# Flue Liner and Stove Pipe



## rawfdawg (Jan 17, 2016)

Hello,

I am a novice add-on wood furnace burner. This is the first year I have used it, and I have quickly discovered it is not as simple as just adding wood to a firebox. I bought a house which had a Johnson Energy Systems J-9900 add-on wood furnace. I had a chimney sweep inspect the flue. It turns out the clay tile had a crack. The chimney sweep noticed that the tile was oriented the wrong direction in the chimney.  This would complicate the install.  The chimney sweep installed a 304 rectangular flex liner.  He sealed off the original location, and and put the thimble with the wide side of the liner. Because of this, he did not use black stove pipe as the connector from the wood furnace to the chimney flue.  It appears he used a round flexible flue liner as as substitute for black stove pipe.
















My concerns are:

1) Is this safe?  I am concerned that it may produce toxic fumes?  Notably, from nickel and chromium.  And secondly, is it acceptable not to use black stove pipe?  I have researched installation manuals for 304 liners, but I can't find anything where it specifically states where it can't be used as stove pipe.  The thinness of the liner concerns me. And no where can I find flexible black stove pipe. I don't think it exists.

2) Too much draft may be a problem too. When discussing with the chimney sweep prior to installation, I had mentioned that most add-on furnace manuals recommended both a manual and barometric stove pipe dampers.  It does not look like there is any way to install one with a flexible liner as a stove pipe. The chimney sweep told me it would not be needed.  He stated that the draft could be sufficiently controlled using the flap thermostat assembly and the ash door dampers.  But so far, no matter what configuration I attempt to use with the intake dampers, it does not seem like the firebox is getting hot enough.  And I have very short burn times.  I am new to this, so there is probability it could be user error too.

Back to the primary question at hand: can I use this flexible liner in place of the traditional black stove pipe?  I am assuming the chimney sweep did not have any other options.  If he had used black stove pipe, it likely would have had too many bends in it to have sufficient draft?

Any feedback or recommendations will be greatly appreciated.  I am brand new to the use of wood furnaces.  I never imagined how complex it can be. Thanks to the experienced users who share their insights with the less knowledgeable.

rawfdawg


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## brenndatomu (Jan 17, 2016)

rawfdawg said:


> Is this safe?


Hi rawf!
Hmm, not sure what to think about this one...it doesn't look too professional, but safe...paging @bholler ...
I don't see why you couldn't put black pipe in there...use as many 45s as you can...limit the 90s. A baro or key damper in there (with a manometer permanently mounted) is very likely needed. Your draft is probably sky high!


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## bholler (Jan 17, 2016)

Well first off he could have kept the crock where it was.  It would have meant opening up the hole and using a custom tee but that is what i would have done personally.  

As far as the liner being used as stove pipe It is not thick enough to be used as connector pipe I forget the gauge requirement but it is definitely thicker than .006" .  But you will not get any fumes off of it.  But like you said not really any way to put a damper in there of any sort and it really does look like crap.  I am sure you could use rigid black pipe.  I would think that 4 elbows most of them being less than 45 would work and the last one at 90 to go into the crock.  I don't think that would hurt draft to much.


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## rawfdawg (Jan 18, 2016)

bholler said:


> Well first off he could have kept the crock where it was.  It would have meant opening up the hole and using a custom tee but that is what i would have done personally.
> 
> As far as the liner being used as stove pipe It is not thick enough to be used as connector pipe I forget the gauge requirement but it is definitely thicker than .006" .  But you will not get any fumes off of it.  But like you said not really any way to put a damper in there of any sort and it really does look like crap.  I am sure you could use rigid black pipe.  I would think that 4 elbows most of them being less than 45 would work and the last one at 90 to go into the crock.  I don't think that would hurt draft to much.



The chimney sweep did have a custom tee made.  But when he received it from the manufacturer, he did not think it was up to his quality standards. And he then decided to keep his plan to move the crock.  In hindsight, I wished I would have told him just to keep it where it was at.  Since the flue pipe/stove pipe is connected directly to the the thimble at the crock, can I install the black stove pipe into the thimble? I guess what I am asking, will a 7" black stove pipe fit into the opening of the thimble?  The way it is now, the flue/stove pipe is just tightened around the end of the thimble itself.

