Second year with QF Isle Royale

[chadlebo]

Hi all! I'm back. So, we've finally gotten stove worthy weather here in Virginia and I've got the IR burning OK, at least a lot better than last year. I attribute that to having seasoned wood over fresh split dead wood like last year. My question is, what's the ideal chimney height for this stove? I'm at 24 feet with two 90's (one into the wall thimble and one in the chimney putting it up the flue). All brand new insulated stainless steel flex liner, except the two sections of single wall inside the house. I'm thinking I may be getting too much draw up the flue, as my flue temp about 12 inches above the stove typically matches my stove top temp. I noticed that when my seconaries are kicking, it almost seems like they're blowing right up the chimney. I checked my chimney and when the secondaries are burning, it looks like a jet blast out the top instead of the slow lazy heat waves like when it's choked down for the overnight burn. Is it supposed to be like that or are my btu's being scattered to the atmosphere? Is there a fix for it? My thought process says that if I slow down the draft, the heat being sucked up the chimney will have more time to be distributed to the house. Any input?

 

[revdocjim]

Glad the stove is working well for you. I couldn't tell from your description, but when you mention secondaries kicking in and the appearance of a jet blast from the chimney... when all of that is happening what are your air intake settings? If left wide open long enough almost any properly installed stove is capable of overfiring. You mentioned choking it down for the overnight burn, but once the stove is going well it needs to be choked down significantly to get the best burn. (please ignore if you already know all of this...)

 

[chadlebo]

Sorry. Yeah, guess I left out some significant information. So, I have a hard time getting any secondaries with a surface temperature below 500° and the only way I get all the jets throwing flame is if I open the air up for about 20 minutes which puts my surface temperature in the 600° range (top left corner of the griddle) and then close the air down to 50% or below. This usually gets all the jets throwing flame but usually for less than half an hour. And the flame that is produced seems to be sucked around the lip of the top baffle. So, an hour later, I'm back downstairs opening the air to almost 100% to get it back up to temp then back down a half hour after that to close it up. Over night, I close the air all the way to keep it going all night. Typically I'll let it burn up to 600, then fill it up and close it down. By the time I get up 7-8 hours later, it's down to coals with a surface temperature of 200 or less. My concern is how hot the stove pipe is. If it's the same as my st

 

[chadlebo]

Stupid phone. If it's the same temp as the stove top, does that suggests that my heat is going out the flue? I really hope I'm just burning this thing incorrectly, because all said and done, I'm $4k into the whole set up and using the same amount of wood as the old timberline and not getting any more heat.

 

[jatoxico]

So, an hour later, I'm back downstairs opening the air to almost 100% to get it back up to temp then back

This has me wondering. Once my insert gets to operating temp cutting air usually raises the temp in the box unless...my wood sucks, then it dies down and I have to give more air. Running with the air well open never lets the stove itself get that hot because the heat is going up the flue but if the wood is not great it won't burn well with air cut so it's a catch 22.

If you're concerned the stove is over-drafting (flames getting sucked up) that's kind of opposite of what you describe. Over draft tends to cause run away (over-fire) stove not one that cools down.

 

[chadlebo]

Ok, again my fault for not enough details. I don't get secondaries until after I close up the air regardless of the temp, I.e., even once I get 600°, there aren't any secondaries burning. Only once I close it up (slow down the air flow) will they start, but they'll only burn for a short while. I'm not a fire scientist, but I'm wondering if maybe my draft is pulling air too quickly for the secondaries to fire and when I close it up, I'm not giving enough air to keep the primaries hot enough to fire secondaries? And that's why I'm only getting secondaries for a short time, because that's as long as the main fire can stay hot enough to kick them off on the reduced air. If I put a flue damper in above the stove, would that slow down the draw so that the main fire could burn hot enough to fire the secondaries, while keeping the air in the fire box long enough for them to ignite? Anyone else dealing with a tall flue having similar issues?

