Hello to all. I have just put in my new woodstove- an Aspen C3. The reason I bought this stove is the automatic air intake regulator. Having spent years heating with an old, unsealed, parlor stove from the nineteen-forties, I am now in wood-heat "heaven." With that old stove, I had to adjust the air intake every ten or fifteen minutes. Very annoying. With the new stove, I load it and get on with life. This automatic intake is the best thing since sliced bread! But this new stove has one issue that I want to solve. Here, in northern Maine, from about December to March, the stove runs all day, every day. I burn only well-seasoned, dense species of wood. I am finding that, after about eight hours of use, the coal bed builds up. It gets relatively high, taking up most of my stove's firebox capacity, and makes adding wood somewhat difficult or impossible. Of course, such a load of orange coals suffices to keep the stove at a proper temperature for a long while. Still, eventually, there does come a point when I want to add in wood and I find the coal bed uncomfortable high. I suppose I could shovel out some of the coal bed into my ash bucket, but I am hoping that I have a better idea. I would like to cut into the bottom of the stove an 'ash dump' to the cellar below. (The cellar is stone/boulder-walled with a dirt floor and could probably take many years of ash dispersal.) I have an ample supply of firebrick, etc. for the build. My idea is to remove the center firebrick on the floor of my stove and install a cast iron dump door. Perhaps a grate, too, so that large coals not be dumped. And maybe I will also remove the legs from the stove and set it on a 'foundation' of bricks. I know the people on this forum are pretty experienced with all things related to wood stove operation. Has anyone here done this mod before? Am I about to embark on a path off a cliff?
How to add an ash dump
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What is the moisture content of your wood? Excessive coaling is usually an indicator of wood that has too much moisture content. And no you cannot just dump hot coals into a pit in the basement. Doing so would almost certainly lead to carbon monoxide poisoning.
bholler, thank you for responding. I do not believe the wood has high moisture. I season yellow birch, beech, and rock maple for two to three years and in the springtime before the winter in which I will use it, it goes into a woodshed. I am good about checking moisture content and it is always below twenty percent- usually sixteen percent or so. Also, I do not intend on simply dumping coals and ash into the cellar. I will build an appropriate enclosure (cement pad and masonry from cellar floor up to the bottom of the stove itself).
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It's hard for me to know what's going on with this stove. It is a new design and with no user input I can't use the normal techniques to reduce coaling. But it certainly sounds like it shouldn't be your wood.
And I understood you were planning an enclosure. It is still a very very dangerous idea
I had excessive coaling from burning punky wood. I had a batch of not-so-great wood that would smolder and shrink slowly so I mixed them in. But having coals doesn't mean heat stops, my stove stays between 300-400 when burning down coals. By the time the stove got to 250 the coals had burned down enough I could reload with normal splits.
There's also the option of shoveling out the coals into a metal ash bucket. Maybe use them again as fire starters when you're re-lighting the stove.
There's also the option of shoveling out the coals into a metal ash bucket. Maybe use them again as fire starters when you're re-lighting the stove.
MongoMongoson
Feeling the Heat
I have found, with good hardwoods, that if I keep loading the stove with fresh logs on hot coals, the coals will build up. You might be reloading too soon rather than running the stove in longer cycles. If you are trying to get the most BTUs per hour out of your stove by reloading to keep a hot fire going, this can be the outcome.
What I do is, before raking coals forward, shovel out some of the ash that is in the front of the firebox. I have "boost air" coming in right in the front at the base of the fire, so that tends to help burn up the coals in the front. It's good to get ash out when you can.
Then I rake coals forward and put one or two small splits on top of them in an E-W orientation. The boost air coming in at the base of the coals (on which the splits sit) helps burn those coals down, and the splits off-gassing still give good secondary flames to help keep the BTUs/hr up. If you have some softer woods, this is a really good use for them. I get box elder in addition to better woods, so here is where I use some box elder. This process really helps burn the coals down before they pile up too much.
Looks like begreen already made this suggestion, now that I'm looking back at the thread. I don't know your stove but this is worth a shot. It works for me.
What I do is, before raking coals forward, shovel out some of the ash that is in the front of the firebox. I have "boost air" coming in right in the front at the base of the fire, so that tends to help burn up the coals in the front. It's good to get ash out when you can.
Then I rake coals forward and put one or two small splits on top of them in an E-W orientation. The boost air coming in at the base of the coals (on which the splits sit) helps burn those coals down, and the splits off-gassing still give good secondary flames to help keep the BTUs/hr up. If you have some softer woods, this is a really good use for them. I get box elder in addition to better woods, so here is where I use some box elder. This process really helps burn the coals down before they pile up too much.