I'm glad to know the flue liner does not emit toxic fumes. In a forum post I had read, someone had mentioned flue pipe vaporizes when heated and emits toxic fumes.  I researched this, but could not find anything which confirmed this.  I found a detailed study on exposure risks of nickel and chromium from stainless steel products. But none of the products were from the inhalation of heated stainless steel fumes. I asked this, because every time I use the wood furnace, I get a continuous headache which lasts till I don't use the wood furnace for a couple days.  I did not know if it was just me? But my wife confirmed she got a headache after she was in the basement.  I thought it might have been from the flue pipe. There is a carbon monoxide detector. And it does not go off. Possibly, there is a leak in the connection emitting flue gases into the basement?  

I


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## rawfdawg (Jan 18, 2016)

brenndatomu said:


> Hi rawf!
> Hmm, not sure what to think about this one...it doesn't look too professional, but safe...paging @bholler ...
> I don't see why you couldn't put black pipe in there...use as many 45s as you can...limit the 90s. A baro or key damper in there (with a manometer permanently mounted) is very likely needed. Your draft is probably sky high!


 
My suspicion is that it sky high also. I have researched manometers and read many forum posts, but I still have not grasped on how to implement the use of one on this flue pipe serving as a stove pipe. My first step is to get a black stove pipe installed. Then I can go about drilling a hole for the manometer.


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## brenndatomu (Jan 18, 2016)

rawfdawg said:


> In a forum post I had read, someone had mentioned flue pipe vaporizes when heated and emits toxic fumes


That is probably galvanized pipe.


rawfdawg said:


> I asked this, because every time I use the wood furnace, I get a continuous headache which lasts till I don't use the wood furnace for a couple days. I did not know if it was just me? But my wife confirmed she got a headache after she was in the basement. I thought it might have been from the flue pipe. There is a carbon monoxide detector. And it does not go off. Possibly, there is a leak in the connection emitting flue gases into the basement?


That sure sounds like CO poisoning, better get someone in there with a good tester before you use the wood furnace again. I'd check the furnace out good, could have a crack in the firebox or heat exchanger.


rawfdawg said:


> Since the flue pipe/stove pipe is connected directly to the the thimble at the crock, can I install the black stove pipe into the thimble?


Is the flex pipe directly connected to the liner or is it just mortared into the chimney?


rawfdawg said:


> My suspicion is that it sky high also. I have researched manometers and read many forum posts, but I still have not grasped on how to implement the use of one on this flue pipe serving as a stove pipe. My first step is to get a black stove pipe installed. Then I can go about drilling a hole for the manometer.


When you get the new pipe installed let me know, I can hook you up with a manometer and how to use it. Its pretty easy really


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## maple1 (Jan 18, 2016)

brenndatomu said:


> That sure sounds like CO poisoning, better get someone in there with a good tester before you use the wood furnace again. I'd check the furnace out good, could have a crack in the firebox or heat exchanger.


 

Good idea. Many local fire departments will do this free of charge. Might be worth a call - and might be worth doing before you make any changes so you can rule some things in or out. And likely the sooner the better.


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## brenndatomu (Jan 18, 2016)

maple1 said:


> Good idea. Many local fire departments will do this free of charge. Might be worth a call - and might be worth doing before you make any changes so you can rule some things in or out. And likely the sooner the better.


Or if you work for a company that has maintenance people that do "confined space entrys", they will have an air monitor that could be used too...if you can borrow high $ tools from work that is...


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## rawfdawg (Jan 18, 2016)

brenndatomu said: Is the flex pipe directly connected to the liner or is it just mortared into the chimney?

I may be getting my terminology mixed up when it comes to thimble/tee.  Here is a couple photos. The flex pipe slides over and is tightened. It appears there is two pipes running from the actual tee itself. From the top of the scratch mark is where the rectangle flex liner in the chimney is. I hope this helps.







