Jotul F 55 Triple Wall Air Cooled Manufactured Chimney (Liner) Connection

[calinb]

The previous owner of our home exhausted a Blaze King wood stove through its manufactured triple wall metal interior chimney, but he replaced the wood stove with a QuadraFire propane stove venting through a 4" liner before we purchased the home. I got a great deal on a new 2019 model and purchased a Jotul F 55 Carabassett to replace the propane stove.

From my online study, a 6" insulated liner seems to be an appropriate and a common installation solution and alternative to completely replacing the chimney ($$$--yikes!). The chimney appears to be in sound condition and well supported, including ceiling support on the bottom end. I plan to connect to a 6" ICC UltraBlack double wall slip length pipe at the bottom.

The Triple wall chimney is 10" ID and 15-3/8" (perhaps 15-1/2" with the flange) OD. It is a perfectly straight 18' - 2" shot from the top down to the ceiling support below.

In my quest for information, I joined this forum. I'd appreciate any advice experienced members can provide.

Homesaver has a nice set of hardware and fittings for their UltraPro liners line, including their "Factory-Built Liner Adapter", (which allows air to circulate and cool between the outer pipes) and their Installation and Maintenance instructions cover this specific application using that adapter.

So why are liners generally not a UL (or other) approved solution for triple wall air-cooled chimneys but typically approved for masonry chimneys?

Given that that total costs are similar, the pre-insulated liner options appeal to me (UltraPro, ForeverFlex, FireFlex, etc.) for both ease of installation and my perceived ruggedness of the exterior of the assembly (outer metal wall).

Thanks much for your help!

-Cal

 

[bholler]

The previous owner of our home exhausted a Blaze King wood stove through its manufactured triple wall metal interior chimney, but he replaced the wood stove with a QuadraFire propane stove venting through a 4" liner before we purchased the home. I got a great deal on a new 2019 model and purchased a Jotul F 55 Carabassett to replace the propane stove.

From my online study, a 6" insulated liner seems to be an appropriate and a common installation solution and alternative to completely replacing the chimney ($$$--yikes!). The chimney appears to be in sound condition and well supported, including ceiling support on the bottom end. I plan to connect to a 6" ICC UltraBlack double wall slip length pipe at the bottom.

The Triple wall chimney is 10" ID and 15-3/8" (perhaps 15-1/2" with the flange) OD. It is a perfectly straight 18' - 2" shot from the top down to the ceiling support below.

In my quest for information, I joined this forum. I'd appreciate any advice experienced members can provide.

Homesaver has a nice set of hardware and fittings for their UltraPro liners line, including their "Factory-Built Liner Adapter", (which allows air to circulate and cool between the outer pipes) and their Installation and Maintenance instructions cover this specific application using that adapter.

So why are liners generally not a UL (or other) approved solution for triple wall air-cooled chimneys but typically approved for masonry chimneys?

Given that that total costs are similar, the pre-insulated liner options appeal to me (UltraPro, ForeverFlex, FireFlex, etc.) for both ease of installation and my perceived ruggedness of the exterior of the assembly (outer metal wall).

Thanks much for your help!

-Cal

I personally would just replace it all. There are just to many unknowns and compromises when you reline an old prefab chimney like that.

 

[BKVP]

I'm with bholler, replace the entire system. Yes, it can be costly, but peace of mind is worth $$!

In doing so you'll eliminate any question of performance problems relating to the chimney. Not that you will have any, such as smoke spillage, but if you do....this group will suggest you start with a new chimney.

As a manufacturer, that would be our first suggestion.

Enjoy the new stove. Jotul makes some beautiful stuff.

 

[calinb]

Thanks for the replies!

Replacing the chimney is not sensibly within the constraints of my family's financial resources during these pre-depression times. There's plenty to worry about these days. Soon, the mitigation of ALL personal risks in life will be competing and stretched for the resources of most of us.

