black glass

[laura]

Have just had a Scan 7 installed. Have come from an open fire, when we moved last winter there was a small wood burner installed that the chimney sweep condemmed! Only just got round to sorting it. Anyway, fired it up for the first time last night, causiously, not to bad. Didn't load enough to get effiient burn initially but it semed to work fine. Put oak logs on, got them going and damped down for the hight. Result totally black glass this morning!

Have been reading around and it seems that closing both primary and secondary dampers renders the air wash inoperative, hence the black glass. So what do I do at night if I want to keep the fire in?

 

[jtp10181]

First let me begin with this.... Your wood probably has too much moisture in it.

Every stove can be different but the ones I have worked with have a startup air control and a primary air control. The secondary air has no control. You always want to close the startup air after about 15 minutes of burning. The primary air if closed all the way (which should still be open a min level set by the mfg) tends to put the stove into smoulder mode which creates a lot of crap and can soot up the glass.

Anyway... the number one culprit I have found for black glass is unseasoned wood. If your wood sizzles or has bubbles coming out of the end when first starting that's your problem. A good hot fire should clean the glass up pretty good, if you can't get it hot enough to clean the glass your wood is not dry enough.

 

[cmonSTART]

The only year we had a problem with blackened glass was the first year when we burned mostly greenish oak. Since then we've bought well seasoned wood and haven't had a problem. We've been burning since early October here this year and I haven't cleaned the glass since we started.

 

[Mike Wilson]

If this is your first experience with the stove, then I think you are asking too much. You need to learn how to burn it well, without smoke, and without having the glass go black. I would load it up during the day, and observe how a burn progression goes. Then, I would learn how to adjust the air, and see what effect that has on the burn, at different stages in the burn process. Some stoves should not have the air all the way down, because if they do, there is not enough primary burn in the stove to touch off the secondary burn at the top baffle plate.... think of the primary burn as a pilot light for your secondary, sometimes you have to keep it lit so that it can light the gasses on the top of the stove, which is secondary (clean) combustion. Try it again, during the day, and observe. You may find that the lowest your stove can go is 1/4 air, maybe 1/8... who knows. But you will learn, and it will take time. I just don't think you can start a fire on day one, let it go, and then damper it down for the night and expect perfection. I know if I damper mine down all the way, I sometimes lose primary, which kills secondary, which results in smoke, and dirty glass.

YMMV, but that's mine...

-- Mike

 

[begreen]

It's possible to blacken the glass if the stove is loaded with wood, then fully dampered down, without allowing the wood to char a bit first. If the wood is not fully seasoned it will smolder all night and leave you with black glass in the morning.

 

[laura]

All duly readand noted with some successes - did try the burning and observing and I can now keep the fire in during the day and successfully get heat out o it with out blackingn the glass so that one step onwards. Doesn't seem to push out the max 8kw it is reported to.... Haven't tried ovenight again yet. Wood is well seasoned, definately not bubbling. Many thanks I think it is a question of getting used to it.

 

[wahoowad]

Put oak logs on, got them going and damped down for the hight

On my stove I can't go to dampen down mode in one big adjustment, even if my wood is raging like heck. I usually close it about 30%, then let the burn adjust to that for another 10 to 15 minutes. Then close another 30% for another 10 to 15 minutes, finally closing it down all the way after that. Takes me anywhere from 20 to 30 minutes to get a full load 'dampened down.'

I also find the type of wood to be a factor. I can reduce my time intervals and even bypass a setting when I'm working with my softer woods like cherry and poplar. I have to be much more attentative when I go through my dampening progressions with oak and hickory.

 

[jpl1nh]

Put oak logs on, got them going and damped down for the hight

On my stove I can't go to dampen down mode in one big adjustment, even if my wood is raging like heck. I usually close it about 30%, then let the burn adjust to that for another 10 to 15 minutes. Then close another 30% for another 10 to 15 minutes, finally closing it down all the way after that. Takes me anywhere from 20 to 30 minutes to get a full load 'dampened down.'

I also find the type of wood to be a factor. I can reduce my time intervals and even bypass a setting when I'm working with my softer woods like cherry and poplar. I have to be much more attentative when I go through my dampening progressions with oak and hickory.

I think Wh'ds point is a very good one as well as the other tips. With an EPA stove the concept of "damping down" for the night changes a bit. I used to have to choke my old Jotul down really far to get coals in the morning. Clean burn wasn't feasible in that condition. Now I find my best ovrnight heating performance comes with the primary air open just a hair more than I could go. With the extra efficiency of the stove, even with the really small 1.5 cubic foot firebox, with good hardwood I've got a really hot bed of coals in the AM and a nice slow but steady burn for much of the night.

 

[Hogwildz]

This all depends on the stove. Some burn cleaner, & better left a lil open. My Summit likes to be air down all the way. But again, it has EBT adding & closing air automatically. Always have a great bed of coals and then some in the morning. Ya have to find what works with your stove, then fine tune from there till you find the best settings for your situation.