Woodstock Keystone installation questions

[DBoon]

Hello All,

I'm considering the Keystone for install in a renovated house. The house is well-insulated and the Keystone will do the job, so my question isn't about heating capability. My question is about suitability for heat radiation.

The install is in a fireplace opening that is 37"H x 41"W. To achieve the 10" front clearance, the body of the Keystone would sit about 5" back into the fireplace opening (the operation levers would sit further back, but would have good access for adjustments. The back 5" portion of the stove body would have about 10" of clearance all around. The front 8.5" of the stove body would sit in essentially free air with good air circulation around it (20" vertically to the masonry lintel, >20" to nearest item on the sidess. .

So, my assumption is that the Keystone would throw most of its heat off the top front half of the stove (where the catalytic combuster sits) or the front glass, with less off the sides or back. Can anyone tell me if this assumption is correct? If so, then I need not worry about this install providing reasonable heat.

FYI, while I plan on burning this stove a lot, I don't believe we'll be hard-core 24/7 burners. The house also has radiant heat and a GSHP, so I anticipate I would really only use the stove a lot during peak winter heating season. And if I lose 1/4 of the heat out the back, it won't be the end of the world.

 

[begreen]

Might work ok with a block-off plate in the damper area. Is this an interior or exterior chimney? Is the flue large enough to fit an insulated 7" liner?

 

[Woody Stover]

Get the optional heat shield for the back. It will reflect the radiation back to the stove and keep it hotter. The rising air flow between the shield and the back will pull heat off the back.
It's a great little stove, BTW.

 

[weatherguy]

My sister is heating 1600 sf in Maine with that stove, heat shield and block off plate as mentioned above and you'll be good.

 

[Woody Stover]

my assumption is that the Keystone would throw most of its heat off the top front half of the stove (where the catalytic combuster sits) or the front glass, with less off the sides or back.

The cat sits pretty much in the middle of the top of the stove but the air flowing up through the shield, and the convection out of the fireplace should flow the heat from the top of the stove out into the room, I'd think. The sides will heat up more if you run some flame in the box. If it's an interior masonry chimney, it will act as a heat sink for any radiation hitting it but that will stay contained in the house over the long haul. If it's an exterior masonry chimney and you find you want more heat, you may want to put a thin insulating layer on the inner front of the fireplace and paint it black to 'disappear it.'
You said 'well insulated,' but what is the layout and sq.ft. you want to heat?

 

[DBoon]

Might work ok with a block-off plate in the damper area. Is this an interior or exterior chimney? Is the flue large enough to fit an insulated 7" liner?

Thanks for your comments/questions, begreen. There is a block-off plate installed, and it is well-insulated above that. The chimney is exterior and contains 1" of rockwool insulation between the masonry core and decorative stone veneer. The liner is an already installed 6" double-wall insulated pipe running straight up about 25'. It's as about as good a setup as can be had, thanks to a lot of info read on this site over the years. I'm a little worried I'll need to use a pipe damper to restrict draft, but we'll see. I've not had to use it on a Lopi 1750 that was temporarily installed there.

Hi Woody, I've read a bunch of your Keystone posts. It's a great looking stove - it was the one my wife was initially drawn too when we visited Woodstock a few years ago, but I thought it would be too small, but now I think it will be just the right size.

convection out of the fireplace should flow the heat from the top of the stove out into the room, I'd think

I have power to the back of the firebox and could potentially just put a box fan back there running at a really low speed to just gently push air out past the stove. I'm pretty much done with the constant low hum of a blower on a wood stove, though, which is one of the attractions of the Keystone.

The cat sits pretty much in the middle of the top of the stove but the air flowing up through the shield, and the convection out of the fireplace should flow the heat from the top of the stove out into the room, I'd think. The sides will heat up more if you run some flame in the box.

The area above the cat will breathe pretty well with 20" of clearance to a bluestone lintel.

If it's an interior masonry chimney, it will act as a heat sink for any radiation hitting it but that will stay contained in the house over the long haul. If it's an exterior masonry chimney and you find you want more heat, you may want to put a thin insulating layer on the inner front of the fireplace and paint it black to 'disappear it.'

It's an exterior masonry chimney, but there is a 1" rockwool insulation wrap around the core. It's primarily a decorative masonry chimney - the "fireplace" is really just an alcove that won't have firebrick, etc. in it to permit making it a real fireplace in the future. I could put some more insulation inside in the back and it would be pretty unobtrusive, for sure. But I don't think I'll need it.

