Hearthstone Clydesdale wood insert - help please

[ClydesdaleBurner]

Thanks for answering my questions. I'm just now learning that the art of getting a "long burn" is having a longer period of coals going. When I first started burning I would reload just after the flames went out. Now I've learned I can hold off on that reload and get 1-2 hrs out of the coaling stage (if there is enough coals) and that makes less wasting of wood. Of course if its cold... then I'll fire it up right away.

Great discussions today for us Clydesdale burners. All very helpful.

 

[bluesisgreat]

It looks like I've been away for a while - the truth is that I just did not notice that I needed to click 'next' at the bottom of the page - so I did not see any of the postings past the first page. I also no longer received notices in my email that someone posted a reply - I'm wondering why.

Thank you everyone - fabulous information. Of course, thanks a lot to Dan with whom I've been emailing offline - and because I knew he was posting his notes on the forum, but could not find them, I looked more attentively. You can tell that I don't participate in too many forums .

My mind is set now. I'll be getting the Clydesdale with the screen option. To make up for the esthetics, I'll be getting the blue-black enamel finish, which is a little less industrial than the painted black, more resistant to bumps, and easier to maintain/clean. I'm still thinking whether to mount it flush or the regular way. BTW - the blowers now come standard on both the Morgan and the Clydesdale. I'll keep you all posted on how I like it, and I make sure I'll post a picture, as well.

The thing I'm dealing with now is finding the right tile to match for the hearth extension and the surround. The requirement for the hearth is 18" from the glass - so if I mount it how everyone recommends, and get the maximum efficiency out of it, I need a 23" hearth. Mine is only 16", so I need an extension either way. So, while I'm looking at tiles, I'll still be thinking about which option to use for mounting.

For the record, I'd like to mention that the Clydesdale is unique in the fact that it requires the least clearance to the mantle: only 24" above the stove, which makes the total distance from the top of the hearth to the bottom of the mantle only 46.5". This is all without any kind of horribly-looking heat shield. I told Hearthstone that they should do a better job at marketing that, it is definitely a differentiator.

The peculiarity is that the Morgan, its smaller brother, needs significantly higher clearance (34"), which does not make too much sense. I had looked at Jotul, too, and there the bigger the insert, the higher the distance to the mantle is required - and all required clearances about the same as the Morgan. Only the Clydesdale was lower - so I was quite worried that it may have been a typo in the manual. My mantle is only about 50" from the floor, so it could've been a problem.

But I double checked these specs with Hearthstone, and they said that this is indeed the case. Any thoughts on that? of the stove makes it better insulating, so I’m still a bit nervous. The Clydesdale is not just a scale-up of the Morgan, but quite different in design (less deep, but wider and taller), so in principle it could have different specs. I called the company to double check - and they stand by their numbers, they said that all those numbers came from independent outside testing. However, I was not able to find out an explanation about what in the design makes that possible. Any thoughts on this?

 

[ClydesdaleBurner]

Bluesisgreat - Rekindling this thread to see if we can get an update from you. Did you end up getting a Clydesdale? Maybe you haven't had it installed yet... However when you do I was hoping you could post a picture or two of the Clydesdale with the blue black enamel finish... I almost got that one, but the shop had the mattle black in stock so I just settled for that.

 

[bluesisgreat]

Thanks, ClydesdaleBurner!

I'm still looking at tiles or other stone to do the hearth and the surround of the fireplace. Since my fireplace is 70" wide, which is not a standard width, it makes more sense to have a mason build the hearth rather than ordering it custom. So, I'm looking into tiles or other stone for doing the surround and the hearth.

I've gotten recommendations for a couple of masons, but none showed up to see the job site yet. My sample tiles did not show up yet - but the sample of the blue-black ename did - so I'm ahead.

I'll definitely post a picture when it will all done.