I can either sell the Jotul and keep running the propane stove for about $2000 per year (current price and assuming propane remains available) or fully inspect the triple wall chimney and line it in a manner that I believe to offer performance that's equivalent (but obviously untested as a system) to an HT type / UL3 chimney, and enable the burning of a fuel that's essentially free and perpetual on our forested property.

All the other requirements listed in the Jotul installation manual can be met so the problem is liners are never formally approved for any wood appliance other than ZC. I'm trying to better understand the reason(s). The low temperature of the 10" too cool-running inner wall is certainly mitigated with an insulated liner while a Homestyle Factory-Built type of adapter can ensure airflow to cool the outer walls.

Modern ZC installations aren't significantly different in combustion qualities and performance vs. modern free-standing wood stoves. Contrastingly, I can think of issues with similar installations into masonry chimneys that somehow are "given a pass" by the manufacturers, and regulatory and certification bureaus.

What am I missing?

 

[begreen]

What am I missing?

Code and insurance compliance.

 

[calinb]

Code and insurance compliance.

Thanks--that's what I suspected.

 

[bholler]

Thanks for the replies!

Replacing the chimney is not sensibly within the constraints of my family's financial resources during these pre-depression times. There's plenty to worry about these days. Soon, the mitigation of ALL personal risks in life will be competing and stretched for the resources of most of us.

I can either sell the Jotul and keep running the propane stove for about $2000 per year (current price and assuming propane remains available) or fully inspect the triple wall chimney and line it in a manner that I believe to offer performance that's equivalent (but obviously untested as a system) to an HT type / UL3 chimney, and enable the burning of a fuel that's essentially free and perpetual on our forested property.

All the other requirements listed in the Jotul installation manual can be met so the problem is liners are never formally approved for any wood appliance other than ZC. I'm trying to better understand the reason(s). The low temperature of the 10" too cool-running inner wall is certainly mitigated with an insulated liner while a Homestyle Factory-Built type of adapter can ensure airflow to cool the outer walls.

Modern ZC installations aren't significantly different in combustion qualities and performance vs. modern free-standing wood stoves. Contrastingly, I can think of issues with similar installations into masonry chimneys that somehow are "given a pass" by the manufacturers, and regulatory and certification bureaus.

What am I missing?

We just don't know what you could be missing because there is no testing or approved procedure or products to do what you want to do. It may be perfectly safe it may not I don't know. I do know you need air to cool that old chimney. That means a fairly large amount of heated air is going to be sucked out of your house to accomplish that. That alone would be enough to make me replace it.

 

[calinb]

<snip>
I do know you need air to cool that old chimney. That means a fairly large amount of heated air is going to be sucked out of your house to accomplish that. That alone would be enough to make me replace it.

Yes--I've noticed the cooling draft is quite detectable with the current propane Quadrafire running (4" uninsulated liner exhaust and air intake supplied within the inner pipe). Even with the insulated liner, perhaps the cooling draft will be even stronger with the Jotul Carrabassett running but, however wasteful of BTUs, firewood costs are almost entirely just the cost of my labor to harvest and store it, whereas lost propane BTUs are very expensive!

 

[bholler]

Yes--I've noticed the cooling draft is quite detectable with the current propane Quadrafire running (4" uninsulated liner exhaust and air intake supplied within the inner pipe). Even with the insulated liner, perhaps the cooling draft will be even stronger with the Jotul Carrabassett running but, however wasteful of BTUs, firewood costs are almost entirely just the cost of my labor to harvest and store it, whereas lost propane BTUs are very expensive!

You seem to have made your decision already.

 

[begreen]

A good quality, insulated, 20' liner system will cost about $800 not including the materials to make the transition.

A class A chimney system is going to cost $1100-1400 in parts. This is not a huge difference and the propane savings will actually pay for it within less than a year. Use the relief check to pay for it and thank uncle sugar.

If the $400-600 difference is amortized over the next 10 yrs. this is a cost of a few dollars a month. What you get for this is a proper venting system, legal and insurable - and sellable. It ends up with a longer lifespan and elimination of the heat loss issue which means you spend less time and gas cutting, splitting and stacking wood. The trees may be "free", but cutting and processing wood definitely is not.