 

[brad wilton]

Hi chadlebo,i have an j.a roby not the same stove at all .but i do have 30 ft of chimney,wouldn't say it's sucking flames up chimney unless i do leave it wide open.i can slow it down to slow rolling flames but i never get that pretty blue flame everybody freaks out on , but the stove still heats the house very well with good burn time .stop fiddling with it and let it do it's job .mho

 

[chadlebo]

It's not doing it's job, though, at least not to the efficiency I was expecting when I bought it. Like I said, I'm not getting any better performance than the 40 year old steel box stove it replaced.

 

[baseroom]

I have an IR with a two story chimney and two tee's as you describe. For me secondaries to light need a full load, dry wood, and cold weather. I find that in this in between weird weather time it is tricky because I have less than a full load and I try to get by with my "pretty good" wood but not my best and driest.

 

[Jags]

Okay - a few things...
I need to be above 500F stove top (taken from the same position as you do) for secondary burn to happen.
I follow both stove top and stack temps during the first stage of the burn and adjust the primary air to maintain proper (albeit high) stack temps. Stack usually follows fairly close to stove until about 4 or 500F mark, then stack will continue to climb faster if I DON'T start tuning the primary back. I maintain a stack temp of 600-800F until the stove top gets north of 500F. At that point, I will shut down the primary to about 10% open and the stove will settle in the 550-650F range and the stack will come down to ~400F internal temp (probe). I walk away till more fuel is needed.

You are running a stack that is quite a bit taller than me but you do have a couple of corners to contend with that I don't have. You may find that you need to be a bit more diligent with the primary air controls (adjust sooner than I), but I would suspect that your stove should behave in a similar manor to the above example. Give it a try.

 

[brad wilton]

The ir is supposed to be a pretty good drafter with your chimney height you might have to jump on turning down air a bit quicker

 

[baseroom]

Okay - a few things...
I need to be above 500F stove top (taken from the same position as you do) for secondary burn to happen.
I follow both stove top and stack temps during the first stage of the burn and adjust the primary air to maintain proper (albeit high) stack temps. Stack usually follows fairly close to stove until about 4 or 500F mark, then stack will continue to climb faster if I DON'T start tuning the primary back. I maintain a stack temp of 600-800F until the stove top gets north of 500F. At that point, I will shut down the primary to about 10% open and the stove will settle in the 550-650F range and the stack will come down to ~400F internal temp (probe). I walk away till more fuel is needed.

You are running a stack that is quite a bit taller than me but you do have a couple of corners to contend with that I don't have. You may find that you need to be a bit more diligent with the primary air controls (adjust sooner than I), but I would suspect that your stove should behave in a similar manor to the above example. Give it a try.

Always great info! Thanks. Quick question. Is your procedure Modified with less than a full load? Or do you always use a full load and just load less often.

 

[Jags]

Most of the time a full load goes into the stove. If for some reason I reload with a partial load (like to time it for an evening/overnight load or temps simply don't call for big heat), I still watch my stove/stack temps. That part of the equation doesn't change as that is simply the way the stove works. I have essentially burned up an entire short load, just to bring the stove to operational temps.

 

[jatoxico]

I don't get secondaries until after I close up the air regardless of the temp, I.e., even once I get 600°, there aren't any secondaries burning. Only once I close it up (slow down the air flow) will they start, but they'll only burn for a short while.

I think mainly the reason you don't get much in the way of secondaries on most stoves is that the fire will pull air from the path of least resistance. As long as the air needs are being met by the primary air, the secondaries are not being fed.

Only very rarely do I get much secondary action with the primary open full or 3/4. On those days that I do, I know when I close it down it's going to be a gates hell fire that wants to run away.

If your shutting air and the secondaries start to burn only to be followed shortly by a drop in temp (assuming there's still good fuel) then I question the wood or the draft and your draft sound OK from what you describe.

Your wood may be better than last year but still not as good as you may need.

So, an hour later, I'm back downstairs opening the air to almost 100% to get it back up to temp

This is the part I'm responding to from your earlier post, if this isn't exactly what you meant then my bad.