	

		
			
		

		
	
 .

brenndatomu said: "When you get the new pipe installed let me know, I can hook you up with a manometer and how to use it. Its pretty easy really.

That would be great!


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## rawfdawg (Jan 18, 2016)

brenndatomu said:


> That sure sounds like CO poisoning, better get someone in there with a good tester before you use the wood furnace again



Could I buy a CO2 meter?  Or would a high priced professional grade meter be needed?


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## rawfdawg (Jan 18, 2016)

maple1 said:


> Good idea. Many local fire departments will do this free of charge. Might be worth a call - and might be worth doing before you make any changes so you can rule some things in or out. And likely the sooner the better.



Thanks for the suggestion. I live out in the county, and my local fire department is volunteer. I'm not sure if they would have a meter?  I might have to buy my own or have a HVAC tech come out.


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## maple1 (Jan 18, 2016)

Only one way to find out, give 'em a shout.

I don't know for sure, but I think the good ones would cost more to buy than it would be worth to the typical homeowner.


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## rawfdawg (Jan 18, 2016)

brenndatomu said:


> I'd check the furnace out good, could have a crack in the firebox or heat exchanger



In order to do this, would I basically have to disassemble the unit, for the most part, in order to clearly see the sides of the firebox and heat exchanger?


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## brenndatomu (Jan 18, 2016)

rawfdawg said:


> brenndatomu said: Is the flex pipe directly connected to the liner or is it just mortared into the chimney?
> 
> I may be getting my terminology mixed up when it comes to thimble/tee.  Here is a couple photos. The flex pipe slides over and is tightened. It appears there is two pipes running from the actual tee itself. From the top of the scratch mark is where the rectangle flex liner in the chimney is. I hope this helps.
> View attachment 172337
> ...


It sure looks to me like you could attach a 90* elbow right to that. I think you said that is 7"...and the furnace is 6" right? I'd attach with a 7" 90* elbow and then a reducer to 6" the rest of the way to the furnace

I dunno how well it would work for sure, but you can get the home CO detectors that actually have a digital readout on them...may tell you what you need to know


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## brenndatomu (Jan 18, 2016)

rawfdawg said:


> In order to do this, would I basically have to disassemble the unit, for the most part, in order to clearly see the sides of the firebox and heat exchanger?


Yeah. It shouldn't be too hard to get the air jacket off...normally. I'm not familiar with that model though


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## brenndatomu (Jan 18, 2016)

rawfdawg said:


> brenndatomu said: "When you get the new pipe installed let me know, I can hook you up with a manometer and how to use it. Its pretty easy really.
> 
> That would be great!


Just shoot me a PM when you are ready


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## maple1 (Jan 18, 2016)

brenndatomu said:


> I dunno how well it would work for sure, but you can get the home CO detectors that actually have a digital readout on them...may tell you what you need to know



I was in on another thread somewhere around this joint a year or two ago, about CO detectors. I think the general feeling I got was that those readout ones weren't accurate - and there might be a threshold they had to pass before they would even show any. Meaning there could be CO there even when it didn't register on the detector.


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## BrotherBart (Jan 18, 2016)

The Kidde digital ones have a button you can push at any time to read the current CO level but only alarms above a threshold.


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## brenndatomu (Jan 18, 2016)

rawfdawg said:


> In order to do this, would I basically have to disassemble the unit, for the most part, in order to clearly see the sides of the firebox and heat exchanger?


And just FYI, you will want to check things out when the furnace is cold...and then hot too. Some cracks open cold, some hot


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## bholler (Jan 18, 2016)

Any fire dept will have a good co monitor.  That tee snout does not stick out far enough.  Honestly i would call the guy who installed the liner and tell him he need to come back and extend the tee snout at least 1.5" out of the chimney and then install proper connector pipe.  You payed for it to be hooked up right and that is not right.  But i agree if you are getting headaches from it everything needs fully inspected and someone with a good co monitor needs to come out when you are burning.  I also think that dispute the shortcomings of the residential ones every house that has any appliance that burns anything should have co detectors.


