Warm Morning Firebrick Chimneys

I recently started burning a warm morning 460 that I purchased to heat my garage. I understand they are optimised to burn bituminous coal with the 4 chimneys in each corner to burn off the volotiles. I live in nepa so I'm burning anthracite in it. I've heard that some people that burn anthracite fill the chimneys solid with ash to block them up. Has anyone done this? What are the benefits of doing that?

If they do, it's likely done to force all the primary air to only go through the firebed ???

Paul

Sunny Boy wrote:If they do, it's likely done to force all the primary air to only go through the firebed ???

Paul

i've seen these comments on various forums but, I don't know anyone with anth. experience with these stoves that blocks the corners.

I don't see a point in blocking them. Anthracite has volatiles as well that need to be burned off . Anthracite cokes as well as bituminous the main difference is the bitumen in the bituminous coal that you are burning off before it becomes coke . These stoves work fine with anthracite so I suggest leaving it a lone and let it do its thing .

those chimneys are a great idea,for many reasons.Burning volatiles greatly reduces puff-back potential.I would not block them.

I still have to wonder,...

A. If the four corner blocks let any air bypass the firebed, what affect does that have on the draft ? Seems to me it'd be like having four by-pass check dampers open 24/7.

B. If it's such a good idea with anthracite, why are anthracite stoves built without it ?

Paul

Sunny Boy wrote:I still have to wonder,...

A. If the four corner blocks let any air bypass the firebed, what affect does that have on the draft ? Seems to me it'd be like having four by-pass check dampers open 24/7.

B. If it's such a good idea with anthracite, why are anthracite stoves built without it ?

Paul

As far as I know they were the only stove manufacture to do this . It's kind of like the secondary air ring although it's primary air being used to burn off the volatiles . I don't think it bypasses like you are thinking . Maybe it would be a problem with someone burning in a weak drafted chimney . But with a good drafting chimney I don't see an issue and I never saw an issue burning anthracite , wood or bit . Now on the other hand you are likely to see different numbers when you burn in a WM verses other stoves . Maybe you burn with a stronger draft than another type of stove but it wouldn't be much of a difference ! I used to only slightly crack the primary on my 414 using anthracite and had no secondary air going to it and it would idle down nice but not to the point where it would go out, not even close .

Also if the chimneys are working properly wouldn't there be a good deal of back pressure from the ignition of the volatiles at the end of the chimneys ? Therefore there wouldn't be much bypass at all if any. I have a photo somewhere of the flame at each flue .

Josh,
There is a large opening right out the top of each corner block. And just one of those top openings looks to be greater in cross section than any internal bypass check damper I've ever seen in anthracite stoves. Certainly larger open area than the check damper on an anthracite stove.

And, just one of those corner block "chimneys" looks to have a greater opening than all the holes in a Glenwood gas ring. Or, the loading door damper wide open.

I can see where that much secondary air would be needed for the much higher volatiles content of bit coal, but it seems excessive for anthracite. Especially when you look closely at how much secondary air opening many stove companies built into their anthracite and wood stoves. And many of those stoves cool down if the secondarys are left wide open all the time with anthracite. DLJ and I already proved that to Lightning in another thread, with Dave's Glenwood #6, and my kitchen range. Both types of stoves cooled down when we left the secondarys wide open with too much over fire air.

So, why wouldn't those four chimney blocks bypass more secondary air than is needed for anthracite ?

Paul

Sunny Boy wrote:I still have to wonder,...

A. If the four corner blocks let any air bypass the firebed, what affect does that have on the draft ? Seems to me it'd be like having four by-pass check dampers open 24/7.

B. If it's such a good idea with anthracite, why are anthracite stoves built without it ?

Paul

I agree with you Paul.. If it were my stove I would block 3 of the 4 corners for burning anthracite. Better yet, if there is any secondary air controls on the load door, I would block all the corners and regulate secondary air manually, unless I found that 1 heated corner provided better results. As ash accumulates on the grates thru the burn cycle, primary air WILL take the path of least resistance and use the corners to bypass the fuel bed. This would be noticed with heat output waning in the 12th hour. Anthracite doesn't require anywhere near the amount of secondary air as bituminous does. I see it time and time again. Excessive secondary air = higher pipe temps while the stove body remains steady or falls, especially after volatiles bake out.

For answering part A of your question, I believe it would make draft stronger since the excessive secondary air would get heated. More heated air mass = stronger draft, as long as there isn't a manual pipe damper choking it.

FWIW,

i believe you guys are drawing these conclusions from theory, outside the "personal experience" pool.

all of the remarks that I've seen that are on par with those thoughts have been and are from people talking about how they would run the stove IF they had one.

another point is the way the grate system and the flue bricks in these stove work together.

by design there is very little secondary going up the flues because of the way the grate ring is formed under them and the way the openings are arranged in the flue bricks.

all the lit. on these stoves recommends filling them to with in 2-3 inchs of the top and just refilling that at tending intervals. in the case of nut anth. in particular that doesn't leave much room for by pass in the round , tall fire pot.

the openings in the flue bricks are along side the column of coal at several levels and since the supper heated gasses are burning at the tops exert a serious draft INSIDE and through out the whole column of coal. this is pulling primary air up thru and to the sides of the fire pot pretty aggressively and there fore encouraging more primary movement than secondary by pass.

another point is thta the stoves have adjustable secondary in the doors. i'm certain that if the flue bricks drew and provided all that much secondary around the fire that these would have been over kill even for Bit.

