Smokey Glass in the Isle Royale

[RossB]

I've got a long thread about the selection and installation of my woodstove, but I thought I'd post my question in a new thread so people wouldn't have to suffer through 10 pages of my rambling prose.

So, the Isle Royale has been running steadily for about 24 hours and the glass is sooted up quite a bit. Any idea what I did to cause it? I don't think I've overloaded it or damped it down excessively to a smoldering mess. The wood is well-seasoned hardwood. I'm just wondering if there's something about my method of use that I might improve.

 

[Dogbyte]

how soon do you close off the air after you reload? im just wondering if the fire isnt getting up to full temp before being restricted...usually the heat will clear the glass soon after reload, before the air is backed off.

 

[begreen]

Are you keeping the wood off of the door glass? Usually this is a sign of either a choked back fire or damp wood.

 

[oconnor]

Are you maintaining a bright flame in the stove when you fail back the air?

 

[RossB]

There are certainly times when I have the fire dampened way down and there are no real flames....maybe that's where I went wrong. I try to open it just enough to maintain some flames, but if I want it to last all night, don't I need to close it right down?

 

[oconnor]

There are certainly times when I have the fire dampened way down and there are no real flames....maybe that's where I went wrong. I try to open it just enough to maintain some flames, but if I want it to last all night, don't I need to close it right down?

Yes, but if it's lasting all night because it's not burning completely, you get creosote. There is a fine line between a clean burn and a long burn. Work on the clean burn and they long burn will come.

 

[cableman]

Make sure u have the rutland glass cleaner on hand! Stuff works great!

 

[northwinds]

The Isle Royale is a different kind of stove; it definitely likes to run hot. If you are running the stovetop below 500 degrees during the first stages of the burn (while the wood is outgassing), you are going to get some smoke. If you have good dry seasoned wood, you won't have any trouble getting an overnight burn at cruising temps of 550-650. It will not burn at that temp all night. You will have several hours at those temps and then it will drift down slowly overnight.

Additionally, not everyone can close their stove all the way down. You will need to find your sweet spot, based upon your chimney set-up. I close mine down about 80% at 550 and then 90% at 600. It will usually settle there. Sometimes, I'll need to make a minor adjustment. Some people with long straight chimneys find this stove runs best with the air shut all the way down, plus a damper. You'll figure your setup out. But smokey glass is unacceptable. If your glass is getting all gunked up, so is your chimney.

 

[Nick Mystic]

When you talk about closing down the primary air control to the point where there are no longer any active flames it will depend on where you are in the burn cycle as to whether this is causing your dirty glass problem. While you are establishing a burn from a reload or cold start you aren't likely going to be able to close off your primary air control to the point where the flames die off and continue with an effective long term burn. However, if you are talking about having the primary closed down after an hour or two of a strong burn and then having the flames die down with the stove temperature still up around 400 F or more, then you aren't likely to build up a lot of creosote in your flue or have a lot of soot on your glass. Therefore, my guess is that your wood either isn't as dry as you think it is, or you are closing off your primary air too soon before the stove gets up to he optimal operating temperature. I have a Jotul F600 and mostly burn oak that is very dry. But, if I happen to get some wood in the stove with higher moisture content then I always have a problem closing down my primary and keeping a hot fire burning.

 

[RossB]

I think was running the stove too low. I opened up the damper a bit and the glass actually cleared. Unfortunately the room went up to about 93 degrees instead of the low 80s that I had been maintaining all day and there was nothing at all left in the stove this morning after about 6 hours unattended. Clearly this is going to be a balancing act of sorts.

 

[northwinds]

Until you figure out the balancing act, a stovetop thermometer is very useful. I put mine on the front left center of the griddle area. If you had a full stove of wood
and there were no coals left after 6 hours, temps might have got a little too hot. The key is to use the start-up air to get the fire started (5-15 minutes). Then use the
primary air after the temps hit about 500. Keep closing off the primary air over the next 15-45 minutes until you get slow lazy flames below. On my stove,
everything usually levels off at around 600-650 with the primary closed 90-95 percent. On reloads, you can skip the primary air and the times to temps are faster.

Last night, I put in 2/3 load of oak and hickory at 9:30 p.m. Still plenty of coals for reload, which I'll do at 7:30 a.m. after dropping the kids off at school. House is 70 degrees. Outside temp 6 degrees. All of the wood was split and stacked at least 3 years ago.

 

[Jags]

Northwinds speaks the truth. There is a learning curve for each unique install. Keep fiddling. For what it is worth, other than running the back of my welding gloves across the glass to wipe off some ash - I have yet to clean my glass for the season.

 

[RossB]

Thanks folks! I'll be ordering a thermometer today. I need a cleaning brush and a set of rods for the chimney anyway. I suppose I should consider a decent ash vacuum while I'm at it.

 

[RossB]

Bought some Rutland Glass Cleaner and a magnetic thermometer today at the Tractor Supply store. I'll probably take another shot at honing my skills tomorrow. The fire went out completely today.