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## rawfdawg (Jan 18, 2016)

brenndatomu said:


> It sure looks to me like you could attach a 90* elbow right to that. I think you said that is 7"...and the furnace is 6" right? I'd attach with a 7" 90* elbow and then a reducer to 6" the rest of the way to the furnace
> 
> I dunno how well it would work for sure, but you can get the home CO detectors that actually have a digital readout on them...may tell you what you need to know



This model actually has a 7" flue collar on the wood furnace. It predates the current models of similar design, which are now 6".  But same difference and still installs as you described. Just use 7" without the reducer.  

Great idea on the CO detector with digital readout.  I found a low level detector which detects and displays down to 5ppm.  Its a bit pricey, but likely worth the cost since it has warnings at lower CO concentrations.


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## rawfdawg (Jan 18, 2016)

brenndatomu said:


> Yeah. It shouldn't be too hard to get the air jacket off...normally. I'm not familiar with that model though



Almost identical to the Hot Blast 1500 or 1537.  I also saw similar models  listed as Clayton and another, sold at Menard's and Tractor Supply. I don't think the Johnson Energy Systems has been in business for quite some time.  I know they were around in the 1980's.


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## rawfdawg (Jan 18, 2016)

brenndatomu said:


> And just FYI, you will want to check things out when the furnace is cold...and then hot too. Some cracks open cold, some hot


 Good tip. Thanks.


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## rawfdawg (Jan 18, 2016)

bholler said:


> Any fire dept will have a good co monitor.  That tee snout does not stick out far enough.  Honestly i would call the guy who installed the liner and tell him he need to come back and extend the tee snout at least 1.5" out of the chimney and then install proper connector pipe.  You payed for it to be hooked up right and that is not right.  But i agree if you are getting headaches from it everything needs fully inspected and someone with a good co monitor needs to come out when you are burning.  I also think that dispute the shortcomings of the residential ones every house that has any appliance that burns anything should have co detectors.



I sent the chimney sweep an email today.  I will wait for his response. I can call the fire department. Once I thought about it more, if someone were to have a CO emergency, they would be the one's who would respond. And thus, have a good CO detector. I have a CO alarm in the basement. I read the manual for it, and saw that it alerts after 70ppm for a given time. I plan on upgrading to a low level detector which it's first alert is set at 10ppm for a given time.


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## maple1 (Jan 19, 2016)

Would be interesting if you could get a new CO detector before the FD gets there. Then you can get a handle on how accurate it is, maybe, by comparing with what they see. Depending on what they see.


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## jb6l6gc (Jan 19, 2016)

yes that looks like an identical unit to my hotblast 1400 which has a johnson energy systems tag on it too.  On a sidenote it may not necessarilly be Co it could be those two chinese junk fans you have on the back are not pushing enough air and overheating your ducts and such. That was the exact problem I had. Fans werent pushing enough air overheating ducts and almost melted an abs pipe that was near one of the ducts. Nasty fumes, headaches etc.  Trust me you will be much happier to replace those junk, noisy, expensive chinese fans with a real furnace fan, the difference is llike night and day.  You can get a furnace fan from one of your local hvac guys or craigslist for cheaper than one replacment just make sure its 110v and it wires in the same.


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## jb6l6gc (Jan 19, 2016)

forgot to say you will have to cut the fan openings larger though, not that hard to do. I have pictures somewhere of when I did mine, if i can find them I will post them


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## rawfdawg (Jan 20, 2016)

maple1 said:


> Would be interesting if you could get a new CO detector before the FD gets there. Then you can get a handle on how accurate it is, maybe, by comparing with what they see. Depending on what they see.



That will be the plan. I ordered two detectors yesterday. They will display as low as 10ppm, with +/-20% accuracy from 30ppm-999ppm.


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## rawfdawg (Jan 20, 2016)

jb6l6gc said:


> forgot to say you will have to cut the fan openings larger though, not that hard to do. I have pictures somewhere of when I did mine, if i can find them I will post them


 
I would be interested in seeing them. In comparison to the propane furnace fan, there is not nearly as much air from the vents with the wood burner fans.