You said 'well insulated,' but what is the layout and sq.ft. you want to heat?

The house is 1750 square feet, 60/40 split between first and second floor. The first floor is mostly open. The heat loss at 0 degrees F is about 18,000 BTUs/hour (modeled) and so far coming in at about this based on radiant floor heating performance. The blower door test came in at 1.6 ACH50 with some gaps now resolved, so it is a tight house (yes, it will have an HRV installed). I think the stove will be sized just about right for supplemental heating for the house, and occasional use as a back-up heater in power outages.

 

[Woody Stover]

liner is an already installed 6" double-wall insulated pipe running straight up about 25'. It's as about as good a setup as can be had, thanks to a lot of info read on this site over the years. I'm a little worried I'll need to use a pipe damper to restrict draft, but we'll see. I've not had to use it on a Lopi 1750 that was temporarily installed there.

The Ks breathes easily, but you can really shut the air down low. I've never really tried to see how low I could run it..I might go a little under .5, rear-vented on ~16' insulated liner. There's a 1/4" hole in the ash pan housing that feeds air to the coals through the ash grate. You could partially block that, but just letting the ash pile up on the grate should have a similar effect. I have a pipe damper in the tee snout, near the rear flue exit, but don't use it. You could probably use one, top-venting into 25'. I'd just go ahead and put it in.

I have power to the back of the firebox and could potentially just put a box fan back there running at a really low speed to just gently push air out past the stove...The area above the cat will breathe pretty well with 20" of clearance to a bluestone lintel.

Heck, you could rig one or two computer fans under the ash pan housing, pointing back. They're all pretty quiet but you can find some really quiet ones. They come in a few different sizes, speeds, construction qualities (bearings,) and some have in-line dip switches to select different speeds. They shouldn't get real hot under the pan housing, if you don't dump all the ash through the grate and empty the pan at the same time. Or maybe you could rig some kind of insulating protection..not violating C to C of course. I'm sure you could also find a really quiet flat, long fan like what some wood stoves use, not sure what they're called..squirrel cage? I heard one at the stove shop on a Lopi Liberty, and it was very quiet. I don't think you even need that much air moving, though. Yep, the high lintel will make it easy.

The house is 1750 square feet, 60/40 split between first and second floor. The first floor is mostly open. The heat loss at 0 degrees F is about 18,000 BTUs/hour (modeled) and so far coming in at about this based on radiant floor heating performance. The blower door test came in at 1.6 ACH50 with some gaps now resolved, so it is a tight house (yes, it will have an HRV installed). I think the stove will be sized just about right for supplemental heating for the house, and occasional use as a back-up heater in power outages.

begreen is undoubtedly more versed in those numbers than I am, but I'm guessing they are pretty good. 18K BTU at 0 degrees, even I can understand. I can tell you that you can feel some radiation if you are sitting within about 20' of the stove, especially if you have it cranked up a bit, running some flame in the box.
Keep us updated. I bet you're looking forward to seeing how it all pans out, and so are we.

 

[DBoon]

There's a 1/4" hole in the ash pan housing that feeds air to the coals through the ash grate. You could partially block that, but just letting the ash pile up on the grate should have a similar effect. I have a pipe damper in the tee snout, near the rear flue exit, but don't use it. You could probably use one, top-venting into 25'. I'd just go ahead and put it in.

I saw this in one of your previous threads. I'd probably do that. The lower and slower I can burn the Keystone, the better. It will be a nice pairing with the radiant heat in the floors.

I have a pipe damper in the tee snout, near the rear flue exit, but don't use it. You could probably use one, top-venting into 25'. I'd just go ahead and put it in.

Yeah, I probably should do that, but the house is super tight, and I have a snoopy sniffer of a wife. The pipe damper I have now has some holes around the rotation mechanism, and I'd prefer not to introduce this unless it is really necessary.

Keep us updated. I bet you're looking forward to seeing how it all pans out, and so are we.

I'll post some 2D images of the install a little later. I am looking forward to finally finishing this project and enjoying what I have designed and helped to bring to fruition.

 

[DBoon]

Attached is a front view and top view that should more fully explain the proposed install.

