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Coal Not Burning/Lots Of Soot

Posted: Mon. Feb. 12, 2018 4:28 pm
by ghoulio
I've posted in this forum a few times. Most recently about a Stokermatic Super Heater we recently got to replace out old heater. Here is what is happening. It's not burning the coal good. We have to take ashes out every 8 hours and sometimes it's 2 buckets full. It's hardly any ashes. It's mostly big chunks of coal stuck together. So big that we have to break them up to fit in the buckets. Soot is shooting out the chimney and getting on everything outside. We have to clean the pipes out once a week because they fill up with soot and smoke starts coming out in the house. The manual says if these things are happening then you need to increase the air flow but we have it almost wide open now and it's not helping. The coal we have is very small, some of it like dust, and I'm wondering if that is the problem but I don't think out old heater would have had a problem burning it. Anyone have an idea of what we can do to get it to burn the coal?

Re: Coal Not Burning/Lots Of Soot

Posted: Mon. Feb. 12, 2018 4:39 pm
by freetown fred
Stick around G, there's more then one BIT burner here. Sounds like ya might of gotten some bad coal. Orrrrr, this new stove isn't quite up to the old ones capabilities. That DUST description don't sound good.

Re: Coal Not Burning/Lots Of Soot

Posted: Mon. Feb. 12, 2018 5:14 pm
by franco b
Anthracite is the only fuel I know of that can be burned clean in badly designed appliances.

Every other fuel needs careful metering of air and fuel as well as the mixing of that air evenly to burn efficiently and clean.

Bit coal and wood are the most difficult because of the two stage effect, when burned, of first, large gas emission, and then a charcoal or coke stage. Each stage has to be addressed differently for best results, or by feeding little and steadily a uniform mix or size both stages can be accomodated. Pellet stoves do this for wood and stokers have the potential to do it for bit coal.

Some pictures of your unit showing the fire pot details will help some of our members more familiar with stokers than I to give some informed advice.

Re: Coal Not Burning/Lots Of Soot

Posted: Mon. Feb. 12, 2018 6:20 pm
by McGiever
Using a high dust coal will limit the air flow alone. So turning up the air won't solve this. You need to use "Stoker Size" Bit Coal to ever get the ability to effectively adjust for more air, if/when needed.

You could experiment by sifting some fines out and burning the larger pieces (3/4"-1") to get a better understanding of what better burning performance is possible.

There are different "coking properties" with different coal sources. With proper coking coal for your stoker the coke tree that grows, as your have describe, is to be burnt down completely into a flatter grayish ash mass that then gets removed and discarded.

Re: Coal Not Burning/Lots Of Soot

Posted: Mon. Feb. 12, 2018 6:57 pm
by Qtown1835
Burning bit sounds like a PITA... Lol. I'm greatful for my anthracite.

Re: Coal Not Burning/Lots Of Soot

Posted: Mon. Feb. 12, 2018 9:04 pm
by CoalJockey
ghoulio wrote:
Mon. Feb. 12, 2018 4:28 pm
I've posted in this forum a few times. Most recently about a Stokermatic Super Heater we recently got to replace out old heater. Here is what is happening. It's not burning the coal good. We have to take ashes out every 8 hours and sometimes it's 2 buckets full. It's hardly any ashes. It's mostly big chunks of coal stuck together. So big that we have to break them up to fit in the buckets. Soot is shooting out the chimney and getting on everything outside. We have to clean the pipes out once a week because they fill up with soot and smoke starts coming out in the house. The manual says if these things are happening then you need to increase the air flow but we have it almost wide open now and it's not helping. The coal we have is very small, some of it like dust, and I'm wondering if that is the problem but I don't think out old heater would have had a problem burning it. Anyone have an idea of what we can do to get it to burn the coal?
I’m no expert by any stretch but I’ve spent my whole life around bituminous coal. Without seeing photos of your system or what is going on it’s hard to make a call. It almost seems to me that you are using a high-vol coal in a system that is meant for low-vol. You mention about the soot and smoke and your bituminous coals that are higher in gas content are a classic example of that. I won’t go so far to say it will not work in your system with the proper settings, but I think what you are using is perhaps best used in an outdoor boiler situation.
Qtown1835 wrote:
Mon. Feb. 12, 2018 6:57 pm
Burning bit sounds like a PITA... Lol. I'm greatful for my anthracite.
I hate it that bituminous coal sometimes gets a bad rap on this forum because we typically only ever hear about the problems with it here, some of that due to folks trying to use it in furnaces and boilers that it was never intended for. I promise that if a good quality and clean coal is used in the proper application, burning bituminous is no different than anthracite and some pushes just as many BTUs. Maintenance and firing intervals are no different.

I had a Great Uncle who lived at the end of the driveway and was a retired dragline operator in the Somerset bituminous fields. That man could burn ANYTHING that was black. Some of the stuff that we cleaned up from the coal yard I would wheel up to him to burn it and get rid of it... it was not fit to keep. He made so much damn heat with it he melted the linoleum on the kitchen floor.

