Question: Coal Does Not Shake Down

I have a Federal Airtight stove, with 2 "revolving shake grates" burning Pea coal. The issue is with the shaking of the rear most grate. I have noticed once the coal dust is shaken out, the burning coal above it does not fall onto the grate again...instead leaving a Pocket of air above the grate. I know this because I have poked a hole in the coal to see what was the matter. the front grate performs well. the "fingers" of the grate are pointed down into the ash bin area as from Dutchwest. The coal burns well but, if I do not attend to it .... it goes out over 6-8 hours. is the pocket of air above the rear most shaker normal? or are there suggestions....? thank you

ZumDish wrote:I have a Federal Airtight stove, with 2 "revolving shake grates" burning Pea coal. The issue is with the shaking of the rear most grate. I have noticed once the coal dust is shaken out, the burning coal above it does not fall onto the grate again...instead leaving a Pocket of air above the grate. I know this because I have poked a hole in the coal to see what was the matter. the front grate performs well. the "fingers" of the grate are pointed down into the ash bin area as from Dutchwest. The coal burns well but, if I do not attend to it .... it goes out over 6-8 hours. is the pocket of air above the rear most shaker normal? or are there suggestions....? thank you

defiantly not normal (coal does not want pockets of air ever ), without seeing pics or investigating the stove my best guess to put it bluntly is your coal may suck LOL. for some reason your coal bed is "binding" above the well burned ash but below the red hot burning coals? This could be a design flaw of the stove or it could be bad coal (your shaker or your poking is obviously working fine because you have nothing but air left to shake or poke between your grate and the bottom of the coal bed )

It sounds like you have a bridge. Are you burning hard or soft coal? Bridging can happen if you fire it too hot or there is a air leak under the grate. Just poke it and it will fall down where it ough to be.

it sounds like maybe the coal bed is "bridging". when this happens in my boiler I clean out as much ash as possible then use my poker to collapse the coal bed. then I use my slicing tool and thin poker that I learned to make from this forum to clear out the remainder of the ash. Ill see if I can locate the thread where pictures of these tool designs were posted.

carlherrnstein wrote:It sounds like you have a bridge. Are you burning hard or soft coal? Bridging can happen if you fire it too hot or there is a air leak under the grate. Just poke it and it will fall down where it ough to be.

If he could post some pics it would help... but Carl is right for sure about it bridging, the question is why is it bridging? I assume you have inspected the stove at least somewhat prior to using it? I would shut the stove down and clean it out and then notice if you see a ledge around the mid section of the firebrick or liner (this ledge would consist of fused together coal that adheres itself to the walls of the firebrick), if this is the case then you have your answer.... you need to carefully chip off or grind down this "ledge" for proper operation. If you have no ledge built up then it could be your operation I suppose but more likely its the coal your using. EDIT: please get me some pics of your stove, inside grate/combustion area? at first glace im not sure how this unit can possibly burn coal well (looks like a 100% wood burner to me) I don't want to make any assumptions but seeing inside it would help me make some suggestions (ill run a search for some schematics now)...

another guess after looking at pics of the stove, your burning good quality anthracite coal in a stove made for wood... its not allowing for proper airflow through the coal bed and therefor is slowly "melting" your coal into a large puddle of sticky kaka instead of "burning" it as it should be.... in this case (get some cheapo Bit coal for it and try that).

have read all the replies, thank you. I purchased the stove as a wood/coal combination stove 15 years ago, this is the 1st year I am burning coal (I have all the parts for this model). I'm burning Anthracite pea coal from Kimmel's, Wiconisco, PA. there are no stove "bricks." the inside of the stove, it is smooth cast iron through out as manufactured, single wall (for wood only). I attach in 4 more smooth cast iron plates (boxing in the coal burning area). the bridging spoke of prior is an excellent description of what is happening. when I poke the fire "bridge" in the area of the back most grate, I am doing just that....poking it in 2-4 places to collapse the bridge and adding more coal. the burn temperature at the top of the stove is 600 F, and the pipe is at 100 F. sorry but, will be a 4 days until I have the opportunity to stop the stove and clean it out for photographing.

when I burn nut coal, I get the gelatinous "ka Ka." lumps of fused ...