Meanwhile, I've been making a fire every night downstairs, where I have a regular fireplace. One funny thing is happening: whenever I have the fire going for a long time - which happened a couple of times during the holidays, something happens with the boiler responsible for the hot water heating - somehow the ouput gases, or gases from the fireplace chimney get drawn back downstairs, my CO detector shows over 160 ppm, and the safety switch shuts off the boiler. The first time it happened, I found myself without heat when I went upstairs. Now I learned that there is a tiny reset button in the back, and I can turn everything back on. The boiler chimney is right next to the downstairs fireplace chimney - I think there is some interference.

Any thoughts?

 

[bokehman]

160 PPM is an extremely dangerous level of CO (life threatening to children and feotuses). Everyone should leave the property immediately and not re-enter it until both fires are extinguished and the property thoroughly vented. Neither of the fires should be used again until the problem has been rectified by a profesional.

What's happening is that boiler and the fireplace both draw combustion air from inside the house. If there is not enough air coming in to maintain both fires (or even one) the two will compete for what air there is. The fire with better draft will win and the chimney of the other fire will stall or flow in reverse. The chimney with the reduced flow (maybe both) will start cooling down and the anti-draft situation will get progressively worse, setting up an accumulative syndrome making the concentration even higher with every passing second.

 

[bluesisgreat]

Thanks, Bokeman - that makes a lot of sense.

As far as my particular situation - the safety switch on the boiler automatically shut it down, so the CO levels came down within a couple of minutes. When I was done with the fireplace, and it was all put out, I reset the boiler, so the heat in the rest of the house came back on.

I guess my house is better in sulated than I thought

 

[Gooserider]

Sounds like Bokeman has it nailed on what the problem is and why. I would STRONGLY reccomend looking at adding a source of outside air to one or both units (these are often refered to as OAKs or Outside Air Kits) This is essentially a duct that goes from the outside directly to the appliance's combustion air intake. It supplies the needed combustion air instead of drawing it from the room, and will often both increase your efficiency, and end that battle for combustion air. In some places they are required by code, especially in new construction. Some folks even like them in older "leaky" houses as they reduce the infiltration of cold makeup air through the cracks so you get fewer drafts.

Gooserider

 

[bluesisgreat]

What a great idea! Thank you very much, I'll look into it.

I assume that this should be added to my boiler - because it would not apply to the fireplace, right? That's already taking whatever it can from the outside.

Eventually, in a year or two, I'll probably get a wood insert in this downstairs fireplace - especially since I expect that I'll really enjoy my Clydesdale upstairs.

For now, it is really frustrating that these masons around here are busy, and I still haven't gotten one to come take a look at the place. It also took forever for the store to send me their insurance information, which I need for the permit. But hopefully I'll have my Clydesdale installed within the next month.

 

[Cath]

blueisgreat,
It looks like you're making good progress. Would you consider posting pictures when you're done? It may be interesting to see what it looks like now.
~Cath

 

[Gooserider]

What a great idea! Thank you very much, I'll look into it.

I assume that this should be added to my boiler - because it would not apply to the fireplace, right? That's already taking whatever it can from the outside.

Eventually, in a year or two, I'll probably get a wood insert in this downstairs fireplace - especially since I expect that I'll really enjoy my Clydesdale upstairs.

For now, it is really frustrating that these masons around here are busy, and I still haven't gotten one to come take a look at the place. It also took forever for the store to send me their insurance information, which I need for the permit. But hopefully I'll have my Clydesdale installed within the next month.

Well I didn't see anything in your earlier descriptions that said you had outside air supplied to either the Fireplace or the boiler - it would seem to me like BOTH could benefit, but I'd probably try to do the boiler first since that's a fixed location for the intake, and it would be easy to hook a duct up to - talk to your local heating and air guys, I'd expect there is a kit designed just for this.

One other "dumb question" - I assume that the boiler and fireplace are using seperate flues? They ought to be, as it is a definite and MAJOR code violation for appliances to share a flue with a couple of minor exceptions, none of which would include a fireplace and an oil burner....