$.02

steve

Sunny Boy wrote:Josh,
There is a large opening right out the top of each corner block. And just one of those top openings looks to be greater in cross section than any internal bypass check damper I've ever seen in anthracite stoves. Certainly larger open area than the check damper on an anthracite stove.

And, just one of those corner block "chimneys" looks to have a greater opening than all the holes in a Glenwood gas ring. Or, the loading door damper wide open.

I can see where that much secondary air would be needed for the much higher volatiles content of bit coal, but it seems excessive for anthracite. Especially when you look closely at how much secondary air opening many stove companies built into their anthracite and wood stoves. And many of those stoves cool down if the secondarys are left wide open all the time with anthracite. DLJ and I already proved that to Lightning in another thread, with Dave's Glenwood #6, and my kitchen range. Both types of stoves cooled down when we left the secondarys wide open with too much over fire air.

So, why wouldn't those four chimney blocks bypass more secondary air than is needed for anthracite ?

Paul

You do remember that I do own two of these stoves and burned with one for 2 years using Blashak anthracite right ?

I understand your thought process but if the chimneys are working as they should they produce a little flame at the top . So I don't think you are getting the same effect as blowing air through one large space with multiple holes . The flues in the brick are going to be cooler than the bed of coals so the natural convection is for the cooler air to pass through the bed of coals before it passes through the little chimneys . I will try and get some photos of the underside . The chimney openings aren't as large as you guys are making them sound . I will measure them as well . I mean we can guess at this all day long but at the end of the day I used this type stove to burn anthracite and it did a decent job of it . Not near what my glenwood does but better than some other stoves I have read about . But from the extreme of what some of you are proposing, then the stove wouldn't hold a coal fire at all.

Once bituminous coal has coked all it needs it under fire or primary air just like anthracite . If the design was a poor one then I don't think it would have been made for so many years .

And the biggest testimony to how these work is this photo Look at where those little flue/chimney openings start . After the grate . So the air must pass through the bed of coals in order to reach the 4 side flues and with what we know about how anthracite burns there is usually ash built up right where the flue openings start as the coal is used up blocking the flues , as the top part of the bed is coked up . Shake, clear, load , repeat . So in a way as the coal Cokes, then turns to ash , it controls the way the air is directed all naturally.

reminds me of a preheater at a coal fired power plant

Steve,
Your right. My experience with a Warm Morning is zero. However, my experience with anthracite and wood in several different types of stoves with secondarys and check dampers, including a lot of testing them, well that's only somewhere over 20 years worth.

Have you yet run any of your Warm Mornings, as originally designed, with just anthracite ?

I'm trying to understand how the large openings up through the corner blocks, that I see in the pictures that Christine posted in her thread - Warm Morning Installation - wouldn't negatively affect the primary air movement up through an all anthracite firebed.

You say the Warm Morning recommended coal level is a couple inches from the top. Is that from the top of the corner blocks ? And you also mention that the design of the grates affects the corner block primary air openings. Would you please how ?

Paul

Sunny Boy wrote:Steve,
Your right. My experience with a Warm Morning is zero. However, my experience with anthracite and wood in several different types of stoves with secondarys and check dampers, including a lot of testing them, well that's only somewhere over 20 years worth.

Have you yet run any of your Warm Mornings, as originally designed, with just anthracite ?

I'm trying to understand how the large openings up through the corner blocks, that I see in the pictures that Christine posted in her thread - Warm Morning Installation - wouldn't negatively affect the primary air movement up through an all anthracite firebed.

You say the Warm Morning recommended coal level is a couple inches from the top. Is that from the top of the corner blocks ? And you also mention that the design of the grates affects the corner block primary air openings. Would you please how ?

Paul

refer to my post above yours. and another point the air moving up the flues is warmed first by coming across the coal bed. The air coming through a check damper, as you compared it, would be a big difference from the flu gas causing more convection as where the air going up the 4 chimneys wouldn't have anymore convection/draft than what was going through the coal bed.

Ok Josh, thanks. We posted at the same time.

So that picture makes perfect sense, now. The corner blocks don't open directly to primary air so they can't act like a bypass check damper.

And as the volatiles burn off, the ash also builds up and automatically limits how much primary air can come up through those corner blocks. Ok, I understand now.

Thank you again.

Paul

Sunny Boy wrote:Ok Josh, thanks. We posted at the same time.

So that picture makes perfect sense, now. The corner blocks don't open directly to primary air so they can't act like a bypass check damper.

And as the volatiles burn off, the ash also builds up and automatically limits how much primary air can come up through those corner blocks. Ok, I understand now.

Thank you again.

Paul

No worries Paul! This was a good discussion. I had to sell myself on it first and actually think about this. I feel like I actually got to exercise my brain at work a little today haha .