Isle Royale - Slowing the burn down?

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.
P

PaulF

Member
Nov 19, 2005
30
I have an Quadrfire Isle Royale purchased January 2009 to replace a Vermont Castings Resolute Acclaim. The stove feeds into a chimney about 30 feet high, where the flue lining is about 7 inches square.

When my Isle Royale has a medium load of wood, it will show 700-800 degrees on my griddle thermometer. I have been surprised that at this this temperature, I can set the air control to minimum (far right) and the temperature will not come down until a significant amount of wood has been burned. There are times when I would like to drop the temperature back a tad, but since air input is on minimum, I have no way to do this.

With several other stoves I've owned, I have always been able to control the air input to reduce the stove temperature while still achieving secondary burn.

I want to be able to reduce the temperature at times to achieve a slightly longer burn, but primarily because I feel that operating the stove so hot gives little margin for something going wrong.

Is this how your Isle Royale operates? I am wondering if I need to add an external damper in the stoves connection to the chimney flue to have more control.

PaulF
 
With a 30ft flue a key damper may be in order. Try it at closed about halfway to start. If that works well, just leave it there.
 
That's a lot of chimney, and a new damper might help. There isn't a lot to lose by installing a damper.

The other item to note is that Isle Royale griddle has hot spots. If your thermometer is in the very middle
of the griddle, that area reads over 100 degrees higher than on the left rear of my griddle. I keep my Rutland
thermometer about three inches to the left of center of the griddle.

Finally, its difficult for me to tell in your post when you are turning back the air. If you don't start shutting down
the air until you hit 650 or 700, temps will continue to increase as you gradually shut down the air, and they will
stay high for some time. If you haven't already, you might try making your adjustments to the air when you hit
500-550 with the aim of hitting a target between 550 and 700. If you want lower temps, try to have your air in
it's final position before you get to 600, If none of that works, a damper might help. Other people have reported
overdraft problems with the IR with a long stretch of chimney. I didn't notice any such problems with my 25 foot
chimney in the previous house and removed the damper without effect.

Edit: It also occurs to me that your thermometer might be not be accurate. Something else to check out.
 
Thanks for the suggestions. I started a fire tonight and was careful to reduce the air flow as the griddle temperature was approaching the 500 degree range. I used two thermometers (a Rutland and a Condor) placed a few inches on each side of griddle center. The thermometers read within 25 deg of each other. With the air control at minimum air (full right), temperature stayed around 500 for an hour or so as I fed it a few logs as needed. After about 2 hours and with a good bed of oak coals, I fed it 3 splits, about 4-5'' in thick, and as they started burning, temperature rose to slightly above 700 for about 30 minutes.

Since I was hitting 700 degrees with a fairly small load of wood and air control at minimum, I am concerned it might get too hot if I fill it with wood and go to bed. I think the suggestion to try a key damper is one I should try.
 
key damper and bigger splits. For us 4" splits in a 3 cu ft stove is what we call kindling. :)
 
I won't tell you not to get a key damper. It might well help.

I can tell you that if I add several new logs with the fire at 400-500, the stove will take off, especially if I've got the air
on full again. Generally, I load up, get it to 500-550, cut the air down in 2-3 stages to the sweet spot where things
level off, let it burn down to embers (200 to 400, depending on heat needs), rake the coals forward, repeat.

As BeGreen pointed out, bigger splits mean that things will happen more slowly. I use the top down method of burning
in my IR. With three big splits, a couple of smaller pieces on top, and then some kindling on top of that, I can light the fire
at 9 p.m. and have coals in the morning.
 
30Ft is alot of stack. Normally a key damper is not needed for the newer stoves, but there are installs where they make sense. Yours may be one of those installs.

It sounds like you are properly operating the controls, and nothing rings out as "wrong", so that would be my suggestion as well.
 
I dont mean to hijack this thread but I'm in the same boat with the OP. I'm trying to get used to how to burn the same isle royale after 20 years with the defiant encore. needless to say I'm impressed with the heat output when shes up and runnin. But alas I'm open to suggestions on how and if you can burn at lower temps.

She seems like she wants to run at 600+-

Also, Why do you guys rake the coals forward? Keeps the glass clean or something else??? I'd think you want to push the coals back seems more in line with the airflow.

