"Back-Fire Problems With a Clayton Wood/Coal Furnace

"Back-fire problems with a Clayton wood/coal furnace

PostBy: fyrguy86 On: Tue Dec 12, 2006 7:50 pm

I am new to coal burning. I have a Clayton 1600H wood/coal furance. Last week I got a good wood fire going. There were lots of red hot coals in the firebox. I added abour 40-50 pounds of nut coal...leveled it out quickly and close the top door. The ash door was open to give it plenty of air. I heard it popping and such. After 2-3 minutes...there was a "back-fire" out of the lower ash door. It shot out about 2-3 feet. I though that was very strange. So after a few days of warm weather, I tried it again. This time I had still a little fire of wood burning. I added the coal and about 3 minuted into it....it backfired out the bottom ash door again. What in the heck am I doing wrong? (My flue temp was arounf 200-300 degrees at the start of the coal. It is anthracite nut coal.) Some needed advice would be great. Thank you!

Visit Hitzer Stoves

PostBy: laynes69 On: Tue Dec 12, 2006 8:06 pm

You need to get a good hot coal bed before loading that much coal into it. Get your wood coals then add a layer of maybe 1 to 2 inches. Let this layer get hot and burning, then add another layer a little thicker. once this layer is caught and going, then add your coal to it. Keep your ash door damper open, but not the ash door. Whats happerning is your smothering the fire and producing alot of coal gas. Once the flames get to the gas whoosh. I had it happen to me 2 times, and that was 2 times too many. Once you add that last bit of coal, close the ash door, keep your damper open, and let it go for about 1/2 hour to 45 minutes, then check it. This should help. Good Luck.

PostBy: barley master On: Wed Dec 13, 2006 8:01 am

i have a little three lid top feed franco that nobody has been able to identify (its that old). when I load it I open the center lid and remove the left lid and block the outlet with the lid so that coal doesnt fall into the little chamber at the rear of the stove outlet. it also allows for easier loading with a five gal bucket that way.

it flashs off on contact with the fuel bed everytime.

as long as you know what is causing it. when it happens and understand why it is happening then there is no reson for alarm. just alter your method of operation and it will go away.
barley master

PostBy: LsFarm On: Wed Dec 13, 2006 2:58 pm

Hello fyrguy, welcome to the forum. Take a look at this thread, it covers the same subject:

The stove 'backfires'....Is this OK???

One way to reduce or prevent the 'backfire is to leave a spot of open fire when you dump on the thick layer of coal. This acts like a 'pilot lite' to ignite the coal gasses from the fresh coal. Then after 45 minutes or so open the loading door and rake the coal bed level, or fill in the 'hot spot' with more fresh coal.

Hope this helps. Greg L
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

It worked...thanks!

PostBy: fyrguy86 On: Wed Dec 20, 2006 8:03 pm

Thank you all for the advise. I got it up and running this past week with no backfires! I did add it in small amounts...like a shovel full at a time, about every 20 minutes, keeping a small area of wood fire exposed, then I added the rest of the 40 pound bucket. It burned from 2pm till 10 pm. Around that time, it was about out. It seems these wood/coal furnaces do not have enough surface area for the bed to get air, thus it doesn't burn as long as a normal coal stove. My next move will be to add the full 100 pounds as the furnace instructions say it will hold. The 40 pounds did come about half way up the firebrick. I'm guessing I will have to shake it more often to get the ash out of the way so not to starve the coal from air? Anyone have these Clayton 1600 furnaces??? Thanks for the info. I'll keep plugging away at it till I get it worked out. All have a Merry Christmas! Thanks!

PostBy: dirvine96 On: Thu Dec 21, 2006 9:18 am

I've got the 1537. The manual says you should burn bituminous. Go
to the US Stove web site and go to the FAQ page. They talk about the different coals and the size of the coal.

I talked with a rep. from the Reading Company and he looked at the stove specs and said the US Stove products are not the best design for burning anthracite. When he said that I just about @*!* myself. Thats all we can get in the Rochester NY area. After we talked a little longer, he got to talking about coal size. US Stove suggests 2.25 inch to 4.5inch coal when you burn anthracite and smaller when you burn bituminous. It bigger anthracite burns much better in these stoves. The guy from Reading went into a whole speel about coal size, the gas they give off and the difference between the way anthracite and bituminus burn. I didn't understand most of it, but what I did get out of it is that nut coal is NOT the coa to burn in these stoves.

