Define - "Over-Firing"

Define - "Over-Firing"

PostBy: I'm On Fire On: Tue Dec 07, 2010 8:18 pm

For a long time I have been confused by what "Over-Firing" a stove meant.

That was until Chuck_Steak clarified it:

Chuck_Steak wrote:We should clarify that overfiring @500 degrees, is 500 'stack' degrees, and not 500 'stove' degrees...


in this thread: Am I not burning stove hot enough?

I felt this was note worthy because I'm sure there are other members like myself whom have been hearing this term since childhood but never really understood what it meant.

I can honestly say that I thought over firing the stove was: Stove Body temp and not 'Stack'.

Thank you Chuck_Steak.

I also feel this should possibly be stickied so it could be referenced from time to time. And it would also be helpful to put max temps that different stoves should be run at to prevent over-fires.
I'm On Fire
 
Hand Fed Coal Stove: DS Machines DS-1600 Hot Air Circulator

Re: Define - "Over-Firing"

PostBy: DOUG On: Tue Dec 07, 2010 8:34 pm

I like the definition given in the Vogelzang cast iron potbelly stove manual on page 9.
http://content.vogelzang.com/Inst/pb65xl.pdf
This link is broken, either the page no longer exists or there is some other issue like a typo.


"YOU ARE OVERFIRING THE STOVE IF STOVE OR STOVEPIPE BEGINS TO GLOW OR TURN RED.
DOUG
 
Stove/Furnace Make: CHUBBY, D.S.MACHINE BOILER
Stove/Furnace Model: CLAYTON 1600

Re: Define - "Over-Firing"

PostBy: I'm On Fire On: Tue Dec 07, 2010 8:41 pm

That's the way I always thought too, but numbers tend to make things better and give good reference points as opposed to; "Glowing Red". :)

But, that is a light hearted definition.
I'm On Fire
 
Hand Fed Coal Stove: DS Machines DS-1600 Hot Air Circulator

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Re: Define - "Over-Firing"

PostBy: VigIIPeaBurner On: Tue Dec 07, 2010 8:46 pm

DOUG wrote:I like the definition given in the Vogelzang cast iron potbelly stove manual on page 9.
http://content.vogelzang.com/Inst/pb65xl.pdf
This link is broken, either the page no longer exists or there is some other issue like a typo.


"YOU ARE OVERFIRING THE STOVE IF STOVE OR STOVEPIPE BEGINS TO GLOW OR TURN RED.


Whooaa YEA! But don't carry that too far if your stove is double walled and your stove pipe is double walled as well :shock: That discribes my set up with a Vigilant II and double walled SS pipe. Hopefully the stove's manual will define where/how to measure so it's both relavent to the stove and done correctly. The VC manual for my stove stated the range and where to measure.
VigIIPeaBurner
 
Hot Air Coal Stoker Furnace: Keystoker Koker
Hand Fed Coal Stove: Vermont Casting Vigilant II 2310
Other Heating: #2 Oil Furnace

Re: Define - "Over-Firing"

PostBy: DOUG On: Tue Dec 07, 2010 9:04 pm

I think that for a high side of the stove temperature is around 700 degrees. Anything over that is really not efficient. I've noticed, depending on the thickness of the stove material, once the stove temperature reaches the 800 degree mark, it starts to glow dark red. So, I would stay 650 degrees or lower and be satisfied with what the size of the stove can produce. If you really need more heat, add another one and run them at a lower temperature. Well that's my opinion from my hands on observations for what it is worth. ;)
DOUG
 
Stove/Furnace Make: CHUBBY, D.S.MACHINE BOILER
Stove/Furnace Model: CLAYTON 1600

Re: Define - "Over-Firing"

PostBy: I'm On Fire On: Tue Dec 07, 2010 9:09 pm

Doug, are you talking Chubby only or just in general? I really hadn't planned on running the Chubby over 600* on those days that require it and I only planned on doing so if I were home to tend to it. 550* so far seems to be the limit for now. Still gives me 12 hours and I don't have to show the wife how to shake down for a mid afternoon recharge at a higher temp; mainly because she has already claimed she's kind of scared to shake the stove down.

