Double or triple wall pipe?

[zig]

Couldn't find anything in search about this particular question so I bow to those brighter than me.
My house has a brick w/ clay flue chimney 12x12 on the east end 10 ft. tall. Dad and I originally built the house for a open fireplace but the mason that did the brick/block work talked Dad into making it for a stove to reduce heat loss. Hearth is inset with a 1/4 in. 3'x3' steel plate at the base and the flue stacked above wrapped in brick.
Had a Fisher type stove w/ 8" pipe running the 18" through the plate and into the flue straight up. Wish I had that stove still but it,s gone. I got a Bosca fs500 in there last winter(saved our butts) set up the same way. Made a reducer plate to 6", But it became a creosote monster. Too little exhaust in too big a flue plus -20 temps cooling the brick. Time for a ridged liner. Drop it straight down in the flue, setting on the steel plate. Make a collar to hold the top square and vent the opening and a top plate on the crown.
Will double wall class A be too hot on the outside pipe and cause condensation? I have all kinds of room in the flue for triple wall and it seems to me the outside would be cooler. I don't want to warm up the inside of the flue enough to cause the brick or clay to sweat.
Thoughts? Am I being a wuss?

 

[DAKSY]

Class A Chimney is not designed for your application. Most of us here will probably recommend a 6" rigid or flexible stainless steel liner with an insulation wrap. A top plate is attached to the higher end of the liner & is also used to seal the 12x12 terra cotta flue at the top. The cap attaches to that plate.

 

[Jags]

I am just here to back up every single word that Daksy posted above. Thats the right way to do it.

 

[zig]

Class A Chimney is not designed for your application. Most of us here will probably recommend a 6" rigid or flexible stainless steel liner with an insulation wrap. A top plate is attached to the higher end of the liner & is also used to seal the 12x12 terra cotta flue at the top. The cap attaches to that plate.

Thank you for the reply. I understand that but isn't a class A the same thing? 22ga. inside pipe, insulation and an extra ss pipe outside for added rigidity. Plus 2x is cheaper than liner pipe and insulation. 3x is about the same money. Still have to buy the bottom fitting to attach to stove pipe and a cap. I can make everything else. Even have a chunk of copper roofing saved for such a use. My concern is keeping a warm pipe or liner from creating condensation in the old flu given how cold the brick will be.

 

[bholler]

no it is not the same and where are you getting your prices? they dont make sence to me at all

 

[begreen]

Frugality is honorable, but when there is fire in the house, the first concern should be safety... tested and certified safety. Do it by the book. Your insurance company and family will rest easier knowing the job is done right.

 

[zig]

Prices from a near by chimney supply. Liner,$120 for 3ft. section; insulation,$33 for 2ft. piece=$153+tax. Metabestos pipe,$137 a 3ft. section. Sixteen bucks isn't the issue but the durability over time.

Thank you for your concern for my family's safety. Rest assured nobody is more concerned than I. I came here to ask a question I didn't have an answer to. Still haven't found one. Is condensation more likely with class A than liner and insulation, or will the gap at the top take care of any that may accumulate?

 

[bholler]

The problem is not necessarily with safety it is that class a is not tested or rated for lining a chimney. And i don't see that there is any gain in safety at all between a liner and class a i personally would not use rigid liner we use heavy wall flex liner But light wall will work fine although not be as durable as heavy wall or rigid. Another option is preinsulated liner

 

[begreen]

I'm not seeing how class A pipe is an option in this case unless as a chimney extension. 10 ft is a short chimney.

 

[DAKSY]

I looked at the install manual & couldn't find a minimum chimney height for this unit.

 

[begreen]

zig, class A pipe is not appropriate for this installation. It is not designed or tested to work in a chimney. What you need is an insulated stainless steel liner. It is supported by a stainless top cap that will need to be installed on top of the tile at the crown of the chimney. This will provide a durable, safe and easy to clean solution. Of course, that precludes that you are burning dry wood. Burn damp wood and creosote is going to be a regular issue, regardless. The only solution in that case is frequent cleaning of the chimney.

http://chimneylinerdepot.com
http://rockfordchimneysupply.com

 

[zig]

The question was condensation between the clay flue and ANY pipe. Called Rockford, said the 1/2" gap under the top plate would vent any condensation, 11ft" of metabestose on the way. Thanks for your thoughts all.

 

[bholler]

Ok so you completely ignored all advice and the recommendations of the manufacturers glad we could answer your questions. Condensation is not an issue inside chimneys if they are properly sealed at all and i would never ventilate the top of the chimney either

 

[begreen]

 

[EMB5530]

Ok so you completely ignored all advice and the recommendations of the manufacturers glad we could answer your questions. Condensation is not an issue inside chimneys if they are properly sealed at all and i would never ventilate the top of the chimney either

To be fair until this post nobody even addressed his main concern of "condensation" so he has a good reason to not take much notice to what is said by others when nobody cared to address his main concern.

 

[begreen]

He was dead set on installing class A in the chimney. The condensation question was just a side concern if he did it. And he did it anyway regardless of what was said or recommended.

 

[MagKarl]

Serious question, how is running class A pipe inside a masonry chimney not OK, but running it up a wood framed chimney is? Seems to me the OP has the right idea. Educate us please.

 

[EMB5530]

He was dead set on installing class A in the chimney. The condensation question was just a side concern if he did it. And he did it anyway regardless of what was said or recommended.

OK

 

[begreen]

Serious question, how is running class A pipe inside a masonry chimney not OK, but running it up a wood framed chimney is? Seems to me the OP has the right idea. Educate us please.

Good question. There are a few things that I would be concerned with.The first is support. In a wood chase the chimney pipe can be supported as the mfg. requires. Not possible in a chimney. The second is a lesser concern of corrosion. The chimney is a corrosive environment and the class A jacket is meant for outdoors. Not sure if this would shorten the life of the jacket. Perhaps not, but how to tell? The last concern would be clearance. The class A pipe requires 2" clearance all around its sides. How does one guarantee that in this installation?

Probably not as important to the OP, but rubbing my frugal hide is the unnecessary cost. An insulated stainless liner would do the job easily as well, is purpose designed at zero clearance, and a heckuva lot less expensive. Plus it is light so the support question becomes moot.

 

[EMB5530]

I just believe if you re-read this entire thread w/ what I have said in mind then think maybe instead of telling a person he is "doing it all wrong" and instead come back w/ what he is interested in learning and then tell him the right way to do it he is going to have a more open mind towards the info your giving. IMHO

 

[begreen]

And that is exactly what was attempted in post #11 in this thread. At no point was an openess to other options shown by the OP. It is as if the decision was already made up and he came here for verification. Perhaps the pipe was already purchased?

 

[begreen]

Closing this thread. It's a done deal and the OP has left the room.