# My pellet stove's exhaust causes the outside of my house to turn black



## splash (Nov 3, 2008)

I am trying to find a solution to this problem. I have a clapboard house.  The stove is vented directly through the wall to the outside.  I have spoken with the company where I purchased the stove and the installers about my outside clapboards turning black.  They don't have a solution.  Does anyone know what can be done?  It is obvious from the street and short of painting my house black, it ruins my curb appeal.  Thanks.


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## kast (Nov 3, 2008)

umm direct vent? no piping?


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## Res5cue (Nov 3, 2008)

try reading this:

https://www.hearth.com/econtent/index.php/articles/installing_pelletstove


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## pelletizer (Nov 3, 2008)

How far out does the vent cap stick out after going through the wall thimble is it like 4" from house?
Mine is at least 18" to 20" away I do not get any black siding issues.


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## splash (Nov 3, 2008)

Res5cue said:
			
		

> try reading this:
> 
> https://www.hearth.com/econtent/index.php/articles/installing_pelletstove



Yep, read it.  "Two important installation factors that are often overlooked are: 1. The need for the pipe to rise above the stove - NOT just straight out behind the stove. 2. The need for outside air hookup"

My pipes goe straight out for the move part but definitely do not rise above the stove and there is no outside air hookup.  The installation company (also where I purchased my stove) said there was no need for outside air.  It's  a Breckwell P23.
I have spoken to them on three occasions regarding the black house but they can't seem to come up with a solution.


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## Xena (Nov 3, 2008)

They can't come up with a solution, or they don't want to?


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## splash (Nov 3, 2008)

pelletizer said:
			
		

> How far out does the vent cap stick out after going through the wall thimble is it like 4" from house?
> Mine is at least 18" to 20" away I do not get any black siding issues.



No it's more than 4" and probably more like 18 to 20 " away.


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## Xena (Nov 3, 2008)

In case you didn't see this, here's a recent
thread discussing this very issue:
https://www.hearth.com/econtent/index.php/forums/viewthread/27212/


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## hearthtools (Nov 3, 2008)

this thread is linked on the sticky help pages at the top of the pellet room
https://www.hearth.com/econtent/index.php/forums/viewthread/13419/


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## hearthtools (Nov 3, 2008)

hearthtools said:
			
		

> this thread is linked on the sticky help pages at the top of the pellet room
> https://www.hearth.com/econtent/index.php/forums/viewthread/13419/



see this post for the solution
https://www.hearth.com/econtent/index.php/forums/viewthread/13419/#148730


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## drtnshtr (Nov 3, 2008)

I guess I got real lucky when installing mine then since its vented out the wall behind my stove with a 3ft section and thats it. I get no black stuff on my vinyl siding at all and to be honest when I go out there when the stove is running there is very little smoke at all coming form the chimney pipe. Normally it looks like its just steam....


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## abbdog (Nov 3, 2008)

So you only need a rise in the event of a power failure.Why would you need natural draft with a mechanical exhaust.


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## MainePellethead (Nov 3, 2008)

Not a fan at all with direct venting.  As Rods advice in the past I am a big fan of.  Direct venting to some may not cause problems at first and depending on the wind conditions etc it may take time.  I have an 8 foot rise and have no problems at all and the only time it puffs smoke is when I first start it up. After that, virtually no smoke.  Absorbing into clapboards may be  done quicker than vinyl too.


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## Tom D (Nov 3, 2008)

my direct vent goes out about 18 inches,i noticed last year i was getting some discoloration on vinyl siding,
cleaned off with simple green,went to heating place and had a 3' by 2' piece of galvanized  cut and he 
put a hole in it for exhaust pipe to go through. bent edges over so it wouldnt be sharp. can remove in spring.