 

[calinb]

A good quality, insulated, 20' liner system will cost about $800 not including the materials to make the transition.

A class A chimney system is going to cost $1100-1400 in parts. This is not a huge difference and the propane savings will actually pay for it within less than a year. Use the relief check to pay for it and thank uncle sugar.

If the $400-600 difference is amortized over the next 10 yrs. this is a cost of a few dollars a month. What you get for this is a proper venting system, legal and insurable - and sellable. It ends up with a longer lifespan and elimination of the heat loss issue which means you spend less time and gas cutting, splitting and stacking wood. The trees may be "free", but cutting and processing wood definitely is not.

These are good points. Thanks! I've not made my decision yet. (Thanks to bholler too!)

The (my) labor required to install the new chimney appears to be considerable. Maybe I need to better study exactly what would be required but, having peered into the chimney and chase from the roof and below, I think I'd need to cut through the walls and into the chase (I think that's what it's called) and also cut into the lower floor wall and alcove-like section (more like a half alcove), which is finished in decorative stone and masonry grout. It would need to be removed from about 3' above the stove to the ceiling level to access the interior and fabricate the new support. Perhaps I could get to it from the other side without messing up the stone but it would be a relatively large summer project for me and it would compete with other projects like a spring (water supply) redevelopment project that's necessary to increase the agricultural output of this old 1908 homestead.

If it weren't for the pending economic disaster looming, I'd probably hire someone to install the new chimney but, if I may point out the actions and consequences of centralized government economic "stimulus" (wealth redistribution) here--as a debt-free saver, I will be paying for many relief checks and my check is merely political bait! Fed.gov's fraudulent CPI (consumer price index) adjustment promises notwithstanding, my social security check, which begins this year, will be decreasing in value along with my cash value and perhaps even most of my hard assets. Our rulers and masters have reacted to the Covid-19 panic-demic with measures that will kill people just as sure as a disease can kill people. The deaths are simply obfuscated when something like a house fire happens, but obfuscation is how the politicians want it!

I'm not predicting that my house will burn down but I agree with you; a new chimney would be safer than the old one. Life is all about risks and odds.

 

[calinb]

<snip>
The trees may be "free", but cutting and processing wood definitely is not.

I know and I just want to add that I spent a few years feeding a hungry old Fisher in my last residence.

 

[begreen]

This sounds like there was a ZC fireplace in there at one time. Is that correct? Can you take some pictures of what is there now? That will help us see what you are seeing. What is interior width of the alcove?

 

[bholler]

These are good points. Thanks! I've not made my decision yet. (Thanks to bholler too!)

The (my) labor required to install the new chimney appears to be considerable. Maybe I need to better study exactly what would be required but, having peered into the chimney and chase from the roof and below, I think I'd need to cut through the walls and into the chase (I think that's what it's called) and also cut into the lower floor wall and alcove-like section (more like a half alcove), which is finished in decorative stone and masonry grout. It would need to be removed from about 3' above the stove to the ceiling level to access the interior and fabricate the new support. Perhaps I could get to it from the other side without messing up the stone but it would be a relatively large summer project for me and it would compete with other projects like a spring (water supply) redevelopment project that's necessary to increase the agricultural output of this old 1908 homestead.

If it weren't for the pending economic disaster looming, I'd probably hire someone to install the new chimney but, if I may point out the actions and consequences of centralized government economic "stimulus" (wealth redistribution) here--as a debt-free saver, I will be paying for many relief checks and my check is merely political bait! Fed.gov's fraudulent CPI (consumer price index) adjustment promises notwithstanding, my social security check, which begins this year, will be decreasing in value along with my cash value and perhaps even most of my hard assets. Our rulers and masters have reacted to the Covid-19 panic-demic with measures that will kill people just as sure as a disease can kill people. The deaths are simply obfuscated when something like a house fire happens, but obfuscation is how the politicians want it!

