Fireplace removed, can I reuse the 10.5" outer chimney?

[Goodburbon]

I had a 1999 yr model heat N Glo with a stone surround that was practically worthless for heat. It would also occasionally and randomly just decide to fill the house with smoke, unrelated to wind. For the last few years I've looked for a viable alternative. At first searching for inserts.

After searching all over the Internet for a suitable insert I found none. So last week I removed the fireplace, completely. Leaving an 8' x 5' hole in the wall, a 10.5" pipe with standoffs inside sized for 8" chimney. The 8" stainless chimney was blued from heat exposure.

I found a suitable stove for a reasonable price in a USSC 2500.

I asked for a quote from the local stove guy for bricking the alcove and installing the stove and he wants $5k. That is pretty unreasonable imo, he is including $1200 in parts for a new insulated chimney and what I estimate to be about $100/hr.

I've elected to do it myself since I'm suddenly mostly unemployed thanks to the crash in oil prices and a sudden redefining of "your job is secure regardless of oil price". I've got the masonry and additional framing needed for the support box figured out. I do need some advice on the chimney though.

I see no problem running a 6" single wall chimney through the original 16' of 10.5". The original 8" pipe above a fireplace was much hotter (as evidenced by heat bluing of the stainless) than a 6" above a modern EPA stove will be. There was already single walled chimney there. There will be 6' of exposed stove pipe before the support box which will dissipate some additional heat The stand offs in the 10.5" are configured such that adequate air spacing around the 6" will be maintained. If I'm wrong, why? I can't justify the $1000 in additional parts and insulated chimney in my mind.

 

[begreen]

Probably can not use the original chimney unless this is class A chimney pipe rated 2100 HT. Is there any label or pipe brand + part number on the pipe? It would be something like SL-8. You can run stainless liner through it, but then there is the issue of clearances and support once out of the pipe. It would be much better to replace the old chimney with new class A if it doesn't meet the wood stove temp requirements.

If installing in an alcove you'll need to be sure it is wide enough to honor the stove clearance requirements. It needs 20" from each side. That makes the alcove 67" wide. It will need to have a ceiling height of no less than 7 ft.. I would use double-wall connector pipe in this area too.

You might want to consider an alternative stove that has good side shielding to reduce side clearances. A Drolet Baltic or Legend requires 12" instead of 20".

 

[Goodburbon]

SL 348 make sense?

 

[begreen]

Yes, I don't believe that is the right temp rated pipe.

 

[Simonkenton]

Yeah, you are right. A bid for $5K, I think that boy earns about $100 an hour.
I have done a lot of construction work and I see this a lot. Certain guys just put out ridiculous highball bids, every time. The first nine people turn him away, some laugh in his face, but, he doesn't care, because the tenth customer hires him and he gets huge money.

 

[Goodburbon]

Makes no sense to me how a pipe that has been exposed to much higher temps and not even discolored the stickers on it won't be suitable.

It is not feasible to remove the 10.5" SL300 series pipe, There is no attic access.


As for stove clearances, I was under the impression that the 20" clearance was to combustibles. I'm lining the interior of the alcove with masonry making that number irrelevant.

 

[begreen]

I also see you are in CO. What altitude are you at? An EPA stove is going to need enough chimney for high altitude burning. Sea Level requires 15 ft. stack. Bump that up to 20 ft at a mile high.

 

[Oldman47]

A solid stone liner would not make that distance irrelevant. Combustibles exist where they exist regardless of intervening non-combustibles unless you add in shielding. Shielding is not just a non combustible, it is a specifically designed barrier with an air passage behind it, not just a gap, to actually remove any heat build up. I am still making a new install but have spent way too much time reading the requirements to miss that point any more.

 

[begreen]

As for stove clearances, I was under the impression that the 20" clearance was to combustibles. I'm lining the interior of the alcove with masonry making that number irrelevant.

Wood stoves are capable of running their flues at much hotter temps than a fireplace that has a high volume of air mixing in with the smoke.

Masonry conducts heat, albeit a bit more slowly. The clearances are measured to the combustibles behind the brick. A true 3.5" thick brick wall can reduce clearances according to the NFPA 211 table by 33%. According to the 2500 manual you'll need to get approval for this by the local inspecting authority. If the alcove width, before adding the brick is 48" this may be ok as long as the local inspector approves and signs off on it.

Here's a link to the applicable clearance reduction chart:
https://www.hearth.com/talk/wiki/nfpa-wall-clearance-reductions/

 

[bholler]

If you can support it you could run class a chimney through the old 10.5" pipe as long as you can ensure that you will have 2" from that class a to combustibles. But no way that it is safe to run single wall through there

 

[begreen]

The ID of the 10.5" SL3 pipe is 8". I don't think you could run class A up it. I'm also wondering if there is enough chimney height to run this stove.

 

[bholler]

The ID of the 10.5" SL3 pipe is 8". I don't think you could run class A up it.

orry for some reason i though that he had removed the inner sleeve if it is still there then no it wont work. At 16' in high elevation it will be close for sure it is hard to say i think i would try it at that height personally and add if necessary.

 

[Goodburbon]

Don't wonder about height any longer. It's around 17'

 

[Goodburbon]

The 8" liner is removed from the 10.5"

 

[Goodburbon]

I'm at 8000' elevation. No one here is running a 20+ft chimney, that's ludicrous high.

 

[bholler]

20+ft chimney, that's ludicrous high.

Not really the majority we work on are 20+' but like i said i think i would try it at your current height. And if the liner is removed class a would fit you just need to be able to support it and be able to confirm that you do have the required 2" clearance to combustibles

 

[begreen]

Sounds more plausible then with class A pipe as long as the class A pipe is properly supported. We get a few problem installs a year reported here with EPA stoves at high altitude. EPA stoves require stronger draft than old stoves because of their manifold ducting. Adding chimney solves the problem. FWIW, I'm almost at sea level and have a 20ft. chimney. The chart shows a 25+ft chimney for 8000ft. The air is much thinner at that height.

 

[Goodburbon]

I'm Building a drop ceiling for the 6" support box and a few recessed lights in the alcove.

 

[begreen]

Sounds good as long as the ceiling height is at least 84" from the hearth floor.

 

[kennyp2339]

Begreen - you are giving awesome advice, just want to say your attention to detail is stellar!! I would have never thought about altitude.

 

[begreen]

I learned it here several years back. My teacher on altitude was Ryan, aka MountainStoveGuy who sold stoves and installations out of Denver.

 

[Goodburbon]

Planned alcove ceiling height is 90". I do have an exposed beam planned at 72" though for aesthetics and to trap a pocket of heat, for use in the room behind the stove through a small in wall fan.

 

[bholler]

The chart shows a 25+ft chimney for 8000ft. The air is much thinner at that height.

ok then if it says 25' i doubt 17 will work i though it called for 20. I am glad we dont have to deal with that crap here lol

 

[bholler]

I do have an exposed beam planned at 72"

From the instructions it looks like that beam needs to be at 84"

 

[Goodburbon]

You've got to be kidding 25' is not an option. Not even close. Not gonna happen. Now you are talking guy wires secured to ??? And a 6" chimney Extending 8' above the chase. I'd need a freaking man lift to sweep it!