Gooserider

 

[bluesisgreat]

Cath - I'll definitely post pictures. It will be beautiful - that I know

Gooserider - no, there is no fresh air intake for either the fireplace or the boiler (that I know of). I mis-spoke when I made the comment regarding the fireplace - I just can't picture exactly its 'intake'. How could it be connected to otside air - would you drill a hole? How woud that affect the chimney draft? I'm quite curious now. For the boiler, I imagine that you'd put a pipe out through the chimney, similarly how they do for the wood inserts. Is that so?

To answer your question - the fireplace and the boiler have separate chimneys, but not too far from each other. I was actually on the roof this morning (I have a flat roof), and looked to see how close they are. I had thought that they are next to each other - but actually the upstairs chimney (the one that will take the Clydesdale) is in the middle. The chimneys are actually built together - there is a common outside wall, with three openings/chimneys, corresponding to the three burning locations. The boiler opening is a little smaller than those for the fireplaces. None of the openings have covers - so this is something else I need to take care of. I could see all the leaves down the middle, unused chimney.

 

[Gooserider]

Cath - I'll definitely post pictures. It will be beautiful - that I know

Gooserider - no, there is no fresh air intake for either the fireplace or the boiler (that I know of). I mis-spoke when I made the comment regarding the fireplace - I just can't picture exactly its 'intake'. How could it be connected to otside air - would you drill a hole? How woud that affect the chimney draft? I'm quite curious now. For the boiler, I imagine that you'd put a pipe out through the chimney, similarly how they do for the wood inserts. Is that so?

The typical approach for doing an outside air kit is to drill a hole in the wall, often going through the sill area since that's easiest, and installing a vent that sort of looks like a dryer vent without the flap. The then run a duct from the vent to the appliance where they have an adapter to connect it to the air intake. Typically the duct is fairly small, 3-4" diameter is typical, some even use dryer vent duct materials. With a furnace this is pretty easy as you have a fairly small area where the burner pulls in the combustion air. With a fireplace, it's harder as the combustion air comes in through the entire fireplace opening, unless that is blocked by doors, and much more air is needed because of the way a fireplace works. For a fireplace they might put a duct into the back of the firebox, but that is hard to retrofit, so mostly they just put the duct near the opening and hope the air makes its way over. Some applications have a fan like that in an HRV ventilator that just tries to bring more air into the room in general.

Stoves and inserts are designed to be mostly run with the doors closed, so they also have small well defined air intakes, and use an approach more like that used on a furnace.

To answer your question - the fireplace and the boiler have separate chimneys, but not too far from each other. I was actually on the roof this morning (I have a flat roof), and looked to see how close they are. I had thought that they are next to each other - but actually the upstairs chimney (the one that will take the Clydesdale) is in the middle. The chimneys are actually built together - there is a common outside wall, with three openings/chimneys, corresponding to the three burning locations. The boiler opening is a little smaller than those for the fireplaces. None of the openings have covers - so this is something else I need to take care of. I could see all the leaves down the middle, unused chimney.

Glad to hear you have seperate flues (minor definition - a "FLUE" is the passage that smoke exits through, a "chimney" is a structure that can contain one or more flues) a multi-flue chimney is no problem, though some will say that you should have slight differences in the heights of each opening. You can either get caps that cover each flue opening individually, or a common cap that will cover the entire chimney top with one peice. You can also do fairly simple or get really elaborate with fancy chimney pots and other such decorative caps.

Gooserider

 

[bluesisgreat]

Thanks, Gooserider for all that interesting information - and I'm really glad to learn the exact difference between chimney and flue. Regarding the caps, I already talked to the people who will install the insert to add caps to all the flues, so it will happen soon.

Regarding the different heights on the chimney - would the firepace chimney be desired to be higher than the boiler chimney? For the Clydesdale installation, I'm just about at the limit of minimum flue height - so I was wondering if it would be desirable to extend the middle chimney higher.