I'm not predicting that my house will burn down but I agree with you; a new chimney would be safer than the old one. Life is all about risks and odds.

Some of what you said there is a bit concerning. Alcove install clearances are usually pretty large. Are you sure you have enough room? Pics would definitely be helpful

 

[calinb]

This sounds like there was a ZC fireplace in there at one time. Is that correct? Can you take some pictures of what is there now? That will help us see what you are seeing. What is interior width of the alcove?

Here are some photos. (Click the thumbnails.) Thanks so much!

I don't know the configuration when the triple-wall factory built AC chimney was installed so I don't even know that it was compatible and consistent with the chimney. I'm curious about your guesses. I know that the previous owner had a Blazeking wood stove venting into this chimney, which I do not think was an approved installation (given that Blazeking is a fairly modern stove). The previous owner complained that it was dirty (probably a result of low unlined 10" ID temperatures?). He became tired of feeding it wood and installed the propane direct vent Quadrafire, which you can see. When I looked down from the top, it appeared that whoever installed the propane burner liner did at least clean it first.

It's now sort of a wall installation with a low ceiling height. My understaing is the stone is of no code clearance benefit, because it appears to have drywall behind it all. The stone is about 88" wide from the corner and about 47" deep to the corner.

I went over to https://inspectapedia.com/chimneys/Class_A_Metalbestos_8482_Chimneys.php

and also

https://inspectapedia.com/chimneys/Super_Chimneys.php

to learn about newer pre-fab chimneys and none of them appear to be HT type/ UL3. It says the "super chimneys" are the closest in test temperture (2000F) but if I'm going to install a new chimney, I need one that complies with the Jotul manual:

2.0 Chimney Requirements
There are two types of approved chimneys:

1. A code-approved masonry chimney with a ceramic tile or listed steel flue liner.

2. A prefabricated chimney complying with the requirements for Type HT (2100°F) chimneys per UL 103 or ULC S629.

Do you have any specific HT / UL3 recommendations?

 

[calinb]

Of course the Jotul is just being stored in its current corner position. When installed in the Quadrafire's position (which is actually somewhat off-center from the chimney and positioned closer to the wall than proper, the Jotul makes clearance requirements (to the drywall behind the stone) with the double wall Ultrablack pipe. As you can see, this really isn't an alcove.

 

[calinb]

According to the Selkirk "SuperVent Model JSC Technical Data Sheet", JSC is an HT / UL3 approved solution. I'm trying to price out parts now but I won't really be able to assess the project until it warms up enough that I can take the Quadrafire offline (maybe in another month or so) and remove it and maybe remove the roof flashing too for a better look into the chase. The roof flashing is well bonded with roofing tar and flexible waterproofing.

Okay--seven 3' segments of Supervent and the ceiling and roof support kit from Lowes only comes to $880 dollars. Locking bands are almost $8 each, if I need them. Of course there will be other supplies and parts necessary but Supervent seems to be well-like here.

This is much less money than I expected for a fully approved solution (I think). I just need to try to see into this can of worms better and decide how much destruction will be necessary to extract the old chimney and install the new one.

 

[begreen]

Thanks. Pictures really help explain an awkward installation. That's a good price on the chimney pipe. Do they have 4' lengths? That may cost less.

The big gotcha I see is the faux-stone overhang. Behind that is likely wood framing. This is not a protected wall or ceiling so clearances look like they are an issue. Best case scenario, with double-wall stove pipe and a flue connector heatshield, he F55 needs to have 6" clearance to the rear. Worst case with singlewall stovepipe is 18". Alcove clearances are higher. The big issue is the ceiling height. Typically the minimum is 84" or in case of an alcove, 72" above the stovetop. Alcove ceiling clearance can be reduced to 59" above the stove top with NFPA protected wall and ceiling shielding.

What material is the wall 'stone' made out of? Is this glued on? It might be better to just remove the entire boxed in overhang.

