Flex stove pipe

[mshute]

Hi all, I have plans to install a Jotul F 100 Nordic into my existing masonry fireplace with a 12x8 clay liner. I'm planning on installing the flexible stainless pipe (6" diam.) up to the first flue tile. My chimney sweep recommended that I not use the ovalized version that is available, he said it would be better to keep the 6" round shape as long as possible and changing to the oval shape would reduce performance, any truth to this theory do you think? If I go with the 6" round, I'm going to have to cut out part of the damper plate as after removing the damper door, I'm left with slightly less than a 6" opening. Thanks for your input,

 

[MrGriz]

I would stick to the round. If you don't want to cut the damper plate, you can simply ovalize a few feet of the end of the liner and "re-round" it to connect to the stove. That is what I did with mine and it worked fine.

 

[Harley]

Hi all, I have plans to install a Jotul F 100 Nordic into my existing masonry fireplace with a 12x8 clay liner. I'm planning on installing the flexible stainless pipe (6" diam.) up to the first flue tile. My chimney sweep recommended that I not use the ovalized version that is available, he said it would be better to keep the 6" round shape as long as possible and changing to the oval shape would reduce performance, any truth to this theory do you think? If I go with the 6" round, I'm going to have to cut out part of the damper plate as after removing the damper door, I'm left with slightly less than a 6" opening. Thanks for your input,

Hi, mshute:

I'm thinking with that size flue.... you might have some drafting problems whether you go with the round or ovalized. If the chimney located outside of the house or is it central? How high is it? Why not line it all the way, then you should not have any problems at all. You may (though not an expert) have code issues with just direct connecting a 6" pipe into a 12 X 8 flue

 

[MrGriz]

Oops, I missed the fact that you were not planning to fully line the chimney (guess that's what I get for not reading carefully).

I would second the opinion that you should strongly consider a full liner. Not only will it probably draft much better, it will be much easier to clean.

 

[mshute]

Thanks for the feedback, exterior dimensions of the flue are 12x8 so the interior is probably 11x7 or so which would meet the stove specs of not exceeding 3x the diameter of the exit flue, but you're all right, it is cutting it close. Can you reline the entire chimney from below by pushing the pipe up? My chimney is about 25' high I'd say, maybe 30 and 2/3rds of it is on the exterior.

 

[RedRanger]

Don`t know about pushing it up? My chimney is 22ft with full reline. But was installed top to bottom and we had that crazy curve like most double chimneys do near the bottom. So when we got to that point it was the chimney sweep (installer) pulling from the bottom and me pushing from the top. Hopefully you don`t have that curve in your chimney, otherwise it`s a "two man job". Smart thing to do though is the full reline.

 

[theheatelement]

We sell kits of Stainless flex with the last five feet of flex being ovalized... if you need to find a dealer or buy from an internet source let me know.

 

[Harley]

As far as pushing it up... not a good idea, and probably a lot more work, because the liner needs to be secured and sealed at the top - so - someone's gotta get up there, so might as well drop it down (gravity is your friend in this case).

Even if you do meet code by doing the direct connect - the full liner is going to save you a lot of work down the road as far as cleaning and maintenance.

 

[DriftWood]

We sell kits of Stainless flex with the last five feet of flex being ovalized... if you need to find a dealer or buy from an internet source let me know.

That is a great idea! I should have ordered mine the same way. most pipe manufactures can ovalize any pipe at the factory.

 

[jtp10181]

You will get a lot better performance with an insulated liner since your brick chimney is exterior. Although with the 8x12 flue its usually pretty hard to get a 6" round liner down, and then you add insulation and its impossible. I would recommend Simpson DuraLiner oval rigid liner, which is double wall insulation wrapped. We have done a few installs with it now and it works awesome for the 8x12 flues.

 

[theheatelement]

I have a new ebay vendor called TheHeatElement who can sell one of our liners... we can ovalize it for you... just request it when you purchase the item... Most of my vendors do not insulate their liners because frankly we have seen no difference... somewhat like getting your brand new car sprayed with that sealant...lol..