Re: Coal Not Burning/Lots Of Soot

Posted: Tue. Feb. 13, 2018 11:51 am
by Willis
Don't throw out the black, that is coke. just break it up an leave in there to burn up. My stoke makes big beautiful coke trees , especially in the milder weather when not running a lot of heating cycles. Soot being blown out of chimney is totally normal. My yard after it snows looks like early industrial revolution black everywhere.
Most stokers do not like more than 10-15% fines.
Where are you located and where are you getting coal? is it stoker sized coal?

Are you getting any clinkers to form? I usually just rake around in coal bed with hook and fish them out. Don't remove any fines unless you absolutely have to as these are need for proper function.

Re: Coal Not Burning/Lots Of Soot

Posted: Tue. Feb. 13, 2018 5:18 pm
by ghoulio
Thanks for the responses so far everyone. As requested, I have some pictures to share with you. From what I'm told the stove feeds coal every so often so I don't think leaving the unburnt coal in it is an option as it fills the fire pot up almost completely and when it feeds more there would not be anywhere for it to go. The pictures of the fire pot I'm posting are after 7 hours of continuous running. I don't think we should have a scene like this after just 7 hours. Any additional input after seeing the pictures would be appreciated. I am also posting an image of the coal we are using and the heater which is a stokermatic super heater model # STC-6587. As far as getting clinkers to form.... it's one big clinker of unburnt coal.

Edit: We are in Southeast Kentucky. We had to turn the stove off last night as we were trying to take ashes out because smoke filled the house. There was still good smoke coming out the chimney though and we had just cleaned the pipes and it was not smoking in house until we tried to take ashes out so I don't think the pipes are clogged right now.

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Re: Coal Not Burning/Lots Of Soot

Posted: Tue. Feb. 13, 2018 6:19 pm
by Willis
Is it constantly running, (thermostat calling for heat) or does it run a while and shut off? I have seen them do that once on a while when they are making coke but can make enough heat to satisfy thermostat. Kinda turns into runaway coke situation like you have.

How many minutes do you have your hold fire timer set to? 2-3 minutes per half hour seems to be the sweet spot for me.

Your coal looks to be property sized. Don't despair, we will get it figured out.

Re: Coal Not Burning/Lots Of Soot

Posted: Tue. Feb. 13, 2018 8:59 pm
by CoalJockey
I agree 100% with Willis on the coal sizing. As far as stoker sized bituminous coals go, that is not a bad looking example at all. Most likely any fines that you are getting is a result of normal handling after it is screened. I have both a high-vol and a low-vol stoker coal at the yard right now and this looks very similar to them both. It is typically a 1-2 inch chip or so.

I just wish I could be more help here, most everything around here these days for bituminous are hand-fed units. Most of the soft coal stokers in these parts were abandoned in the ‘80s and 90’s as the units were worn out and replaced with anthracite stokers.

Sure seems to me like there is a problem with the settings... something very simple. Will keep following closely and help in any way I can.

Re: Coal Not Burning/Lots Of Soot

Posted: Wed. Feb. 14, 2018 9:24 am
by ghoulio
It runs probably 95% of the time. The fan never seems to go on high, it stays on low. I'm not sure if this is because we have it wired wrong (The wiring is complicated). I'm not sure about the hold fire timer. I'll have to ask my brother-in-law what it's set to. I'll get back to you on that.

Re: Coal Not Burning/Lots Of Soot

Posted: Wed. Feb. 14, 2018 1:38 pm
by ghoulio
I'm going to post a picture of the hold fire timer later so you can see what it is set on. I just cleaned the fire pot out a few minutes ago from when we turned the heater off the other night. The fire pot was completely full and 90% of it was coal that had not been burnt. It was one big clinker.

Re: Coal Not Burning/Lots Of Soot

Posted: Wed. Feb. 14, 2018 4:05 pm
by ghoulio
Ok, here is a picture of the settings. The manual says "The top damper regulates the over-fire air jet and the bottom damper regulates the air through the tuyeres. To regulate properly, turn the over-fire air off completely. Turn tuyeres air on until the fire burns normally with no smokeyness. Turn air toward 'off' until smoke appears on the flame tips, then turn on over-fire air until it disappears again." We have tried to do this but it's hard to tell if we're getting it right.

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Re: Coal Not Burning/Lots Of Soot

Posted: Wed. Feb. 14, 2018 10:51 pm
by Willis
Ok now we are getting somewhere. Open your bottom air up all the way. We can adjust it back down later.

I can't remember, is there more than one groove on the belt pulley?


When you said it is running 95 percent of time is the auger running that much or just the fan on the back the blows the air?

The fan on the back should run most of the time that you have heat in it. The auger should only run when your thermostat calls for heat or on hold fire cycle.

Don't try to give it a big heat load to try to make all at once. Try taking your thermostat up a degree or 2 at a time until you get to you desired temp. This may take a few hours.

Re: Coal Not Burning/Lots Of Soot

Posted: Thu. Feb. 15, 2018 6:57 am
by ghoulio
The fan runs 95% of the time. I'm told the auger runs every 30 minutes or so. We'll fire her back up within the next day and open the bottom up all the way like you said. I'll ask about the belt.

Edit: Brother-in-law says only one groove.