New install, Stovepipe questions

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Madhatter

Member
Mar 11, 2011
26
Northampton County, PA
I’m getting ready to install my Harman Advance pellet stove and I have a few questions about the exhaust. I have an old victorian farm house with a porch that goes around the house on the first floor. This porch has a roof over it.

I am not too keen on exhausting my stove anywhere near the 150 year old woodwork, so here is what I am contemplating doing.
I want to use 4†pipe, come out of the stove horizontally for about 2’, a 90, then up about 7’, another 90, thru the wall and horizontally for about 5’, another 90, then through the porch roof with another 3’ of vertical rise, then finally a cap. I’m also thinking that the first 90 outside should be a cleanout piece.

Does anyone see any flaws in this plan? My main concern is that the pipe will end about 4 1/2’ directly in front of an openable window. The Harman book really doesn’t cover this exact scenario. It only states that it must be 4’ from an openable window, but they are picturing that being on the same plane.
Anything obvious that I’m overlooking here?
 
Madhatter said:
I’m getting ready to install my Harman Advance pellet stove and I have a few questions about the exhaust. I have an old victorian farm house with a porch that goes around the house on the first floor. This porch has a roof over it.

I am not too keen on exhausting my stove anywhere near the 150 year old woodwork, so here is what I am contemplating doing.
I want to use 4†pipe, come out of the stove horizontally for about 2’, a 90, then up about 7’, another 90, thru the wall and horizontally for about 5’, another 90, then through the porch roof with another 3’ of vertical rise, then finally a cap. I’m also thinking that the first 90 outside should be a cleanout piece.

Does anyone see any flaws in this plan? My main concern is that the pipe will end about 4 1/2’ directly in front of an openable window. The Harman book really doesn’t cover this exact scenario. It only states that it must be 4’ from an openable window, but they are picturing that being on the same plane.
Anything obvious that I’m overlooking here?

That is alot of pipe. You should not go any more that 4' of a horizonal run. this could give you a bad draft and not be good for the stove. I think I would go out the wall and up into the roof and cap in off there. You could be looking at alot of problems.
 
That is a whole lot of Pipe.. You EVL is 25' the way I see it. Which over 15' EVL you go to 4", which you said you were going to use... BUT.... Three 90*'s and 7 ft of Horizontal total, is a bit much to add up to 25' .. With Horizontal runs, you are supposed to also add 1/2" of rise per foot of Horz. So in a 7 ft run. There would be 3.5" of rise.. I would always do more than suggested. More like 1"

msmith66 said it right.. Go out the wall and then go up. Or is there something else prohibiting you from doing so??

As far as the window goes... 4 ft in any direction from a window is good. Or 1 ft above (If memory serves me correct) any window.
 
[quote author="msmith66" date="1315784578
That is alot of pipe. You should not go any more that 4' of a horizonal run. this could give you a bad draft and not be good for the stove. I think I would go out the wall and up into the roof and cap in off there. You could be looking at alot of problems.[/quote]

Hmm, that might be doable, I would need a 45 at the stove, about 2 1/2' feet horizontal to get outside, then a 90 or a clean out tee, then about 15' vertical rise(which would have to penetrate the porch roof). Then what would you cap it with a 90 into a horizontal cap?

I would end up pretty close to the upstairs window, but it looks like Harman cuts the window distance down to 18" if using an outside air vent, which should be doable.

This brings a few more questions to mind, How high above the porch roof would you go? I'm in snow country, we generally don't get that much, but occasionally it can pile up. I'm thinking 2'?

And, how about the porch roof penetration, the pipe would be centered between the roof rafters. Would you just cut a hole large enough to give a three inch clearance to the wood of the roof decking , then seal it with a cone roof flashing and a storm collar?

This porch really complicates things!
Thanks for the input!
 
Sounds similar to what I am doing. I can't tell you if it works yet as it's not installed yet but FWIW here's what I'm doing.

I'm coming 12" straight out through the thimble with 3" pipe and into a 90 deg 3" to 4" cleanout tee, then up 6 ft into a 90 deg elbow and then 8 ft across the porch ceiling and into a rain cap. I vent straight out from the run across the porch ceiling into the rain cap and don't have your added horizontal and vertical runs. Do you really need them?

My other option, similar to you, was to go straight up from the cleanout tee through the porch roof, jog around the 2nd floor gable overhang and vent above the 2nd floor roof. I went over both options with my stove/pipe retailer and while clearly the latter is better (less horizontal run), I'm going to try going across the porch ceiling because it's easier (I'm installing myself) than cutting through the roof and I think aesthetically it will look better. My retailer thinks it will work fine, especially with 4" pipe. If it doesn't I can always eliminate the 90 deg bend and go through the roof with the same straight pipe so I could convert without much added expense.
 
PS My dealer advised me to pitch the horizontal run about 1/4" per foot of horizontal run.

Don
 
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