more newbie questions

[drobbins]

Hello All,

Another newbie, this one from North Carolina.
Not as cold here as where some of you folks live but we still gotta keep warm in winter.
We built a 2 story house several years ago and it has a pre-fab fireplace in the basement which has worked well but it really sucks down the wood. I buddy recently found an old VC Dutchwest used and installed it and it's quite impressive. I was thinking of getting something similar and placing it in front of my pre-fab unit and venting it up the chimney. Sounds pretty straight forward to me, but then, I'm a newbie.
The existing unit is made by Heatilator and has a 8" triple wall stainless flue running straight up something over 16' (upper floor has vaulted ceiling). Current unit has a cultured stone surround and the floor is slate tiles over a concrete slab so nothing flammable anywhere nearby except maybe the ceiling.
Do you folks see any gotcha's in my plan? It all looks pretty straight forward to me.

Another question. The stoves I've been looking at come in both catalytic and non-catalytic models.
I understand what the catalyst does and how it works and it seems like all upside to me, why are the non-cat models available and why are the ones I looked at slightly more expensive.

So far I'm looking at a Dutchwest 2461

Thanks for any thoughts/Ideas
Dave

 

[Grisu]

A pic of your current fireplace would help but so far it does sound pretty straightforward. You will need to drop an insulated 6" liner down the chimney to make the flue compliant. What is the height of your fireplace opening measured from the hearth? That will determine which rear exit stove can be placed there (the pipe needs to fit under the lintel).

A catalytic stove usually has longer burn times and a more even heat output than a secondary burn stove especially when burned on low. Slight gains in efficiency and lower emissions are also often found. For a rear-vented cat stove I would look at Woodstock stoves. How much of an area do you want to heat and how well is your home insulated? Does that heat travel well through the house? Those will determine which size stove/firebox will be best.

Non-cat, secondary burn models deliver most of their heat early in the burn and then taper off more rapidly than cat stoves. On the other hand, they don't require replacement of the cat (usually about every 5 to 8 years) and are more forgiving with improper fuel (like treated wood, colorful paper etc. although you should not really burn that anyway). The flame show can also be sometimes lacking a bit in a cat stove especially on a low air setting. Secondary burn stoves with rear flue exit can be found from: Jotul, Hearthstone, Quadrafire, Morso

 

[drobbins]

pic attached (hopefully)
as you can see the surroundings are pretty non-flammable
it's 27" from the hearth to the underside of the inside of the firebox and another 11" from the hearth down to the floor
The room it's in is about 900 sq ft with smaller rooms of about 150 sq ft each on each end
Smaller rooms are left shut off when not in use
Basement is underground on 3 side so well insulated but that 4th side has a LOT of glass (walk out basement)
I figure I could sit the stove I mentioned on the hearth if I left off the legs but was more planning on sitting it (with the legs) in front of the hearth, better air circulation around it
So I'd still need to drop something down inside a triple wall flue? Seems like overkill but shouldn't be a problem
The flue gasses from a stove aren't going to be as hot as that fireplace stoked up

 

[drobbins]

reading about the insulated flue liner at chimney depot
Pricey, but it looks like the proper way to do things
Thanks for tip

 

[Grisu]

You will need a liner because the flue diameter has to be matched to the flue outlet or your draft will likely be insufficient. A woodstove flue also needs to be rated HT (2100 F) in case of a chimney fire. Plus, don't overestimate the flue temps of an open fireplace. Since a lot of cooler room air goes up together with the smoke from the fire, the heat is actually "diluted" more.

If you place the stove in front of the hearth on the floor you will have no problem to fit any rear pipe under the lintel. You could choose pretty much any rear-vented stove then. Be careful, though, with the assumption that you have no problems with clearances. Are you sure there is no wood framing under the stone?

That's not really a large room. I would look at a smaller/medium catalytic stove if you desire long burn times. The Woodstock Keystone/Palladian may already be enough if insulation is as good as you say. Otherwise, the Woodstock Fireview would be a good option. For a non-cat stove, you want a firebox of at least 2 cu ft to be able to get overnight burns (= plenty of coals left for an easy restart in the morning). The Jotul F500 or F45, the Hearthstone Heritage, Castleton, or Shelburne, or the Quadrafire Explorer 2 would be options. For a smallish stove the Quadrafire Yosemite, Hearthstone Craftsbury, or Jotul F400 would be ok. However, those will give you burn times of about 5 to 6 hours only.

I suggest the review section: https://www.hearth.com/talk/link-forums/stove-reviews.35/ and a forum search to get the pros and cons of each stove.

 

[begreen]

Probably just be me but in this situation I would probably not insulate the liner. It is going up a high temp, triple wall, interior chimney with 2" min clearances. Someone will probably disagree.

