Newbie coal burner

Newbie coal burner

PostBy: imaddicted2u On: Sat Jan 04, 2014 1:23 am

I'm new to burning coal. I'm burning bituminous coal for the first time in a 1957 American Standard Severn boiler. It is gravity feed to the cast iron radiators in the house. Up until now I have been burning wood in it during the milder weather. The Severn has an ash pit damper, over fire slots in the loading door, a manual damper in the stove pipe and a barometric damper that is in the stove pipe of the oil boiler which is attached to the same chimney as the coal boiler. I have a manometer connected to the breech of the coal boiler. I can set the baro to bring the coal boiler draft down to .05" and be in the middle of its control range. Then I use the manual stove pipe damper to bring the coal boiler draft down to between .02" to .04". The baro smooths out the coal boiler draft, even though it is in the oil boiler stove pipe. Does this sound like an acceptable way to operate? If I was to burn oil, I would reset the baro to the oil boiler draft spec.
I've read on this forum that bituminous coal likes some over the fire draft. Is there a way that you can tell the draft slots in the loading door are at the right opening?
I pretty much filled the fire box for the first time tonight. I think the fire box holds about 2 cubic feet. How can you tell when the optimum time to add more coal? With the boiler water temp at only 115 degrees F, the temp in the house is around 77 degrees F, the outside temperature is 14 degrees F. Is it ok to close up the ash pit damper and manual pipe damper and open the baro cool things down? If so, how long before you lose the fire? Should the over the fire draft be closed too or should it be left open to burn off combustible gasses?
Sorry for all the questions, I'm not used to controlling the coal fire yet, any suggestions would be helpful.
imaddicted2u
 
Hand Fed Coal Boiler: American Standard Severn (1957) on bituminous
Coal Size/Type: Unscreened-Fist sized lump to powder-Bituminous

Re: Newbie coal burner

PostBy: casino_boy On: Sat Jan 04, 2014 10:19 am

Sounds like you have a hand fed boiler furnace.
Your ash pit damper will control your heat output and yes you will need some over fire air to burn off gasses.
How much you will have to play with.
On my hitzer furnace I need just 1 half spin oppen.
Dont know your funace but in genral this should help.
casino_boy
 
Hand Fed Coal Furnace: Htzer 82 FA
Coal Size/Type: sub-bit pea, kentky 2 x 6 bit

Re: Newbie coal burner

PostBy: imaddicted2u On: Sat Jan 04, 2014 4:18 pm

Yep, hand fired coal boiler. I corrected it in my profile.
I've been experimenting with setting the draft in the door. I can see a big difference in the burn, especially right after loading in some coal. Funny that when I was out shoveling snow today, 2 neighbors said they couldn't believe I was burning coal. They couldn't smell it or see any smoke. They said that when the previous owners of my house burned coal the smell and smoke were terrible.
I started with a few coals this morning and got the fire going with no problems. Inside it was still 72.5 degrees F and boiler water temp was 96.9F. While I was getting the fire going, the house temp dropped to 71.9. Outside it's 8.6 degrees F and very windy. Over the space of an hour I put 40 pounds of coal in the firebox. The temp gradually climbed back up to 72.5 and boiler water temp rose as high as 114F and it settled in at 107F . Six hours later I still had plenty of coals and added 40 pounds more, this time all at once. We'll see if it burns any longer now that I'm getting a handle on controlling it.
I think I'm going to like burning coal compared to wood, except for all the extra ashes. ;-)
Here is a pic of the 6 bedroom house I'm heating:
Image
imaddicted2u
 
Hand Fed Coal Boiler: American Standard Severn (1957) on bituminous
Coal Size/Type: Unscreened-Fist sized lump to powder-Bituminous


Re: Newbie coal burner

PostBy: franco b On: Sat Jan 04, 2014 4:29 pm

Like wood bit coal gives off a lot of gas when first heated. You will need lots of air over the fire at this point. With a large batch of coal it is more critical.