I have prior to burning, replaced all the seals, ensured it was leak tight, and control all draft through the bottom (dial) valve or door. thank you again for all the input, if you have others, i'm more than happy and thankful to listen

ZumDish wrote:have read all the replies, thank you. I purchased the stove as a wood/coal combination stove 15 years ago. I'm burning Anthracite pea coal from Kimmel's, Wiconisco, PA. there are no stove "bricks." the inside of the stove, it is smooth cast iron through out as manufactured, single wall (for wood only). I attach in 4 more smooth cast iron plates (boxing in the coal burning area). the bridging spoke of prior is an excellent description of what is happening. when I poke the fire "bridge" in the area of the back most grate, I am doing just that....poking it in 2-4 places to collapse the bridge and adding more coal. the burn temperature at the top of the stove is 600 F, and the pipe is at 100 F. sorry but, will be a 4 days until I have the opportunity to stop the stove and clean it out for photographing.

when I burn nut coal, I get the gelatinous "ka Ka." lumps of fused ... I have prior to burning, replaced all the seals, ensured it was leak tight, and control all draft through the bottom (dial) valve or door. thank you again for all the input!

ok... cast iron firepot pretty much rules out fused on ledge. describing your "coal" attachments it sounds like its possible that the manufacturer geared this stove for Bit coal and not anthracite (you can think about Bit coal being softer and more like wood which allows it to be used with more success in a wood designed stove), I know you bought it as a Wood & Coal Burning stove but don't believe what they tell you! One key thing to look for is any possible airflow that could be getter from the lower door "intake draft area" to the upper door without having to go up "through" the coal bed! Its great that you made sure gaskets are all good, etc. but if you can do something to ensure that all the airflow from draft dials on the lower door goes up through the coal bed maybe you can get this baby functioning much better and MUCH more efficiently for you! after you post pics we will put out heads together

also, try not to bank the coals up towards the rear (thinking thats helping you gain longer burns, etc.) with coal you want to try to keep a level bed pea size 4-6 inches nut size 6-9 inches deep. banking up coals to one side or another thereby creating different depth beds hurts in coal burning.

ok DKrane! I understand my mission will do what I can to make "certain" all air coming from dial only! and post pictures next week when I get the chance to squirrel my way inside

ZumDish wrote:ok DKrane! I understand my mission will do what I can to make "certain" all air coming from dial only! and post pictures next week when I get the chance to squirrel my way inside

added a tip, im not sure if you got it.... "also, try not to bank the coals up towards the rear (thinking thats helping you gain longer burns, etc.) with coal you want to try to keep a level bed pea size 4-6 inches nut size 6-9 inches deep. banking up coals to one side or another thereby creating different depth beds hurts in coal burning."

It is Definitely bridging and it's not that uncommon. The easiest "fix" is to use a poker just before you reload and shake down. The poker with a 90° on the end will work best. Not all coal will do this and don't discount nut coal just because you had a clinker experience with some brand. Try another. Lastly, I'm not familiar with your stove but if you are burning coal exclusively you should think about some type of refractory lining. Your stove will thank you for it and they 'insulate" the fire so that it has better heat transfer where it should.

[/quote] added a tip, im not sure if you got it.... "also, try not to bank the coals up towards the rear (thinking thats helping you gain longer burns, etc.) with coal you want to try to keep a level bed pea size 4-6 inches nut size 6-9 inches deep. banking up coals to one side or another thereby creating different depth beds hurts in coal burning."[/quote]

AH YES! That is what I have been doing! banking towards the back, thinking it would fall to the front as it burns. LOL !!
ok, will 'rake' the coal flat from here on out! thank you!

my current fire (w help) has been cooking for 7 days which, is truely a blessing! i'm keeping a 1600 sq ft house at 58 F, haven't used a drop of oil yet this winter! which was my intent through burning coal. down the road I may want another (real) coal stove....but, for now this one is like training wheels (and my 1st ever attempt at using coal to keep my house warm). thanks to all for their thoughts...this is truly an excellent forum!

and thank you too Steve, i'll make a 90 degree tool this weekend!

