My IS Install

What brand pipes, particularly the 45's are those?

 

Heatfab 2611B

 

I added 3 more feet of pipe outside. The draft seems to be nice and strong now. In the yurt, I am only able to get 6 hours of heat before I have to add wood. Once 6 hours comes, the heat on the stove top drops under 300 and the yurt cools down quickly. I figured it wouldn't work as good in a yurt as it does in a house, but I was really hoping for 8 hours. I am open to any suggestions?

I am currently burning some really good seasoned yellow birch, maple and beech. I have about 50/50 ratio between large and small splits. I restrict the airflow to under 1/4. I have tested several levels within 1/4.

 

Don't know much about yurts, or what set-up you already have, but is further weather-proofing an option? I found a forum where yurt owners are discussing this. I don't endorse them since I just web searched it a minute ago, but thought it could be informative:

Insulation - Yurt Forum - A Yurt Community

 

I actually own that forum lol. Insulation is not something you want too much of in a yurt. It causes condensation/mold/mildew issues.

 

Ha! What are the odds?

 

I have a few ideas but I'll limit my response to one.

I have been thinking about covering up the bottom intake for the secondaries with a magnet.
The idea would be turn it into more of a cat stove.
I don't know if it would help or not. It might give it more of a steady longer output. Or it might make it worse.

 

Therein lies the rub, it is not how long the stove 'burns' but how long it puts out what amount of heat. It is not a problem to get an Ideal Steel (or similar, modern, combustor- based woodstove) to burn for 12, 16 even 20+ hours. The problem is how much heat the stove can put out for what part of the burn.

This is a typical, overnight, hard (Easy Boys!) burn for me using hardwood in an IS.


The stove reload is around 10:00 PM (2200 on the chart shown) and the combustor is very well engaged and burning off the volatile gasses for about 4 hours. After that, the rest of the wood / charcoal continues to burn pretty steadily until the end of the chart, which clearly shows the stovetop temp. dropping below 400F but remains pretty steady, at or just above 300F, until 8:00 AM the next morning. So that would be a 10 hour burn and the stove's heat output was sufficient to keep up with my house with the outside temp. being 6 F in the morning. I find this typical behavior for a well- packed IS full of <reasonably> dry oak. By well- packed, I mean just moving the coals around and shoving splits in the stove until I could not fit anymore but nothing special such as filling all the air pockets in the stove, picking through a big pile of splits to find just the right one, etc. Just plain' ole' filling the stove up and letting it run at a little less than 1/4 draft. That was mostly a 'cat burn' with few visible flames; note that the firebox temp. (when the thermocouple worked :-( ) shows the temperature in the firebox was well under 1,000F, indicating a smoldering fire.

In the end, the key to heating with firewood in any stove is about having control of the burn, having the stove burn cleanly and efficiently (which is where cat. and hybrid stoves excel) and the size of the firebox. As long as you use fairly dense, dry hardwoods such as oak, hard maple, etc., the stove should easily be able to maintain a stovetop temp. of 300F for an 8 hour burn.

I cannot even guess at what you might need to heat anything like a yurt though- no experience with those so I have no idea if the Ideal Steel is enough stove or not. ?? But if it is not enough stove, the only way I can see to really improve the situation is a larger stove as there are not many, if any, more efficient than an IS in my limited testing.

Brian

 

So, here's my thought. What if we could get that cat to peak out and hold at 1000 degrees instead of 1400? I think we are all looking for a long even burn. I wonder how much the secondary air feed effects cat temperature.

 

Not sure how the methodology would work out regarding numbers but I agree with the general sentiment. Also, I believe these stoves (the Ideal Steels) need more bottom draft, either from increased hole sizes in the angle steel in the front or through the grate at the bottom. But in the end, yep, I agree that an outside control would be of significant benefit. I was working on same when I had a small set back regarding my house (structural roof failure and ins. co. hijinks) and two fingers (mangled in an entirely self- caused wood splitting incident). I will again re- visit this issue but it may be some time yet.... I am still typing slowly due to right hand index finger lagging :-( Still, not complaining 'cause I could have just as easily lost one or two digits so really, in a left- handed way- I am lucky.

Brian

 

Right, and since we know the IS is one of the most efficient stoves then about the only thing to consider would be a larger stove that is at least as efficient. And in the 6" flavor I'm not sure if there are any bigger than the IS that are as efficient? The BK King could give you more btu's for longer but then your into 8" territory and would need a new venting system.

My IS is still sitting on the pallet in the shop. Been so busy all summer. Still trying to find a local source of bricks for a temporary hearth pad. Menards has the ones with holes in it, maybe I'll just use those and lay the bricks on their side, but it'll cost me more bricks.

 

I almost feel like a large tube style stove would be better for this application. With no insulation you aren't looking for a stove that can burn at 350 degrees for 16 hours, you want one that will burn at 750 for 3 hours, and 300-600 over the next 5. Your heat loss is pretty huge, so you're going to be hard pressed to find anything that will keep the place warm for more than 8 hours in the winter. That being said, I think the burn cycle characteristics of a tube stove would heat your house better, albeit with larger temperature swings between reloads.

