Huge Puffback!

Smokeyja wrote:I just loaded the first bit of the bituminous coal I bought today to try out and I just got my first "PUFF BACK" I had the top damper slightly open and the MPD was fully open as I was letting this stuff fire up and PUFF , the stove shoots out black smoke out into the living room and it didn't smell too nice either. This is good bit from WV from what the seller has told me. http://www.martincoal.com It seems like pretty good stuff so far and maybe I just don't have enough experience with it but it seems to be very hard to rangle if you ask me. With Anthracite I have it down pat and can control my temps easy with the dampers. But with this bit I am having one heck of a time getting a steady burn. it seems to burn way too hot! maybe I just need some more time with it. I definatly don't like the puff back though !

Start out with less coal fed into the stove at a time. Use much less primary air and a whole lot more secondary air. In a little while the yellow flames will die down and then you can give it a little more primary and cut back on the secondary air. I grew up with this type of coal. It is a different animal than Anthracite. You can start your Bituminous fire much easier than an Anthracite fire. All you need are a few sticks of kindling to get it started. You will also notice that once the big lumps get hot you can hit them with a poker and they will break up into smaller pieces.

wsherrick wrote:

Smokeyja wrote:I just loaded the first bit of the bituminous coal I bought today to try out and I just got my first "PUFF BACK" I had the top damper slightly open and the MPD was fully open as I was letting this stuff fire up and PUFF , the stove shoots out black smoke out into the living room and it didn't smell too nice either. This is good bit from WV from what the seller has told me. http://www.martincoal.com It seems like pretty good stuff so far and maybe I just don't have enough experience with it but it seems to be very hard to rangle if you ask me. With Anthracite I have it down pat and can control my temps easy with the dampers. But with this bit I am having one heck of a time getting a steady burn. it seems to burn way too hot! maybe I just need some more time with it. I definatly don't like the puff back though !

Start out with less coal fed into the stove at a time. Use much less primary air and a whole lot more secondary air. In a little while the yellow flames will die down and then you can give it a little more primary and cut back on the secondary air. I grew up with this type of coal. It is a different animal than Anthracite. You can start your Bituminous fire much easier than an Anthracite fire. All you need are a few sticks of kindling to get it started. You will also notice that once the big lumps get hot you can hit them with a poker and they will break up into smaller pieces.

Well one thing I have learned it I like the smell of anthracite a lot better! I am starting to figure out how this stuff burns but I'm scared to leave the house now for fear of over fire. Good things I have a little over 3,000lbs of Amthracite and not bit, my throat is starting to burn from this stuff ack!

Edit* Well finally got it under control it seems. It is very touchy! I can see why some people want a Baro as well. With the anthracite the the mpd works perfect and even when the wind changes it still holds steady but the bit seems to change whenever the wind blows.

I see a common thing in all the previous posts, they all try to use a MPD to

control their burn rate,and with air tight stoves this is not needed.

It is especially bad with Bituminous Coal because the damper becomes a trap

for the soot and restricts the chimney.

I can burn any coal in my boiler and use a barometric damper to control the

draft to .02" where I get the heat without using high draft.

I don't believe that the amount of air that goes through the baro affects the

flue temperature to a degree that would change the performance of the

appliance.The chimney must be of proper height and clear all obstacles near

it,as Berlin said these specifications are a bare minimum so any additional

height is really a plus.


BigBarney

BigBarney wrote:I see a common thing in all the previous posts, they all try to use a MPD to

control their burn rate,and with air tight stoves this is not needed.

It is especially bad with Bituminous Coal because the damper becomes a trap

for the soot and restricts the chimney.

I can burn any coal in my boiler and use a barometric damper to control the

draft to .02" where I get the heat without using high draft.

I don't believe that the amount of air that goes through the baro affects the

flue temperature to a degree that would change the performance of the

appliance.The chimney must be of proper height and clear all obstacles near

it,as Berlin said these specifications are a bare minimum so any additional

height is really a plus.


BigBarney

An MPD works for me. I took the baro off my stove at the end of last season with the help of Coalfire because I was seeing my draft drop to .00"WC and I was afraid of it reversing back into the house. I only use an MPD now and a draft inducer when I feel that I'm going to have a problem. Now, the lowest my stove goes without the draft inducer is .02" on an 180* fire. Of course I turn the inducer on at that point but I have run it at .02"WC when I'm home and can watch it closely. I still get puff-backs even with the draft inducer because I don't use it all the time and I only get them when I'm really shaking and refilling and the whole bed gets covered. It of course doesn't happen quite as often. I used to have a lot more explosions with the baro.

If you are experiencing puff backs in a hand fired, bank your coal when reloading!

coaledsweat wrote:If you are experiencing puff backs in a hand fired, bank your coal when reloading!

How do you bank when it's hopper fed?


Eric

I'm On Fire wrote: I still get puff-backs even with the draft inducer because I don't use it all the time and I only get them when I'm really shaking and refilling and the whole bed gets covered.

Gasses have to be burned or exhausted which you already know. Exhausting them wastes heat.

To burn them a hot bed and enough air is required.

Maybe add more over fire air or a two stage shakedown with a 10 or 15 minute pause between shakes.

I would let the thermostat control all under fire air because at the end of a burn it should be fairly wide open to compensate for the ash buildup

Why is your draft so weak? You really have to address that problem to get air to those gasses in a timely manor.

franco b wrote:

I'm On Fire wrote: I still get puff-backs even with the draft inducer because I don't use it all the time and I only get them when I'm really shaking and refilling and the whole bed gets covered.

Gasses have to be burned or exhausted which you already know. Exhausting them wastes heat.

To burn them a hot bed and enough air is required.

Maybe add more over fire air or a two stage shakedown with a 10 or 15 minute pause between shakes.

