Recommendations on Existing Wood Stove

Couldn’t this same type of thing be done on an existing chimney? Of course you are talking about reducing draft and I am talking about doing it to further heat a larger chimney in order to increase draft. One fella told me he did this on a chimney years ago and he said it works perfectly still today and stays cleaner. Of course, I’m talking about hurry-rigging something instead of by code. Lol!!


He actually took a section of well casing and welded a plate on each end to fit inside the chimney. The top plate was bigger and kept this contraption from falling downward, but the length of it was inverted and placed in the pipe. The bottom plate served to block off the upper part of the chimney. Sounds crazy, but he said I’m he did this as a young man and it’s still there today. He said it helped hold heat and increased the draft some as well. I understand how he did it, but I’d still like to see it, and then see down below it.

 

It may work yes but I doubt it. Reducing volume at the top usually resricts draft considerably. Installing a properly sized and insulated liner would be much more effective

 

The Yukon I used to have would crap up a chimney with the best of them...the Kuuma I have now doesn't have that issue, and the baro doesn't seem to affect the cleanliness at all...but, they are also the worlds cleanest burning forced air wood furnace.
Sorry to the OP for helping to take this thread waaay off track!

 

I would agree, but it would be interesting to take manometer readings before and after as well as temperature readings at the top of the chimney, before and after, just to see and be something to tinker around with. Something you’d try in an empty garage or barn, not your home.

 

I would be interested in seeing the results.

 

So you would need to cut a small hole in the flue?

Are you measuring static pressure or what I believe is called dynamic pressure? The difference is that static the pressure would be measured on the side of the flue (perpendicular to the stack flow) and for dynamic it would be measuring the pressure of the airflow (the measured pressure of the air blowing against it.

As I recall one way to measure regular ductwork airflow is taking both pressures.

 

When I have cleaned it from the bottom I scrape with the poly brush and more seems to come out. It does seem like a lot of the creo is in the exposed part I can take outside and clean.

 

Yes you drill a hole in the connector pipe. Usually 1/4". I then use a metal plug to cover it when done. You follow the directions on the gauge you are using

 

You are measuring the negative pressure in that the chimney puts on the stove...usually (in the USA) shown in inches of water column (" WC) commonly expressed something like this: -0.04 to -0.06" WC.
I use a Dwyer Mark II model 25 manometer to check draft, and it can be used to check SP in ductwork too...when checking the draft you leave one side of the gauge (port) open to the house atmosphere, and the other hooked to the stovepipe.
Yes, a hole in the stove pipe...between the firebox and any dampers installed in the pipe...I usually drill a 1/4 hole to insert the tube.
For draft, I have not noticed much difference in where or how the tube is placed inside the pipe...there may be an "official" way to do it though...

 

Thank you both for clarifying.

Where do you get this metal plug you are talking about?

So far on my stove I don't seem to have a problem with it getting too hot and can use the damper on the stove (air intake) to cut back when necessary.

I haven't cleaned the flue in like a month or so and I am sure if I do that it will help. This weekend I will also try and make sure I have the piece in my stove that some have mentioned and make sure there are no holes.

 

Down once and up once. That should be enough polymer bristle scraping to remove first and second degree creosote and ash typically found in a chimney in which has been used for burning well seasoned wood properly.
You "clean" once a month because it needs it or because of paranoia ?


Scaling up and down from differing heat loads for testing draft for measuring and estimating typical draft is rather basic physics.

 

Yes if all other variables are constant it is pretty basic. But anyone who has spent much of any time diagnosing stove performance problems knows that is far from reality. And if this is so simple why has not one professional on either of the discussion boards said they use this technique?

 

If you are not having any performance problems there really is no need to worry about testing draft or a damper. My question about that was directed towards a poster who was having trouble turning down their stove.

 

What don't you like about restricting the top? Is it because it's just another thing you have to take off when you go back to clean the chimney?
From the operator's standpoint, I'd think that restriction would make it harder to establish and maintain draft when it's not very cold outside, and might make smoke roll-out more of a problem in shoulder burning..?
With the flue dampers instead of restriction, the operator can easily open or close them as needed.