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## jb6l6gc (Jan 20, 2016)

rawfdawg said:


> I would be interested in seeing them. In comparison to the propane furnace fan, there is not nearly as much air from the vents with the wood burner fans.


Yes that was exactly my problem too, I went onto kijiji (canadian equivalent to craigslist) bought a used lennox furnace fan and installed that. Like I said what a difference. CFM of my wood furnace fan is identical to my forced air electric furnace now.  Those fans on those units are junk, I bet yours are noisy as hell I know mine were. Bearings go bad on those frequently and theyre a ton of money to replace, I think like $100 ea.   Furnace fan cost me $25 + a little labour, best decision and modification I ever made.


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## maple1 (Jan 20, 2016)

rawfdawg said:


> That will be the plan. I ordered two detectors yesterday. They will display as low as 10ppm, with +/-20% accuracy from 30ppm-999ppm.


 
Great - make sure to update us on results. I would like to have a decently accurate one here too that displays levels.


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## jb6l6gc (Jan 20, 2016)

rawfdawg said:


> I would be interested in seeing them. In comparison to the propane furnace fan, there is not nearly as much air from the vents with the wood burner fans.


Thats why I said it may not necessarily be co causing your headaches. Ductwork is galvanized and if overheated due to the crappy blowers not pushing enough could be causing headaches. I only re-interate this because what you described is exactly what was happening to me 3 years ago when i bought my house and started using that exact same furnace.  I've always had the readout type of monitor in my basement and upstairs that has never even displayed 1ppm.  If no co's when you measure this would be my next culprit.


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## rawfdawg (Jan 20, 2016)

jb6l6gc said:


> Yes that was exactly my problem too, I went onto kijiji (canadian equivalent to craigslist) bought a used lennox furnace fan and installed that. Like I said what a difference. CFM of my wood furnace fan is identical to my forced air electric furnace now.  Those fans on those units are junk, I bet yours are noisy as hell I know mine were. Bearings go bad on those frequently and theyre a ton of money to replace, I think like $100 ea.   Furnace fan cost me $25 + a little labour, best decision and modification I ever made.



They are pretty loud. With the age of this wood furnace, I think the motors I have predate the Chinese takeover.  They are Dayton motors.  But still, I understand where you are coming from.


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## rawfdawg (Jan 20, 2016)

jb6l6gc said:


> Thats why I said it may not necessarily be co causing your headaches. Ductwork is galvanized and if overheated due to the crappy blowers not pushing enough could be causing headaches. I only re-interate this because what you described is exactly what was happening to me 3 years ago when i bought my house and started using that exact same furnace.  I've always had the readout type of monitor in my basement and upstairs that has never even displayed 1ppm.  If no co's when you measure this would be my next culprit.




I will definitely take this into consideration.  I do notice that the propane furnace fan will kick on when things start getting pretty hot.  I leave the thermostat down low on the propane furnace, so when the wood furnace fire gets low, heat will kick on.  I am not sure if I should do this? But I am also nervous the propane furnace might get damaged if it gets too hot. I don't know if the way the duct work is setup is good?  There is no back draft dampers on the two 8" ducts from the wood furnace.  And I'm pretty sure there is not a back damper to the propane furnace. The previous owner used it like this for 25years, and had no problems.  But I question it?


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## jb6l6gc (Jan 20, 2016)

looks very similar to my setup, however I have automatic backdraft dampers on the 8" ducts. My cold air intake comes off cold air plenum before the electric furnace  and I replace electric furnace filter with a piece of wood as a damper when running the wood.  My ducting goes around the wood furnace blower to keep it all an enclosed system. I found when it was open it was drawing too much air from the basement and creating a negative pressure zone. Made it very hard to distribute the heat evenly through a two story house.  The easiest way to picture mine is hooked up in parrallel but because I block off where the filter is on the electric furnace it cant keep cycling in a circle, therefore distributing through the house better.  Only issue with mine is I can only run one at a time and its a manual switchover. One of these days I keep saying I'm going to figure out a better way but I'm not gonna bother until after I replace the hotblast for a drolet tundra next year.  I will post some pics when I get home from work tommorow.


