Stack Temperatures Hand Fired Stoves

Stack Temperatures Hand Fired Stoves

PostBy: skobydog On: Tue Dec 17, 2013 3:28 pm

Would it be abnormal to see a 600 degree (internal probe thermometer) temperature on a coal stove?

I ask because I noticed the other day (and today) that my stack temperatures shot up to 600 degrees (internal probe thermometer appr 24 inches above stove and MPD closed) when the stove was given some air. This is the Hitzer with the automatic damper on the back so it adjusts the air automatically. I could hear the flames going up the stove pipe. Maybe I just never noticed it because I'm not always here.

Normally my stack temp sits a bit under 200 degrees. Maybe I just never noticed the stack temp rising that high before as I'm not always home to see it.

Is this is a normal stack temp for a hand-fired stove? Thanks
skobydog
 
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Nut Anthracite

Re: Stack Temperatures Hand Fired Stoves

PostBy: wsherrick On: Tue Dec 17, 2013 6:43 pm

A 600 degree stack temperature is really, really high.
wsherrick
 
Hand Fed Coal Stove: Glenwood Base Heater, Crawford Base Heater
Baseburners & Antiques: Crawford Base Heater, Glenwood, Stanley Argand
Coal Size/Type: Chestnut, Stove Size

Re: Stack Temperatures Hand Fired Stoves

PostBy: EarthWindandFire On: Tue Dec 17, 2013 6:56 pm

If everyone had a 600 degree stack temp, we would melt the polar ice caps and send Santa's workshop crashing into the Arctic Ocean. ;)

Anything above 350 degrees would be unacceptable.
EarthWindandFire
 
Hot Air Coal Stoker Furnace: Leisure Line Lil' Heater.
Hand Fed Coal Stove: Hitzer model 75.
Other Heating: Oil and Natural Gas.

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Re: Stack Temperatures Hand Fired Stoves

PostBy: fastcat On: Tue Dec 17, 2013 7:10 pm

That temp is normal to see with the Hitzer when running a little higher temps in the stove due to low outside temps. Mine has been doing the same thing. Myself I'm not worried about it because it is only for a short time till the flapper closes. :D
fastcat
 
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Blaschak Nut/Stove Mix

Re: Stack Temperatures Hand Fired Stoves

PostBy: mmcoal On: Tue Dec 17, 2013 7:17 pm

My 50-93 does the same thing. It doesn't happen all the time, but I do get 500-600 degree stack temps after a shake down once in awhile. For me once it spikes, it usually calms down within about 15-20 minutes. It also doesn't matter whether I have my MPD is open or closed either. I think sometimes the new coal igniting right after a shake down starts to rage a little too much before the stove temperature raises enough for the bi-metal damper to respond and close. At least that's my thought on it.
mmcoal
 
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: nut

Re: Stack Temperatures Hand Fired Stoves

PostBy: skobydog On: Tue Dec 17, 2013 7:46 pm

mmcoal wrote: It doesn't happen all the time, but I do get 500-600 degree stack temps after a shake down once in awhile. For me once it spikes, it usually calms down within about 15-20 minutes. It also doesn't matter whether I have my MPD is open or closed either. I think sometimes the new coal igniting right after a shake down starts to rage a little too much before the stove temperature raises enough for the bi-metal damper to respond and close. At least that's my thought on it.


Looks like you and fastcat have had the same experience with this stove.

What you described is exactly what happened today. I shook down the stove. A short time later (not sure how long) the stack temp spiked for a number of minutes until the back flapper closed. Then within 20-30 mins the stack temp dropped back to around 200 degrees and stayed in that range.

When I opened the flapper again shortly after there was on spike in the stack temp. Like you said, I guess it's just the new coal being introduced at that time.

I suppose it doesn't happen all the time because the back flapper isn't always open after shaking. 8-)
skobydog
 
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Nut Anthracite

Re: Stack Temperatures Hand Fired Stoves

PostBy: JohnnyV On: Tue Dec 17, 2013 7:53 pm

I believe that is normal. It is only temporary, until the flap closes.
JohnnyV
 
Hand Fed Coal Stove: hitzer 254
Coal Size/Type: Nut
Other Heating: Pellet stove far end of house
Stove/Furnace Make: Hitzer
Stove/Furnace Model: 254

Re: Stack Temperatures Hand Fired Stoves

PostBy: skobydog On: Tue Dec 17, 2013 8:10 pm

JohnnyV wrote:I believe that is normal. It is only temporary, until the flap closes.


I'll have to experiment over the next couple shake downs. If I can replicate it then I'll know. I'll purposely keep the flapper open and then closed to see.