You will get a lot better performance with an insulated liner since your brick chimney is exterior. Although with the 8x12 flue its usually pretty hard to get a 6" round liner down, and then you add insulation and its impossible. I would recommend Simpson DuraLiner oval rigid liner, which is double wall insulation wrapped. We have done a few installs with it now and it works awesome for the 8x12 flues.

 

[BrotherBart]

I have a new ebay vendor called TheHeatElement who can sell one of our liners... we can ovalize it for you... just request it when you purchase the item... Most of my vendors do not insulate their liners because frankly we have seen no difference... somewhat like getting your brand new car sprayed with that sealant...lol..

]

Or like meeting building codes for unlined or defective chimneys.

Elk is gone but sanity is still on the forum Ranier.

 

[theheatelement]

With that being said it depends on the liner... MagnaFlex Liners are approved by UL without insulation.. usually liners that are 304 need insulation and liners that are 316ti do not....

I have a new ebay vendor called TheHeatElement who can sell one of our liners... we can ovalize it for you... just request it when you purchase the item... Most of my vendors do not insulate their liners because frankly we have seen no difference... somewhat like getting your brand new car sprayed with that sealant...lol..

]

Or like meeting building codes for unlined or defective chimneys.

Elk is gone but sanity is still on the forum Ranier.

 

[jtp10181]

I have yet to see a documented install manual for a liner system that says it is UL 1777 listed for installation into an unlined brick chimney without insulation, 316Ti or not. Do you have an install manual or something for download I could look at? I like to read up on all the different liners and how they get installed. I can't find anything but pictures on your webpage.

 

[Gooserider]

I feel the same way, I would really like to see just exactly what the UL listing says. My recollection from Elk and others is that IF a chimney is already UL 1277 compliant, and the liner is being installed ONLY to meet cross-section requirements, then insulation is optional, no matter what the liner is made from - haven't really seen any challenges to that, although it can be debated just what it takes to prove UL 1277 compliance in a chimney you didn't watch them build.

OTOH, if you are installing the liner to in order to meet UL 1277, - i.e. unlined chimneys, damaged tiles, older metal insert stacks, or any other situation where the chimney wouldn't be UL 1277 without a liner, then ALL flex liners must have 1/2" insulation on them in order to be qualified to bring the chimney into compliance... (an inspector might let you slide if the fit is to tight to get the insulation in...)

From the code quoting that was being tossed around at the time this was discussed / beaten to death / the insulation was part of the UL 1277 requirement, NOT a vendor specific item like getting a less than NFPA clearance number.

IOW, Until I see a specific document stating that Magnaflex's liners are UL 1277 compliant without insulation when installed in a NON-UL 1277 chimney, I frankly don't believe his claim that they are!

As a side note, when installing my Encore, I had purchased a welded stainless "T" from a local stove shop, which was very nice except that the arm of the "T" where the cap went was longer than my old steel pipe "T". Since my flue essentially requires that it be cleaned from the bottom, I was concerned about the clearance between the hearth and the bottom of the "T", so I swapped with Elk for a "T" that he said came from Magnaflex as an unused part from a kit purchased for a donor install, and that had a shorter cap arm. After I got it home and examined it more closely, I was NOT impressed by the quality... The cap had visible gaps between the side wall metal strip and the bottom peice. the side arm was screwed onto the main tube rather than being welded, and I've had to seal leaks at that joint with refractory cement several times. It is the only part of my install that I don't feel totally comfortable with, and I suspect that I may change it out after burning season is over.

Gooserider

 

[theheatelement]

Chimney Liners
UL 1777

1 Scope

1.1 These requirements cover metallic and nonmetallic chimney liners intended for field-installation into new or existing masonry chimneys that are used for the natural draft venting of Category I gas-fired, Type L vented oil-fired, and solid-fuel-fired residential-type appliances in which the maximum continuous flue-gas outlet temperatures do not exceed 1000°F (538°C).

1.2 Chimney liners are intended to be installed in existing masonry chimneys with or without a liner of fire-clay tile, or to be used as a substitute for masonry fire-clay tile flue liners in new chimneys.

1.3 Chimney liners are intended to be installed in accordance with the Standard for Chimneys, Fireplaces, Vents, and Solid Fuel Burning Appliances, NFPA 211; National Fuel Gas Code, NFPA 54 and codes such as the International Building Code, International Gas Code, International Mechanical Code, International Residential Code, and the Uniform Mechanical Code.