While on the roof, I also noticed a couple of pipes sticking out, in some other parts of the roof. One was far away, the other about 8-10 ft. away from the chimney. They looked like air intake pipes - about 3-4" diameter, made out of metal. What do you think they are? What other appliances need venting or air intake? The one far away is somewhere above the kitchen.

Silvia

 

[jadm]

I have learned a lot - as always - reading replies to your topic. I am a current insert (Napoleon 1101) owner who has never had a free standing stove and am considering switching to a Hearthstone Phoenix hoping to get more heat and longer heat into the area where our insert is.

Thanks to the person who explained the heat diff. between an insert and a stove.

 

[Gooserider]

Thanks, Gooserider for all that interesting information - and I'm really glad to learn the exact difference between chimney and flue. Regarding the caps, I already talked to the people who will install the insert to add caps to all the flues, so it will happen soon.

Sounds good. As a minor note, the one downside that some folks experience with caps is that they can get clogged with creosote, but this usually isn't a problem if you are burning good wood and operating your stove properly. If it is, then enlarging the holes in the screen can help reduce the problem.

Regarding the different heights on the chimney - would the firepace chimney be desired to be higher than the boiler chimney? For the Clydesdale installation, I'm just about at the limit of minimum flue height - so I was wondering if it would be desirable to extend the middle chimney higher.

I'm not sure of the exact rule, but my understanding is that the shortest chimney is the one that should stick up the highest, and the difference only needs to be about 6" to a foot. Since you are putting the Clydesdale on the upper floor, that is the one that should be pushed up. The other question is how you should extend it. With a masonry chimney, the most common approach is to add a short section of clay flue tile. Or if you're getting a liner, make the top section rigid and let it stick up a bit extra, or use flex (preferably insulated) and one of the "Extenda-flue" units that our fearless webmaster sells.

While on the roof, I also noticed a couple of pipes sticking out, in some other parts of the roof. One was far away, the other about 8-10 ft. away from the chimney. They looked like air intake pipes - about 3-4" diameter, made out of metal. What do you think they are? What other appliances need venting or air intake? The one far away is somewhere above the kitchen.

Silvia

Well I don't know what is in your house, but normally you will have "stink pipes" that vent your sanitary sewer plumbing (drains) - these are a critical part of your sewer system as they prevent the build up of potentially explosive sewer gases - however in a newer house they are usually PVC plumbing. Typically they will stick straight up a few inches to a foot or so, and have no caps or covers on them. The ones I've seen have been made of pipe, and are more like about 2-3" diameter. They will be located more or less directly over each plumbing "stack" or set of drains. Other possibilities could be kitchen or bathroom vent fan outlets, drier vents, etc. These are normally light guage sheet metal, and are larger, 3-6" diameter, and will typically have some sort of cap on them

Gooserider

 

[bluesisgreat]

Thanks a lot - like always, a wealth of information.

I think the pipes must be from the sewer system - my drier and the hood above the cooktop vent on the side of the house, just like you said, with about 5-6" light metal pipes with a flap on them. Just for the record, my house is old, and I have a septic system and well water.

I'll keep everybody posted on my progress on all fronts.

 

[bluesisgreat]

I now have a question regarding the hearth and the R value. Is a slab of granite about 1" thick good enough? My understanding is that it has a very low R value, so it needs something else below it to meet the wood insert installation spec, which calls for R=1 (two orders of magnitude higher than granite).

However, all the installers I talked to seem to think that it would not be a problem, and don't know too much about R-values. Ready-made hearths are constructed with some 1" material (dura??? - I can't remember the name) for the fire-resistance, plus tiles on top, just for the esthetics - consistent with my understanding that such thin granite would no be adequate.

The hearth would extend only 2" farther than the existing hearth - which is made of stone, and flush with the floor. I imagine that the existing hearth has the same issue of not having an appropriate R value, but the comment I got from the fireplace inspector when I bought the house was that it was only too short, and nothing about not having the right construction. I have hardwood floors around it.

