I have a new Jotul 450. The wood I am burning is well seasoned. The connection to the liner is tight and the chimney is insulated. The thing will burn for 9+ hours. But, each morning, my glass is almost completely black. Any thoughts?
Glass blackens overnight
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Just getting used to the same unit myself - my experience is that when you burn it hot, the glass (and the firebricks) remain clean. If you're burning 9+ hours, I'm guessing you're not burning hot at all. I would guess that your firebricks are dark as well?
I also would not be able to achieve those burn times without getting the glass dirty. Burning hot, I get about 4-5 hours max at this point, although I'm sure this can be extended.
I also would not be able to achieve those burn times without getting the glass dirty. Burning hot, I get about 4-5 hours max at this point, although I'm sure this can be extended.
Are the butts of your splits close to the glass? This can cause blackening of the glass. Also you say that your wood is well seasoned. Might be that you are not correct on this point. Try turning your air down during the day and watch what happens. Sounds like you have the fire hot all day then turn down at night for long burn. If this is the case the I would strongly suspect wet wood.
Completely black glass is from wet wood smoldering all night, making cool firebox temps which allows the cold smoke to condense on the even colder glass. Just imagine the gunk accumulating in your chimney. Pretty much nomatter what you do, if you have dry wood, the fire will eventually clean up and burn efficiently enough to prevent total blackening of glass. Thank the EPA's minimum air setting for this feature.
I dont think it is a problem provided you can get the glass clean with a good hot fire. Keeping the wood back from the glass is a good suggestion.
I had the same problem last season with my C450. I too thought my wood was well seasoned. This year I purchased wood from a different supplier and I am here to tell you there is quite a difference with truely dry wood. I can now burn all night and my glass stays really clean.
Some stove glass will darken up and you just have to get use to it, clean them in the morning when the stove is the coolest. Our 4300 is known to have a good self cleaning system...its mentioned a lot in the reviews. Did you try burning hotter like 450-500* stove top temp? See what that does for the glass.
Yeah I would follow onto savageactor's ideas there - get it hotter to begin with, so the load is fully engaged before closing down the primary. sounds like you are starting off too cool to get the load to burn properly.
And if you ever hear any sizzle or see water boiling out the ends, then sorry - you got moisture and/or seasoning issues
And if you ever hear any sizzle or see water boiling out the ends, then sorry - you got moisture and/or seasoning issues
Black "anything" inside of a stove or flue is from incomplete combustion. Really its that simple. Incomplete combustion occurs from only a small hand full of things.
1.)Not hot enough
2.)Not enough oxygen
3.)poor fuel quality
4.)a combination of one or more of the above.
Each is easy enough to test for. To start with, I would go with your running temp or fuel quality.
1.)Not hot enough
2.)Not enough oxygen
3.)poor fuel quality
4.)a combination of one or more of the above.
Each is easy enough to test for. To start with, I would go with your running temp or fuel quality.
Jags said:
+1 . . . and the usual suspect seems to be the fuel not being seasoned enough . . . but as mentioned not getting the whole she-bang hot enough or cutting off too much oxygen can also produce the same effect as unseasoned wood.
I am also in the same boat.
during the daytime, my wife likes to run the stove wide open and hot. With the outside air wide open, the airwash and combustion keeps the glass clean. (goes thru the wood faster - but shes happy) When we top it off at night and damper it down, come morning the glass is brown - but not completely black. I also suspect that wood that is not fully seasoned contributes to this. I am hoping my wood will be better this year. I also noticed that when the stove was new - it did this more then it does now. Sometimes I can go a week to 10 days and not clean the glass - Once the season is full on and I am burning 24/7.
In the morning - I clean it up when I rake the coals and get the fire going again. I use a stove top cleaner sponge and a razor blade. Takes about 20 seconds. No big deal - and the glass is good for viewing all day.
Even though I had this same issue last year and my purchased wood was not what I would consider well seasoned, my flue was really clean and did not have any of the same black on it - like the glass did. No creosote build up - looks good.
during the daytime, my wife likes to run the stove wide open and hot. With the outside air wide open, the airwash and combustion keeps the glass clean. (goes thru the wood faster - but shes happy) When we top it off at night and damper it down, come morning the glass is brown - but not completely black. I also suspect that wood that is not fully seasoned contributes to this. I am hoping my wood will be better this year. I also noticed that when the stove was new - it did this more then it does now. Sometimes I can go a week to 10 days and not clean the glass - Once the season is full on and I am burning 24/7.
In the morning - I clean it up when I rake the coals and get the fire going again. I use a stove top cleaner sponge and a razor blade. Takes about 20 seconds. No big deal - and the glass is good for viewing all day.
Even though I had this same issue last year and my purchased wood was not what I would consider well seasoned, my flue was really clean and did not have any of the same black on it - like the glass did. No creosote build up - looks good.
firefighterjake said:
+2 ... Thought mine was dry last year, but now it really is dry, and I get no black at all on the glass. Burning hot has never been an issue for me :red:
New user with a new C450...been burning 2-3 weeks now. Woods was cut and split 3 years ago, so its dry.