I dont think we've had a cold enough night/day to let her run but I want to be prepared. Any tips or pointers will be appreciated.
 
maxed_out said:
I dont mean to hijack this thread but I'm in the same boat with the OP. I'm trying to get used to how to burn the same isle royale after 20 years with the defiant encore. needless to say I'm impressed with the heat output when shes up and runnin. But alas I'm open to suggestions on how and if you can burn at lower temps.

She seems like she wants to run at 600+-

Also, Why do you guys rake the coals forward? Keeps the glass clean or something else??? I'd think you want to push the coals back seems more in line with the airflow.

I dont think we've had a cold enough night/day to let her run but I want to be prepared. Any tips or pointers will be appreciated.
Click to expand...

There's nothing wrong with running at 600+. That's right in the sweet zone for this stove.

By raking the coals forward, the fire catches in the front first instead of the entire firebox. This produces better control
and longer burns. In doing so, the last wood in the stove to burn is the stuff in the back. So raking it to the front completes
the previous burn cycle. Loading on a full bed of coals from front to back will get the fire going very quickly but is more difficult
to control in my experience and results in shorter burns.

The primary air enters the stove above the ash pan and directs air to the front of the firebox. Start-up air enters through the
combustion tubes in the back, but I don't use start-up air on a reload--only on a cold stove.
 
The entire draft and internal burn flow is different between the defiant and the isle royale. Best to leave the old stove burning habits behind and learn the new.
 
Northwinds and BG nailed it.

And to confirm - yeah, the beast likes 600+. It just does. Smaller wood loads are called for if you need less heat.
 
definetely a beast! She seems to burn less wood than the defiant encore but maybe its just wishful thinking. It seems that with3-5 splits I can get this sucker way hotter than the DE in a much shorter ramp up.

Can you guys offer anything here? I get differing patterns on the glass depending on outside temps. I hooked up an OAK. No sense in burning when its 50 out you'd roast. At 40 I get brown buildup on the outboard sides of both door. At 35 outside I get a little on the lower right side of the right door. Below 35 outside doors ares clear. Once shes hot enough all burns off. Do you guys get brown stuff at these temps/ My guess is the stove is just too "cold". I'm probably fussing over nothing because we arent there yet as far as the cold weather but it would nice to know what your experience has been.
 
maxed_out said:
I'm probably fussing over nothing because we arent there yet as far as the cold weather but it would nice to know what your experience has been.
Click to expand...

I don't seem to have a problem keeping the glass clean - AS LONG AS - I keep the temp up where it is supposed to be. Relax. That baby will do you right. Heck, it ain't even cold out yet. That is when you can let it stretch its legs and run.
 
maxed_out said:
definetely a beast! She seems to burn less wood than the defiant encore but maybe its just wishful thinking. It seems that with3-5 splits I can get this sucker way hotter than the DE in a much shorter ramp up.

Can you guys offer anything here? I get differing patterns on the glass depending on outside temps. I hooked up an OAK. No sense in burning when its 50 out you'd roast. At 40 I get brown buildup on the outboard sides of both door. At 35 outside I get a little on the lower right side of the right door. Below 35 outside doors ares clear. Once shes hot enough all burns off. Do you guys get brown stuff at these temps/ My guess is the stove is just too "cold". I'm probably fussing over nothing because we arent there yet as far as the cold weather but it would nice to know what your experience has been.
Click to expand...

Once in awhile I get a little brown on the lower right side of the right door if I have longer burns with warmer temps out.
Doesn't sound like anything to worry about. If I'm around to tend the stove, and the stove dips below 450 before the coaling
stage, I'll give it a little more air to help complete the combustion. A good way to tell if you're burning clean is to see if
there's any smoke coming out your chimney. If there's little to no smoke, no worries.
 
I got rid of my beloved 1996 Defiant Encore this year and also bought an Isle Royale. The one big difference I noticed immediately was the draft on the new stove seemed much greater than on the Defiant. I can start with kindling and Oak logs without using Pine to get the fire going and have it at 600º in about 30 minutes. The Defiant took 2 or 3 times longer to put out that much heat. The IR jumps into action quickly and one time I was caught off guard during its break-in. The temperature jumped to 700º (I was shooting for 600º) before it leveled off probably because I was using mostly kindling and logs that were very small. Our temperatures in California are probably quite a bit higher than yours at this time of the year so we usually only put 1 or 2 Oak logs in at a time and can "usually" control the fire to burn between 500º and 650º without a problem. For your info, our connector pipe to the ceiling is 8' and the chimney is about another 10'.