 

The stove he has does the same thing as a tube stove. It just has a cat added to it for added efficiency. All he would need to do is turn the air up a bit more and it would do that.

 

Suggestion for lengthening the burn? I have one.
First, has anyone else noticed on the PH and IS the first load of wood is mostly used to get all that mass hot? Seems that way for me. Yes the stove tops get hot but the sides take much longer. My mom has an IS and its a touch faster but not by much.

My suggestion is try to break the rules. I've tried it just once in my PH and it seemed to work well although I don't really have an issue with burn times. The PH stays at 400 through most of the coaling stage.
When your IS is coaling and still up at or near 400. Fill it up, close the door, let it sit for a minute or two to allow the firebox gain back some of the heat lost. Don't allow any large flames or charring to occur. Shut the bypass and shut the air down. My PH runs with air fully shut YMMV.
This seems to throw it down into a cat only function and secondaries seem to not ignite.
It seems to me when you let the secondaries char the wood as recommended they might go out when you shut the stove down but they quickly come back. I'm cool with that but,,,,,,,,,

I'm not sure how good this is for your cat and welcome opinions and scolding. I know it's breaking the rules. Possible to coat the cat etc etc.
Once again, stoves gotta be hot and the wood had better be dry. I ran my fireview like that quite a bit last year and it never complained. I don't think I'll need to do that this year with the PH, just wanted to see if I could.

 

Yes, I've mentioned that many times, that the PH does take a while to heat up all the mass during a cold start. One thing I noticed though, which speeds up the process is there is no need to wait for the stove TOP to get to 260 to flip the bypass. In fact sometimes my top is still only 100 degree's when I flip the cat, BUT, the stove pipe 12" above the stove is well above the 260, usually I wait for it to hit 300 which is only another minute. At that point, the cat is 260 or close to it and you know it lights up right away because you can immediately hear it "ticking" from heating up quickly as soon as you flip the bypass. I don't mean the normal stove iron ticking slowly as it heats, I mean the cat starts giving off really fast "tick tick tick tick tick" (about 10 ticks in 1 second!), and that only lasts for about 10 or 20 seconds. The stove top then heats up VERY quickly after that which indicates the CAT lit up and is putting out 1500+ degree heat per design.

And PS, the cool thing is all that heat that gets built up in the soapstone during the cold start, is all released long after the fire is out at the end of the burn... that sucker stays hot and gives off a lot of heat for several hours after the coals are gone.

 

I'm still learning the ticking
Yep, odd to see just a few coals inside and the stove top is still past 300. I like that in a stove.

 

Just my opinion so take all of this for what it is worth..... I do not think we can actually restrict the temperature of the cat. burn, at least not directly. The cat. simply burns whatever fuel (smoke) it is fed provided it gets sufficient oxygen to do so, and we certainly do not want to restrict that as it would simply have the cat burning some amount of smoke and the rest going up the chimney.

What dictates how much heat the cat. puts out is the amount of smoke the wood below it is feeding it. In a pure cat. burn, the wood below just pyrolyses, meaning it basically smolders without producing any flame, much like a cigarette. And that is the problem with throttling a large load of firewood, especially if it is a fresh re-load. The wood has to be hot enough to pyrolyse and throttling that too far back will basically 'put out the fire' in the firewood, as well as shutting down the catalyst. To get the whole thing going again, the fuel usually has to be heated up well beyond where it would just maintain a slow burn and basically produce more heat than desirable until it can again be throttled back to some minimum burn rate. The only way around this restriction that I know of is to externally heat the combustor, which of course takes additional, outside energy and that kind of defeats the whole purpose of heating economically with firewood in the first place.

All of that said, I have had some success relaoding an IS and immediately shutting it down to 'idle' status as another poster mentioned. But it only seems to work when the bed of coals in the stove is a pretty large amount compared with the amount of fresh wood being loaded- in other words, it does not seem to work when the stove is, say, 90% empty. But if there is, again say, a 40% intact coal bed, then filling the rest of the stove seems to allow the process to keep going without the whole high burn rate needed. But that also makes the the stove behave as if it is much, much smaller and it cannot go well overnight like that because it was only loaded to 60% capacity with fresh splits to start with.

This whole wood burning thingy is a tricky business if we try to regulate it closely and restrict how it burns. That is where a much smaller load of wood, burning 100% all the time is much more efficient.... those are called pellet stoves.

Brian

 

Thanks everyone for your advice on this; I am reading it all. One problem I have is that that I am only up at the yurt during weekends and other short excursions, so I haven't had a lot of test/burn time.

I find that from a cold start, I have to get at least one normal burn through it, to establish a good bed of coals, then load it up, let it burn for about 3-5 minutes, then restrict the air flow accordingly. It appears to be working as designed at that point. I put the temp gauge on the top, right above the cat, and the temp climbs immediately, along with the clicking noises.

When the first starts to cool, there are rather large coals in the bed. At that point, I usually disengage the cat, open the air and heat them up. I then stir them up and add more wood. The coals will take up almost 20% of the room in the firebox in many cases.