Minor Explosion In Coal Stove

Re: Minor Explosion In Coal Stove

PostBy: freetown fred On: Wed Nov 14, 2012 1:05 pm

I find that with my 50-93--the thermo flap takes any of my lil or big booms --Oh hush Rick--below the flap door I can usually see an ash dusting, nothin major, but it's there. Of course that's with following SOP for the tending process on the 50-93
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
Coal Size/Type: BLASCHAK Nut/Stove mix

Re: Minor Explosion In Coal Stove

PostBy: Boots On: Mon Nov 19, 2012 6:59 pm

I'm having an issue with "puff backs" lately. but I'm not getting them while loading. its happening an hour or two after loading. and they are big, had one last night that blew the bottom part of the barro door off ( the part you flip around depending on if its a vertical or horizontal install). that one and the one i had the day before shook the floor of the house. but the the first of the two sent flames up the flue past the barro for about 30 seconds. To try to correct this issue last night and today i ran the stove with the over fire draft knob (i think thats what its called) cracked open just a touch. When i got home today the barro was intact so i guess i did not have a large puff back today.

My stove is a natural draft boiler, when it go's into "high fire" an actuator opens a small flap on the ash door and when it reaches its preset temp the flap closes. I think that my stove is going into high fire, building temperature, the flap closes and the fire dies down, the 2 hour old coal releases more gas, and eventually enough heat and oxygen build up with the gas and.... boom....

my thought is that by leaving the over fire damper knob open just slightly it will keep enough oxygen in the firebox that it will continually burn the gas off rather than all at once.

Am i on the right track? is leaving the over fire open some going to hurt anything? will it cause me to burn more coal? any input would be a great help.
Boots
 
Stoker Coal Boiler: KA-6 In the basement........
Hand Fed Coal Boiler: Burnham SFB 101

Re: Minor Explosion In Coal Stove

PostBy: franco b On: Mon Nov 19, 2012 7:19 pm

I think you have it figured out. I would leave more than a crack in that over fire air. I don't think you will see a noticeable difference in the coal burned.
franco b
 
Hand Fed Coal Stove: V ermont Castings 2310, Franco Belge 262
Baseburners & Antiques: Glenwood Modern Oak 114
Coal Size/Type: nut and pea

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Re: Minor Explosion In Coal Stove

PostBy: Boots On: Mon Nov 19, 2012 8:19 pm

franco b wrote:I think you have it figured out. I would leave more than a crack in that over fire air. I don't think you will see a noticeable difference in the coal burned.


just to make sure we are talking about the same thing. i was planing to leave it open pretty much indefinitely. is this what you had in mind?
Boots
 
Stoker Coal Boiler: KA-6 In the basement........
Hand Fed Coal Boiler: Burnham SFB 101

Re: Minor Explosion In Coal Stove

PostBy: franco b On: Mon Nov 19, 2012 8:26 pm

Yes. Some over fire air all the time. It is not just to burn the gasses from fresh coal but to burn the carbon monoxide that builds up in an established fire when starved for air. Ideally some sort of fixture similar to the antique stoves intended for bit coal that feed heated air just above the fire pot would be best.
franco b
 
Hand Fed Coal Stove: V ermont Castings 2310, Franco Belge 262
Baseburners & Antiques: Glenwood Modern Oak 114
Coal Size/Type: nut and pea

Re: Minor Explosion In Coal Stove

PostBy: Lightning On: Mon Nov 19, 2012 8:57 pm

I also leave just a smidge of over the fire air. I used to run mine sealed tight from any over fire air but was having puffing issues. This is copied from another post I made and my opinion based on my own observations - some may disagree :D

Come on Fred, who doesn't like some hot lil blue dancin ladies I'll throw in my opinion on the whole thing, cuz I've wondered the same. Bear with me, there is a lot going on here... It seems to me that if the coal bed is under a particular temperature, there are no flames and any over the fire air will result in wasted heat going up the chimney, although you may need this heat to help support your draft. BUT, if it gets above a particular temperature, there is enough combustible gases coming off the top of the coal bed to support flames when air coming in over the fire is introduced (like you've noticed). There are a couple things that can happen at this point.

