class a chimney diameter

[bkoltai9]

I am getting ready to install an Ashley wood circulator model BEC95.

http://www.efireplacestore.com/uss-bec95.html

I'm planning to install the Ashley in front of an old fireplace and run a new class A chimney right through the old brick chimney (which is cut off below a new metal roof).

There is plenty of space to work with and I was wondering if there's an advantage to using 8" class A chimney instead of 6". The Ashley has a 6" flue coming out the back. It will be a short horizontal run through the fireplace to the center of the chimney and then 20' vertical to get 2' over the peak of the house.

Also, i'm planning to use stainless duratech purchased from Hart's Hearth. I see they offer DIY warranty, which I haven't found anywhere else. Can anyone recommend a better option or does this seem reasonable?

 

[jeff_t]

You don't want to run class A inside of an existing chimney. It isn't tested or approved for that, and supporting it is a big issue. What I have seen done here before is to run an insulated, stainless liner to the top of the chimney, an adapter plate on top of that, and then class A thru the roof. The liner should be less expensive than class A, as well.

A thread on the subject. I know there are more.
https://www.hearth.com/talk/threads/stove-pipe-help-2-1-2-story-through-attic.131001/#post-1773686

Match the diameter to the flue outlet on the stove. If you ever want to switch stoves in the future, most modern units are 6", unless you go really big.

A very good metal roof flashing. I'm using one on a standing seam roof with Selkirk pipe.
http://www.icc-rsf.com/main.php?t=chem_produits&i=95&d=&l=en

Personally, I'd look for something more efficient than the Ashley. There are plenty of stoves in that price range that burn cleaner, and make more heat with less wood.

 

[bkoltai9]

What you suggested describes my original plan.

https://www.hearth.com/talk/threads/new-install-in-old-chimney-complicated-with-many-options.135673/

It seems to me that going from liner to class A chimney would add complication, whereas a straight shot of class A would be easier to install? I also figured that just class A would draw better.

I had a lot of trouble trying to find the sort of anchor plate that transitions from as liner to class A chimney. I'm not yet 100% sold on duratech for class A chimney, but I'm inclined toward double wall instead of triple wall.

Aside from supporting the class A chimney, is there any reason why I shouldnt run it inside an existing masonry chimney?

I know there's better options than the Ashley, but it was the better (I think) of the two options on sale locally.

 

[bholler]

Aside from supporting the class A chimney, is there any reason why I shouldnt run it inside an existing masonry chimney?

because that is not what it is meant to do and yes go with double wall over triple

 

[bholler]

Dropping a fuly assembled class a chimney down a chimney will be much harder than tracking down the right part and doing it right

 

[bkoltai9]

Thanks for helping again with suggestions bholler. I'm waiting for a call back from mg duravent regarding the appropriate anchor plate piece.

I had in mind to build it up from the bottom rather than drop down from the top. I know its very heavy, but its less than 10' from the floor to the top of the masonry and I can stand up inside. Its less than 5' where its narrowed down to 13x18.

 

[zig]

Understand these guys and gals here are very experienced at the things they tell you. That said, they gave me all kinds of hell for asking about running class a inside my chimney too and it worked better than i thought it would. The pipe's made to run outside of the house or inside a chase made of combustible materials with 2in. clearance. There is nothing combustible inside a brick chimney.
You'll have about 200lb. of pipe to support. How are you planning to do that? The support is the big problem. I've got 11ft. of it in my chimney but it sets on 1/4 in. steel plate set into a brick hearth and built into the brickwork of the chimney so no support questions for me. If you have something solid to take the weight on the bottom it should be fine. DuraTech makes a transition anchor plate http://www.northlineexpress.com/6-d...transition-anchor-plate-6dt-ap17x21-7057.html Maybe that would work. If in doubt, hire it done. If you want to do it yourself and have questions about the product, call them. Though I used a different pipe, I called them with a question and someone from their engineering department called me back! Their some nice folks.

 

[bholler]

That said, they gave me all kinds of hell for asking about running class a inside my chimney too and it worked better than i thought it would.

I have no doubt what so ever that doing this will work just fine. The problem is you are using a product in an application that it is not designed for. When you do that you open your self up to allot of liability issues and besides the fact that it is a real pain to install the way the op is planning i know from dropping them into existing chases it sucks

 

[zig]

I have no doubt what so ever that doing this will work just fine. The problem is you are using a product in an application that it is not designed for. When you do that you open your self up to allot of liability issues and besides the fact that it is a real pain to install the way the op is planning i know from dropping them into existing chases it sucks

Dropping down or pushing up will be a pain but I don't know and haven't seen the op's setup; he has. If there's room to push up from the bottom and block as you go or sling them from the top and lower 1 piece at a time. The support of the pipe is the question. Get that figured out and the rest of it's practically done for you. A good quality ridged liner isn't that much lighter either. If your reasonably intelligent and use common sense it can be done.
As to the design, a screwdriver isn't suppose to be used to open a paint can either but I've always used one. If there's a issue with homeowners, contact the agent and show him/her the setup. I did. Your putting fireproof stainless steel inside fireproof brick made to vent a fireplace. If you have a chimney fire,and it breeches the pipe, it's contained inside a non-combustible inclosure. I fail to see a downside with that.
This site continues to impress me as to the knowledge of the members and the way questions are answered. Sure there's some snobs that think theirs is the only way but there's even more who know each situation is unique and what may not work for A will work for B with safety. For the record, I think your in the latter group.

 

[bkoltai9]

I hadn't thought to look through the duraliner catalog to find the anchor transition Zig has recommended, but actually seeing the piece I'd need for the hybrid design at least opens the possibility back up again for me.

With regards to support, won't either method require a support piece at the bottom? If the chimney liner comes to a T that has the horizontal stove pipe coming to it, surely I don't leave it just hanging, right?

The chimney liner and class A above are both supported by the brick at the top of the chimney. If I use just class A, I thought it would also be supported by a roof support piece

http://www.woodlanddirect.com/Chimney/DuraTech-Chimney-System-Parts/6-inch-DuraTech-Roof-Support

I figured a roof support like that could go on top of the brick chimney or a foot above in the actual roof. Does this piece actually hold any weight or does it just keep the chimney in place?

Given the roof pitch and height, I'll surely also need an extended roof bracket.

http://www.northlineexpress.com/6-duratech-extended-roof-bracket-6dt-xrb-7082.html

 

[bholler]

If the chimney liner comes to a T that has the horizontal stove pipe coming to it, surely I don't leave it just hanging, right?

Yeah pretty much just hang it you should do a block off plate that will hold it in place but not support it they typically hang from the top plate

If I use just class A, I thought it would also be supported by a roof support piece

that should work as long as you dont have more that 20' below that support bracket.

A good quality ridged liner isn't that much lighter either

class a will weigh almost twice what an insulated rigid liner weighs and a rigid liner is meant for that application not class a. And besides the class a will cost allot more with no real benefit over a liner and class a extension

 

[Heatsource]

IF you were to put class a inside the chimney be sure to use all stainless pipe inner and outer... galv wont hold up well