We too are getting some blackening on the glass but it's usually because we let the fire burn too low. With the Defiant, the first couple of times I cleaned the glass, it was very hard to get clean. However, after using a stove glass cleaner a couple of times, I was able to very easily do it with a moist tissue. I'm hoping that's the case with the IR as well.

Good luck with the new stove!
 
Thanks all for your posts....some good info and its helping out.

Sierra Guy, our weather now on the east cost is like 60 during the day and 30 at night kinda like CA but it wont last. Tonight I lit the stove a little differently. I really let it run and char a load and i started backing down the air at about 700. She's now cruising now at 625 ish and glass is all CLEAR. I used the driest wood I could find. Yup about 30 minutes to back down.

I think my problem seems to be not letting it run up to 600 then level off. Just gotta get used to that. Never could do this with the Defiant Encore at 45 degrees out.
 
Usually, the next day's fire wipes away any darkening of the window corners. Once in awhile, I'll take a moist paper
towel dipped in ash to clean off any residue on the glass. Comes off very easily. I use the other half of the paper
towel to make the glass look good as new.
 
I installed a key damper about a foot above my stove. It did not seem to make much difference in the burn and griddle temperatures with the damper about half-closed. I was reluctant to close it much more, but I have had 3 burns since installing the damper, and I have even run with it in the damper fully closed position. In this position, it has some affect. This is with the stove air input at minimum (fully to the right).

Of course when the damper is fully closed, it does not completely restrict the air flow because there is a gap of a quarter to a half inch between the outer edge of the damper plate and the stove pipe, and the damper plate has a few small openings in it to be able to insert the shaft.

My first thought was that the damper plate was not really moving, maybe only the shaf twas moving; but there is a sheet metal screw sticking into the pipe. I can feel the plate hit the screw when it is very close to the fully closed position.

Tonight after I let the fire go down to a good bed of hot coals and griddle at about 500 degrees, I dropped several logs on the coals and moved the damper to the closed position. After about an hour, the stove is running at 600 degrees rather than the 700+ it runs with the damper more open.

I have no previous experience with key dampers. Has anyone else had an experience similar to mine?

PaulF
 
In the other house, with the air all the way to the right and the key damper closed, my fire would shut
down completely with temperature dropping rapidly. I don't have a strong draft in my present house, so
I can shut the fire down completely with the primary air off and no key damper.

You've either got one heck of a draft or a leak somewhere. Forgive this stupid question. But you do have
the start-up air closed when the primary air is closed, correct? I only ask this because once I forgot and
the temperature kept rising with the start up air open and the primary air closed all the way.

Also, try letting the fire/temps come down more before adding more wood. At 500 degrees, you've got more than
just a hot coal bed. Try to time your night time load so that you are adding wood at 300-400 degrees with
a smaller active coal bed. The fire temps shouldn't jump nearly as high if you let the loads cycle all the way
through.
 
Thanks for the comments.

I have not yet forgotten to shut off the start-up air control, but I am sure I will some day.

My flue does go a bit over 30 feet. I use 6 six-foot rods to clean it, and I know I have plenty of the last rod sticking out of the chimney top when I bottom out. I would estimate it at 33 feet.

Paul
 
Well that sucks, literally! This stove is a pretty easy breather for an EPA stove. At 33 ft, the flue is over twice the tested height (12-14'). It is going to need to be throttled back. Try it with the key damper fully closed for a day or two and let us know if she settles down with the lower draft.
 
Yes, I'd consider one with that height flue connected to an IR.
 
Will rear venting make any significant difference as far as making for a slower burn? My apologies to the OP if I've hijacked the thread.
 
Status
Not open for further replies.

Similar threads

J
Quadrafire isle royale maintenance
Replies
6
Views
1K
The Hearth Room - Wood Stoves and Fireplaces
begreen
begreen
R
Exit Gas temps on alternative stoves?
Replies
6
Views
618
The Hearth Room - Wood Stoves and Fireplaces
rashomon
R
P
Quadra Fire Isle Royale flue transition gasket replacement
Replies
5
Views
642
The Hearth Room - Wood Stoves and Fireplaces
phrinda
P
I
  • Locked
Do I need a key damper?
Replies
68
Views
2K
Pacific Energy
begreen
begreen
M
Finally found a solution to my short burn times and my fire going out.
Replies
4
Views
517
The Boiler Room - Wood Boilers and Furnaces
mjstef
M
Top Bottom
Back