#1 - These gases, without any over the fire air will simply float up and out the chimney. (wasted potential heat)
#2 - These gases, without any over the fire air could build up in the fire box and flash. (puff back)
#3 - These gases, WITH just the right amount of over the fire air, will yield me a few more BTU's

Number Three is tricky.. Meaning too much over the fire air will net you lost heat going up the chimney (in the form of heated air) and at the same time, not enough over the fire air will also net you lost heat going up the chimney (in the form of unburnt combustible gases). SO in my opinion, the perfect case scenario is the right combination of under the fire air (primary) and over the fire air (secondary) and that these air feeds are completely independent of each other. Meaning, primary air can't bypass the coal bed and act like secondary air, which was a huge problem for me. This combination will change based on just how hot you are pushing the fire. This is based on my own thought and observation. I would love to hear some others' thoughts on this also! Results and opinions may vary, some side effects could be life threatening (probably not) or are just a lot of fun to watch (Fred)
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Minor Explosion In Coal Stove

PostBy: Boots On: Tue Nov 20, 2012 5:55 pm

Thanks for your input Lightning and Franco b.

i burned last night and today with the over fire air open some. I had foil over the baro because it was going to be warmer here today (~50F) and my draft is POOR at those temps. when i got home the foil was pushed back away from the baro, so i guess i did have a puff back today. it must not have been too bad because the foil was not pushed back very far. after i discovered this, i opened the over fire air up a little more. it is currently at 3/4 turn open.
Boots
 
Stoker Coal Boiler: KA-6 In the basement........
Hand Fed Coal Boiler: Burnham SFB 101

Re: Minor Explosion In Coal Stove

PostBy: BPatrick On: Thu Oct 24, 2013 10:10 am

I read a lot of the sticky threads as I'm learning what not to do from people who have learned the hard way. This makes total sense. I use two types of coal. I use Nut Coal which has a lot of bigger pieces in it and then I also use Pea Coal. On mild days I'd use Pea Coal or I'd do a combination, Nut coal 3/4 and then the last 1/4 is Pea Coal. You can really control a fire as this gets in between the spaces and slows down the burn. I've really gotten the hang of shaking, not too much and this helps dramatically with the temps and burn rates but so does adding Pea Coal. The only thing I've had to be careful of is the loading of too much Pea Coal at once and completely sealing off the fire. I never have this happen with Nut coal as there is too much room for the flames to peak out. With Pea Coal, you can smother the fire and every once in a while I get a little poof, nothing major and the smoke puff comes out the bottom ash pan door. Everything is screwed down tight so that isn't an issue, it just reminds me that when working with the Pea sized coal to not cover completely. Again, I never have this happen with the larger Nut Coal.
BPatrick
 
Baseburners & Antiques: 2 Crawford 40 Baseheaters
Coal Size/Type: Stove Coal
Other Heating: Herald Oak No. 18

Re: Minor Explosion In Coal Stove

PostBy: michaelanthony On: Tue Oct 29, 2013 11:07 pm

BPatrick wrote:I read a lot of the sticky threads as I'm learning what not to do from people who have learned the hard way. This makes total sense. I use two types of coal. I use Nut Coal which has a lot of bigger pieces in it and then I also use Pea Coal. On mild days I'd use Pea Coal or I'd do a combination, Nut coal 3/4 and then the last 1/4 is Pea Coal. You can really control a fire as this gets in between the spaces and slows down the burn. I've really gotten the hang of shaking, not too much and this helps dramatically with the temps and burn rates but so does adding Pea Coal. The only thing I've had to be careful of is the loading of too much Pea Coal at once and completely sealing off the fire. I never have this happen with Nut coal as there is too much room for the flames to peak out. With Pea Coal, you can smother the fire and every once in a while I get a little poof, nothing major and the smoke puff comes out the bottom ash pan door. Everything is screwed down tight so that isn't an issue, it just reminds me that when working with the Pea sized coal to not cover completely. Again, I never have this happen with the larger Nut Coal.