 

[KennyK]

Hey @DBoon, clearly you've done, and are continuing to do, your homework. That said, I thought I'd add just a few thoughts, for whatever it's worth. I just installed a Fireview and am loving it! I put in a pipe damper as I have about 25 feet of 6" liner in my chimney, and while I'm just getting to know the stove, I have been using the damper and so far it seems to be helpful. For the little extra cost of a damper, strikes me like it might be worth it to put it in from the start so you can calculate that in all your other lengths of vent run and not have to do some parts over should you decide you need it later.

Also, any thought of going for a Fireview instead of the Palladium. Amongst other things, you only need 8" of front clearance, so even thought it's a bigger stove, it's not any deeper, and seems you'll be able to get more stove outside of the fireplace opening. In general, I feel like any radiant stove like this is going to do much better without any of it being inside a fireplace (or at least as little as possible) - mine is a fireplace install, but I have the stove in front of the fireplace with about 19" horizontal run to the T, and it's running beautifully! With 1750 square feet in central NY, even with a tight house, you might grow to really appreciate the extra space in the box. You can really dial in all of the Woodstock stoves, so I don't think overheating the space is a concern. I looked at the Palladium and liked that it had an ash pan and larger window, but I'm sure happy I went with the Fireview - the view is great, and so far I'm not really worried about the lack of ash pan as it's not hard to empty ashes. With either stove, might you consider building out the hearth a little bit in front to be able to get the stove in front of the fireplace and not in it? You could pretty easily build or put a prefab hearth-pad over the existing fireplace hearth. Just a few more thoughts...

 

[begreen]

Will the mantel be non-combustible? The Keystone requires at least 30" clearance to a combustible mantel.

 

[Woody Stover]

Attached is a front view and top view that should more fully explain the proposed install.

Nice and roomy. With my lintel at 28-3/4", it's not real easy to see the surface meter I have on the horizontal tee snout. I can't see the cat probe too well without a mirror but I have the paper clip marker attached, marking 1000. You can see it in the above pic, behind the bypass lever.

1/4" hole in the ash pan housing that feeds air to the coals through the ash grate. You could partially block that, but just letting the ash pile up on the grate should have a similar effect

I'd probably do that.

This morning I stirred the ash into the grate pretty well to where there were some open slots. The wind had come up and I heard a whistle that happens once in a while. I had assumed it was coming from the primary air but I reached under the ash pan housing and found it was coming from that hole. If you use a magnet to partially or fully block it, you can easily remove it when you want to try your hand at playing along with some of the pan flute mega-hits. Apparently that hole can pull an appreciable amount of air if you clear the grate. You can use that for starts and see how it works..if you pull the coals forward and clear the front of the grate I think it should promote a burn on the front of the load to get more heat up to the cat early, and you'd have flame that could more easily reach the cat scoop intake to kick it off. If I have the right fire I can easily get the cat rockin' immediately when I close the bypass at 175 stove top.

 

[Woody Stover]

Will the mantel be non-combustible? The Keystone requires at least 30" clearance to a combustible mantel.

Yeah, in that case you'll have to rig a shield for it. Maybe a sheet of copper, or I'm sure you can come up with something that will be attractive. Try the forum search for some ideas..

 

[KennyK]

Will the mantel be non-combustible? The Keystone requires at least 30" clearance to a combustible mantel.

With a mantel shield, it only requires 12" to combustible mantel.

 

[begreen]

With a mantel shield, it only requires 12" to combustible mantel.

Where did that number come from? I have not been able to find any specifics for this.

 

[KennyK]

With a mantel shield, it only requires 12" to combustible mantel.

Where did that number come from? I have not been able to find any specifics for this.

Look at page 5 here, sixth paragraph under Fireplace Installation and corresponding picture to the right of the page: (broken link removed to https://www.woodstove.com/images/editorial_support/KP%20PDFs/Installation-KP%202013%20email.pdf)

This is the same with clearances to mantel for the Fireview (30" without shield 12" with). Woodstock may literally have the world's best customer service of any company and a phone call will always result in speaking with someone who really knows the ins and outs about their stoves and will help you as much as you need. However, their website and manuals could be a bit more user friendly - had I been able to figure this out sooner, I may have gotten a Fireview years earlier! Here is where all their manuals live (https://www.woodstove.com/index.php/support), but for each stove you need to poke around to find all the info as it's broken into separate sections and you have to look through multiple links for each stove to get all the necessary information. Woodstock will, however, mail you complete manuals for any of their stoves free of charge. Hope this helps!