 

[lopiliberty]

Bought some Rutland Glass Cleaner and a magnetic thermometer today at the Tractor Supply store. I'll probably take another shot at honing my skills tomorrow. The fire went out completely today.

If the thermometer is a Rutland you just as well take it back. A lot of people here myself included hate those Rutland thermometers because of inaccuracy. Best brand of thermometer is Condor or an IR thermometer

 

[RossB]

If the thermometer is a Rutland you just as well take it back. A lot of people here myself included hate those Rutland thermometers because of inaccuracy. Best brand of thermometer is Condor or an IR thermometer

I wasn't holding out much hope for accuracy in a $10 thermometer...maybe +/- 100degrees...but the question is whether or not it is repeatable. I suppose I could use my Fluke DMM and a thermocouple to get an accurate reading and compare the two of them. I just want to identify the sweet spot and then be able to find it again.

 

[begreen]

I have picked up a couple cheap Drolet thermometers (2" round, black and grey dial) thermometers as gifts that weren't too bad. Got them at the local True Value. They certainly are more discrete than the Rutland.

 

[Dave52]

Sharing a newbe experience here - when I switched from loading the wood sideways to front-to-back, so the stub ends of the splits were facing the glass, I haven't had to clean the glass again, and thats 2 weeks later.

 

[northwinds]

How's it going, Ross? Stove behaving itself?

 

[RossB]

Actually, things are going pretty well. I had let the stove go out on Monday so it was nice and cold on Tuesday. I cleaned the ashes out of the firebox and cleaned the glass. The glass cleaner worked very well. I tried Windex first just to see if it would cut it, but the really black stuff wasn't coming off. Then I tried the Rutland glass cleaner and the black came off with almost no effort at all. I restarted the fire and ran it wide open for a while with kindling and some really thin pieces of split wood which I added every 15 minutes or so. Once I had some good hot coals going, I dropped in some more substantial pieces and waited for them to ignite. Once everything was burning strong and the temp on my cheapy thermometer was just over 500, I started dialing down the air to see how low I could go while still maintaining actual flames. Somewhere around 25% open I had hot orange coals in the bottom and wispy flames dancing above the wood.


Anything lower than this and the flames disappeared all together. However, the burn time at this level is way short and a full load of wood is gone in about 4 hours. I'm going to have to keep experimenting with this. The good news is that the glass did stay clean though.

 

[Jags]

Once you are up to operational temps (my opinion for this stove is above 500F), you don't need to maintain constant flames. There are times that my wood appears to just have glowing embers, but the burn tubes are still hot enough to do the job and the exhaust is clear. Keep fiddling. You will get it fine tuned.

Note: for the record, from a cold stove my load seems to burn up faster than you would expect. Reload on a bed of coals at about 350F, get it running and then tune it to 5 or 10% open. Report back.

 

[RossB]

Once you are up to operational temps (my opinion for this stove is above 500F), you don't need to maintain constant flames. There are times that my wood appears to just have glowing embers, but the burn tubes are still hot enough to do the job and the exhaust is clear. Keep fiddling. You will get it fine tuned.

Note: for the record, from a cold stove my load seems to burn up faster than you would expect. Reload on a bed of coals at about 350F, get it running and then tune it to 5 or 10% open. Report back.

The 4 hours noted above were after about 8 hours of burning. I started the stove around 2:00PM, ran it hot all afternoon and evening, loaded it fully at about 10:00PM, and then dialed down the air until I was just maintaining a few small flames. I got up at 2:00AM to check on it and all the wood was gone with a bed of hot coals remaining. I loaded it up again, cranked open the air to make sure the wood was ignited, and then dialed it back down to just enough air to maintain flames...all the wood was gone again by 6:00. I might just run it good and hot, load it up, turn the damper all the way down, and see what happens. Sure it might get a little sooty, but couldn't I just clean the stove and chimney more frequently to combat creosote?

 

[Jags]

I wouldn't go all the way down to begin with. Try the 5-10% position (a pretty common setting for this stove).

 

[RossB]

I'll give that try. I may have to add a graduated scale to the stove just above the damper knob for more control of my science experiments.

 

[northwinds]

Actually, things are going pretty well.
Anything lower than this and the flames disappeared all together. However, the burn time at this level is way short and a full load of wood is gone in about 4 hours. I'm going to have to keep experimenting with this. The good news is that the glass did stay clean though.

The burn you have going in that pic looks great. I think you just need to keep experimenting with how full you load the stove and the degree/speed to which you dial it down after you reach operating temps (above 500). You should easily be able to reload this stove on coals after a ten hour burn. Be aware that the stove isn't going to be
putting out the same heat at hours 6 to 10 as during the first four or five hours. That temperature variation is typical for secondary burn stoves.

Also, bigger wood burns longer than smaller splits.. Wood that's tightly packed in the firebox will also burn longer. Most people find that east/west loads burn longer than north/south.