Anti Puff Back Device for AA... Isn't Working

Stoker Coal Boilers automatically feed the coal and have controls and pumps just like any conventions boiler. They are intended to be used as a primary heat and often have domestic hot water coils as an added bonus. They can be set up independently or in dual sytem with your existing oil/gas boiler. They can accommodate both hot water base board or steam plumbing.
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Freddy
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Posts: 6604
Joined: Fri. Apr. 11, 2008 2:54 pm
Stoker Coal Boiler: Axeman Anderson 130 (pea)
Hot Air Coal Stoker Stove: Reading piece o' junk in the barn (rice)
Coal Size/Type: Pea size, Superior, deep mined
Location: Orrington, Maine

Post Wed. Nov. 26, 2008 8:37 pm

P-p-plug the hole? You're a braver man than I! LOL Ohhhh, you coud be right, but I'm thinking of the people that have one or two big puff backs a year. I've read of at least one AHS that has had one now....one months later. I wish we totally understood the circumstances that lead to such a seldom behavior.
Orrington, Maine
Fred

"If you can't say something nice, don't say anything at all".

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coal berner
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Posts: 3591
Joined: Tue. Jan. 09, 2007 12:44 am
Stoker Coal Boiler: 1986 Electric Furnace Man 520 DF
Stove/Furnace Make: Electric Furnace Man
Stove/Furnace Model: DF520
Location: Pottsville PA. Schuylkill County PA. The Hart Of Anthracite Coal Country.

Post Thu. Nov. 27, 2008 12:10 am

Take a Poll you will find out it happends more often then Not On Both AA & AHS 95% On The First time lighting one.
Nothing Seldom About it.
J.C.

Heating house & water with a 1986 electric furnace man DF520 using buckwheat Anthracite coal

mwcougar
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Posts: 136
Joined: Mon. Sep. 11, 2006 10:37 am
Stove/Furnace Make: ahs 130 heating 3700sq ft
Location: central Bradford county pa

Post Thu. Nov. 27, 2008 12:56 am

hi all

from some experiance with my ahs 130.. wet or damp or really wet coal just adds to the problem. just from my experiance of having finding parts of my baro on the floor and on the other side of the ATV. just 2 cents......
center of Bradford county pa

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Yanche
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Posts: 3032
Joined: Fri. Dec. 23, 2005 12:45 pm
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea
Location: Sykesville, Maryland

Post Thu. Nov. 27, 2008 9:46 am

I've had numerous buff backs on my AHS 130. Some strong enough to blow the barometric damper door off. None this season. My chimney is different this year. Same height as before but the thimble is much higher. Now my flue pipe slopes steeply upward all the way, no horizontal runs. The baro is now at the chimney thimble and is of the suggested A-A concentric design. My idle fire draft has increased, now at least -0.02 to -0.03 inches water. I've also replace the stock combustion chamber inspection port door spring with a longer one. It keeps the top portion of the door cracked open door during combustion blower operation.

Now, with all this said, I've never been able to purposely cause a puff back condition. Then eliminate the condition and have no puff backs. The exact conditions for puff back are unknown. For example my coal is now a season older and it's now outgassed more. So maybe that's the reason, not my better chimney draft. My $.04, $.02 per paragraph. :-)
Yanche
Alternate Heating Systems S-130
Stoker Boiler burning Anthracite Pea Coal

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LsFarm
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Posts: 7385
Joined: Sun. Nov. 20, 2005 8:02 pm
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland
Location: Michigan

Post Thu. Nov. 27, 2008 10:29 am

Hi Yanche,, pretty frustrating for the scientific mind, huh? It's pretty interesting that here we have a really interesting combustion setup, big forced combustion fan, great efficiency, and.. then this trapped combustible gas situation shows up.. :mad: It's like we just can't win..

Thankfully for some reason,, my AA260 doesn't seem to have any puff-backs.. I have experienced one or two very minor puffs that just rattled the inspection port door. I experienced these only during initial fires.. but the volume of air in the 6" flue, and the larger heat exchanger area, larger inspection port size.. all seem to reduce the violence of the 'puff-back' to a meer... 'puff'.

Happy Thanksgiving.

Greg L
Burning Pea/Buckwheat through an antique stoker [semi retired SSboiler],
Running an Axeman-Anderson 260M boiler burning Pea, About 150-250#per day
Farming, Fixing, Fabricating and Flying: 'spare time' what's that?

mwcougar
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Posts: 136
Joined: Mon. Sep. 11, 2006 10:37 am
Stove/Furnace Make: ahs 130 heating 3700sq ft
Location: central Bradford county pa

Post Thu. Nov. 27, 2008 10:35 am

other oberservation.... currently burning hudson as a experiment. havent heard any after vroom, vrf ,vrf fifff.vroom after combustion blower shuts off..... would hear this when I was burning harmony and south pocket coal......also after reading yanche's post I did notice that my flapper has been a little cocked to one side during combustion blower run.... so maybe doing the same effect.... spring getting dirt in it..... just 2 more cents.. :)
center of Bradford county pa

RICHARD2
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Posts: 27
Joined: Sun. May. 04, 2008 1:34 pm
Stoker Coal Boiler: KA2
Location: Upstate New York

Post Thu. Nov. 27, 2008 10:38 am

Testing.
It is now 10:38am EST. I am wondering why the posts from Yanche and LSfarm are dated later than the current time.