Of course, this fireplace with the existing small hearth has been used for almost 50 years with no problem - but I don't know what th story is with a wood insert.

Any thoughts?

 

[bluesisgreat]

PS) I just went through the picture gallery on this site, and if my understanding is right, I saw a lot of installations (stoves and inserts) that would not have a high R value - just a thin layer of stone/brick of one sort or another. So, I would assume that those houses did not go up in flames, and thus a slab of granite should be OK - even though not to spec.

But I'm still intrigued by this spec - when I first read about R value for the first time, I thought that this was one of the reasons that some fireplaces are installed high, and have a hearth on the order of one foot in front of them - thicknes brings the total R value up.

Thanks!

 

[Gooserider]

Traditional fireplaces are generally built in large part on a masonry foundation, so they have good fire resistance / R-value inherently on the firebox, and pretty good on the hearth, Zero-Clearance pre-fab units are pretty well insulated, but may have additional specs on the hearth - both generally pull so much air into them, and put out so little heat, that they don't need huge hearth R-values, and most of the reasons for the raised hearths is aesthetics - get the fire up where people can see it... There are code requirements for clearances and such, and they have tended to go up over the years as fire safety has become more of a science, and possibly because the loss of the skills involved in heating with fire due to most people relying on automated technology more and more, causing more accidents... However they are not as clearcut as a stove manual is, and may be

An insert or stove however, can potentially put out MUCH more heat, and a lot of that heat comes in the form of radiant heat coming out the front of the stove, which increases the need for insulation on the hearth. Further, the nature of an insert or stove allows them to be tested scientifically to determine just how much insulation is needed, which can (and does) vary from model to model. There is an article on hearth construction in the wiki which, among other things lists a great many materials and the R-value of common thickness layers. Granite is listed at R= 0.083 for a 1" thickness, which would not even be close if that was all that you used and the appliance manual called for an R-1 value for the hearth. However many inserts don't require as much, so you might be able to find a different brand where it would be adequate. The other alternative that I would suggest would be to build a "sandwich" of one layer of Micore, a layer of Durock, followed by a layer of 1/4" granite tiles - this would give a nice look and meet the insulation requirements.

You might also talk to your building inspector (the only opinion that really counts since he's the one that signs off on your permits and inspections) and see what he will require. The requirements are in a bit of flux right now, as the code in the US recently changed from 16" in front of loading doors to 18" - but many manuals haven't been updated yet to reflect the new distances, and there are disagreements about what value should actually be required. Further, while the stove manuals mostly will only list one value for the required R value, mostly to keep things simple, one could argue that the value for the edge away from the stove doesn't really need to be as high as directly in front of it - thus SOME insepectors will allow a little flex in their requirements, especially when looking at upgrading a pre-existing install - however this purely discretionary on their part, so you need to make a case for it.

Gooserider

 

[bluesisgreat]

Thanks a lot, everything makes sense now.

I am wondering why you suggested adding the durock layer, as well - I found that 0.5" of micore has R=1.1 - so that should be plenty already. Are there some mechanical issues with putting granite right on top of micore?

I also found another brand of ceramic board, fibrefrax, which has the same R value as micore. Is one better than other, or easier to find? A while back when I talked to the people who are selling me the stove, I was told that the bottom layer should be some metal sheet, and then the sandwich. What's behind that?

This is a useful link for the various materials and their R values.

(broken link removed to http://www.chimneysweeponline.com/horvalue.htm)

 

[bluesisgreat]

I posted before reading the Wiki - I think now that you suggested added the Durock on top just for added protection - along the lines that more R is better. Maybe then I should use a thicker micore? I want to use granite slab, not tiles - so I need to talk to the installers and find a solution for the edges.

I still find it amazing that in my neck of the woods the professional installers are not familiar with the R value. Maybe few people have inserts, and they only know about fireplaces...

I also learned that micore may be hard to find. I'm hoping that my stove dealer will be able to procure it - even though they mentioned durarock when I talked to them.