 

[calinb]

Thanks. Pictures really help explain an awkward installation. That's a good price on the chimney pipe. Do they have 4' lengths? That may cost less.

The big gotcha I see is the faux-stone overhang. Behind that is likely wood framing. This is not a protected wall or ceiling so clearances look like they are an issue. Best case scenario, with double-wall stove pipe and a flue connector heatshield, he F55 needs to have 6" clearance to the rear. Worst case with singlewall stovepipe is 18". Alcove clearances are higher. The big issue is the ceiling height. Typically the minimum is 84" or in case of an alcove, 72" above the stovetop. Alcove ceiling clearance can be reduced to 59" above the stove top with NFPA protected wall and ceiling shielding.

What material is the wall 'stone' made out of? Is this glued on? It might be better to just remove the entire boxed in overhang.

Thanks for your help, begreen!

According to the manufacturer's catalog, the longest Supervent model JSC chimney sections are 36 inches.

It appears to be actual stone and grout. I don't see how it could be flammable but the drywall and suspected wood structure behind the drywall is of course flammable. I actually make the F 55 Double Wall Connector / Unprotected Walls clearance to the drywall, as specified as "N" in the F 55 manual. There's just over 6" of clearance to the stones so, depending on whether going by the stones or the drywall, it makes the required clearance with Flue Collar Heat Shield ("T") or without to the drywall ("N").

I don't know what is supporting the stone, other than the grout. Going by the uneven backsides of the stones that are visible at the edges, it's just grout! I believe it was installed before the previous owner's time, so over 25 years ago. The owner at that time was a very successful Realtor in this area and she had a lot of very unusual upgrades installed for an old rural homestead, including a 2nd phone line, Ethernet wiring, a built-in Gunite swimming pool, and probably this Chimney.

There's only about 35" inches from the F 55 stove top to the stone "ceiling." Coincidentally, the F 55 specifies 35" to a combustible fireplace mantel too.

 

[begreen]

It might be worth comparing to other brands that offer 48" lengths.

https://www.efireplacestore.com/class-a-chimney-pipe.html

If this were my project I would tear down the entire boxy overhang. It appears to have no functional value, adds complication and doesn't help a lot aesthetically. Getting rid of it should simplify installation and it will eliminate a length of chimney pipe.

There's just over 6" of clearance to the stones so, depending on whether going by the stones or the drywall, it makes the required clearance with Flue Collar Heat Shield ("T") or without to the drywall ("N").

Assuming double-wall stove pipe, yes.

There's only about 35" inches from the F 55 stove top to the stone "ceiling." Coincidentally, the F 55 specifies 35" to a combustible fireplace mantel too.

This is irrelevant. A fireplace install will have most of the stovetop inside of the masonry fireplace. The dimension is not applicable here.

 

[calinb]

It might be worth comparing to other brands that offer 48" lengths.

https://www.efireplacestore.com/class-a-chimney-pipe.html

If this were my project I would tear down the entire boxy overhang. It appears to have no functional value, adds complication and doesn't help a lot aesthetically. Getting rid of it should simplify installation and it will eliminate a length of chimney pipe.

Or maybe just leave the propane stove where it's at and find a new place for the Jotul and chimney.

Assuming double-wall stove pipe, yes.

I have double-wall ICC Ultrablack, but I'll need more to reach the ceiling.

This is irrelevant. A fireplace install will have most of the stovetop inside of the masonry fireplace. The dimension is not applicable here.

The boxy overhang makes all code and requirements irrelevant, because it doesn't conform to any standard installation. In fact, it doesn't really conform to the approved installations for the current propane stove either, but it's a pretty conservative interpolation from those requirements at least. For a wood stove, the approved requirements provide only a basis for a guess, at the very most. It's not really a ceiling. It's not really an alcove. It's not a basement or an attic. It's simply non-conforming.

 

[bholler]

Or maybe just leave the propane stove where it's at and find a new place for the Jotul and chimney.

I have double-wall ICC Ultrablack, but I'll need more to reach the ceiling.