 

[begreen]

Excellent, that is nice documentation, thanks for the link. My docs are old, from 2013. Looks like I need to update them. They've added a couple pages.

A heat shield will need to be on spacers to allow air to freely circulate behind it. It can be fabricated out of sheet metal and painted black so it almost disappears when viewed on edge. Or it can be made out of copper for an interesting visual contrast.

 

[DBoon]

Will the mantel be non-combustible?

Rest easy, all, the mantel will be a non-combustible bluestone - a variety of sandstone locally quarried in this part of NY state and parts of Pennsylvania. I made sure the design satisfied a few important needs - non-combustible mantle to avoid an ugly heat shield, a nice deep lintel to shield the TV above it from excessive heat, and a lintel low enough that my short wife can reach things on it, and can open the TV cabinet too.

I put in a pipe damper as I have about 25 feet of 6" liner in my chimney, and while I'm just getting to know the stove, I have been using the damper and so far it seems to be helpful. For the little extra cost of a damper, strikes me like it might be worth it to put it in from the start so you can calculate that in all your other lengths of vent run and not have to do some parts over should you decide you need it later.

Hi KennyK, thanks for your post. I already have the pipe damper, and several lengths of pipe. Realistically, the cost of a pipe re-do won't set me back appreciably. I'm pretty philosphically committed to a tight home, and all the holes in that damper just rub me the wrong way. And if you had to live with the nose on my wife, you'd think about it twice also. So I'm pretty sure I'm going to try it without at first, and be careful with overloads and overfires, and see how it goes. I can always add it in later.

Also, any thought of going for a Fireview instead of the Palladium.

I did look at the Fireview. It's a nice stove, for sure, and I've read and heard only good things about it. A friend of a friend has one and he loves it. But at the end of the day, it is too Victorian looking for my taste, and my wife agrees. When we visited Woodstock, she liked the Palladium the most and the Fireview the least. She liked the Ideal Steel a lot (shocking to me) and even thought the Absolute Steel was pretty nice. But the stove is not going to go into that big of a house, I'm getting to the point where I am likely not that interested in trying to burn 24/7 and cut all the wood required of that (I refuse to buy wood), and I don't want the stove to dominate the design of the room - I want the opposite - a stove that fits in and just looks like it is a supporting part of the rest of the room. I'm guessing that the Fireview side door might have some clearance issues for me also. But in any case, we just don't like how the stove looks.

might you consider building out the hearth a little bit in front to be able to get the stove in front of the fireplace and not in it?

The hearth is professionally constructed and is all masonry through to the bottom into the basement. If I were to extend it even a little, it would cost me a lot of money for just a little benefit (my opinion) and realistically, it already sticks into the room the maximum amount without dominating the room.

One option is to possibly raise the stove a couple of inches - if I could do that without it looking ridiculous and without tripping over anything every time I walk past the stove (i.e., no fully raised hearth) I think I would do that. I might try to find someone who can forge me a 2" leg extender that matches the stove style. If I raised it 2 inches, I could bring it within 8" of the hearth edge and more away from the alcove.

...You can use that for starts and see how it works..if you pull the coals forward and clear the front of the grate I think it should promote a burn on the front of the load to get ... the cat rockin' immediately when I close the bypass at 175 stove top.

I've learned a lot about this stove from just reading your posts, so I look forward to trying it out next burning season. I fiddle a lot with my little Lopi stove to optimize the burn, so that comes naturally to me.

 

[Woody Stover]

I've learned a lot about this stove from just reading your posts, so I look forward to trying it out next burning season. I fiddle a lot with my little Lopi stove to optimize the burn, so that comes naturally to me.

I didn't discover all that stuff; Like you, I learned from reading posts of other users, some of whom are no longer around here. One of them mentioned the hole in the pan housing. One thing I considered doing is to drill a hole in the top of the stove so I can drop a short cat probe straight down to within 1/2" of the face of the cat. As you probably read, using a long probe in the hole provided in the back of the stove doesn't give a true cat temp reading. Yes, you can tell if the cat's taking off by a rise in stove top temp, but that's slower to happen. But you can also hear a certain tic, tic, tic as the cat expands the heat shield above it.
You probably wouldn't want to drill a hole in the top of your pretty, new stove and now I've kind of talked myself out of it as well. Yep, like you, I find tinkering to be half the fun with burning wood.