Coalgun- Puff Backs & Explosions

Re: Coalgun- Puff backs & Explosions

PostBy: Joe On: Mon Oct 19, 2015 7:16 pm

Thanks Mike, those pictures are just what I was looking for. I actually installed mine on Saturday, and the thermocouple is in the same place as your picture. I will do as Pete did and take the temperatures there for awhile before switching over so I have an idea where to set the controller temps. I will post back at some point when I have some runtime with the new setup.
Joe
 
Stoker Coal Boiler: AHS-130
Coal Size/Type: Pea

Re: Coalgun- Puff backs & Explosions

PostBy: macdabs On: Thu Oct 29, 2015 8:16 am

I had the timer control to take care of the puff backs and explosions . What is the thermo coupler do ? Is this another feature to eliminate the timer control ?

Mac
macdabs
 
Stoker Coal Boiler: AHS 260
Coal Size/Type: Pea
Other Heating: Pellet,oil
Stove/Furnace Make: AHS
Stove/Furnace Model: S260

Re: Coalgun- Puff backs & Explosions

PostBy: greenftechn On: Thu Oct 29, 2015 8:39 am

macdabs wrote:I had the timer control to take care of the puff backs and explosions . What is the thermo coupler do ? Is this another feature to eliminate the timer control ?

Mac


This control uses a different location for the thermocouple. We refer to it as "Point of Burn", since the thermocouple is located at the end of the inlet tube, above the fire. It may be more reliable at indicating the position of the fire. From my perspective, it does have one nice advantage -- it will not dump the burn pot when the fire goes out. :)
greenftechn
 
Stoker Coal Boiler: Coal Gun S130
Hand Fed Coal Stove: Alaska Kodiak
Coal Size/Type: Nut
Other Heating: Wood Gun
Stove/Furnace Make: Alternate Heating Systems
Stove/Furnace Model: E100

Re: Coalgun- Puff backs & Explosions

PostBy: McGiever On: Thu Oct 29, 2015 9:44 am

macdabs wrote:From Jan. 31, 2015
Darrell fixed me up also and I have had no issues last year or this year . I probably have burned almost 15 ton and not even a burp. I love my boiler !! :D :D
Mac


Mac,
Are you now saying this is/was not the "POINT OF BURN" measuring method?
McGiever
 
Stoker Coal Boiler: AXEMAN-ANDERSON 130 "1959"
Coal Size/Type: PEA / ANTHRACITE
Other Heating: Ground Source Heat Pump
Stove/Furnace Make: Hydro Heat /Mega Tek

Re: Coalgun- Puff backs & Explosions

PostBy: macdabs On: Thu Oct 29, 2015 6:28 pm

I added the timer relays that slow the grate rate . Like I said I have not any issues since the relay timer change. Everything has been great. I have yet to fire this year yet since the weather has been decent. I would say another week or so.

Mac
macdabs
 
Stoker Coal Boiler: AHS 260
Coal Size/Type: Pea
Other Heating: Pellet,oil
Stove/Furnace Make: AHS
Stove/Furnace Model: S260

Re: Coalgun- Puff backs & Explosions

PostBy: mikeandgerry On: Mon Jan 16, 2017 5:19 am

After having run my Axeman-Anderson 130-M (similar to the Coalgun) since the fall of 2007 and having had minimal puff back issues and no explosions, I have this season just run into several sizable puff backs that I would have to characterize as true explosions. Unlike my first experience, they did cause loud noises. They also allowed sulfur odor to enter the boiler room and adjacent room.

On two occasions the "combustion bump" as Axeman calls them in their manual, was enough to set off my smoke alarm at the time of the puffback. Not sure why. It went off simultaneously with the bump on two occasions. I witnessed one directly and it scared the bejesus out of me. I was lucky to have just moved away from the inspection port seconds earlier! At no time did these puff backs set off the CO detector! I assume they had burned up the CO in the minor explosion.

The first time I experienced the problem was at the very beginning of using the AA 130 in 2007. After increasing the amount of air to the boiler room, I no longer had the minor smelly puff backs. Nine years later, nothing has changed about venting, chimney, settings on my system operation. I did remove the baro about three or four years ago because I felt is was unnecessary as we did not have excessive winds and the Type M baro was expensive and highly susceptible to rust. Also, the 5 to 6" jump up in vent pipe size before the chimney was a velocity killer for fly ash and soot which built up too high each year. By removing the baro and switching to a 5" pipe run directly to the vertical portion of the chimney, the velocity is maintained and I don't have to clean the horizontal pipe at mid season of fly ash. My coal supplier has been the same for two years but I think this year his source was different and I have yet to query him on this. I will have to report back. I haven't paid much attention to where my coal comes from because the Axeman hasn't been picky. I have burned pea Reading and Superior and pea and buck from Superior and Blashak, but this last load I believe came from another mine/source, possibly the new Lehigh Coal.

