Another newbie question-- Wow, too much heat!

Re: Another newbie question-- Wow, too much heat!

PostBy: Rex On: Sat Dec 22, 2007 3:15 pm

Im glad we put an automatic air damper inline with our 6 inch stove pipe. Actually Im not sure why its called a damper because it doesn't "dampen" anything but rather allows air to flow up the pipe.

Nothing worse than being away from the house and have an updraft occur in your stove on a windy day. Nice to have the damper open up allowing air up the chimney versus the air being sucked in through our stove where it could burn the house down.

Once my stove was getting a strong draft of air being feed in through the stove on a cold windy day and the pipe and stove was quickly running over into the red. I noticed my air damper door was "stuck" from allowing it to open. After I unstuck it, the baffle door opened up all the way allowing the excessive air draw to occur. Things cooled down immediately. Once the wind died down the baffle door closed, allowing normal airflow through the stove.
Rex
 
Stove/Furnace Make: D.S. Machine
Stove/Furnace Model: Circulator 1500

Re: Another newbie question-- Wow, too much heat!

PostBy: coaledsweat On: Sat Dec 22, 2007 3:26 pm

JerseyCoal wrote:Can anyone tell me under what circumstances a manual damper would be of any use??


Its only function here is to start an argument. :roll:
I have and use one. The manual that came with the boiler makes no mention of one for or against. The guy I bought it from said his father could not heat the entire three family house with it until he installed the hand damper. He was burning stove coal flat out and went through a pile of grates to do it. Its a small boiler, I would guess 100-120,000 BTUs and it has a draft blower.
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

Re: Another newbie question-- Wow, too much heat!

PostBy: coalstoves On: Sat Dec 22, 2007 3:46 pm

JerseyCoal wrote:Hi Guys:

I have never had a manual damper on my hand fired coal stoves and, in my ignorance, can't imagine a situation in which I would want to have one.
Can anyone tell me under what circumstances a manual damper would be of any use??

John C.

A partially or fully closed Pipe Damper reduces the volume not the amount of flue draft and exhaust, with the damper partially closed heat tends to be retained by the stove longer and secondary combustion tends to be more complete . Note that even when a damper is fully closed it still allows about 30% of the original flow because of openings in the face of the damper and space around the sides.
These statements are confirmed by manometer readings taken by member coaledsweat in the locked thread regarding MPDs .
Last edited by coalstoves on Sat Dec 22, 2007 4:03 pm, edited 1 time in total.
coalstoves
 
Stove/Furnace Make: Harman and Liberty
Stove/Furnace Model: Magnum and Victory 700

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Re: Another newbie question-- Wow, too much heat!

PostBy: coaledsweat On: Sat Dec 22, 2007 3:53 pm

coalstoves wrote:Note that even when a damper is fully closed it still allows about 30% of the original flow because of openings in the face of the damper and space around the sides.


Also, the reduced flow is traveling at a higher velocity through the damper to maintain the draft.
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

Re: Another newbie question-- Wow, too much heat!

PostBy: Cap On: Sat Dec 22, 2007 4:32 pm

Coalstoves wrote at 0212hrs on 12/22
A partially or fully closed Pipe Damper reduces the volume not the amount of flue draft and exhaust, with the damper partially closed heat tends to be retained by the stove longer and secondary combustion tends to be more complete . .


Ok. I'll bite. What is secondary combustion? We'll talking coal chunks here. Not solid rocket booster fuel.

BTW, I put foil over my baro last night. (don't think really helpful for my setup) Burn temps have not changed and has my flue temps are equalized with the heat temp output..165F today all around. The stove hand damper easily controls the draft.
Cap
 
Hand Fed Coal Boiler: Harman SF 250, domestic hot water loop, heat accumulator

Re: Another newbie question-- Wow, too much heat!

PostBy: coalstoves On: Sat Dec 22, 2007 4:47 pm

Cap wrote:Ok. I'll bite. What is secondary combustion? We'll talking coal chunks here. Not solid rocket booster fuel.


Gases

Volatile Gases released during primary combustion contain a large percent of potential heat in the coal. Their combustion is important to achieve high overall efficiency.
coalstoves
 
Stove/Furnace Make: Harman and Liberty
Stove/Furnace Model: Magnum and Victory 700

Re: Another newbie question-- Wow, too much heat!

PostBy: Cap On: Sat Dec 22, 2007 7:20 pm

Yea, but wouldn't gases burn off fairly rapidly? How would a combustible gas escape a 1000F bed of coal fire? Aren't the blue flames the gases in which you refer?
Cap
 
Hand Fed Coal Boiler: Harman SF 250, domestic hot water loop, heat accumulator

Re: Another newbie question-- Wow, too much heat!

PostBy: Wood'nCoal On: Sat Dec 22, 2007 7:35 pm

JerseyCoal wrote:Hi Guys:

I have never had a manual damper on my hand fired coal stoves and, in my ignorance, can't imagine a situation in which I would want to have one.

Assuming a constant draft, the burn rate is regulated by the amount of underfire air flow. I accomplish that with the bi-metal thernostat which controls the flap on the air intake.

If weather or wind conditions distort the draft in the chimney, my barometric damper will prevent an increase of the desired burn rate.

Can anyone tell me under what circumstances a manual damper would be of any use??

John C.


As Richard has indicated, every situation is different-every stove, every chimney, every ton of coal. I prefer a Barometric Damper. I like it because it will maintain the draft at the point that I set it to, regardless of the conditions. Manometer readings show my chimney can work up quite a high draft to the stove without it. Some people like the manual damper, for their own perfectly good reasons. So be it. The important thing is to maintain a safe environment around the stoves and boilers.
Wood'nCoal
 
Stoker Coal Boiler: 1959 EFM 350
Hand Fed Coal Stove: Harman Magnafire Mark I
Coal Size/Type: Rice and Chestnut
Other Heating: Fisher Fireplace Insert

Re: Another newbie question-- Wow, too much heat!

PostBy: coalstoves On: Sat Dec 22, 2007 10:32 pm

Cap wrote:Yea, but wouldn't gases burn off fairly rapidly? How would a combustible gas escape a 1000F bed of coal fire? Aren't the blue flames the gases in which you refer?


It gets a bit technical at this point and you must remember I'm just a Truck Driver who burns coal.

From my understanding the Gases escape the 1000F bed of coal you reference because at that point the oxygen needed is being consumed by the primary combustion (1000F bed of coal) which is why the damper is beneficial in reducing the volume of the flow so the gases have a chance to oxygenate (scientific part) and combust and I am told that while a flame as we know it to see it may not exist the gases are indeed burning .

I buy in to this idea because with my Victory stove if I sit and watch it I will often see little blue wiffs moving across the coal bed and around the edges of the fire box also if conditions in the stove are just right I can open the feed hatch on the top of the stove and the entire stove fills with the prettiest blue fireball that just sort of swirls around inside for a fraction of a second.
coalstoves
 
Stove/Furnace Make: Harman and Liberty
Stove/Furnace Model: Magnum and Victory 700

Re: Another newbie question-- Wow, too much heat!

PostBy: Wood'nCoal On: Sat Dec 22, 2007 10:37 pm

Sometimes with a load of fresh coal in the stove, I'll have little blue flames swirling around at the top of the firebox right under the baffle. Have to practically lay on the floor to see it.
Wood'nCoal
 
Stoker Coal Boiler: 1959 EFM 350
Hand Fed Coal Stove: Harman Magnafire Mark I
Coal Size/Type: Rice and Chestnut
Other Heating: Fisher Fireplace Insert

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