Coal Stove Heat Duct Temps

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tmbm50
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Location: Lancaster PA

Post Thu. Nov. 08, 2007 6:51 pm

I'm getting my HyFire II very shortly. I have a 10" pipe that will feed into some existing duct work to feed the house. But I'm worried about the temps of the hot air and the fact that after about 5 feet of pipe duct work, the "duct" is nothing more than a sealed wall cavity. I guess with the normal heat pump this was ok becuase the temps for the air are never greater than 100. But with the coal stove I suspect the air temps to be far greater.

Does this pose a fire risk?

An engineer friend told me wood can ignite as low as 300 degrees. But I'm just not sure how hot the exhaust air will be.

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coaledsweat
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Post Thu. Nov. 08, 2007 7:56 pm

If you can get you air temperature up to 300*, you won't have to worry about the house catching on fire. :)
Wood that is exposed to very high temps for long periods can ignite at much lower temps, perhaps 220*. I would place a thermometer at the opening and see what the actual air temp is flowing into the duct. If it is less than 200* there should be no problem. If it exceeds that, insulate the duct.
Nothing is impossible for people who don't have to do it themselves.

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WNY
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Post Fri. Nov. 09, 2007 7:40 am

Depending on the blower setup, I am using the stock blowers on the stove.
I have Temp probe in the 8" duct going upstairs which about 4 feet from the stove, it doesn't get much over 120 degrees so far.
- Dave
Hyfire I & Keystoker 90K heating an 1890 Victorian
- Amsoil Authorized T1 Certified Dealer


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e.alleg
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Post Fri. Nov. 16, 2007 10:34 am

coaledsweat wrote:If you can get you air temperature up to 300*, you won't have to worry about the house catching on fire. :)


Why? because the house is already on fire if the duct is 300 degrees? :lol:
Burning coal is definitely worth the extra work involved.
"Good enough" is not good enough.

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WNY
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Hot Air Coal Stoker Stove: Keystoker 90K, Leisure Line Hyfire I
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Stove/Furnace Model: 90K, Hyfire I, VF3000 Soon
Location: Cuba, NY
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Post Fri. Nov. 16, 2007 11:21 am

Actually not a bad Idea, we had the rehostat fail that controlled the fans and the duct temps going upstairs got up around 200 degrees.....luckily we were home when I smelled something getting HOT and I unplugged the rehostat/fans and plugged into an outlet. :)
- Dave
Hyfire I & Keystoker 90K heating an 1890 Victorian
- Amsoil Authorized T1 Certified Dealer

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Matthaus
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Post Fri. Nov. 16, 2007 6:46 pm

Installing a bimetallic type "snap switch" rated to open at whatever temp you think is reasonable is a cheap way to ensure that an overtemp will not occur.

If you wire the stove power through the switch it will shut things down till the lower limit is reached. :)
Matthaus
Leisure Line Stove Company
http://www.leisurelinestoves.com/

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