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## jb6l6gc (Jan 20, 2016)

another thing I'm gonna do when I replace it next year is build a block pedestal to raise it up so I dont have to bend down so much everytime when I'm loading the damn thing! I'm still young but at some point I wont be anymore and I'll wish I had've done that.


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## jb6l6gc (Jan 22, 2016)

Here's the pics I'll post some of the fan install if I can find em on computer they were on my old phone


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## rawfdawg (Jan 24, 2016)

maple1 said:


> Great - make sure to update us on results. I would like to have a decently accurate one here too that displays levels.



I received the detectors on Friday.  I think it was a great purchase.  They monitor as low as 10ppm. First alert is at 30ppm. Continuously displays current ppm beginning at 30ppm. Press one button to see ppm from 10ppm-29ppm.  Shows the peak ppm, along with the amount of time is was at that peak level. Claims to have 20%  accuracy from 30ppm-999ppm. Has a ten year lithium battery. And a 10 year warranty.

I fired up the wood furnace again after I activated the CO detectors.  I have not got a reading indicating a level of at least 10ppm.  I was going to wait till I had at least a measurable reading before contacting local volunteer fire department.  Therefore,  I do not a comparison yet on this unit's reading to a good CO meter.  I will be sure to let you know if I do.


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## rawfdawg (Jan 24, 2016)

jb6l6gc said:


> Here's the pics I'll post some of the fan install if I can find em on computer they were on my old phone



Thanks for the pictures. I have a better understanding now of your venting. Did you do the ducts yourself?  And is that the average fuel load you use? What kind of burn times do you get?  I'm still trying to figure out how much wood to load. I don't want to over fire the wood furnace.


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## rawfdawg (Jan 24, 2016)

bholler said:


> That tee snout does not stick out far enough.  Honestly i would call the guy who installed the liner and tell him he need to come back and extend the tee snout at least 1.5" out of the chimney and then install proper connector pipe.  You payed for it to be hooked up right and that is not right.



I spoke with the chimney sweep for 1.5 hours. I told him my desire to have black stove pipe and a damper. He told me he could do it if that is what I wanted. He explained why he used flexible liner. It was because it was more of gradual flow. With the black stove pipe, he stated he would have to use two 90 degree elbows.  He had a concern for the turbulence which would be created with the the elbows.  He stated he uses flex liner on his own wood furnace as assurance.

The chimney sweep also seemed to be in the school of thought that key and barometric dampers can cause more harm than good.  One of the issues is that dampers can allow cool air in creating the likelihood of more creosote buildup.  He mentioned with a barometric damper, if you have a chimney fire, it would be hard to put out because it would allow air flow to continue.  I'm not really in a position to argue with him. He has 30 years experience as a chimney sweep and a very successful business. In some ways, I question it. But at the same time, who am I to say? I just started burning a couple months ago. He is very friendly. He took all the time in the world to answer my questions in much detail.  And he was very patient with my bombardment of questions. But even with his viewpoints, I think I'd still want to go with black stovepipe and damper.  I understand what he was telling me, but I also understand the feedback I have received here. I'm thinking I like the idea of black stovepipe with a damper better.


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## bholler (Jan 24, 2016)

rawfdawg said:


> One of the issues is that dampers can allow cool air in creating the likelihood of more creosote buildup. He mentioned with a barometric damper, if you have a chimney fire, it would be hard to put out because it would allow air flow to continue.


I totally agree with him on that point.  But i dont see an issue with a key damper



rawfdawg said:


> He told me he could do it if that is what I wanted. He explained why he used flexible liner. It was because it was more of gradual flow. With the black stove pipe, he stated he would have to use two 90 degree elbows. He had a concern for the turbulence which would be created with the the elbows.


