Question About Unburned Coal When Using Coal and Wood

Sunny Boy · Post by **Sunny Boy** » Mon. Nov. 13, 2017 11:46 pm

Jgib4 wrote: ↑
Mon. Nov. 13, 2017 11:16 pm
That makes perfect sense. Does the upper layer of coals not need as much air as the bottom to stay lit? I was concerned with that which is why I was making it so shallow.

Yes, but like the lower part of the firebed, it needs very hot air - which it gets from having some excess air coming up through the firebed.

Some stoves supply smaller amounts of over-fire air to help burn off the carbon monoxide gas produced, so that it's heat it not wasted. Either with a secondary air damper, which is usually mounted in the loading door, or an air bypass from below the firebed.

The depth not only adds more fuel to burn longer, think of it like layers of blanket that help slow the heat loss as the burning gases try to rise. That resistance to air and hot gases rushing through keeps that heat in the firebed longer to help burn the coal more efficiently.

The term "liner" often refers to the firepot or firebox having some type of liner to help retain heat in the firebed. Many coal stoves use fire bricks, or a one piece refractory liner for the firepot/firebox to further retain heat in the firebed. Or some, called "suspended pot" base burners, channel the hot exhaust down around the outsides of the firepot to help keep it extremely hot without need of a liner. Those all are, generally, the easiest stoves to maintain long burning coal fires.

Paul

Jgib4 · Post by **Jgib4** » Tue. Nov. 14, 2017 6:02 am

joeq wrote: ↑
Mon. Nov. 13, 2017 11:22 pm
Your Firecheif looks like it holds a fair amount of coal. Once these guys have you honed in on properly burning coal, don't think you'll want to go back to wood. At least in the middle of the winter. If you have wood available, save it for the shoulder months, but the coal will out perform the wood in the cold winters. I can't see you starting a coal fire for night use, and then throwing wood in it, in the mornings, and having to repeat that on a daily basis. Once you fill your stove to the hilt, you'll probably be amazed how hot she'll get, and long she'll burn before needing attention.

The plan was to eventually go over to all coal. But for right now I have a decent access to wood on my lot so I plan on burning both until it’s gone. It has been nice so far with the 12-14 hour burns I’ve been getting compared to the 3-4 I normally do.

Jgib4 · Post by **Jgib4** » Tue. Nov. 14, 2017 6:05 am

Sunny Boy wrote: ↑
Mon. Nov. 13, 2017 11:46 pm
Yes, but like the lower part of the firebed, it needs very hot air - which it gets from having some excess air coming up through the firebed.

Some stoves supply smaller amounts of over-fire air to help burn off the carbon monoxide gas produced, so that it's heat it not wasted. Either with a secondary air damper, which is usually mounted in the loading door, or an air bypass from below the firebed.

The depth not only adds more fuel to burn longer, think of it like layers of blanket that help slow the heat loss as the burning gases try to rise. That resistance to air and hot gases rushing through keeps that heat in the firebed longer to help burn the coal more efficiently.

The term "liner" often refers to the firepot or firebox having some type of liner to help retain heat in the firebed. Many coal stoves use fire bricks, or a one piece refractory liner for the firepot/firebox to further retain heat in the firebed. Or some, called "suspended pot" base burners, channel the hot exhaust down around the outsides of the firepot to help keep it extremely hot without need of a liner. Those all are, generally, the easiest stoves to maintain long burning coal fires.

Paul

I will try loading more in this weekend since I will be home for the week. Should give me enough time to make the tool I need to help clear the ashes. Thanks for the help.

windyhill4.2 · Post by **windyhill4.2** » Tue. Nov. 14, 2017 6:36 am

If you want to burn wood.... burn wood !
If you want to burn coal.... burn coal!
Stop burning wood on top of the coal & then expecting the next coal added on top to burn.
I tried doing the same thing a few yrs ago,the wood ashes on the top of the coal just mess everything up. Just can't ever get it working properly.

lsayre · Post by **lsayre** » Tue. Nov. 14, 2017 6:42 am

You can't treat anthracite coal as if it was bituminous coal. Bituminous has a chance of coexisting comfortably with wood. Anthracite does not.

joeq · Post by **joeq** » Tue. Nov. 14, 2017 9:32 am

I know clearing the ashes on a coal fire can get pretty tedious in itself. I can't imagine how bad it must be to contend with a pile of wood ash contaminating a coal fire. After a long night burn W/ coal, I can see burning wood on top for daytime heat. But I can't imagine how much time it must take in the evenings, to shovel out all remaining daytime ashes, resupplying the stove with a bed of fresh coal, and trying to get it burning for the evening. But I guess if a person hasn't any other hobbies, or any responsibilities to take care of, then such a regiment would be welcome. Me personally would use the wood from say Oct. to Dec., convert to all coal till Feb. and then return to wood from the beginning of March till spring weather hits. That's about the heating season in these parts.