 

[Gooserider]

I posted before reading the Wiki - I think now that you suggested added the Durock on top just for added protection - along the lines that more R is better. Maybe then I should use a thicker micore? I want to use granite slab, not tiles - so I need to talk to the installers and find a solution for the edges.

Not really - it's more a "nature of materials" thing - Micore is comparitively "soft and squishy" so even though 1/2" of Micore is more than you need purely for the R-value, it isn't suitable as underlayment for tile or your granite slab, the Durock is there as underlayment... While it is true that more R is theoretically better, and you would get that with the added Durock, it isn't really all that necessary, the only time I really suggest adding extra R would be if trying to do "future-proof" construction where you could accomodate any stove that you might want to put there without having to worry about inadequate R-value making you need to reconstruct. In the case of an extension, this generally isn't as big of a deal - there is no real benefit in making the extension have a higher value than the original hearth.... In terms of how to handle it, as long as the extension ends up being larger than the minimum, it doesn't really matter in code terms how you handle the edges - some people use wooden moldings. What might also work would be to use the method I did with my extension of cutting out some of the subfloor, and building back up with the Micore and Durock so that only the granite would show above the floor.

I still find it amazing that in my neck of the woods the professional installers are not familiar with the R value. Maybe few people have inserts, and they only know about fireplaces...
I also learned that micore may be hard to find. I'm hoping that my stove dealer will be able to procure it - even though they mentioned durarock when I talked to them.

I'm surprised the installers don't know about this sort of thing as well, you'd think they would want to meet safety standards, but... I'm less surprised about the materials though, Durock is a very standard material, most building supply places carry it, with the possible exception of Home Depot... Micore is not a commonly used construction material so it can be harder to find. However it is one of the best things to use to get a lot of R-value in a minimal thickness.

Gooserider

 

[bluesisgreat]

hi, Gooserider - well, I was able to find a place that sells micore - they also sell fireplace surround/hearths kits. I talked to them, and I was told that it is OK to use micore alone, it is not necessary to add durock - but I want to check with you, especially since the people who will be doing the installation have never worked with this material.

For me, using micore alone seems like an advantage, especially because it is squeshy - it means that whatever irregularities are in the stone that I have right now on the hearth would be evened out, I would not have to worry about some high spots that would produce stress on the granite slab on top. I also need the least height possible on the hearth because of the mantle clearance.

Could you please comment?

-Thanks!

 

[bluesisgreat]

I've uploaded the picture of the fireplace where the insert will be. Once I have it done, I'll change the picture with the new one. Now I'm curious if it will show.

 

[Gooserider]

hi, Gooserider - well, I was able to find a place that sells micore - they also sell fireplace surround/hearths kits. I talked to them, and I was told that it is OK to use micore alone, it is not necessary to add durock - but I want to check with you, especially since the people who will be doing the installation have never worked with this material.

For me, using micore alone seems like an advantage, especially because it is squeshy - it means that whatever irregularities are in the stone that I have right now on the hearth would be evened out, I would not have to worry about some high spots that would produce stress on the granite slab on top. I also need the least height possible on the hearth because of the mantle clearance.

Could you please comment?

-Thanks!

Well most of the discussion I've seen has been for folks using tile, or stone that works the same way - for instance I used 1/4" slate on my own extension - and when working with tile, you MUST have a rigid underlayment or the job will fail in short order - either the grout lines will break, the tiles will pop, or crack, etc. The reference stuff that I've seen says that Micore by itself doesn't have the rigidity required, but that adding a layer of Durock, with thinset between the layers does, assuming the floor underneath is OK.

You are using a single granite slab as I understand it, which may change things. However the basic idea stays the same, you either have to have a slab that is thick enough to support any loads on it's own, or have a substrate under it that can give it full support - such as a mortar bed on a rigid substrate... The Micore might be OK for that, but I'm not sure, and I don't really know who to ask, unless you can go to the manufacturer's website and get a tech support person to help.

Gooserider