Aah, none of this mumbo jumbo is true until it happens to you. Well let me explain, This is my fourth season burning coal and I just experience this scenario and it is a little settling the first time. I was able to procure a new 30 yr. old door for my gold marc hand fed stove. My old one leaked like a sieve and I new it would make a difference. My wife had accidentally ordered some pea size instead of 'nut but I'm ok with it I plan on getting a V.C. 2310 going soon. Anyway I built a nice wood fire in the basement stove which burns 'nut or stove size but since all I have is pea I covered the grates with a nice bed of coal and put the pea right to 'er.
Aaand low and behold on the second load I noticed a nice blue swirling fire as I was loading and on about the fourth or fifth shovel full---dead calm, like stairing at the night sky and no stars out.I closed the load door and started opening the secondary air and I swear it was slow motion, the ball reflected off the bottom of the ash pan as I could see it through the air vent The gap at the secondary air spinner and the load door glowed blue and spit a little fire...I swear it moaned :shock: :|
michaelanthony
 
Hand Fed Coal Stove: Vigilant 2310, gold marc box, vogelzang pot belly
Coal Size/Type: Pea, and a little nut
Other Heating: Very cold FHA oil furnace

Re: Minor Explosion In Coal Stove

PostBy: SMITTY On: Tue Oct 29, 2013 11:11 pm

LOL Nice description! :lol:

I've had some EPIC explosions using nut :lol: - that's the only size I've ever burned in a handfired.
SMITTY
 
Stoker Coal Boiler: Patriot Coal - custom built by Jim Dorsey
Hand Fed Coal Stove: Harman Mark III (not currently in use)
Coal Size/Type: Rice / Blaschak anthracite
Other Heating: Oil fired Burnham boiler

Re: Minor Explosion In Coal Stove

PostBy: I'm On Fire On: Fri Nov 22, 2013 11:41 am

I've had several like that myself. Only my house shook. Scared the crap out of me. Those are fun times. I've learned though not to touch anything. I don't open the air, don't touch the MPD. I just shake it down and load coal and let it be. I had far less explosions last year than the season before that. I haven't experienced one explosion yet this season; though admittedly the season is still very young.
I'm On Fire
 
Hand Fed Coal Stove: DS Machines DS-1600 Hot Air Circulator

Re: Minor Explosion In Coal Stove

PostBy: lsayre On: Fri Nov 22, 2013 12:17 pm

Im On fire, did the corner air vents that you installed in the firebox help with this situation? How many did you put in?
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Anthracite Pea
Other Heating: Resistance Boiler (if I ever get it fixed)

Re: Minor Explosion In Coal Stove

PostBy: I'm On Fire On: Fri Nov 22, 2013 12:23 pm

lsayre wrote:Im On fire, did the corner air vents that you installed in the firebox help with this situation? How many did you put in?


I put two in. One on the front corner and the other on the opposite side in the rear. The help but don't eliminate the puff-backs. They aren't as bad or as frequent but they still occur.
I'm On Fire
 
Hand Fed Coal Stove: DS Machines DS-1600 Hot Air Circulator

Re: Minor Explosion In Coal Stove

PostBy: KingCoal On: Fri Nov 22, 2013 4:51 pm

i must say i'm confused by all this in a DSM. i haven't had a single episode of this.

IOF, i would change your tending practice just a bit.

try opening the MPD wide open, the ash door just enough to close against the latch rod and put 4-5 ash shovels of fresh coal across the unshaken fire.

leave it, but stay close to watch, shouldn't take but 2-3 mins. tops for it to be going real good. close the ash door and shake it down, re-open ash door and add your coal. be sure to leave an opening where active flames are working. close both ash door and MPD and you should be good.
KingCoal
 
Hand Fed Coal Stove: DSM 1400, Riteway # 37, Comforter Stove Works
Coal Size/Type: Nut Anth.
Other Heating: none
Stove/Furnace Model: 2013 1400 Circulator

Re: Minor Explosion In Coal Stove

PostBy: Lightning On: Fri Nov 22, 2013 4:57 pm

King Coal, I think your secondary air vents keep the hydrocarbon gases diluted enough that you don't get puff backs.
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

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