Sunny Boy · Post by **Sunny Boy** » Tue. Nov. 14, 2017 9:42 am

I have availability to free wood here, too. It became "camping wood". I gave up using it in the coal stove because it was easier to keep a coal fire going 24/7 then feeding a wood fire every few hours and having to relight it every morning, or if I go away for the day. Plus, the wood sucks a lot of stove and house heat up the chimney than coal does, and I have to clean the chimney system much more often, too !!!!

There's a reason coal stoves replaced a lot of wood stoves in much the same way oil/gas heat replaced coal.

Like others have said, sell the wood and use the money to buy coal - you'll have more consistent heat, and less stove aggravation !

Paul

Jgib4 · Post by **Jgib4** » Tue. Nov. 14, 2017 1:55 pm

It does take around a hour for clearing, and then getting everything going again. And I definitely have better stuff to do with my time, I’m just trying to figure this all out.

Post by **Lightning** » Tue. Nov. 14, 2017 3:04 pm

Jgib4 wrote: ↑
Mon. Nov. 13, 2017 10:07 pm
Liners?

The multi fuel units usually have a cast iron or steel liner at each end of the fire box. These liners many times have a passage that leads down to the ash pan area. I believe the liners have a dual purpose #1 they protect the fire box wall and #2 they allow a portion of the primary combustion air to come up to the top of the fuel bed. This is great for bit coal and wood but not so great for anthracite.

With anthracite, it will start out good while the bottom of the fuel bed and grates are clear of ash. Later in the burn once some ash starts to clutter things up a little, the primary air will get diverted up thru those passages instead of feeding the fuel bed. The result is a fire with dwindling heat output and if left unattended will starve itself out while still having a lot of unused coal left. This is why those passages need to be blocked with insulation.

Jgib4 · Post by **Jgib4** » Tue. Nov. 14, 2017 3:24 pm

Lightning wrote: ↑
Tue. Nov. 14, 2017 3:04 pm
The multi fuel units usually have a cast iron or steel liner at each end of the fire box. These liners many times have a passage that leads down to the ash pan area. I believe the liners have a dual purpose #1 they protect the fire box wall and #2 they allow a portion of the primary combustion air to come up to the top of the fuel bed. This is great for bit coal and wood but not so great for anthracite.

With anthracite, it will start out good while the bottom of the fuel bed and grates are clear of ash. Later in the burn once some ash starts to clutter things up a little, the primary air will get diverted up thru those passages instead of feeding the fuel bed. The result is a fire with dwindling heat output and if left unattended will starve itself out while still having a lot of unused coal left. This is why those passages need to be blocked with insulation.

Thanks I found your way of blocking it not long after I posted that. So when I switch to wood during the shoulder seasons would you unblock these areas to help it burn?

Post by **Lightning** » Tue. Nov. 14, 2017 3:49 pm

Jgib4 wrote: ↑
Tue. Nov. 14, 2017 3:24 pm
Thanks I found your way of blocking it not long after I posted that. So when I switch to wood during the shoulder seasons would you unblock these areas to help it burn?

Yes, and that's exactly what I did last spring. When I was done burning coal for the winter I washed out the fire box to remove all the coal ash completely and also reopened the bypasses. Then on chilly nights thru the spring I ran several wood fires.

Jgib4 · Post by **Jgib4** » Tue. Nov. 14, 2017 6:46 pm

Lightning wrote: ↑
Tue. Nov. 14, 2017 3:49 pm
Yes, and that's exactly what I did last spring. When I was done burning coal for the winter I washed out the fire box to remove all the coal ash completely and also reopened the bypasses. Then on chilly nights thru the spring I ran several wood fires.

Thanks!

lsayre · Post by **lsayre** » Tue. Nov. 14, 2017 7:41 pm

You need to fill it up if burning anthracite.

Jgib4 · Post by **Jgib4** » Thu. Nov. 16, 2017 5:49 pm

Lightning wrote: ↑
Tue. Nov. 14, 2017 3:04 pm
The multi fuel units usually have a cast iron or steel liner at each end of the fire box. These liners many times have a passage that leads down to the ash pan area. I believe the liners have a dual purpose #1 they protect the fire box wall and #2 they allow a portion of the primary combustion air to come up to the top of the fuel bed. This is great for bit coal and wood but not so great for anthracite.

With anthracite, it will start out good while the bottom of the fuel bed and grates are clear of ash. Later in the burn once some ash starts to clutter things up a little, the primary air will get diverted up thru those passages instead of feeding the fuel bed. The result is a fire with dwindling heat output and if left unattended will starve itself out while still having a lot of unused coal left. This is why those passages need to be blocked with insulation.

Are these what you are referring to?

Post by **Lightning** » Thu. Nov. 16, 2017 6:01 pm

Yep, sure is.

Question About Unburned Coal When Using Coal and Wood

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