece since this problem started.

We've been tracking the wind and that doesn't seem to make a difference. Originally I was worried about the height and location of the top of the chimney but taking to a couple of stove sales places, there should not be a problem with it.

What is different that I'm aware of this year.
1) The screen on the top of the chimney was pretty much gone, I replaced it with a stainless steel screen with the same size wire and squares.
2) We're burning earlier than last year, so obviously it is warmer out side, 40-50 degrees.

As a side note, I have the strangest looking chimney cap I've ever seen. I'm not sure how to post a picture so I'll try to explain what it looks like.
o Same diameter as the pipe 6"
o The rain cap is the same diameter as the pipe.
o The screen I replaced sits inside the top.

Any suggestions would be greatly appreciated.

 

[DAKSY]

Have you tried starting a top down fire? When does it smoke, at startup or during refueling?

 

[kborndale]

Just to be sure, when you are checking the moisture on the wood you are doing it on a piece you resplit right before checking?

 

[Prometeo]

Do you have an external air intake? The stove takes in a lot of air from inside the house, if the house is airtight or almost, will tend in turn to vacuum from anywhere, even from any joint of your stove, sucking in smoke.

 

[begreen]

2) We're burning earlier than last year, so obviously it is warmer out side, 40-50 degrees.

Depending on the flue setup, this can be a major factor. It will be less so with a straight-up interior flue system, but potentially a major point with a flue system that has a couple of right angle turns before heading up in an exterior chimney. With an outdoor temp of <40º the draft will strengthen and this issue should go away.

 

[Eman85]

Can you remove the chimney cap and try burning?

 

[shoe]

Starting from the top.

No I have not started with a top down fire. I assume it is as described - placing kindling on top of a heavier wood and lighting the kindling. I can try that.

I have tested the moisture of the wood after it has been split down to the size I bring it into the house. I actually have one rack where the 'rejects' go to dry some more. [Being retired does have a few advantages, other than moments of boredom.]

No external air intake. Ah ha. Another change from last year. This summer I removed all the vinyl siding, added 1" of foam board insulation, taping all the joints, residing with Hardie board lap siding and doing an excellent job of caulking according to a couple of folks that stopped by to see what the new person was up to - gotta love us retired folks.

There is plan for adding an exterior air intake which was for next spring. Maybe I need to investigate it much sooner.

The chimney is straight up. Since we didn't have a problem last year and started burning when it was colder. I'll have to try that. (Un)fortunately, we're headed into the sixties next week in here central west MO.

I have not tried taking the chimney cap off and trying it. We're very short on rain in this area, I guess I could take the cap off and try it along with inducing some rain!

Thanks everyone. I

 

[30WCF]

I was going to suggest pulling the cap off since you said you put new screen in it, and the old screen was almost gone. Maybe the new screen is too much since it could breathe with some missing screen.

As far as sealing the house and the air intake… troubleshoot that by opening the door and or window close by. Let some fresh air in the house and see if that stops the smoking. If it does, install an OAK.

 

[begreen]

It's possible that the house is tight enough to affect combustion. Try opening a nearby window 1/2" to see if that helps.

 

[shoe]

I had to wait for the right temperatures to continue with my evaluations and your suggestions.

Starting a top down fire didn't seem to make a difference.
Opening a window near the stove [~3'] away didn't seem to make a difference.
Temps are now dipping to low thirties at night, that didn't seem to make a difference.
Again I verified the moisture content of the wood which is 9-14%. I even put an new battery in my tester [Proster Digital Moisture Meter] prior to using.

Looks like I need to get up on the roof and take the cap off, as that is the last suggestion.

Another note to add to this issue. With a temp gauge on the stove I've noticed this the following:
1 ) if the temp is 400 degrees and higher there doesn't seemed to be a problem.
2 ) I can get the stove to that temp on startup and hold it there for a while, but then it seems to fizzle down no matter what I do.
3 ) Over night with the air vent closed down seems to aggravate the problem.

When it gets to the point where I can't maintain the stove temp to 400+ I can open the ash door a bit and of course it heats up in no time flat. I close it and within a few minutes it starts to fire starts to drop and the stove starts to cool down. Almost if there is not enough air getting into the stove. So I let the stove go cold and checked, there are no obstructions from where the room air enters the stove to the where it enters the fire box.

It used to work great. I'd have a nice bed of coals going, the stove would maintain 400+ degrees, every so often I would toss in a couple of more chunks of wood, within minutes of closing the door they would ignite .

I almost feel as if it just isn't getting enough air to burn anymore - I suppose I could take the cap as maybe it isn't the intake but the 'exhaust,' or maybe replace the 1/4" screen with 1/2" screen?

 

[bigealta]

Are you closing the draft?
"3 ) Over night with the air vent closed down seems to aggravate the problem."

Does it work ok if you run it with open draft?

And don't open the ash pan door unless u want to crack the cast iron and ruin your stove.

i'd check that screen for sure.

 

[begreen]

This may be related to chimney location on the roof, or in relation to the surrounding topography if atmospheric pressure is positive at the chimney cap.
This series of 6 articles on how chimney's work and related issues may be helpful. See if anything rings a bell.

A non-commercial service in support of responsible home heating with wood - How Chimneys Work

The Wood Heat Organization was formed to support the public in the responsible use of wood energy in the home. We fulfill our mandate by providing reliable information, by conducting research into wood heating-related issues and by representing the public interest in discussions of policies that...

www.woodheat.org

 

[shoe]

Problem solved, I hope. So I was looking at the chimney cap with binoculars. I finally dragged a ladder out and got on the roof. It would seem that the screen visible from the ground was open and fine. The screen I couldn't see was clogged with, well, with whatever. I removed the cap, removed the screen, replaced the cap and problem solved.

A bit about the screen, the screen that was in there was ripped up pretty bad, so I replaced it during the summer with the same size opening 1/4" squares stainless steel [316]. I had thought maybe the old screen had rusted away. Now I'm thinking that the previous owner may have went at it with some sort of tool to open it up. This of course now opens the chimney up to birds which we've have had a few visiting over the summer.

I'm going to try 1/2" screen and see if that works, if not, move onto 3/4", then 1".

Thanks to everyone for their help and suggestions. I really enjoyed reading the info on how a chimney works.

 

[begreen]

Good to hear that fixed the problem. Yes, 1/4" screen is too fine. I think 1/2" is what is used on DuraTech cap screen.

Note - as tempting as it is, don't use the ash pan door as an air supply to boost or start a fire. This can crack the stove base around the grate area, leading to a very expensive repair.