1.4 Chimney liners as covered by these requirements are not intended for use with Category II, III, or IV gas burning appliances as defined by the National Fuel Gas Code, NFPA 54, or other appliances that result in condensation of corrosive acids on the liner of the chimney, or that create positive pressures in the chimney system.

I feel the same way, I would really like to see just exactly what the UL listing says. My recollection from Elk and others is that IF a chimney is already UL 1277 compliant, and the liner is being installed ONLY to meet cross-section requirements, then insulation is optional, no matter what the liner is made from - haven't really seen any challenges to that, although it can be debated just what it takes to prove UL 1277 compliance in a chimney you didn't watch them build.

OTOH, if you are installing the liner to in order to meet UL 1277, - i.e. unlined chimneys, damaged tiles, older metal insert stacks, or any other situation where the chimney wouldn't be UL 1277 without a liner, then ALL flex liners must have 1/2" insulation on them in order to be qualified to bring the chimney into compliance... (an inspector might let you slide if the fit is to tight to get the insulation in...)

From the code quoting that was being tossed around at the time this was discussed / beaten to death / the insulation was part of the UL 1277 requirement, NOT a vendor specific item like getting a less than NFPA clearance number.

IOW, Until I see a specific document stating that Magnaflex's liners are UL 1277 compliant without insulation when installed in a NON-UL 1277 chimney, I frankly don't believe his claim that they are!

As a side note, when installing my Encore, I had purchased a welded stainless "T" from a local stove shop, which was very nice except that the arm of the "T" where the cap went was longer than my old steel pipe "T". Since my flue essentially requires that it be cleaned from the bottom, I was concerned about the clearance between the hearth and the bottom of the "T", so I swapped with Elk for a "T" that he said came from Magnaflex as an unused part from a kit purchased for a donor install, and that had a shorter cap arm. After I got it home and examined it more closely, I was NOT impressed by the quality... The cap had visible gaps between the side wall metal strip and the bottom peice. the side arm was screwed onto the main tube rather than being welded, and I've had to seal leaks at that joint with refractory cement several times. It is the only part of my install that I don't feel totally comfortable with, and I suspect that I may change it out after burning season is over.

Gooserider

 

[Gooserider]

OK, but that does not say anything either way about insulation. It does have a reference to NFPA 211, but mostly it seems to me like the kind of "non-answer" you get when asking a politician an awkward question...

As I recall the prior discussion, which was a while back, the way that UL listed was to test AS A SYSTEM, including liner, insulation, and so on, and that failure to include all the parts that were used in the test listing voided the listing for the installation.

Gooserider

 

[jtp10181]

Goose, that's how I understand it. Without the insulation you must rely on the existing chimney structure to meet code, and the uninsulated liner is just resizing it. That's why we just started insulating everything, since there is no easy way to check if every chimney is up to code.

 

[theheatelement]

Correct our base tees are not welded so that the snout can be removed for easy cleaning... because of the design of the chimney system a base tee does not have to be fully sealed because a chimney system uses negative air pressure. If you have any questions on how a chimney system works feel free to give me a call at work.

As a side note, when installing my Encore, I had purchased a welded stainless "T" from a local stove shop, which was very nice except that the arm of the "T" where the cap went was longer than my old steel pipe "T". Since my flue essentially requires that it be cleaned from the bottom, I was concerned about the clearance between the hearth and the bottom of the "T", so I swapped with Elk for a "T" that he said came from Magnaflex as an unused part from a kit purchased for a donor install, and that had a shorter cap arm. After I got it home and examined it more closely, I was NOT impressed by the quality... The cap had visible gaps between the side wall metal strip and the bottom peice. the side arm was screwed onto the main tube rather than being welded, and I've had to seal leaks at that joint with refractory cement several times. It is the only part of my install that I don't feel totally comfortable with, and I suspect that I may change it out after burning season is over.

Gooserider

 

[Gooserider]

Correct our base tees are not welded so that the snout can be removed for easy cleaning... because of the design of the chimney system a base tee does not have to be fully sealed because a chimney system uses negative air pressure. If you have any questions on how a chimney system works feel free to give me a call at work.