The boxy overhang makes all code and requirements irrelevant, because it doesn't conform to any standard installation. In fact, it doesn't really conform to the approved installations for the current propane stove either, but it's a pretty conservative interpolation from those requirements at least. For a wood stove, the approved requirements provide only a basis for a guess, at the very most. It's not really a ceiling. It's not really an alcove. It's not a basement or an attic. It's simply non-conforming.

What do you mean by for a wood stove, the approved requirements provide only a basis for a guess. That is a ceiling and doesn't meet the clearance requirements. No guessing involved

 

[calinb]

What do you mean by for a wood stove, the approved requirements provide only a basis for a guess. That is a ceiling and doesn't meet the clearance requirements. No guessing involved

Physically (thermally and convectively), it's not even close to a ceiling, because it doesn't span the walls of the room. It's just a relatively small overhang--again, not even close to a ceiling in terms of its properties. It's 2' deep and doesn't come close to subtending between even two walls of the room. This overhang (not a ceiling) will obviously "shed" warm air much better than a ceiling, because the warm air has a very large space to enter above with a short and level path separating it from that space. In fact, that space is actually much larger than what is illustrated in my photos, because 30% of the ceiling in this first floor room is open to the floor above, including the space immediately above the overhang, and not shown in the photos (which again, is a configuration far from the worst case and common scenario addressed by testing and code). Do you know of code that's sufficently sophisticated to accommodate the effects of a loft or parital ceilings at non-standard heights and arbitrary dimentions? I don't think these sorts of configurations are tested or even dynamically thermally modeled and simulated (finite element analysis, etc.).

Obviously, testing and code cannot address anything but the most common scenarios and it's understandable that only the most common scenarios are valid and "covered." By the "book", all other scenarios and configurations must be avoided. I understand this. Similarly, this overhang is not an alcove.

Assuming the testing and code is devised to addresses worst case, a worst case ceiling subtends between ALL the walls in room. Given the limitations of the testing behind code, it is necessary to assume an overhang to be a ceiling, but even this sort of an assumption has its dangers. Again, code should not be counted on to apply to "awkward installations" at all, as you correctly called this one. One might as well ask if a stove could be installed into an igloo and still meet code!

 

[bholler]

Physically (thermally and convectively), it's not even close to a ceiling, because it doesn't span the walls of the room. It's just a relatively small overhang--again, not even close to a ceiling in terms of its properties. It's 2' deep and doesn't come close to subtending between even two walls of the room. This overhang (not a ceiling) will obviously "shed" warm air much better than a ceiling, because the warm air has a very large space to enter above with a short and level path separating it from that space. In fact, that space is actually much larger than what is illustrated in my photos, because 30% of the ceiling in this first floor room is open to the floor above, including the space immediately above the overhang, and not shown in the photos (which again, is a configuration far from the worst case and common scenario addressed by testing and code). Do you know of code that's sufficently sophisticated to accommodate the effects of a loft or parital ceilings at non-standard heights and arbitrary dimentions? I don't think these sorts of configurations are tested or even dynamically thermally modeled and simulated (finite element analysis, etc.).

Obviously, testing and code cannot address anything but the most common scenarios and it's understandable that only the most common scenarios are valid and "covered." By the "book", all other scenarios and configurations must be avoided. I understand this. Similarly, this overhang is not an alcove.

Assuming the testing and code is devised to addresses worst case, a worst case ceiling subtends between ALL the walls in room. Given the limitations of the testing behind code, it is necessary to assume an overhang to be a ceiling, but even this sort of an assumption has its dangers. Again, code should not be counted on to apply to "awkward installations" at all, as you correctly called this one. One might as well ask if a stove could be installed into an igloo and still meet code!

I have been doing this a long time dealing with lots of inspectors and code officials. That does not meet the requirements for height above the stove. Call it what ever you want it will never pass inspection and is a definite potential safety issue.

 

[begreen]

Sorry, this discussion is not helpful and going nowhere. It sounds like you are going to do what you want to do, so why waste time discussing it?