Average Stack Temp. ??

Average Stack Temp. ??

PostBy: plumb-r On: Thu Aug 07, 2008 5:22 pm

Could some one give me an idea of the average stack temp. after the draft regulator on a coal furnace. Is it comparable to that of a oil burner. Thanks for the help!
Stove/Furnace Make: Hitzer
Stove/Furnace Model: 608 Energy Master I Stoker

Re: Average Stack Temp. ??

PostBy: LsFarm On: Thu Aug 07, 2008 5:50 pm

I have no idea what the temp of an oil burner's flue is..

For a hand fired stove the temp can vary from ~250* to 8-900* or even higher at times
A stoker is usually around ~150-300*

My AA boiler when idling is around ~120*, but will reach 400* after a 10 minute burn in the dead of winter. This is measured about a foot above the boiler's exhaust.

Most will run around 4-500* when making heat.. higher if the appliance isn't able to extract as much heat from the firebox to the surrounding room.

Greg L

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

Re: Average Stack Temp. ??

PostBy: WNY On: Fri Aug 08, 2008 7:48 am

Depends on how hard you are running it, my hyfire I running full bore and AFTER the baro damper usually averages 200-250+ Deg. F before going up the chimney. I have a digital temp. probe in the pipe. I don;t think I have ever seen it over 300.

The baro damper usually opens and helps cool the exhaust when it starts really drawing up the chimney, to keep a constant draw on the stove.
Hot Air Coal Stoker Stove: Keystoker 90K, Leisure Line Hyfire I
Coal Size/Type: Rice
Stove/Furnace Make: Keystoker, LL & CoalTrol
Stove/Furnace Model: 90K, Hyfire I, VF3000 Soon

Re: Average Stack Temp. ??

PostBy: Devil505 On: Fri Aug 08, 2008 7:53 am

WNY wrote:Depends on how hard you are running it

There is no such thing as an "average" stack temp. (kinda like saying what is your average driving speed?........While you can figure it out mathematically after a road trip, it is totally variable & under your control)
Your oil furnace runs at a constant temp & provides heat to your house based on the amount of time it is on. A coal appliance is burning all the time & you regulate you home's heat by varying the heat output of the appliance. (I've only run coal stoves so I am no expert on running coal furnaces, but I think the principle is the same......Higher stove/furnace temps create more heat for your home, not just time on. If I am wrong about this, I'm sure one of our resident furnace experts will correct me. :D
Stove/Furnace Make: Harman
Stove/Furnace Model: TLC-2000

Re: Average Stack Temp. ??

PostBy: Machinist On: Sat Aug 09, 2008 10:49 pm

The last time I cleaned my 39 year old oil fired boiler, Sept '07, the stack temp was 585 degrees before cleaning.
540 after cleaning. :shock: :mad:

Don't know about coal yet. As soon as the oil tank is empty, a few days I expect, I will be installing my Keystoker boiler.

I think newer boiler manufacturers advertise their stack temps much lower.
Stoker Coal Boiler: Keystoker KAA-2
Coal Size/Type: Rice
Other Heating: None

Re: Average Stack Temp. ??

PostBy: 218Bee On: Sun Aug 10, 2008 12:27 am

My KA-6 was hitting 165+/- during the stoke cycle last weekend.
Almost no load (140/160) and 45 sec. idle burn every 15 min.

I was surprised at how low the temps have been.
I need a new 9 volt for the meter. I'll give you more data, as I collect it.
Stove/Furnace Make: Keystoker
Stove/Furnace Model: KA-6