You are doing the right thing in gradually feeling your way to learn the properties of the particular coal you are using. Be careful about soot build up on the manual pipe damper even though I think it is 9 inch
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: Newbie coal burner

PostBy: imaddicted2u On: Sat Jan 04, 2014 5:22 pm

It was originally 9", It looks to have been modified and is only 6" stove pipe now. I found the original 9" cast iron stove pipe adapter in the basement. The casting is broken. It actually had a 6" reducer where it entered the chimney. The flue only has a 6" square liner anyway. I think that's why I get puff back when I open the door, burning either wood or coal, even though I have lots of draft at the boiler breech. I brush out the heat exchanger, stove pipe and chimney every week or two. The chimney has been pretty clean. When burning wood I've only found creosote in the firebox and heat exchanger, none in the chimney. I guess the creosote condenses out on the water cooled surfaces. I usually find the holes in the MPD plugged up. I have a Dwyer manometer connected all the time and I set the MPD opening based on it rather than its position. I set the MPD for a draft at the breech of between .02" and .04". If I close it too much smoke puffs out the over fire draft slots. Just to be safe I open the MPD and close the ash pit and baro dampers anytime I open the door. At least that minimizes but doesn't eliminate the puff back.
imaddicted2u
 
Hand Fed Coal Boiler: American Standard Severn (1957) on bituminous
Coal Size/Type: Unscreened-Fist sized lump to powder-Bituminous

Re: Newbie coal burner

PostBy: rockwood On: Sat Jan 04, 2014 6:19 pm

Good to see that you're starting to use coal :)

I would consider not using the manual stove pipe damper because it can clog up very quickly when using bituminous coal...I'm not saying you can't use it but it can be a problem.

I would just use the baro by itself to keep the draft at around .04. I my opinion, .02 is a bit on the low side for this kind of set-up.
If the baro damper can't achieve the .04 range, then I would consider adding a second baro or installing a bigger one instead of using the manual pipe damper.

BTW, the baro damper should fall to a closed position on its own when you open the door...you shouldn't have to close it manually.

Be careful not to smother the fire when adding fresh coal. Leaving an area of live coals exposed and air over the fire as franko b mentioned will limit the potential for puffback/explosions.

Be sure to have a couple CO detectors just to be safe ;)
rockwood
 
Hot Air Coal Stoker Furnace: Stokermatic coal furnace
Hand Fed Coal Stove: Rockwood Stoveworks Circulator
Baseburners & Antiques: Malleable/Monarch Range
Coal Size/Type: Soft coal: Lump and stoker (slack coal)

Re: Newbie coal burner

PostBy: imaddicted2u On: Sat Jan 04, 2014 8:31 pm

Yep, the baro closes when the door is opened, I just clamp it shut for my peace of mind. The baro can get the draft down to .05". I have a ton of draft up the 29 foot high chimney. Keep in mind that the baro is actually in the oil boiler flue pipe on the other side of the chimney. There is 17" between the boiler breech and the chimney so that limits my options. I have to use the MPD to choke the smoke pipe in order to reduce the fire, even with the ash pit and over fire dampers closed. Otherwise it would be so hot in the house it would be unbearable. It certainly isn't a modern air tight design but I have added rope gaskets to the doors so it is tighter than it used to be.

When I add fuel, I use an old garden hoe to slope the coals up the back boiler wall. Then I add fuel to the front of the fire box. For the smoke to get out it has to pass over the sloped hot coals. The smoke ignites very quickly.

I ran into a very dangerous situation today, I have been burning wood for months and not had this happen. I could detect the faint smell of smoke in the house. I figured it was a lingering odor from opening the door. Later I discovered that when I closed the MPD got to around .04" a thin wisp of smoke would come out of the joint where the stove pipe is attached to the boiler breech. I've set the draft to .01" when burning wood and not gotten any smoke leakage. Odd it would occur when I start burning coal, good thing I discovered it. I sealed it with hi-temp RTV. I have a CO detector less than 10 feet from the boiler and it wasn't triggered.