I would let the thermostat control all under fire air because at the end of a burn it should be fairly wide open to compensate for the ash buildup

Why is your draft so weak? You really have to address that problem to get air to those gasses in a timely manor.

Short chimney, lots of trees and I'm on the middle of a hill. Those probably contribute to the low draft. Though I probably should've stated that on a low fire I lose my draft, but anything 350° on the top odd the stove and above my draft is fine.

I'm On Fire wrote:Short chimney,

That is #1. Build the chimney high enough, the rest won't matter much (if at all).

I'm On Fire wrote:Short chimney, lots of trees and I'm on the middle of a hill. Those probably contribute to the low draft. Though I probably should've stated that on a low fire I lose my draft, but anything 350° on the top odd the stove and above my draft is fine.

OK, so we have to get more draft by either building the chimney higher or lessening the heat loss in that chimney to increase draft.

I seem to remember that you are using a fireplace chimney, probably on an outside wall, so the chimney is big. Lining it is expensive and adds other problems. Adding to the height might also have problems to accomplish. What you might try is to simply close off the top of the chimney to a smaller hole with a piece of light sheet metal with a 6 inch hole to see what effect it has. Another way which I have never tried but might work is to suspend from that sheet metal a 24 inch length of 6 inch galvanized into the chimney. It should collect heat there and increase draft. Cheap to try and if it works you could work up something better, but it should last a few years.

franco b wrote:

I'm On Fire wrote:Short chimney, lots of trees and I'm on the middle of a hill. Those probably contribute to the low draft. Though I probably should've stated that on a low fire I lose my draft, but anything 350° on the top odd the stove and above my draft is fine.

OK, so we have to get more draft by either building the chimney higher or lessening the heat loss in that chimney to increase draft.

I seem to remember that you are using a fireplace chimney, probably on an outside wall, so the chimney is big. Lining it is expensive and adds other problems. Adding to the height might also have problems to accomplish. What you might try is to simply close off the top of the chimney to a smaller hole with a piece of light sheet metal with a 6 inch hole to see what effect it has. Another way which I have never tried but might work is to suspend from that sheet metal a 24 inch length of 6 inch galvanized into the chimney. It should collect heat there and increase draft. Cheap to try and if it works you could work up something better, but it should last a few years.

Yes, it is on an outside wall, on the north side of the house. It's already lined with an SS liner and I have a piece of slate cemented to the top of it with a 6" hole through it. I have been thinking of making it taller, but I know nothing about adding on or building chimneys, it's terra cota lined but the upper most piece is broken. It's a stone chimney so I don't think it'd be too difficult to make higher. But finding rocks to match what is already there may prove difficult. Although, in my book function over form has always won.

I did stuff insulation into the throat about 4'. I didn't insulate the top. The other thing I have contemplated is building a wall around the outside of the chimney on the exterior of the house and insulating the space between the wall and chimney. It's kind of hard to explain. But kind of make the chimney an inside chimney. It's probably a pretty dumb idea though.

I'm On Fire wrote:I did stuff insulation into the throat about 4'. I didn't insulate the top. The other thing I have contemplated is building a wall around the outside of the chimney on the exterior of the house and insulating the space between the wall and chimney. It's kind of hard to explain. But kind of make the chimney an inside chimney. It's probably a pretty dumb idea though.

If that insulation can get wet it has no value, assuming it is fiberglass. The best thing is mica pellets (vermiculite) that you can pour in. Did you add a cap?

I don't think your idea of a wall around the chimney is dumb but too much work.

Another possibility is to add a 3 or 4 foot section of insulated stainless pipe with cap. Would require some mason work to get a socket on the chimney top to plug it into. Craigslist often has some listed cheap. If you lived closer I could give you a piece of 30 inch long.

franco b wrote:

I'm On Fire wrote:I did stuff insulation into the throat about 4'. I didn't insulate the top. The other thing I have contemplated is building a wall around the outside of the chimney on the exterior of the house and insulating the space between the wall and chimney. It's kind of hard to explain. But kind of make the chimney an inside chimney. It's probably a pretty dumb idea though.

If that insulation can get wet it has no value, assuming it is fiberglass. The best thing is mica pellets (vermiculite) that you can pour in. Did you add a cap?

I don't think your idea of a wall around the chimney is dumb but too much work.

Another possibility is to add a 3 or 4 foot section of insulated stainless pipe with cap. Would require some mason work to get a socket on the chimney top to plug it into. Craigslist often has some listed cheap. If you lived closer I could give you a piece of 30 inch long.

Yes, there is a cap. It has a rain guard on it so I think that also hinders the draft. I've been meaning to buy one without the cap. But I have to buy it from the same place I bout the liner from and at $100 and money in short supply its on the back burner.

About pouring in vermiculite, I'm not sure how well it'll work. The plate on the bottom of the throat doesn't quite fit square or snug, the throat is also not square so I think the vermiculite would just pour out. I'd still like to make it taller over next summer but I'd have to probably pay someone to do it since I don't know how.

I'm On Fire wrote:About pouring in vermiculite, I'm not sure how well it'll work.

You can just stuff some fiberglass into the gaps to hold back the mica.

This is a very interesting thread, folks. I"ve been reading about these puffbacks now for a while. I guess those of you who have a furnace get a much larger reaction. My FB does something like this, but only if I take the lid off my hopper too fast, or if I open the stove door too quickly. The worst is the lid on the hopper. The first time I did it, the blue flames jumped out of the hole a good 6 inches (the hopper was almost full). I know that might not seem like a lot, but it was enough to scare me. You get that "whoosh" and up come the blue flames. It's quick, but it still takes you by surprise. So of course I've learned my lesson on that. Don't blow yourselves up!

Good day to you all!