old chimney "rebuild" advice

[whiskeyrichard]

Hello, new member here from northern california. This is my first post. I am in my first house that uses wood stoves for sole source of heat. I love cutting, hauling, splitting, stacking and sitting in front of with a beer and burning wood in my wood stoves.

Here in northern california, you can get permits from the Forest Service to go into the forest and cut firewood. It's 15 per cord with a maximum of 10 cords. That is just a little tidbit about where I live, but has nothing to do with my question.

Here is my situation:

I have a two story house. It has a gambel roof (shaped like a barn), the upstairs celing has open rafters and the downstairs is a daylight basement.

There is a brick chimney that is right in the center of the house and it runs from the lower level, up through the main level and out the roof. Inside this chimney there are two seperate terracotta liners. One is for the stove that is downstairs (an old trail blazer) and one is for the stove that is upstairs (a new country s160.

Each stove has an elbow that comes right off the top of the stove, goes into a hole in the brick chimney, that goes right up that stoves flue.

The downstairs stove will heat the entire house if you burn the heck outta it, but I like to have a fire upstairs when we are home.

The new stove upstairs will draft enought to get and keep a good fire going, but when I open the door to put more wood in, I can only open it about 1/4 of the ay at the very most before I get some smoke coming out.

What I would like to do is replace the two terracotta flues for each stove with a rigid SS stove pipe. It seems to me I could go up on the roof and ust up and extract the two old flues and then proceed from there.

Am I crazy?

Anybody have other suggestions?

What questions (like dimensions and the like) would I need for you guys to help me get started on this?

Thanks for the help

 

[berlin]

yes, you're crazy.

your problem stems from something else, clean the chimney, clean or remove chimney cap and screen, check for obstructions, check for obstructions in the stove and make sure that you are operating it properly. even an 8/12 flue tile gives an incredible draft through a woodstove utilizing a 6" pipe, especially with a chimney in the center of the home; you have other issues than the chimney liner, solve your problem, dont' go blindly tearing through what sounds like an excellent masonry chimney setup.

 

[Hogwildz]

Just my opinion, and we all know about opinions. First off, to install new s.s. liners, there is no need to tear out ther clay tiles if its large enough to put the s.s. liner inside the clay liner. Extra cost for an uneeded operation. This depending if the existing clay liner is large enough to slide the s.s. liner inside.
My personal belief is a new s.s. liner is safer and would certainly draft better than the old larger one, which may be your back puffing problem. If you have room to insulate the s.s., that would also help the draft.
When was the last time the chmimney's were cleaned?
I must have missed where you typed in the 8-1/2" teracota that the previous poster read.
Anyways, if it calls for a 6" liner, then a 6" liner can't hurt. The s.s. will offer better protection just in case theres a chimney fire also.
Like Berlin stated, if its a stove problem, fix that first. But if it is indeed a liner problem, I have learned from seasoned woodburners on here the proper flue size the stove calls for will usually draft better. I know the insert I just tore out, that if I didn't open the doors slowly, it would puff back. Are yu oepning the door slowly, or just unlatching and pulling it open? Even my new insert directions state to open door slowly to avoid back puffing.
Knowing what I know now, I would reline any exisiting chimney I was going to run my stove/insert through.
You would have to install a separate liner for each stove. Not sure by your post if you were thinking of runnin both in one. Thats a nono.
You would not have to remove any of the old chimney or teracota lining from it. I am guessing its a larger size than the 6" s.s. liner?
Good luck

 

[whiskeyrichard]

I had started out with the idea that the existing setup needed to be replaced. Maybe I should have asked about that first.

The existing chimney was built in 1963. Is it possible that the tiles inside the chimney are OK after all that time, and that this setup is considered safe by todays standards?

The tile liner that the new stove (that is not drafting well) is attached to was cleaned last march and has probably less than 40 hours of burn time through it until I installed the new stove, so I assume that the chimney does not need to be cleaned. I have inspected the cover on top and it is clear of debris and or blockage.

This particluar flue is about 11 feet long, made out of 8 1/2 inch tiles and has a 6 inch connector coming from the stove. Does this sound adequate for a country S160?

I am going to take a loook throught the literature I got with the stove to see if it has specifications fr chimney. I read it pretty well and do not remmeber seeing any, but I'll look again.

Thanks for the reply. Getting others input on this stuff helps me out a ton.

Thanks again.

 

[Corie]

It sounds to me like maybe you just need to crack the door and wait a few extra seconds before popping the door open.

Or as an alternative you can open the air control fully 5 minutes before you anticipate reloading. Not only will this help to establish a stronger draft, it will also help invigorate the coal bed for the incoming fresh wood.

If that's what you're doing, then check the chimney. I highly doubt there's an obstruction, but anything is possible. Does your chimney adhere to the 2-3-10 rule?

What stove top temperatures are you seeing? I.E are you satisifed with the heat output of the stove, but just upset about the smoke into the room, or overall is the county stove a poor performer right now?