As a side note, when installing my Encore, I had purchased a welded stainless "T" from a local stove shop, which was very nice except that the arm of the "T" where the cap went was longer than my old steel pipe "T". Since my flue essentially requires that it be cleaned from the bottom, I was concerned about the clearance between the hearth and the bottom of the "T", so I swapped with Elk for a "T" that he said came from Magnaflex as an unused part from a kit purchased for a donor install, and that had a shorter cap arm. After I got it home and examined it more closely, I was NOT impressed by the quality... The cap had visible gaps between the side wall metal strip and the bottom peice. the side arm was screwed onto the main tube rather than being welded, and I've had to seal leaks at that joint with refractory cement several times. It is the only part of my install that I don't feel totally comfortable with, and I suspect that I may change it out after burning season is over.

Gooserider

I don't quite see how removing the snout would make for easier cleaning - especially since to get access to the two screws that hold the snout on you would need to disassemble the system leading to the "T"...

As to the question of gaps... Yes a chimney uses negative air pressure, produced by hot stove exhaust rising up the chimney. Gaps DESTROY draft two different ways - by introducing cold air into the base of the chimney you cool the exhaust stream going up the chimney reducing it's tendency to rise, and by providing a second source of air, you dilute the force pulling air through the stove.

You will search this entire forum and have a hard time finding ANY place where gaps are considered "acceptable" in a chimney system - with the exception of the limited (and generally challenged) use of barometric dampers - and you will find that one of the first steps reccomended is to ELIMINATE gaps by sealing up all the joints... To say that a chimney "...does not have to be fully sealed because a chimney system uses negative air pressure." is grossly incorrect and likely to cause draft problems. I will refrain from explicit comment on what that sort of statement from a "pro" makes me think about the accuracy of anything else that he might say....

Gooserider

 

[theheatelement]

Well I will argue no more... My company has been selling kits for more then 20 years and my dad used to work for another manufacture who's name commonly comes up on this forum... but I must be wrong and soon to be out of business because of your compelling statement.... I don't see a reason to continue this topic because obviously what we and many other companies have been doing this incorrect and you as a moderator will probably edit anything to compel your statement. By the way why is ELK no longer on this board... he had almost 5,000 posts.. just curious..

Correct our base tees are not welded so that the snout can be removed for easy cleaning... because of the design of the chimney system a base tee does not have to be fully sealed because a chimney system uses negative air pressure. If you have any questions on how a chimney system works feel free to give me a call at work.

As a side note, when installing my Encore, I had purchased a welded stainless "T" from a local stove shop, which was very nice except that the arm of the "T" where the cap went was longer than my old steel pipe "T". Since my flue essentially requires that it be cleaned from the bottom, I was concerned about the clearance between the hearth and the bottom of the "T", so I swapped with Elk for a "T" that he said came from Magnaflex as an unused part from a kit purchased for a donor install, and that had a shorter cap arm. After I got it home and examined it more closely, I was NOT impressed by the quality... The cap had visible gaps between the side wall metal strip and the bottom peice. the side arm was screwed onto the main tube rather than being welded, and I've had to seal leaks at that joint with refractory cement several times. It is the only part of my install that I don't feel totally comfortable with, and I suspect that I may change it out after burning season is over.

Gooserider

I don't quite see how removing the snout would make for easier cleaning - especially since to get access to the two screws that hold the snout on you would need to disassemble the system leading to the "T"...

As to the question of gaps... Yes a chimney uses negative air pressure, produced by hot stove exhaust rising up the chimney. Gaps DESTROY draft two different ways - by introducing cold air into the base of the chimney you cool the exhaust stream going up the chimney reducing it's tendency to rise, and by providing a second source of air, you dilute the force pulling air through the stove.

You will search this entire forum and have a hard time finding ANY place where gaps are considered "acceptable" in a chimney system - with the exception of the limited (and generally challenged) use of barometric dampers - and you will find that one of the first steps reccomended is to ELIMINATE gaps by sealing up all the joints... To say that a chimney "...does not have to be fully sealed because a chimney system uses negative air pressure." is grossly incorrect and likely to cause draft problems. I will refrain from explicit comment on what that sort of statement from a "pro" makes me think about the accuracy of anything else that he might say....