I haven't run the Chubby over 550* yet. Seems to do a good job keeping the house around 70*. I'm not looking for more heat, just information. ;) I really felt the definition that Chuck_Steak was a bit more explanatory than I had ever heard and wanted to get some more figures up so people can reference them.

I used to run my wood stove around 800* but that was body temp, never had one on the stack. Didn't have room for one on the stack. Never got it to glow but did get a lot of stove "groaning". But on the Chubby I've got a lot more information to use.
I'm On Fire
 
Hand Fed Coal Stove: DS Machines DS-1600 Hot Air Circulator

Re: Define - "Over-Firing"

PostBy: Coalfire On: Tue Dec 07, 2010 9:25 pm

Just a question, wouldn't 500 degree stack temp put most stoves at 800-900 degrees? right not I am running 450 with a stack temp of 220. if my stack was at 500 I think my stove would be melting :) , not really but don't you mean stove temp and not stack temp?
Just wondering, Eric
Coalfire
 
Hand Fed Coal Stove: DS Machine 96K btu Circulator
Coal Size/Type: Nut

Re: Define - "Over-Firing"

PostBy: DOUG On: Tue Dec 07, 2010 9:29 pm

I'd say all burners in general. I have my Clayton 1600 furnace fired on wood right now and have a magnetic thermometer attached right below the draft pull out rod. This is the point where the flue gases goes right into the secondary heat exchanger before the flue collar. I have a forced combustion draft fan attached to the high limit fan switch, which is set to shut the combustion fan off when the furnace jacket bonnet temperature reaches 250 degrees. I noticed that every time the fan switch cuts off the combustion fan, the magnet thermometer is right at 650 degrees.

As for the Chubby, I've run it at 650 degrees and it was very happy, but it was more hungry for fuel and the burn times became shorter, like 8 hours. The stovepipe temperature was around 350 degrees when the Chubby stove temperature was 650 degrees.
DOUG
 
Stove/Furnace Make: CHUBBY, D.S.MACHINE BOILER
Stove/Furnace Model: CLAYTON 1600

Re: Define - "Over-Firing"

PostBy: CapeCoaler On: Tue Dec 07, 2010 9:42 pm

600*-650* is a good rule of thumb for stove body temp...
Some can go higher...
Think of it this way...
If you are running your stove at 600* all the time just to maintain 70*...
And winter is yet to really hit...
You need a bigger stove if you want to heat 100% with coal...
I ran a Mark II hard just to keep the house 68* in the winter...
So the next season I picked up the DSM almost double the btu/hr of the Mark II...
It is at 350* and the house is 76*...
The wife was home today so she gets to pick the temp... ;)
The DSM is just loafing to heat the house most days in winter...
When it gets real nasty out I can push it to 550*-600* if I need to for a few days...
I can leave for 24 hours and not worry about the stove going out...
And the house will be at 65* the whole time...
I can drop it to 55* and leave for the weekend if I want...
The gas will be set to kick on at 50* just to be safe...
Frozen pipes are no fun to return to...
CapeCoaler
 
Stoker Coal Boiler: want AA130
Hand Fed Coal Stove: DS Machine BS#4, Harman MKII, Hitzer 503,...
Coal Size/Type: Pea/Nut/Stove

Re: Define - "Over-Firing"

PostBy: VigIIPeaBurner On: Tue Dec 07, 2010 9:47 pm

You could bet that once an operator has the draft properly regulated, flue gas temps are most certainly a reliable indication of over firing. But consider this....