My first 40 pounds of coal lasted 6 hours and the second 40 pounds lasted 7 hours. If I assume 10,500 btu per pound, 40 pounds is 420,000 btu, so the 6 hour run was 70,000 btu/hr and the 7 hour run was 60,000 btu/hr with the outside temp running between 6.8 and 10.4 degrees F. The house temp stayed between 71 and 73 degrees F.
imaddicted2u
 
Hand Fed Coal Boiler: American Standard Severn (1957) on bituminous
Coal Size/Type: Unscreened-Fist sized lump to powder-Bituminous

Re: Newbie coal burner

PostBy: casino_boy On: Sun Jan 05, 2014 12:30 am

/when you go a shake down the stove open the ash door damper for a few minutes to living up the fire then shake it you will find you will have less ash in your pan.Then add your coal as you have been doing and shut the ash door damper to were you had it set.
See if this dont help with less ash.
casino_boy
 
Hand Fed Coal Furnace: Htzer 82 FA
Coal Size/Type: sub-bit pea, kentky 2 x 6 bit

Re: Newbie coal burner

PostBy: imaddicted2u On: Sun Jan 05, 2014 6:51 am

casino_boy wrote:/when you go a shake down the stove open the ash door damper for a few minutes to living up the fire then shake it you will find you will have less ash in your pan.Then add your coal as you have been doing and shut the ash door damper to were you had it set.
See if this dont help with less ash.

Thanks, I'll give it a try.
imaddicted2u
 
Hand Fed Coal Boiler: American Standard Severn (1957) on bituminous
Coal Size/Type: Unscreened-Fist sized lump to powder-Bituminous

Re: Newbie coal burner

PostBy: imaddicted2u On: Sun Jan 05, 2014 7:11 am

I took a closer look at the ash pit door draft regulator. As you can see in this pic, the ash pit draft is never really closed. There is a gap where the plate should mate with the upper surface when closed. You can't see it in the pic but I can see the red glow from the ash pit through the gap. The gap is up to 1/4" so it's no wonder I can't turn the fire right down.
Image
imaddicted2u
 
Hand Fed Coal Boiler: American Standard Severn (1957) on bituminous
Coal Size/Type: Unscreened-Fist sized lump to powder-Bituminous

Re: Newbie coal burner

PostBy: rockwood On: Sun Jan 05, 2014 7:01 pm

imaddicted2u wrote:The gap is up to 1/4" so it's no wonder I can't turn the fire right down.

Yep, get that and any other gaps fixed and you will be able to extend the burn times.

imaddicted2u wrote:I ran into a very dangerous situation today, I have been burning wood for months and not had this happen. I could detect the faint smell of smoke in the house. I figured it was a lingering odor from opening the door. Later I discovered that when I closed the MPD got to around .04" a thin wisp of smoke would come out of the joint where the stove pipe is attached to the boiler breech. I've set the draft to .01" when burning wood and not gotten any smoke leakage. Odd it would occur when I start burning coal, good thing I discovered it. I sealed it with hi-temp RTV. I have a CO detector less than 10 feet from the boiler and it wasn't triggered.


That's kinda strange...you might want to re-calibrate the draft gauge to make sure it's reading right. Running the draft at -.04 should work well for this unit.

Your method of banking the live coals and adding fresh coal in front is right on the money :)
rockwood
 
Hot Air Coal Stoker Furnace: Stokermatic coal furnace
Hand Fed Coal Stove: Rockwood Stoveworks Circulator
Baseburners & Antiques: Malleable/Monarch Range
Coal Size/Type: Soft coal: Lump and stoker (slack coal)

Re: Newbie coal burner

PostBy: imaddicted2u On: Mon Jan 06, 2014 4:40 am

I got the ash pit damper so it seals well now. I used a wire brush on my dremel tool to clean up the mating surfaces. Then I covered the draft plate with plastic wrap. I put a bead of high temp silicone on the non moving surfaces. I closed the draft plate and put a couple of bricks on it and let the silicone set up. Since the plastic wrap didn't stick to the silicone it was easy to remove and the silicone makes a nice gasket seal.