Well you would only need 1 90.  And the lightwall liner does not meet the thickness requirement for connector pipe so it does not meet code.  The stainless snout also does not extend far enough out of the wall to meet the requirements either.


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## bholler (Jan 24, 2016)

rawfdawg said:


> I'm not really in a position to argue with him. He has 30 years experience as a chimney sweep and a very successful business.


It is your house so yes you are in a position to argue.  What does your manual call for for connector pipe?


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## rawfdawg (Jan 25, 2016)

bholler said:


> It is your house so yes you are in a position to argue.  What does your manual call for for connector pipe?



Very good point. There is not a manual I could find for any wood furnace which did not call for black stove pipe.  And I could not find any manual for the installation of chimney liner which states it can be used as connector pipe.


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## rawfdawg (Jan 25, 2016)

bholler said:


> I totally agree with him on that point.  But i dont see an issue with a key damper
> 
> 
> Well you would only need 1 90.  And the lightwall liner does not meet the thickness requirement for connector pipe so it does not meet code.  The stainless snout also does not extend far enough out of the wall to meet the requirements either.



I will bring this up.  I also will try to find a site which will allow me to view UL 1777 and Fire Code 211 for free.


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## jb6l6gc (Jan 25, 2016)

rawfdawg said:


> Thanks for the pictures. I have a better understanding now of your venting. Did you do the ducts yourself?  And is that the average fuel load you use? What kind of burn times do you get?  I'm still trying to figure out how much wood to load. I don't want to over fire the wood furnace.


I did the return ducting when I switched the fan for better flow and distribution. As far as loading I don't do much more than that. The intake air controls on these units are not very good! I keep it set just below high 
Burn times are about 6hrs doesn't really get any better on this unit for me at least. It dirties up chimney allot too, I clean about 3 times a season. If you have the money and can afford I'd recommend an upgrade when you can. I personally am gonna get the tundra, bonus is it hooks up exactly the same.  
+1 here on changing for black stove pipe, have a key damper but always leave it open. I fear with how dirty it burns slowing it down would create more creosote buildup


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## rawfdawg (Feb 6, 2016)

bholler said:


> I totally agree with him on that point.  But i dont see an issue with a key damper
> 
> 
> Well you would only need 1 90.  And the lightwall liner does not meet the thickness requirement for connector pipe so it does not meet code.  The stainless snout also does not extend far enough out of the wall to meet the requirements either.



Here is the chimney sweeps reply:

24 gauge connector pipe thickness was arrived at determining and taking in consideration the corrosion resistance of the material used. The 24 gauge requirement was arrived at for steel pipe or galvanized pipe which is allowed. Both of the aforementioned pipes can burn through and have low corrosion resistance as compared to stain less steel. Neither of the two steel  pipes carry a warranty. The stainless steel connector pipe currently being used carries a lifetime warranty. It is highly corrosion resistant as similar metals are used in jet aircraft exhaust ports. Stainless steel connector pipe is tested to 2100°. Galvanized steel pipe cannot withstand these temperatures repeatedly. I would always recommend to a client with an add on woodburning furnace, to use at least a 304 alloy stainless steel. And not to consider a 400 series. Whether it be rigid or flexible. I would not use steel pipe, and especially not galvanized pipe. Remember, firecode or standards are the MINIMUM requirement. In layman's terms, it is a grade C or D. It is just passing. I would prefer in this more rugged (type of )use installation, that we would choose to use the best materials for the class of service. Please remember that we used the flexible stainless steel to minimize resistance to flow.
   As far as how far a thimble should come in to the room? I do not know anywhere in NFPA 211 that it covers the protrusion into the room. However, NFPA 211 does speak of masonry thimbles being flush to the inner walls of the masonry chimney. (not your case) Any manufactured system, the authority having jurisdiction would be the UL listed manufacturer instructions In class a chimneys, is most common to see a six-inch protrusion into the room from the wall of the manufactured Chimney, or a 3 inch protrusion in the room of a manufactured Chimney from the ceiling. This is not (your installation) an installed class a system. This is a liner system. We kept the protrusion in the room to a minimum on purpose, to allow less protrusion or obstruction into the walkway or room.
  Please let me know if you ever lock down the code by section number or chapter. I am not aware of it currently. As far as the manufacturer instructions go, I believe as long as the pipe can be easily removed/readily accessible/ and inspected would be the only pertaining criteria, if that in and of itself even exist. 
   The current edition of NFPA 211 is the year 2013.