It's a common Newbie complaint that they can't keep an anthracite fire going over night. Also that they find the dead fire with gray and black coal sized pieces on top of the dead fire. Sounds familiar? ;) In almost all of these cases the out-fire complaint was that the stove wasn't transferring enough heat to the room(s). So they open the air more. When they move up on the next rung of the anthracite learning curve, they discover - usually through help from this forum :) - that they had the air feed too high and all the heat was rushing up the stove pipe/chimney with out spending enough time in the stove to transfer to the room(s). Usually the draft was much higher and likely > -.15. If stack temperatures were measured in such a situation they would be quite high but the complaint was no heat and short fires. Is this an over fire? No glowing red or super hot stove but the stack temps sure would have all those BTUs boogying up & out of the chimney!
VigIIPeaBurner
 
Hot Air Coal Stoker Furnace: Keystoker Koker
Hand Fed Coal Stove: Vermont Casting Vigilant II 2310
Other Heating: #2 Oil Furnace

Re: Define - "Over-Firing"

PostBy: I'm On Fire On: Tue Dec 07, 2010 10:02 pm

VigIIPeaBurner,

I am definitely guilty of that complaint. But..I can honestly say that I have had the same fire for 9 weeks now with no worry of it going out. But now I generally set the stove and walk away from it. I don't touch the air settings once the stove is re-charged for the morning or night.

CapeCoaler,

I know the Chubby is not going to heat my entire house; but that is another topic for me to discuss come tax season (either a Hitzer 50-93 or a Keystoker A-250 Warm air furnace will go in). Just wanted a clear definition of what an over-fire was. With some more information to back it up. :)
I'm On Fire
 
Hand Fed Coal Stove: DS Machines DS-1600 Hot Air Circulator

Re: Define - "Over-Firing"

PostBy: VigIIPeaBurner On: Tue Dec 07, 2010 10:29 pm

IOF - don't feel guilty, none implied. You've just "been there and done that". On to the next rung :D
VigIIPeaBurner
 
Hot Air Coal Stoker Furnace: Keystoker Koker
Hand Fed Coal Stove: Vermont Casting Vigilant II 2310
Other Heating: #2 Oil Furnace

Re: Define - "Over-Firing"

PostBy: CapeCoaler On: Tue Dec 07, 2010 10:31 pm

Take a good look at what DS machine has to offer...
No fans just nice quiet heat...
Priced right too...
CapeCoaler
 
Stoker Coal Boiler: want AA130
Hand Fed Coal Stove: DS Machine BS#4, Harman MKII, Hitzer 503,...
Coal Size/Type: Pea/Nut/Stove

Re: Define - "Over-Firing"

PostBy: I'm On Fire On: Tue Dec 07, 2010 10:34 pm

VigIIPeaBurner wrote:IOF - don't feel guilty, none implied. You've just "been there and done that". On to the next rung :D


I know, I ask a lot of pretty dumb questions that revolve around the same topic. But I am trying to understand a lot of this stuff. When I get into something I really like I try to learn as much as humanly possible and I tend to beat dead horses. Ask my wife about slot cars.

CapeCoaler,

Googling them now. :) I really need a unit to replace my oil furnace come summer time.
I'm On Fire
 
Hand Fed Coal Stove: DS Machines DS-1600 Hot Air Circulator

Re: Define - "Over-Firing"

PostBy: oliver power On: Tue Dec 07, 2010 10:47 pm

I agree with the above. May I add results of over firing; 1.) short burn times. The coal doesn't burn down. It kind of keeps its form of a bed of coals, yet the coals are grey & the usefull energy is used up, or spent, as Greg would put it. 2.) warped/damaged stove parts.
oliver power
 
Stoker Coal Boiler: KEYSTOKER Kaa-2
Hand Fed Coal Stove: Hitzer 50-93 & 30-95, Vigilant (pre-Vigilant-II)
Baseburners & Antiques: MANY (Mostly when burning wood)
Stove/Furnace Make: HITZER / KEYSTOKER
Stove/Furnace Model: 50-93 & 30-95 , Kaa-2

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