I've had a much easier time with the stove coal. I had three ton delivered and the driver said the next time he could mix the load and put in about 25% nut. He said some of his custumers like that mix. I keep about 4 or 5 bags of nut around just in case I need to re start the fire.

Well any ways, I'm new as this just like you. Maybe some of the oldtimer have some suggetions.

Thanks Don
Stove/Furnace Make: Hitzer 82FA

PostBy: Yanche On: Thu Dec 21, 2006 11:43 am

My third generation coal dealer has told me it's best to burn the largest size anthracite coal that will burn in a stove, furnace or boiler. He claimed the small sizes pack and choke off the draft through the coal bed. Of course you need to start the coal with smaller sizes and work up.

Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

PostBy: laynes69 On: Sat Dec 23, 2006 12:35 pm

dirvine96 I have a few questions for you. My furnace is basically the same thing, and I was wondering do you have the forced draft, if so do you use it. Also do you fill it to full capacity, when you do whats your ashpan damper set at, and whats your burntimes with anthracite. When I burn anthracite, I think I don't give it enough air, then it doesn't keep up with the heating demand on the house, wood isn't a problem. I guess i'm used to burning wood, and I feel that the coal will burn out in 6 to 8 hours like wood will.

Visit Hitzer Stoves

PostBy: LsFarm On: Sat Dec 23, 2006 2:29 pm

Hi Laynes, the duration of burn with coal is determined by the depth of the coal bed. It took me a long time to learn this. Several experienced guys told me this, but I just had to figure it out for myself.

I looked at the .pdf owners manual for your furnace. You may be able to block off the rear portion of the shaker grates, and make a smaller, but much deeper coal fire up near the front of the firebox.

On my grates there is a raised steel edge on the sides of the sliding grate. I cut a piece of steel plate to cover the back half of my grates. [my grates are 48" long]. Then I built a new back wall at about the half-way point in the firebox. This allowed me to burn the same amount of coal every night, about 60#, but it was about 12-14" deep and burned all night long. Instead or 6-8" deep and only lasting 6-9 hours.

For my firebox, I get about an hour of burn for every inch of coal depth. I have blocked all air except for air under the coal fire. This is working pretty well for me.

I'll be glad to chat on the phone about this if you want. Just PM me and leave me your number and we'll talk coal.

Have a SAFE and Happy Christmas and New Years!

Greg L
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

PostBy: dirvine96 On: Tue Dec 26, 2006 9:54 am


When I first got the stove I was having real problems keeping a fire going. I called the factory and coned me into buying the forced draft unit. Didn't help at all. I just needed to keep burning and learning what to do and and what not to do. This forum has been a huge help.

I fill the stove all the way and use the bigger coal. I just have not had any luck with nut coal and the stove just doesn't like small loads.

The weather has been real screwy in western NY. The temps are up and down, so I havn't been able to really dial the stove in. I'm waiting for temps to stay in the 20s or low 30s so I can start messing with the lower damper and see how she runs best. Its been going up into the 40s and 50s and then it rains. I don't know why but when it rains and is in the 40s it just kills my fire. Up to thisw point I've been running the lower damper wide open or turned in about two full turns and my flue damper wide open. From what I've been reading, when it get colder I should be able to get a good bhurn going set the output with the spin damper.

Someone wrote me that the learning curve for burning coal was very sharp. Its razor sharp, but I'm having fun learning and when I finally figure it out. It will all be worht it.

Stove/Furnace Make: Hitzer 82FA

PostBy: coaledsweat On: Tue Dec 26, 2006 10:55 am

dirvine96 wrote:laynes69I fill the stove all the way and use the bigger coal. I just have not had any luck with nut coal and the stove just doesn't like small loads.

Do you mean the stove or stove size coal? When burning Anthracite the firepot must be filled, there is no such thing as a small fire with Anthracite. Fill it up and damp it down for less heat.

Let me know how the stove size coal works out, I'm thinking of switching to it with my boiler as it gets difficult to maintain after a few weeks. I think it chokes off after it matures from the ash because I'm using nut.
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

PostBy: laynes69 On: Wed Dec 27, 2006 11:42 pm

I got my ash damper where it will come out 6 1/4 turns. I have burned nut coal in mine and had luck one time but didn't pay enough attention to get it to burn like that again. I don't use my manual flue damper anymore, never did any good. But the barometric damper made the world for me. I need to find that line where I have enough draft to get the longest burn, and the most heat. I easily achieve this with wood, but have a hard time with coal.

Visit Hitzer Stoves