What I'm Learning about too much build up off ash and embers

Many of you may have already figured this out, but it has taken me a while to learn this by experience. The issue of too much ash and coal filling the firebox with often not enough room to fit a hearty amount of wood for the next burn cycle. In years past I had this problem so bad I often had to shovel out my embers in order to free up space in the firebox. The last few years I've not had to do this since I adopted a regular practice of shoveling out a few scoops of ashes every other time I reload (I wish I had an ash pan, but this is an insert). This ash scooping practice has helped to circulate air and burn the embers down more effectively leaving me with enough room to load with plenty of new firewood and no need to remove still glowing embers.

Okay, onto my discovery and hypothesisWhen outside temps reach that dead of winter cold you need to keep an active fire burning complete with secondary combustion in order to keep the house comfortable and the thermostat from kicking on the furnace. This requires reloading more frequently and burning more wood. This in itself doesn't necessarily explain all the excessive coal build up, but burning more wood logically contributes to the problem. Also it helps to burn premium seasoned wood, so definitely try to get your wood up to snuff in that regard.

When weather is not so dramatically cold or you don't live in an extreme climate you can let the stove cruise much longer before instigating another blaze with new wood. When you let the burning embers cruise for long periods without interruption or fussing they develop natural air pockets, fissures, and spaces that allow air circulation to continue to percolate and eventually turning almost completely into ashes. If you interrupt this natural progression burn cycle you wind up smashing and compacting the half burned embers down with your new wood load. This will get the new wood burning with desired flames and heat output, but now you have crushed the existing airy and "fluffy" composition of embers down into a densely packed bed of smaller embers.

Though you now have your new wood blazing, the covered base of embers is instantly starved for air and essentially becoming cooled black charcoal choked off from any significant further burning and off gassing. Instead of burning down more completely into ashes, the crumbled and fragmented embers are now destined to become squelched charcoal nuggets. Repeat this scenario over the course of a day or two and you will eventually have lost all your free firebox space to this now overgrown pile of compacted small charcoal bits. Without a way to pump or force air through this pile of carbon crumbs it's only going to continue to snuff itself out completely and provide no heat. You now have to take action and manually evict your unhelpful guests full of unrealized btu potential and turn them into some kind of hipster "Biochar" for the garden.

So in conclusion I'm thinking that if you need to keep loading the stove before the last cycle of wood gets completely exhausted you may not have enough stove for the size of your home. This may very likely be my case as there is only my one large insert heating a rather large drafty 2200 sq ft. Victorian home with no roof insulation and balloon framing....Almost a barn! Well not quite. I wish I had room for another wood stove which would most likely solve the problem during those very cold spells, but I really don't have the layout to make a second stove practical. Again the problem for me is only when extremely unseasonably cold so I'm not going to make major investments for it. Instead I'm going to settle for my disciplined regiment of frequent removal of spent ashes to free up airflow to embers and consider insulating the roof. Also now with my new understanding of the problem I allow the wood to burn a bit longer before reloading even if that means hearing my gas furnace kicking on and my steam pipes hissing. I'm still saving a ton of money and enjoying the wood burning lifestyle with all you guys and gals.

I hope this helped to explain a possible cause and effect scenario to anyone facing this problem of ember build up in the firebox. I realize there are other factors involved, but this is a significant one in my case and I suspect for others as well.

 

I haven’t tried it yet but I have heard people talking about throwing a split of dry pine on the coals to burn them down. I have a bunch of pine from a scrounge on deck for next year I’ll let you know...

 

Yes Warner I do that and it does help. That said, in doing that you are still raking up the coals into a pile towards front draft and that will pack them together tight keeping the inner mound a bit protected and the reduction rate is minimal and slow. On cold nights this pine trick doesn't really throw much heat so it can be futile. Keeping this in mind what I often do is keep a nice amount of pine on hand and when I can see the coals starting to become problematic I don't wait for their numbers to grow out of control and start preemptively burning a few loads of pine. This is very effective and heat output remains constant. So yeah to your point, pine can be your friend.

 

Urban Woods being my very 1st burning season I know exactly what you are referring to. I have run into this numerous times initially starting out but have since become better at timing my reload cycle so that the coals have dwindled down far that they are not to much and easy to rake forward but yet are still hot enough to get the next load going. As you mentioned having dry wood on the reload is key so it has little problems igniting. Sometimes there is a bit of coals and I have no choice but to reload on top of them starting from the back working my way forward. Sometimes I will get some smoke in the house doing that but it's a rare occasion. I also load mostly east/west as well!

 

With good dry wood and cold temperatures you can get excessive coals. My solution has been and it works really well, your rake the Ash and coal. throw on 3 splits of pine which makes almost no coal and reload in an hour and a half.

 

I burn poplar to get my coals down. A couple splits will keeps my stt at 450 if I have the air cranked up. It works good.


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When you guys open the air to burn down the coals, do you keep the cat engaged?

 

So that I don't clean out as often I open my stove door as if it's a fireplace when I get down to embers.The heat off the emblers is substantial and it seems to burn down into a smaller amount of ash.

 

Yep, I love those "deep pockets!" The ashes from the burning coals falls away and lots of air continues to get to the coals. My stove has the added benefit of a 1/4" hole they put in the side of the ash pan housing, so the coals get some air from the bottom through the ash grate. From my cruise air setting of .5 on a scale of 4 (cat-only burn,) I open the air to about 1.25. With the glowing coals I can push the stove top and sides back up close to 400 degrees for a few hours, and that's enough to hold room temp until it's time to reload, even with temps just above 20 and wind outside, like today.

I can relate...no wall insulation in this cabin and maybe R-20 in the attic, plus a lot of air leaks I haven't addressed yet. With improvements on that front, I'll do even better when these cold snaps hit. But if we put on a room addition, I'll have to "stove up," maybe a Ws AS.

I haven't burned enough Tulip to really notice, but they say it ashes heavily, which could block some air to the coals. Pine might work better in that regard, I don't know.

 

Yes I engage the cat as long as the temps are high enough for it.


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I don’t think it makes a lot of ash. At least a couple splits don’t make much. As long as it’s not making more coals is what I’m after.


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Welcome aboard Rich L


I have done that as well with our old stove, but beware of carbon monoxide


It surely will kick out the heat though


I generally do as Backwoods Savage does, I try to watch the temp and open the primary back up to allow for a good burn. I usually catch it in time to keep the cat engaged, but if not I will open the cat to allow more draft.

$.02

 

Absolutely

 

Air control helps an awful lot - cranking the air up at the beginning of coaling stage rather than at the end as Savage and others describe. Pine is great, too! Another thing that can help is anticipation: if you know coal mountain needs to come down, let the load before run real hot to drive the house temp up so a lower stt can keep the house warm while you let the coals burn down.

 

Good game plan BigPapi ! I'm gonna give "Operation Anticipation" a try. It's a multi-faceted approach and a lot of good ideas have been revealed in this thread that can all be used in combination to keep this problem under control.

 

Yes sir! Your write-up says that you are definitely going to win this battle - very detailed and well thought.

 

Yes. The exhaust path through the stove is longer with the bypass closed, so the stove can extract more heat rather than sending it up the flue.