The first overnight burn attempt, I loaded it up, ran full open for 5-10 mins., then closed air intake all the way. Next morning, I had coals, but glass was totally black. I tried removing with newspaper and ash, but most would not come off, so I scraped it with a razor blade. Attempted another overnight, with air open slightly...same issue, so I am experimenting with how far open the air will need to be so as not to turn glass black.
I have run a few nights with air half open, fully loaded and the fan will shut off after 6-7 hours, and no coals...so I'm working back from there.
I have not been able to get my glass clean by running a hot fire. It requires scraping with a razor.
Has anyone found the magic point of open air and not blackening the glass?
The first overnight burn attempt, I loaded it up, ran full open for 5-10 mins., then closed air intake all the way. Next morning, I had coals, but glass was totally black. I tried removing with newspaper and ash, but most would not come off, so I scraped it with a razor blade. Attempted another overnight, with air open slightly...same issue, so I am experimenting with how far open the air will need to be so as not to turn glass black.
I have run a few nights with air half open, fully loaded and the fan will shut off after 6-7 hours, and no coals...so I'm working back from there.
I have not been able to get my glass clean by running a hot fire. It requires scraping with a razor.
Has anyone found the magic point of open air and not blackening the glass?
bclmread said:
OK, sounds like wood is most likely not the culprit . . . so that leaves the air and heat. How hot is your insert before you start to shut it down? Also, are you shutting down the air in steps -- try shutting it down 3/4 of the way open . . . if the secondaries are still going strong after 5 minutes . . . shut it down half way . . . wait and observe . . . if things are still good try shutting it down so it is a quarter open . . . and if after 5 minutes or so the secondaries are still going strong try shutting it down all the way.
My experience has been if the wood is good and the glass blackens up it often comes down to the fact that I cut off the air too soon or too much before the stove was really up to temp . . . well that and I'll get some black if a split or round rolls up against the glass or ash builds up and prevents the air wash from doing its magic.
I suspect that once you get things hot enough and start to slowly back down on the air you may be able to get it so that the air control is only open a quarter of the way . . . the secret (well it's not really much of a secret since I tell everyone) is to shut things down incrementally and watch and see if the secondary is doing its thing rather than just shutting the whole kit and kaboodle all the way all in one step.
Leaving the air half open means you're losing quite a bit of the heat up the chimney . . . and most likely not getting really good secondary fires.
I too am burning well seasoned wood, and I've found that my stove responds poorly to large, sudden adjustments in the combustion air. I like to make the overnight process about a 30 minute "ordeal". I load up well seasoned oak around 9:00. Once the load is engaged well, I close my stove's bypass damper (it's a feature on my stove and some others) and make the first initial adjustment to the primary air, reducing it about 1/3 to 1/2. Then I begin making smaller, more incremental changes over the course of the next 20 minutes. I end up with the control open about 1/4" for the final setting. If I walked over to my stove and shut the primary completely after allowing a fresh, full load to burn only 5-10 minutes, it would be a smoldering disaster in about 10 minutes.
I'd recommend allowing more time for the process and making smaller adjustments to your air. You'll soon learn your stove's "sweet spot" for getting clean overnight burns.
I'd recommend allowing more time for the process and making smaller adjustments to your air. You'll soon learn your stove's "sweet spot" for getting clean overnight burns.
Pagey said:
I typically start the process of setting up my overnight fire and my "overday fire" a half hour before I turn into bed or head into work . . .
I pulled out the owners manual (...when in doubt, RTFM)
It says "As a general rule, try to avoid burning the insert at the lowest air control settings. Although a low setting will prolong burn time, it may also result in incomplete combustion...."
Looking for that sweet spot still.
It says "As a general rule, try to avoid burning the insert at the lowest air control settings. Although a low setting will prolong burn time, it may also result in incomplete combustion...."
Looking for that sweet spot still.
Yep, trial and error with a new stove. Sounds like you turned it down too soon. Try turning it down after 20 minutes, it can take that long just to warm that chimney up enough to get that pull needed for a low burn.
Sort of an update...am still looking for that sweet spot...
I use the medallion on the ash lip of my 450 as a reference point. It seem when I put the primary air control right at the left most portion of the medallion for an overnight burn, my glass stays pretty clean. Last night, I got greedy and went 1/2" or 3/4" further to the left of the medallion and had completely black glass this morning, though there were some good coals left after 8 hours of burn. I had been burning all evening so the chimney was good and warm.
That said, I really like the insert.
I use the medallion on the ash lip of my 450 as a reference point. It seem when I put the primary air control right at the left most portion of the medallion for an overnight burn, my glass stays pretty clean. Last night, I got greedy and went 1/2" or 3/4" further to the left of the medallion and had completely black glass this morning, though there were some good coals left after 8 hours of burn. I had been burning all evening so the chimney was good and warm.
That said, I really like the insert.
bclmread said:
Not being completely familiar with your stove - on mine a 1/4" adjustment can make for a big difference in performance. Try smaller adjustments.
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