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Author Topic: Heat Duct question  (Read 6783 times)

Offline Kirk Allen

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Heat Duct question
« on: February 16, 2010, 08:56:59 PM »
I have a propane furnace in the basement with a 4" flexable exhaust that angles upwards to the base of the chimney and then goes vertical 22' to the top of the chimney.

I picked up a wood pellet stove for the basement and would like to tie the wood pellet exhaust to the same 4" flexable exhaust coming from the furnace.  The wood pellet is 3" exhaust and I picked up the adapter to take it to 4" but before I tie it in I wanted some opinions.

The manual says do not use the same exhaust as any other appliance but I was thinking since its alreay up sized from 3" to 4" and would be angled in an upward flow direction it should not be a problem.

Thoughts?

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Offline Carl Middleton

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Re: Heat Duct question
« Reply #1 on: February 17, 2010, 04:54:21 AM »
I would go for it. Shouldnt be to much exhaust from the pellet stove no bigger then the flame is. My brother put in a pellet stove two months ago and says the furnace has NOT kicked on sence  ;D

Offline Stevem

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Re: Heat Duct question
« Reply #2 on: February 17, 2010, 11:04:52 AM »
FWIW

I'd make sure the current exhaust pipe is rated to handle the temperature.  Pellet stove exhaust is a lot hotter than natural gas.  High effiency gas stove can now use PVC for exhaust because of the low exhaust temps.

A key question would be are the two appliance going to be running at the same time?  Area of a 3" pipe is 7 sq in verses the area of a 4 inch is about 12.55 in. 
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Offline Kirk Allen

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Re: Heat Duct question
« Reply #3 on: February 17, 2010, 03:15:47 PM »
The current exhaust is rated to handle the temps.  Its a Type L flex pipe which is suppose to be what it needs. 

I dont think I would have any issues with pipe size but after more research it looks like I am going to run a seperate dual wall flew for the stove.  I dont want the chance of any creasote causing a burn through in the flex pipe, which even though they say it cant happen, I KNOW it happens as we have had several chimney fires from that very problem. 

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Offline mike p

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Re: Heat Duct question
« Reply #4 on: February 17, 2010, 06:43:04 PM »
the wood pellets will be hoter i beleve than an PL furnace
so do you have an option at all on the sawdust burner of last year
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Offline Kirk Allen

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Re: Heat Duct question
« Reply #5 on: February 17, 2010, 10:58:08 PM »
Wood mizer scrapped the whole program.  I think the economy hit them hard like everyone else.  They gave me my money back after getting the computer controls.  The entire system is still here but without controls and time to figure out what to do with it I think its current home in a 6 foot snow drift will have to do!
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