Anti puff back device for AA.... isn't working

Re: Anti puff back device for AA.... isn't working

PostBy: Freddy On: Wed Nov 26, 2008 9:37 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.
Freddy
 
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

Re: Anti puff back device for AA.... isn't working

PostBy: coal berner On: Thu Nov 27, 2008 1:10 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.
coal berner
 
Stoker Coal Boiler: 1986 Electric Furnace Man 520 DF
Stove/Furnace Make: Electric Furnace Man
Stove/Furnace Model: DF520

Re: Anti puff back device for AA.... isn't working

PostBy: mwcougar On: Thu Nov 27, 2008 1:56 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......
mwcougar
 
Stove/Furnace Make: ahs 130 heating 3700sq ft

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Re: Anti puff back device for AA.... isn't working

PostBy: Yanche On: Thu Nov 27, 2008 10:46 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
 
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

Re: Anti puff back device for AA.... isn't working

PostBy: LsFarm On: Thu Nov 27, 2008 11:29 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
LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

Re: Anti puff back device for AA.... isn't working

PostBy: mwcougar On: Thu Nov 27, 2008 11:35 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.. :)
mwcougar
 
Stove/Furnace Make: ahs 130 heating 3700sq ft

Re: Anti puff back device for AA.... isn't working

PostBy: RICHARD2 On: Thu Nov 27, 2008 11:38 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.
RICHARD2
 
Stoker Coal Boiler: KA2

Re: Anti puff back device for AA.... isn't working

PostBy: gambler On: Thu Nov 27, 2008 11:51 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.
gambler
 
Stove/Furnace Make: Leisure Line
Stove/Furnace Model: Pioneer

Re: Anti puff back device for AA.... isn't working

PostBy: RICHARD2 On: Thu Nov 27, 2008 12:10 pm

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.
RICHARD2
 
Stoker Coal Boiler: KA2

Re: Anti puff back device for AA.... isn't working

PostBy: coaledsweat On: Fri Nov 28, 2008 11:22 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?
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

Re: Anti puff back device for AA.... isn't working

PostBy: LsFarm On: Sat Nov 29, 2008 12:10 am

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

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

Re: Anti puff back device for AA.... isn't working

PostBy: U235a4 On: Sat Nov 29, 2008 12:28 am

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.
U235a4
 
Stove/Furnace Make: 1958 Axeman-Anderson
Stove/Furnace Model: 260M

Re: Anti puff back device for AA.... isn't working

PostBy: Freddy On: Sat Nov 29, 2008 7:50 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).
Freddy
 
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

Re: Anti puff back device for AA.... isn't working

PostBy: gregolma On: Sun Nov 30, 2008 5:34 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.
gregolma
 
Stove/Furnace Make: Axeman Anderson
Stove/Furnace Model: 1980 Anthratube 130

Re: Anti puff back device for AA.... isn't working

PostBy: LsFarm On: Sun Nov 30, 2008 8:36 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

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

Visit Lehigh Anthracite