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## rawfdawg (Feb 6, 2016)

jb6l6gc said:


> I did the return ducting when I switched the fan for better flow and distribution. As far as loading I don't do much more than that. The intake air controls on these units are not very good! I keep it set just below high
> Burn times are about 6hrs doesn't really get any better on this unit for me at least. It dirties up chimney allot too, I clean about 3 times a season. If you have the money and can afford I'd recommend an upgrade when you can. I personally am gonna get the tundra, bonus is it hooks up exactly the same.
> +1 here on changing for black stove pipe, have a key damper but always leave it open. I fear with how dirty it burns slowing it down would create more creosote buildup



Thanks for the information.  I hope to upgrade at some point.  Maybe for next season if I can afford it. I was thinking Tundra or Caddy myself.


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## bholler (Feb 6, 2016)

While i agree that code are a minimum and we regularly exceed them the minimum thickness of a connector pipe is 24 gauge.  I would agree that stainless would be better but it still needs to meet that minimum thickness.  As far as 304 versus 400 series.  all of the commercially available stainless connector pipes are 400 series and they last a long time i see absolutely no problem with it and they will last much longer than that light wall liner which can and will eventually burn through.  Also there is nothing in any code allowing for a flexible connector pipe it simply is not there and his claim that is will flow better is just wrong the corrugated pipe reduces flow more that a couple low angle elbows with smooth pipe would.  The projection past the wall is a requirement of the liner manufacturer and any i have worked with require 1.5"  I don't know what brand he used but I have never come across one that required less than that.  And following manufacturers instructions is a code requirement


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## jb6l6gc (Feb 6, 2016)

Just looking back on this thread any word on the co readings?


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## rawfdawg (Feb 7, 2016)

jb6l6gc said:


> Just looking back on this thread any word on the co readings?



So far, no measurable readings.  Therefore, nothing to compare it to yet.  If I get a reading of 10ppm, then I can call someone with a good meter for a comparison.


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## rawfdawg (Feb 7, 2016)

bholler said:


> While i agree that code are a minimum and we regularly exceed them the minimum thickness of a connector pipe is 24 gauge.  I would agree that stainless would be better but it still needs to meet that minimum thickness.  As far as 304 versus 400 series.  all of the commercially available stainless connector pipes are 400 series and they last a long time i see absolutely no problem with it and they will last much longer than that light wall liner which can and will eventually burn through.  Also there is nothing in any code allowing for a flexible connector pipe it simply is not there and his claim that is will flow better is just wrong the corrugated pipe reduces flow more that a couple low angle elbows with smooth pipe would.  The projection past the wall is a requirement of the liner manufacturer and any i have worked with require 1.5"  I don't know what brand he used but I have never come across one that required less than that.  And following manufacturers instructions is a code requirement



Thanks so much for your insight.  Now only if you made visits to south central Ohio. I'd be set.


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## brenndatomu (Feb 7, 2016)

rawfdawg said:


> The 24 gauge requirement was arrived at for steel pipe or galvanized pipe which is allowed


I don't think galvanized is allowed as a stove pipe on a wood furnace...could be wrong


rawfdawg said:


> Stainless steel connector pipe is tested to 2100°. Galvanized steel pipe cannot withstand these temperatures repeatedly


Or at all, bad things start to happen to galvanized steel at 660* IIRC, regular duty is under 400*. Not so sure about this guy.
Best install would be regular ole stainless stove pipe, one n done. I agree with bholler, only need 1 90* elbow


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## bholler (Feb 7, 2016)

brenndatomu said:


> I don't think galvanized is allowed as a stove pipe on a wood furnace...could be wrong


you are correct no galvanized it should be black or stainless 24 g or thicker


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