Looks like begreen already made this suggestion, now that I'm looking back at the thread. I don't know your stove but this is worth a shot. It works for me.
begreen, yes, that is pretty much what I did. I just recharged with smaller pieces. But in the dead of winter up here, I would be looking to get in a larger charge of wood for the overnight.
jotulf45v2, I am fortunate in having excellent quality firewood up here in Aroostook County. We also sell firewood and have a loyal customer base. The mountain of orange coals I get does, indeed, keep the stove at 400 deg.f. for a good while. And yes, as the stove goes down to 250 deg.f., the 'mountain' has gone down a good bit. But by about 11 pm (bedtime) it needs to be refilled for the night and the remaining coals seem to be in the way of things. I found myself wishing that I could just flick a lever and be rid of them. A few years ago I built a Russian masonry stove for a friend and we did an ash dump down into the cellar. It just seems so nice to have such a dump when the temps outside go below zero, the wind is howling, and I have three feet of snow outside to greet me with my full ashcan, lol.
MongoMongoson, I think you might be right about me perhaps reloading prematurely. I will pay more attention to this and see if things improve. But I still like the idea of that ash dump.
Have you tested your draft to see if it is within spec for your stove? I would think that with a stove like yours which has no user control it would be very important
Bad LP
Minister of Fire
Stir the coal bed more often and ramp up the intake. Reload and lower intake.
That coal is heat!! Your MC content is similar to mine on a fresh split so I don’t believe it’s the wood.
I’m south at Moosehead.
That coal is heat!! Your MC content is similar to mine on a fresh split so I don’t believe it’s the wood.
I’m south at Moosehead.
bholler, the automatic regulator seems to be a godsend. A full charge of the firebox goes for about six hours. Then the coals carry on for about another two or three hours. That is when I come to recharge and find the somewhat high mound of very hot coals. I can add wood, but not enough get another six hours of heat.
Bad LP, I think you are right about the fact that I ought to stir and poke the hot coals. They are certainly good heat. I need to wear my welder gloves when I go in there!
Yes a godsend unless it isn't doing what you want it to do. Have you tested your draft to see if it is withing the specified draft for your stove?
After wet wood which yours isn't running with too much air and reloading too soon is the next most common cause of excessive coaling
No. I have not done that test. Do I correctly understand you to be referring to excess draft?
This is not really an ideal overnight stove for very cold climate weather. It would take a bit large firebox, more in the 1.6-2.0 cu ft range. We had the Jotul F3CB for a few years and the longest burns we got in it were in the 4-6 hr range, with 4 being more average in cold weather. An 8 hr burn was a rare one and that was a <200º stove in the morning with just enough coals to start a kindling fire.
How large an area is the stove heating and how well insulated is the house?
begreen, I first saw this stove in operation at a friend's house in northern Maine during that brutal 2017-18 winter and I was impressed. I believe he had it in a room that was about two hundred square feet. He used the blower system from his oil burner to spread the heat throughout his house. I spent the weekend and we filled the stove twice a day and sometimes threw in a log in between. As I initially said here, the automatic air intake is what got my attention. I do not recall any issue of the coals such as I have found with my stoves, but then it may be that I did not pay attention to it. I have the stove heating a one-hundred-seventy square foot sitting room and I use cold air drops in the other rooms to bring the heat over. The house is well insulated. So far, I am quite pleased with this stove. I don't really need eight hours of full burn overnight. Six hours is our overnight here. Last winter I was burning oil in the early morning hours, but this coming winter we do not want to use the oil. I know I will have nice coals in this stove in the early morning hours and that I will just toss in some logs and get good heat pretty fast. I am just thinking that I will get heat all the way through our six-hour overnight if I charge the stove well at bedtime. That is why I noticed the mountain of hot coals in the stove and looked for a solution. Aside from the coals issue, I think it would be very convenient to have an ash dump. The wife and I are pensioners, not getting any younger, and taking out the bucket of ashes every few days is a task that I would not miss, lol. I have been advised here on this forum that I might stoke the coals a bit and refrain from adding in logs until really necessary and thus not build up a mountain of hot coals. It seems to me that this might be my answer.
A 2017 Aspen is entirely different from the new Aspen C3 model. This was an almost complete re-engineering. I would not expect it to run the same as the older Aspen design. One decision was to line the floor with firebrick, which probably is what is keeping the coal bed hotter longer.
Was his older Aspen set burn rate as well? I thought that was a new addition for the 2020 compliant stove
Bad LP
Minister of Fire
Please just take the ash and any coals outside in a steel bucket and don’t put the bucket on the porch or place it near the house.
Your lives depend on it.
The older one has thermostatic control, but with user override, like other VC stoves.
begreen, I suppose the bricks might keep the coal bed hotter longer. And perhaps I should let it burn down some more before adding logs. Anyway, I am going to remove one of the floor bricks- the center one, and put in an ash dump to the cellar. I do not see any real downside and an ash dump would be really convenient.
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