ZumDish wrote:

added a tip, im not sure if you got it.... "also, try not to bank the coals up towards the rear (thinking thats helping you gain longer burns, etc.) with coal you want to try to keep a level bed pea size 4-6 inches nut size 6-9 inches deep. banking up coals to one side or another thereby creating different depth beds hurts in coal burning."[/quote]

AH YES! That is what I have been doing! banking towards the back, thinking it would fall to the front as it burns. LOL !!
ok, will 'rake' the coal flat from here on out! thank you!

my current fire (w help) has been cooking for 7 days which, is truely a blessing! i'm keeping a 1600 sq ft house at 58 F, haven't used a drop of oil yet this winter! which was my intent through burning coal. down the road I may want another (real) coal stove....but, for now this one is like training wheels (and my 1st ever attempt at using coal to keep my house warm). thanks to all for their thoughts...this is truly an excellent forum!

and thank you too Steve, i'll make a 90 degree tool this weekend![/quote]

We love coal burners, wood burners and barn burners here! your doing fine, I learn new things everyday on this forum (todays lesson was the EPA has no jurisdiction over coal stoves ).
Hope the tips help you and look forward to some pics of your unit when your able!

SteveZee wrote: think about some type of refractory lining. Your stove will thank you for it and they 'insulate" the fire so that it has better heat transfer where it should.

did find this link here on this forum regarding refractory linging...the stove in picture is just like mine.

Added a Refractory Lining to My Stove

was curious, this fellow in the link used it on the front coal grate (picture in link). is this cement/lining used on all burning surfaces where coal is? thank you

ZumDish wrote:

SteveZee wrote: think about some type of refractory lining. Your stove will thank you for it and they 'insulate" the fire so that it has better heat transfer where it should.

did find this link here on this forum regarding refractory linging...the stove in picture is just like mine.

Added a Refractory Lining to My Stove

was curious, this fellow in the link used it on the front coal grate (picture in link). is this cement/lining used on all burning surfaces where coal is? thank you

Ohhhh good lord in heaven That liner does not appear like it will withstand coal for long, the sides just don't seem near the thickness needed (but because of the dead/cool area an inch on either side they get away with it) and clearly the front failed in one firing (dudes running 695 surface temps which is OK for a serious quality coal stove but he's going to beat the bloody blazes outa' this thing! I don't like seeing the side of my coal fire through a glass view window either!

You do need to have a liner using coal or the outsides of the stove itself will buckle and distort in time, this unit clearly needs more liner then they provide you (which is why this guy is adding firebricks to the front edge in an attempt to save the poorly designed front "so called" coal grill that allows you to view the side of the coal bed). I would put brick right up to the top of that front "see through" grill )

I can tell you that he has similar issues as you in terms of shaking and clunkers and dead spots and hot spots and cold spots, he obviously got it blazing good for the pics but I don't see this as being friendly towards shaking and ash removal, plus we got doors on all sides and top load openings and all kinds of ways air can go every which way on this thing This is definitely a wood stove my friend and Bit coal would probably burn better in it but try to keep a level bed of appropriate depth and if you have to use a poker to keep her running then so be it (we all do it). The sides of their coal kit are at such a steep angle down towards the grate that it could be working as a "ledge" instead of a funnel (you could test this by using firebrick behind those sides to make them stand up in less of an angle and more strait up and down).

ZumDish -

The refractory lining did not last, nor did the front grate. The rest of the stove did hold together just fine, though. I think the grate might have gotten too hot due to the ash door not sealing tight enough, the fire would always burn hottest towards the front of the stove. What really led me to move on to a different stove though, is the loading process. Getting a good full charge of coal into these stoves it a royal pain. I got my best burns when I would heap the coal up almost to the grate that covers the secondary burn area. This is my idea of a fully loaded stove : If it's available, you may want to try burning some bituminous coal in the stove. The pre-heated combustion air that is intended for the catalyst works pretty well at burning the secondary gasses. I could get the blue ladies to dance in the secondary combustion chamber!

Here is the front grate in December 2011, I have a bunch of pictures in my Dutchwest Stove album : http://s1034.beta.photobucket.com/user/LDPosse/li ... ove%202011



Attached are pictures of the parts as of today. The stove ran pretty much continuously from mid-December 2011 though May 2, 2012.