While I have solved the combustion bump problem, I still have had a couple quiet but smelly puff backs since I installed, NOT a Freddy style ANTI-BOOM device, but rather a mikeandgerry variation on the paper clip trick, i.e. a paper clip bent into an acute angle and placed in the site port tube to keep the site port door from closing. I used two hair pin style clips like you would use on a clevis pin on each side of the site port door to hold it open a little bit more and a little more visibly and reliably. Since I am using buck, I also have the 3/4 " plug out of the site port door for additional air-over-fire as recommended by Axeman Anderson. Again, no more explosions but a couple mildly smelly puff backs.
mikeandgerry
 
Stoker Coal Boiler: Axeman-Anderson Anthratube 130-M

Re: Coalgun- Puff backs & Explosions

PostBy: greenftechn On: Mon Jan 16, 2017 9:26 am

The percentage of volatiles in the coal is a big factor here. Low ash coals (LOVE 'em!) tend to also be higher in volatiles. Position of the fire has been key for prevention, since keeping the fire high means less raw coal sitting on top to produce the gasses. Beyond that, and keeping the inside of the boiler and venting system clean and open, I can't offer further insight on the AA unit, as I've never operated one.
greenftechn
 
Stoker Coal Boiler: Coal Gun S130
Hand Fed Coal Stove: Alaska Kodiak
Coal Size/Type: Nut
Other Heating: Wood Gun
Stove/Furnace Make: Alternate Heating Systems
Stove/Furnace Model: E100

Re: Coalgun- Puff backs & Explosions

PostBy: lsayre On: Mon Jan 16, 2017 10:03 am

Lower your ashing temperature a bit to raise the height of the fire. Make small adjustments. Perhaps 5 degrees.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Blaschak Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

Re: Coalgun- Puff backs & Explosions

PostBy: McGiever On: Mon Jan 16, 2017 10:23 am

There are Not any single degree marks on a Athrastat...like 7 spaced apart dash marks from min. to max.

An aging Anthrastat (ashing t'stat) in a AA may not be performing as it once had .

:idea: Might consider recalibrating, replacing with same or upgrading to a digital version.

Of course, the coal's volatile gas to air ratio still has it's effect on setting up for a puff back, but having precise adjustable controls can allow for finer positoning of of fire height/thickness, which does also play a part in having a puff back.
McGiever
 
Stoker Coal Boiler: AXEMAN-ANDERSON 130 "1959"
Coal Size/Type: PEA / ANTHRACITE
Other Heating: Ground Source Heat Pump
Stove/Furnace Make: Hydro Heat /Mega Tek

Re: Coalgun- Puff backs & Explosions

PostBy: coaledsweat On: Mon Jan 16, 2017 11:22 am

Should be running pea in that thing, I doubt the buck is helping matters.
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

Re: Coalgun- Puff backs & Explosions

PostBy: mikeandgerry On: Tue May 09, 2017 6:18 pm

I don't like to change a lot of variables at one time, that way I can get a better handle on what fixed the problem! Since posting in January, I have not had any major or minor combustion bumps. I am inclined to believe that low ash coal was the culprit. I did notice that my ash pails were not very full this entire winter. While I didn't change the anthrastat and I am sure it is properly calibrated, the hairpin style clips on the sight tube door apparently did the trick AND the high volatile coal which was used first this year, has now been mixed with last year's coal as it runs down. I thank you all for the advice and I am sure all of it is good regarding fire height, ashing, and coal size! That's what I love about this forum!
mikeandgerry
 
Stoker Coal Boiler: Axeman-Anderson Anthratube 130-M

Re: Coalgun- Puff backs & Explosions

PostBy: greenftechn On: Wed May 10, 2017 9:39 am

Good to hear that you got on top of this!
greenftechn
 
Stoker Coal Boiler: Coal Gun S130
Hand Fed Coal Stove: Alaska Kodiak
Coal Size/Type: Nut
Other Heating: Wood Gun
Stove/Furnace Make: Alternate Heating Systems
Stove/Furnace Model: E100