 

[whiskeyrichard]

My door opening procedure is very cautious. I open a very small bit, pause, and then open it a little bit more. It's all good till I get it about 1/3 the way open and then out comes puffs of smoke.

My chimney was cleaned last year about March.

I was planning on running two seperate liners. One for each stove.

What is the 2-3-10 rule?

The stove is creating good heat. I can get the house as hot as I want to, and can get the stove top to 600+ if I try. Other than the back puffing, I am very happy with the stoves performance.

I am going to try and call the manufacturer and see what they say. Stupid me, I had not thought about that.


Thanks again for the opinions and suggestions.

 

[Hogwildz]

I had started out with the idea that the existing setup needed to be replaced. Maybe I should have asked about that first.

The existing chimney was built in 1963. Is it possible that the tiles inside the chimney are OK after all that time, and that this setup is considered safe by todays standards?

The tile liner that the new stove (that is not drafting well) is attached to was cleaned last march and has probably less than 40 hours of burn time through it until I installed the new stove, so I assume that the chimney does not need to be cleaned. I have inspected the cover on top and it is clear of debris and or blockage.

This particluar flue is about 11 feet long, made out of 8 1/2 inch tiles and has a 6 inch connector coming from the stove. Does this sound adequate for a country S160?

I am going to take a loook throught the literature I got with the stove to see if it has specifications fr chimney. I read it pretty well and do not remmeber seeing any, but I'll look again.

Thanks for the reply. Getting others input on this stuff helps me out a ton.

Thanks again.

Chimneys are capable of lasting that long. But unless you lived there since new, and know how it was up-kept or not. There's no telling. Other than a good inspection.
11 feet seems a little short from what I have been reading around the forum. Did the previous stove have same problem? What was the outlet size on the old stove?
Whats the piping configuration? top/back outlet? etc. how is it run into the chimney? horizontal? vertical? Give as much details about the stove & piping and how its run, these guys will have good input if they have the info to work with. If you do reline it, I am thinking it would also help to extend it up also. The more seasoned experts will have answers for you.

Does the other stove have similar problem? the other is the lower level stove correct? Longer chimney, better draft?

 

[whiskeyrichard]

Maybe I'll start out by getting a good inspection. Good idea.

The old stove did not have the same problem as the new stove. The old stove was, well, an old stove. Not a more efficient model like the ones made now.

The current stove pipe comes out the top of the stove. There is just one 90 degree elbow that goes straight into the brick chimney.

The stove downstairs does not have the same problem. I think that is because, like you said, the chimney is quite a bit longer and drafts much better.

Thanks.

 

[berlin]

11' is quite short and is likely the cause of your problems, being in cali, with most places getting quite warm in the day even if it gets cold at night, adds to the lack of draft. an 8/8 clay flue is the best setup with just about any coal/wood stove installation imho. btw, i mentioned the 8/12 liner above simply because of the assumption that having a chimney designed for stove use rather than open fireplaces there is only two flue sizes that are commonly used 8/8 and 8/12, and even 8/12 with a proper height interior chimney drafts very well.

btw, clay/masonry chimneys last much longer than 50 years, unlike stainless they can last hundereds if properly cared for and sometimes even if not.

 

[Hogwildz]

11' is quite short and is likely the cause of your problems, being in cali, with most places getting quite warm in the day even if it gets cold at night, adds to the lack of draft. an 8/8 clay flue is the best setup with just about any coal/wood stove installation imho. btw, i mentioned the 8/12 liner above simply because of the assumption that having a chimney designed for stove use rather than open fireplaces there is only two flue sizes that are commonly used 8/8 and 8/12, and even 8/12 with a proper height interior chimney drafts very well.

btw, clay/masonry chimneys last much longer than 50 years, unlike stainless they can last hundereds if properly cared for and sometimes even if not.

Good points.
I have a masonry fireplace and the clay liner in this sucker is 11" x 11" inside dimension. I will be installing new S.S. liner as soon as it arrives.
Not questioning you, I just thought I missed that size, and read & read his post LOL, and still didn't see it. You know better than I if your assuming right size

 

[Gooserider]

My door opening procedure is very cautious. I open a very small bit, pause, and then open it a little bit more. It's all good till I get it about 1/3 the way open and then out comes puffs of smoke.

My chimney was cleaned last year about March.

I was planning on running two seperate liners. One for each stove.

What is the 2-3-10 rule?

The stove is creating good heat. I can get the house as hot as I want to, and can get the stove top to 600+ if I try. Other than the back puffing, I am very happy with the stoves performance.

I am going to try and call the manufacturer and see what they say. Stupid me, I had not thought about that.


Thanks again for the opinions and suggestions.

The 2-3-10 rule has to do with the relationship between the chimney top and its surroundings. It says the chimney must be at least 3' higher than the point where it comes out of the roof, and 2' higher than any other object within 10' of it. This is a MINIMUM standard - taller may be better and probably won't hurt.