Yeah, I'm sure that if you scrub it, more stuff will come out, but I don't like trying to reverse the brush numerous times in the middle of the chimney. If you go the full length, where it's easier to reverse, several passes might get more stuff out. When I make a single pass, I see some stuff remaining in the chimney at the top, but I can also see some bare metal. But I don't think that little bit of dust is too much of a danger. I'm no expert, though. It may be better to scrub it as clean as possible, to prevent any of it from glazing and building up in the chimney. Or glazing may occur further down, where residue is more likely to get baked on and it's hard to see. I guess sweeps with cameras can tell what's going on everywhere in the pipe.
Bottom line, it's no doubt better to get as much out of there as possible, as you've been doing.

 

Restricting the top makes the issue of a top ring building up worse.

When I clean with a brush I always make atleast 3 passes. But honestly I only use a brush once a week at most now. Almost everything is don't with a rotary cleaner.

 

I clean my flue from the bottom up so can't do the "down once and up once" and maybe it doesn't make any difference. Again I see a lot of stuff just in the flue that is in the house before it hits the ceiling. I take that portion outside and clean.

My cleaning once a month (probably more like 1.5 months or so) is perhaps both due to paranoia and to my not at least buying my wood in spring and at least having it season over the summer. I have a post where I discussed some of this. I have unfortunately gotten my share of wood that sellers claim is dry but really isn't. Also some was Oak that I have learned takes longer to dry than other types.

I hopefully have learned my lesson this year. I am basically now purchasing a cord every time my storage capacity gets below a cord. I also now have enough storage for a winter's worth of usage and may create even more storage.

 

over-cautious would have been a better choice of term than paranoia. Nothing wrong with it and it's probably (a lot) safer than blasé.

 

Well I just checked before lighting the stove and this piece is intact. I see no holes or openings beside a uniform series of small holes. Thus it is in good shape which I am glad to hear. It is good to be aware of this part and if damaged could lead to less than ideal performance of my stove.

Thanks to those who pointed out this part.

 

I'm learning new stuff on here all the time. This discussion of draft and overdraft got me thinking... I have a 30' insulated double wall stack for my basement installation. My stove is a air tube secondary burn type. It always seemed to be burning on the hot side with the primary shut all the way down. It wasn't way too hot and in any danger zone like turning the stove top to a glowing scary monster, but even with the primary closed it still had strong flame action at the splits. "LIGHT BULB ON" So many other posts talk about the slow lazy flames barely coming from the splits with most of the action at the secondary tubes. My secondaries are fully active too, but flame on the splits was pretty active still as well.

When I did the initial install I did put in a flue damper just as a backup in the outside chance of a chimney fire although I keep the chimney swept, burn dry wood, and generally keep an eye on things. I will do some experimentation with using the damper to throttle back the stove once the secondaries are up and running (glowing red) after a reload. I have been wishing to have a lower temperature burn that lasted longer and I will play with this to get the flue temperature down while keeping the secondaries active. Hopefully this will give me a more steady heat output and possibly lower my wood usage, heat the house better, or both.

I had never even thought overdraft could be a problem since I wasn't really seeing anything really dangerous going on and we've been burning for years, mostly with old smoke dragons. The fact that these newer tube stoves are designed for a certain draft with a set low point on their primary air adjustment didn't really sink in since all my prior experience was alway just "make sure your have enough draft". This was complicated even more by my exterior chimney that has reverse draft during start up and I have to warm the chimney prior to starting a fire from a cold box. The concept of low / no draft at cold vs. tall chimney with tons of draft when hot was just beyond my brain cells' ability until this discussion by this fine site's members. This thread's discussion got me thinking about it.

I will start throttling with the flue damper once the stove is up on the secondaries and the primary air is all the way closed. Thank you all again for kick starting my brain.

Sorry Steve for taking your post even further off track, but THANK YOU for asking these questions and inciting this discussion. I'm thinking the knowledge I've gained from this thread will enhance my home warming experience. It for sure has flipped on a light bulb for me and taken my thinking on wood burning and my home's heating set-up to the next level.

I'm always looking for a better way, but I'm no Sherlock... LOL

 

What pipe temperatures are you usually running at?