I'm still with this stove and would like to make sure for piece of mind while I'm at work.
skobydog
 
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Nut Anthracite

Re: Stack Temperatures Hand Fired Stoves

PostBy: Keepaeyeonit On: Tue Dec 17, 2013 8:30 pm

Skobydog,I have a thermometer 2" above the stove outlet and a thermocouple at the same level to check flue gas temp and at shake down/reload I see 500* pipe and 700* to 800*(1000* was the max I ever saw but the pipe never got above 550*) gas temp but thats for a very short amount of time.During normal use with the stove above 500* the pipe is 350* or so and the gas temp is 400*, the pipe is 145* 6' from the stove and after the baro.Keepaeyeonit
Keepaeyeonit
 
Hand Fed Coal Stove: Hitzer 983 insert
Coal Size/Type: Mammoth nut
Other Heating: oil furnace,and a crappy heat pump

Re: Stack Temperatures Hand Fired Stoves

PostBy: skobydog On: Tue Dec 17, 2013 10:43 pm

Keepaeyeonit wrote:Skobydog,I have a thermometer 2" above the stove outlet and a thermocouple at the same level to check flue gas temp and at shake down/reload I see 500* pipe and 700* to 800*(1000* was the max I ever saw but the pipe never got above 550*) gas temp but thats for a very short amount of time.During normal use with the stove above 500* the pipe is 350* or so and the gas temp is 400*, the pipe is 145* 6' from the stove and after the baro.Keepaeyeonit


Because I am using double-wall stove pipe I am using a probe thermometer.

Would I be correct in assuming a probe thermometer would be closer to the thermocouple vs a magnetic stick-on stove pipe thermometer?
skobydog
 
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Nut Anthracite

Re: Stack Temperatures Hand Fired Stoves

PostBy: 2001Sierra On: Tue Dec 17, 2013 10:51 pm

My old Buderus never exceeded 300 degrees, 59000 BTU stove rated.
2001Sierra
 
Hot Air Coal Stoker Stove: Keystoker 90 Chimney vent
Coal Size/Type: Rice
Other Heating: Buderus Oil Boiler 3115-34
Stove/Furnace Model: Keystoker 90 Chimney Vent

Re: Stack Temperatures Hand Fired Stoves

PostBy: oliver power On: Wed Dec 18, 2013 5:29 am

OK, here's what's happening; If you have a good hot fire at tending time, no problems. Your stack temp may, or may not rise. If it does rise, it wouldn't be much (Example: 25* - 50*) ,then settles back down. Now, if your fire is low at tending time, the first thing you need to do is shut the fan off. You don't want the fan taking any heat off the mass of the stove. As you loose heat off the mass of the stove, the back flapper door will open wider, and wider. Once the fire gets going, it has to heat the entire mass of the stove back up, till the flapper door closes again. By that time, you have a roaring fire, and way higher stack temps than you should. The flapper door acts like a mini ash pan door being left open. The stove runs away on you. Stack temps surge. You loose control (not good). I wouldn't except these high spikes in stack temps as "Normal". The secret is not to loose the stoves heat mass. Also, should the fire be low; it should be built up a little to a time (as if starting a fresh fire), till you have a good hot bed of coals to start with. Because the fan is off, the mass of the stove is heated back up. Or at least rapidly heading in that direction. Only then, the hopper should be topped off. And yes, you're correct about many people not seeing this happen, as off to work they go. All the while, never knowing how close they are to having a house fire Every Day.
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

Re: Stack Temperatures Hand Fired Stoves

PostBy: Keepaeyeonit On: Wed Dec 18, 2013 8:02 am

Skobydog,OP brings up something I forgot your stove has dial-a-temp so your tending routine is going to be different then mine.The other thing is not tending the stove and running out the door, I leave myself 25 to 30 minutes after a reload to make sure that everything settles down before I leave the house.Keepaeyeonit
Keepaeyeonit
 
Hand Fed Coal Stove: Hitzer 983 insert
Coal Size/Type: Mammoth nut
Other Heating: oil furnace,and a crappy heat pump

Re: Stack Temperatures Hand Fired Stoves

PostBy: coalkirk On: Wed Dec 18, 2013 8:25 am

If you are using an internal probe thermometer you need to make sure the probe cannot "see" the fire in the stove. If it does you are getting a radiant effect on the probe instead of measuring the stack temp.
coalkirk
 
Stoker Coal Boiler: Harman VF3000
Coal Size/Type: antrhcite/rice coal

Re: Stack Temperatures Hand Fired Stoves

PostBy: bksaun On: Wed Dec 18, 2013 8:33 am

Big difference between an internal temp and an external magnet temp, 600 was normal for my hitzer, I used a grill thermometer so it measured the internal temp, also had a magnet type beside it and the temps were 175-200 degrees different when running on high.

We need to compare apples to apples here.

Bk
bksaun
 
Stoker Coal Boiler: Hybrid, Gentleman Janitor GJ-6RSU/ EFM 700
Hand Fed Coal Stove: Hitzer 503
Coal Size/Type: Pea Stoker/Bit, Pea or Nut Anthracite
Stove/Furnace Make: Hitzer/ EFM-Gentleman Janitor
Stove/Furnace Model: 503 Insert/ 700/GJ-62

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