You have to run a seperate flue / liner for each stove, code prohibits putting two wood burning appliances on the same flue.

I would certainly start with an inspection / cleaning done by a qualified sweep, get his recomendations.

In a marginal draft situation, an old stove will do better than a new one, as a new stove sends less heat up the chimney. It will help as mentioned earlier to open your primary air a few minutes before the door in order to increase the draft air flow.

Remember that you really have TWO 90* bends - one where the pipe bends to go into the chimney, and another inside the chimney where it turns to go up. Each bend subtracts a certain amount from your effective flue height - I forget the exact number, but it's large. Modern stoves are intended to require about 10' minimum so you are definitely on the short side.

The key question is what cross section flue size does the new stove call for? The best approach is to have the nominal dimension all the way to the top. You CAN feed into a larger flue as long as the ratio of the cross sectional areas is within certain limits. An 8x8 flue is within the limits, but is marginal.

Given that, I would probably go with a 6" Stainless liner the full height of the chimney - and possibly get an "extend-a-flue" or increase at least that flue's height some other way.

Gooserider

 

[GVA]

Given that, I would probably go with a 6" Stainless liner the full height of the chimney - and possibly get an "extend-a-flue" or increase at least that flue's height some other way.

Gooserider

Ya better hurry on the extenda flue Craig seems to be melting them all down ;-)

 

[berlin]

"An 8x8 flue is within the limits, but is marginal"

that is nonsense. more often than not larger flues draft very well, even very large flues, sure sometimes it's an issue but mostly on exterior/poorly located chimneys. the issue began to be raised because of condensation of flue gasses; on the issue of simply the draft, large interior flues often draft very well irregardless of the EGT temp of the stove emptying into them.

 

[Corie]

Berlin, what you just said may have real world experience backing it up, but from a physical standpoint what you said does not make sense.

Draft is derived from temperature differential, which you know. Therefore a LARGE interior flue with LOW exhaust gas temperatures could certainly result in marginal draft.

Can you possibly back up the statement that dumping a 6" stove into a flue with 3, 4 or 5 times the cross-sectional area, at fairly low temperatures is going to produce a strong enough draft to properly operate a modern wood stove?

Not trying to start an argument here, just looking for some substance to these claims?

 

[berlin]

"Draft is derived from temperature differential" ... among many other factors.

"Therefore a LARGE interior flue with LOW exhaust gas temperatures could certainly result in marginal draft." ... yes it could, but most often on interior chimneys it is not the case.

as a mathematics project one time in college a group of us had to do a project to show the exact temperature at any time in a home, me being picky about real world conditions took 40 pages to figure out that i was overcomplicating things for a math class; i thus greatly simplified things, ended up with 15 pages and still recieved better than a perfect score on the project. point being there are many many things to consider in "real world" situations when wondering why so many large chimneys draft very well irregardless of temperiture, but most (interior) chimneys do.

 

[laynes69]

Our chimney is a 7x11 or 8x12, exterior masonry chimney. Its about 35 feet high and will draw when ice cold. We have never had an issue with draft and this year I fixed my barometric damper because we were over drafting.

 

[Gooserider]

"An 8x8 flue is within the limits, but is marginal"

that is nonsense. more often than not larger flues draft very well, even very large flues, sure sometimes it's an issue but mostly on exterior/poorly located chimneys. the issue began to be raised because of condensation of flue gasses; on the issue of simply the draft, large interior flues often draft very well irregardless of the EGT temp of the stove emptying into them.

In some cases an oversize flue might well draft OK, I'll agree. If you are lucky enough to have one of those flues, great. However in THIS CASE we have a flue that is not drafting well. Given that it isn't, we need to look for the cause, and ONE of the possibilities is that the flue is larger than it needs to be, and that an older inefficient stove might be able to drive it, but a newer one wouldn't.

A liner wouldn't be my first choice of things to try, but it would be on the short list after cleaning and making sure everything is sealed well. However I think the first thing I might try would be to do a temporary extension to the chimney in order to see if making things taller helped.

Given that it is an interior chimney, I think I'd be more worried about the flue height than the 8x8 size, and consider extending first, especially since if I were extending it would change what I needed for a liner length. If it were me, I would probably get a length of flue tile the right size and just mortar it in place temporarily, possibly with some sort of guy lines to stabilize it. - if that helped then I'd get bricks to more firmly attach it and make it look better.

Gooserider

 

[berlin]

"Given that it isn’t, we need to look for the cause, and ONE of the possibilities is that the flue is larger than it needs to be"

true, however having mentioned that it's only 11' high, and it does draft, just not well when the door is full open, the height is THE factor, not the flue size, an 11' tall 6" chimney straight from the top of the stove may draft decent, but not with any bends in the fairly warm cali climate. adding a 6" liner would have little effect other than perhaps reducing draft. velocity and volume is needed, and when the speed is already slow, reducing volume could potentially have a negative effect. my advice would be to hire a mason or do it yourself and extend the chimney another 6' at least; liner or not.