 

[bholler]

Probably just be me but in this situation I would probably not insulate the liner. It is going up a high temp, triple wall, interior chimney with 2" min clearances. Someone will probably disagree.

I think safety wise as long as there actually is the required clearance which there often is not i don't see a need for insulation. But from a performance standpoint insulate it absolutely that chimney is air cooled so temps will be pretty low which will hurt performance

 

[drobbins]

Wow, a lot of good info, I really appreciate it.
Especially the info on other stoves to look at

The liner down the existing flue isn't really all that much $ so I'm good with that.
Can you really slide that thing in with the insulation wrapped around it? Sounds like it would be a tight fit.
The upstairs gas fireplace is directly above this one
As a result the flue doesn't go straight up, it's more like 2 feet up, 30 degree jog over to the side to get around the upstairs fireplace, then another 15-18 feet straight up
Sounds like it would be hard to make that bend with the insulation

 

[bholler]

Yeah it wont be easy but it is possible

 

[begreen]

I think safety wise as long as there actually is the required clearance which there often is not i don't see a need for insulation. But from a performance standpoint insulate it absolutely that chimney is air cooled so temps will be pretty low which will hurt performance

What if the chimney is insulated on the interior jacket and air cooled on the outer jacket as a lot of triple wall is. Seems to me the performance gain would be minimal.

 

[bholler]

What if the chimney is insulated on the interior jacket and air cooled on the outer jacket as a lot of triple wall is. Seems to me the performance gain would be minimal.

I agree with that but honestly that type of chimney is rare on prefab fireplaces like that from what i have seen. Pretty much every one i have seen was either double wall air cooled or triple wall air cooled. But yes if there is insulation there the gain would be minimal. But regardless i would strongly recommend a level 3 inspection of the whole system before going any farther.

 

[drobbins]

I'm not knowledgeable in chimney design but if the current flue draws fine and is safe I fail to see the need for the insulation.
I might do it anyway just because "overkill is good" but I am concerned the insulation would be very difficult to install with the bend in the existing flue.

Also, the existing flue has a damper right where it enters the firebox, I assume I'd need to remove this to insert the liner?

 

[drobbins]

I believe it's triple wall air cooled
There was no insulation on the outside and I was told it draws air in from the top into the chamber between the outer wall and the center one, that went down to the bottom and entered the chamber between the inner wall and the center one where it gets pulled up by convection

 

[begreen]

Could be totally air cooled. You will need to have the chimney swept anyway before installing a liner. With the cap off it usually is easy to see the construction of the pipe. If it's easy access take a picture of the pipe end and post it here. Or if there is a label on the pipe that says something like SL3 then that will determine it.

Yes, the damper will probably need to be removed.

Do you know the make and model of the fireplace? It's usually on a tag in the door frame.

 

[drobbins]

it's a Heatilator A36C
You can find the manual here, I'd attach it if I could figure out how

http://www.heatilator.com/Owner-Resources/Install-and-Owners-Manuals.aspx

 

[begreen]

SL3 chimney. That is air cooled.

 

[drobbins]

I'm not afraid of the cost of the insulation, just the difficulty of installing it
The stuff I saw at chimney depot was the liner with a blanket around it
is something available that is a double wall liner with insulation between the walls?
I like the safety aspect of the insulation more than keeping the flue gasses hot, but both are bonuses

 

[begreen]

Yes, you can get preinsulated liner.

 

[drobbins]

searching their website now
that sounds like the ticket
thanks for all the info

 

[drobbins]

ever had experience with something like this?
this would give me a 5 wall flue with insulation, I ought to sleep well at night ;-)

(broken link removed to http://www.fireplace-chimneystore.com/catalog/item/8837421/9950354.htm)

 

[begreen]

The outside dimension is 2" larger than the inside dimension.

 

[begreen]

I would use DuraLiner in this situation. It's rigid, goes together easily with ss pop rivets. The OD is 6 5/8". They make a flex connection for getting past the damper area to the stove.
(broken link removed to http://www.duravent.com/Product.aspx?hProduct=6)
(broken link removed to http://www.woodstovepro.com/store/Chimney-Pipe-Venting-Pipe/Wood-All-Fuel-Piping/6-inch/DuraLiner-c180/)

 

[drobbins]

thanks for the link
this advice is wonderful

 

[bholler]

I would use DuraLiner in this situation. It's rigid, goes together easily with ss pop rivets. The OD is 6 5/8". They make a flex connection for getting past the damper area to the stove.

It is going to be a pretty long flex section that still needs insulated separately i am sure it will work but the existing pipe is 8" A regular 6" wrapped liner will fit easily and be allot cheaper

 

[begreen]

Right all of 3 ft.