Gooserider

 

[Gooserider]

While I CAN edit posts, my personal policy is that I do NOT edit posts except under very limited circumstances. Those are essentially limited to deactivating links in the very few spam posts that I might allow to continue on the board. (I think there have been about two of those...) or if I've been requested to by another user. In either case I leave a blurb in the post saying I edited it. Likewise, if I move a thread, I make a post in it saying that I moved it, and why if needed.

I am far more likely to eliminate a post entirely than I am to edit it, and even that option I take extremely rarely, and only for posts that were blatantly abusive and / or obscene...

Part of the "job requirements" for being a moderator is to have the restraint not to use the extra powers for advantage in a thread - I actually tend to go the other way, and will hold back MORE than I might normally if it's a thread I'm involved in - if I feel there is a judgment call needed, I will ask Craig or one of the other mods to look at it as I don't ever want to be in the position of being accused of misusing my powers....

Elk is no longer posting on the board, (I think he still reads it) suffice to say there were disagreements about actions and philosophy of handling things, if you want to know more details, please ask Craig.

I also will have to assume that since you have failed to provide any language or listing evidence to the contrary, that you were mis-stating the facts when you claimed that your products are acceptable for use in bringing a damaged or unlined chimney into compliance with UL 1777 without insulation.

I know that I and others are waiting for your explanation of how a Magnaflex 5.5mm thick 316 Stainless liner makes up the clearance to comustibles that normally takes clay liners and 4" of UNDAMAGED solid masonry, or 1/2" of INSULATON to create a compliant installation when using other product, some of which are also made from 316ti Stainless of the same or greater thickness...

Gooserider

 

[webbie]

Wow, I go skiing for ONE day and next thing you know, we are all bent out of shape here!

I would add the following:

1. Just about everyone has been wrong on the board a number of times, and word-for-word accuracy is not the full intent of this (or ANY) discussion board - meaning it is a "discussion" board. The entire reason for local installers and inspectors, plus manuals and codes - is so people DON'T go just getting their advice from word of mouth.

2. As to the "facts" of the matter(s), these change quite a bit, sometimes depending on which "code" or "workmanship manner" one subscribes to! The facts themselves change with BOTH the code itself (every 3-4 years), plus with the manuals of particular stoves.

I have mentioned before that lots of work that is done in the field fits into "harm reduction" - example being a chimney where insulation cannot be fit down along with the liner - in this case, just the liner certainly improves the existing situation....and may even bring the unit up to code!

If either myself, Goose, Magna or anyone else has the "answer" (and we wish it was that simple), then we can publish a web page or article on it and there would be nothing left to say! No reason to discuss!

All that said, my understanding is that most all single wall liners are equiv. in exactly what they can do - in terms of the actual problem(s) they help take care of. If a chimney is already up to snuff, insulation is often optional. If the chimney is not up to existing code(s), then the combination of the liner and insulation bring it up to the highest temperature code. An extreme example of this is someone who has a brick chimney with no liner in it, just the brick. In this case, the combo of the insulation and liner bring it up to the HT standard.

It is my understanding that most chimney liner makers do not test their liners without insulation. Maybe Magna can inform me if I am wrong (in his case) and tell us the circumstances on how they test them.....

As far as US STATES - no, I do not believe there is any difference in how the codes apply. There may be different "in the field" approaches being used, but these are not compliant with the code.

This is a debate which will never be settled for this reason - circular logic! The code says one things, the liner listing another, and the owners manual (often looked at as the Bible) may allow something else (less).....so some folks would say you have to do the "least" of all three, while others would say you have to BEAT all three! Realistically, that is often the call of the installer and inspector.

 

[Shane]

This is a debate which will never be settled for this reason - circular logic! The code says one things, the liner listing another, and the owners manual (often looked at as the Bible) may allow something else (less).....so some folks would say you have to do the "least" of all three, while others would say you have to BEAT all three! Realistically, that is often the call of the installer and inspector.

I always tried to go with the most stringent code/requirement/instruction. Figured it lessened liability.

 

[theheatelement]

Selkirk also uses a two piece base tee that is not welded together...