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gambler
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Posts: 1594
Joined: Mon. Jan. 29, 2007 12:02 pm
Stove/Furnace Make: Leisure Line
Stove/Furnace Model: Pioneer
Location: western Pa

Post Thu. Nov. 27, 2008 10:51 am

RICHARD2 wrote:Testing.
It is now 10:38am EST. I am wondering why the posts from Yanche and LSfarm are dated later than the current time.
Not on my computer.
Do you have your forum clock set correctly? It is under user control panel at the top of the page.
Take Care and God Bless
Rick

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RICHARD2
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Posts: 27
Joined: Sun. May. 04, 2008 1:34 pm
Stoker Coal Boiler: KA2
Location: Upstate New York

Post Thu. Nov. 27, 2008 11:10 am

gambler wrote:Not on my computer.
Do you have your forum clock set correctly? It is under user control panel at the top of the page.
Thank you. I did not know that on this site I had to manually switch the time display from DST to EST. My computer clock is correctly set for EST; thought the time shown in the posts was determined by the NEPA server; Pennsylvania is also in EST zone.

Changed the setting as you suggested; now shows correct time. Thank you.

Please forgive my off-subject post.

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coaledsweat
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Posts: 9826
Joined: Fri. Oct. 27, 2006 2:05 pm
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea
Location: Guilford, Connecticut

Post Fri. Nov. 28, 2008 10:22 pm

Hey Freddy, I was just thinking about this. When I picked up my AA 260M, I noticed the viewing port door that hangs there had a noticeable air gap. I wasn't sure if it was supposed to be like that but a series of locknuts on the bolt it hangs on convince me that it was set like that for a reason. Is yours set up with an airgap?
Nothing is impossible for people who don't have to do it themselves.

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LsFarm
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Posts: 7385
Joined: Sun. Nov. 20, 2005 8:02 pm
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland
Location: Michigan

Post Fri. Nov. 28, 2008 11:10 pm

Your inspection plate [door] needs at least a 1/2" air gap.. I have mine set at about 3/4" you need quite an air gap to let the natural draft pull air over the fire..
It seems the concentration of burnable gas in the smaller 130 boilers is high enough and hot enough that it ignites easily compared to the 260 sized boiler..

Greg L

.
Burning Pea/Buckwheat through an antique stoker [semi retired SSboiler],
Running an Axeman-Anderson 260M boiler burning Pea, About 150-250#per day
Farming, Fixing, Fabricating and Flying: 'spare time' what's that?

U235a4
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Posts: 321
Joined: Mon. Oct. 29, 2007 8:26 pm
Stove/Furnace Make: 1958 Axeman-Anderson
Stove/Furnace Model: 260M
Location: South Central PA

Post Fri. Nov. 28, 2008 11:28 pm

for what it's worth I have had about every other problem out there with my AA260 but never a puff back bomb, AKA (PBB). now my chimney is a 12"x12"x30' (clay liner surrounded by red brick) and on a 70*F day and a cold boiler I still pull -.02 overfire draft, at this time of year 30-40F here boiler flue gas temps of 200*F I'm getting around -.04 and thats with a 8" type RC damper open full tilt. On windy days with the damper pegged I can see -.15 with a strong gust. over the winter summer months I'll be installing a 130 and I interested to see if I can avoid the PBB with the knowledge of the 260m.

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Freddy
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Posts: 6604
Joined: Fri. Apr. 11, 2008 2:54 pm
Stoker Coal Boiler: Axeman Anderson 130 (pea)
Hot Air Coal Stoker Stove: Reading piece o' junk in the barn (rice)
Coal Size/Type: Pea size, Superior, deep mined
Location: Orrington, Maine

Post Sat. Nov. 29, 2008 6:50 am

coaledsweat wrote:Is yours set up with an airgap?
Yup, that's how they work... when stoking is sucks the view door shut. When it stops stoking the view door swings open by gravity and dangles with 1/2 to 3/4" gap. As Greg was saying, with it dangling open it allows narural draft to go over the fire. When it stokes & shuts, all the air is drawn through the fire. (Except the 5/8" hole in the view door and whatever leakage here & there).
Orrington, Maine
Fred

"If you can't say something nice, don't say anything at all".

gregolma
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Posts: 140
Joined: Wed. Dec. 19, 2007 11:58 am
Stove/Furnace Make: Axeman Anderson
Stove/Furnace Model: 1980 Anthratube 130
Location: Buffalo, NY

Post Sun. Nov. 30, 2008 4:34 pm

I've never had this puff back problem ever with my AA130. I don't have a barometric dampener. I even have a nearly horizontal run of 6" stove pipe with a 90 in it.

I do have a nearly 100 year old house with an enormous brick chimney with 2 - 10" clay flues that run about 4 stories tall.

I have a window in my boiler room than has a damaged sill that lets in a bit of air and an enormous draft in my flue. The bottom clean out is open (the door is missing). My 130 will sometimes keep a fire going about 2-3 days without power, when I shut it down.

Moral of the story: a good quantity of fresh intake air is needed to prevent this dreaded phenomenon.

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LsFarm
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Posts: 7385
Joined: Sun. Nov. 20, 2005 8:02 pm
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland
Location: Michigan

Post Sun. Nov. 30, 2008 7:36 pm

Steady draft venting the combustion chamber of flamable gases in burnable concentrations is what is needed,, the burnable concentration is easier to create and maintain in the 130 size boiler, and the 5" pipe.. the AA 260's larger heat exchanger size and 6" flue pipe quickly dilute the gas to a non burnable mixture. This is providing you have a steady draft..

Greg L

.
Burning Pea/Buckwheat through an antique stoker [semi retired SSboiler],
Running an Axeman-Anderson 260M boiler burning Pea, About 150-250#per day
Farming, Fixing, Fabricating and Flying: 'spare time' what's that?

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