While the silicone was setting up on the coal boiler ash pit damper, I was using the oil boiler and confirmed the proper operation of the baro draft regulator with my manometer attached to the oil boiler breech. It is bang on the money. I think I may have shut the MPD too soon after adding fresh coal. For safety sake, I'm going to take the flue pipes apart tomorrow and reseal them with high temp silicone. I think it best to keep the smoke in the pipe...lol.

I cleaned the heat exchanger tonight, OMG the soot was unbelievable for only burning coal for a couple of days. I've been thinking that the coal boiler is over sized and it's likely there was no liner in the chimney. When it was installed the house would have been much less energy efficient. I wonder if somehow reducing the size of the firebox would allow me to burn a hotter fire and maybe reduce the the soot buildup through improved burn efficiency? It might help reduce my puff back problem as well by reducing the amount of fuel down to something the chimney can handle. I think the BTU capability of the coal boiler exceeds what the 6"X6" chimney liner can handle.

After cleaning the heat exchanger I tried the paper test on its door seals. Along the whole bottom of the heat exchanger door the paper pulled out with no effort, it was barely touching, so I did the same as I did with the ash damper door. I had glued rope gasket to the doors, so imagine how leaky they were before, downright unsafe I think! I put hi temp silicone on the door side and covered the mating surface on the boiler with plastic wrap so the silicone wouldn't stick to it then shut the door so the silicone would fill the gaps and let it set up.
imaddicted2u
 
Hand Fed Coal Boiler: American Standard Severn (1957) on bituminous
Coal Size/Type: Unscreened-Fist sized lump to powder-Bituminous

Re: Newbie coal burner

PostBy: Lightning On: Mon Jan 06, 2014 6:34 am

I tried bit coal for a couple weeks. I found the soot build up to be horrendous too. It also clogged my manometer probe giving me false readings. Keep an eye on that probe for clogging.
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Newbie coal burner

PostBy: imaddicted2u On: Mon Jan 06, 2014 7:02 am

Good advice,
thanks
imaddicted2u
 
Hand Fed Coal Boiler: American Standard Severn (1957) on bituminous
Coal Size/Type: Unscreened-Fist sized lump to powder-Bituminous

Re: Newbie coal burner

PostBy: McGiever On: Mon Jan 06, 2014 9:46 am

imaddicted2u wrote:Yep, hand fired coal boiler. I corrected it in my profile.
I've been experimenting with setting the draft in the door. I can see a big difference in the burn, especially right after loading in some coal. Funny that when I was out shoveling snow today, 2 neighbors said they couldn't believe I was burning coal. They couldn't smell it or see any smoke. They said that when the previous owners of my house burned coal the smell and smoke were terrible.
I started with a few coals this morning and got the fire going with no problems. Inside it was still 72.5 degrees F and boiler water temp was 96.9F. While I was getting the fire going, the house temp dropped to 71.9. Outside it's 8.6 degrees F and very windy. Over the space of an hour I put 40 pounds of coal in the firebox. The temp gradually climbed back up to 72.5 and boiler water temp rose as high as 114F and it settled in at 107F . Six hours later I still had plenty of coals and added 40 pounds more, this time all at once. We'll see if it burns any longer now that I'm getting a handle on controlling it.
I think I'm going to like burning coal compared to wood, except for all the extra ashes. ;-)
Here is a pic of the 6 bedroom house I'm heating:
Image



107*F is a little too cool for a boiler, real bad for wood, not so good for bit. coal either. :)
Since you are getting great control w/ door tightness, try running the water temp up to 170*F.
McGiever
 
Stoker Coal Boiler: AXEMAN-ANDERSON 130 "1959"
Hot Air Coal Stoker Stove: HARMAN MAGNUM
Hand Fed Coal Stove: RADIANT HOME AIR BLAST
Baseburners & Antiques: OUR GLENWOOD 111 BASEBURNER "1908"
Coal Size/Type: PEA / ANTHRACITE, NUT-STOVE / ANTHRACITE
Other Heating: Ground Source Heat Pump
Stove/Furnace Make: Hydro Heat /Mega Tek