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## cac4 (Nov 4, 2008)

I don't understand how having a rise in the pipe has any bearing at all on "sooting" on the outside of the house, (unless said "rise" goes all the way up through or above the roof, with a vertical cap).  

measuring out the vent kit that I bought, which holds the vertical rise 3" off the outside wall of the house, the horizontal cap that goes onto a 90 degree elbow on the top, puts the exhaust cap about a foot away from the wall.  What's the difference between that, and a foot away from the wall with no rise?  

seems to me, if there is "soot", thats because the stove isn't burning properly.  Whether its due to inadequate air supply, being dirty, or just crappy pellets...a rise in the pipe isn't going to make the stove "breath" any better, in and of itself.  

I have an oil-fired hot air furnace, that is vented with a power venter.  The exhaust isn't very far off the wall...I doubt its even a whole foot.  I get soot on the siding with that...when the furnace is in need of a cleaning/adjustment;  not otherwise.  
(slightly off the topic:  The exhaust from this thing is really hot;  I was there when the furnace guy was tuning it up, and he was measuring like 600 degrees, or some really high temp like that...I bet thats hotter than pellet stove exhaust.  maybe not...I just remember checking out the running pellet stoves at the fair, where they're just sitting outside, running with no chimneys on them.  I could hold my hand up to the exhaust.  The air coming out of the front was hotter! )


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## hearthtools (Nov 4, 2008)

The vertical pipe and T will act as a ash trap and build up in the pipe and not on the wall or Sidewalk/deck


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## cac4 (Nov 4, 2008)

Ok.  makes sense.  thats why I asked  ;-)


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## sinnian (Nov 4, 2008)

Could just be an O2 mix issue, but I agree on not liking short horizontal direct vents.


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## pelletizer (Nov 4, 2008)

Ya but what if the wind tends to blow toward the side of the house that the vent is on would it not tend to blow the smoke against the house?


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## splash (Nov 4, 2008)

I asked this question on this board and also sent it to my breckwell pellet stove rep.  Also to the best of my recollection this soot build up on my clapboards just happened the last two seasons.  The first two seasons that I had my stove it did  not do this.  I clean my stove weekly and have it professionally cleaned at the end of the season.  I don't see any smoke coming out of the vent.  I can smell it and I can feel it but I can't see it.  

The Breckwell Pellet Stove reps reply:

Sent: Monday, November 03, 2008 10:48 AM
Subject: Breckwell inquiry: soot removal

Good Morning 

I am responding to your inquiry regarding soot stain removal from your siding.
 I refer to a professional site that recommends 1st cleaning attempt when dry. (You are beyond this point.) The website is: http://www.parish-supply.com/dry_cleaning_sponge.htm 
 Thereafter use of a citrus degreaser. Test an inconspicuous spot first to be sure it does not discolor siding.

 Now, more importantly...why did the unit produce black soot?
 Generally, there are 3 reasons the exhaust will produce any smoke other than gray (moisture.)
1) Improper operation controlling air mix in firebox. 
2) Improper or restrictive vent configuration.
3) Excessive flyash build up before thorough routine cleaning (once per ton recommended.) 

 Solutions:
1) Air issue: stir burnpot daily to avoid clinkers or ash buildup. Observe flame when adjusting air and heat levels. Example: for levels 1,2; push the air damper rod all the way in and pull out about ½ inch For level 3, push closed and pull out about 3/4 inch. For level 4, pull all the way, or almost all the way open.  You do not want so much air the pellets jump out of the burnpot, but you want a lively stiff flame that consumes most of the lellets before the auger drops more into the burnpot.

2) Vent issues:Too many bends or too cold a vent pipe slows the exhaust movement, which slows the burning cycle, causing a sooty flame in the firebox. The vent should terminate at least 6 inches from the building and pointing away and slightly downward. If this faces the prevailing winds, you are guaranteed to experience smoke issues and all exhaust will be blown against the siding. The only way to guarantee to avoid discoloration of the siding, in any case, is to rise above the roof and terminate vertically as shown in the owner's manual.

3) Cleaning: The owner's manual specifies cleaning schedules, and this is critical to a clean burn.
 As the sparks fly up with the heated exhaust thru the top of the stove, the exhaust is routed down behind the fireback. The sparks cool and become flyash. These accumalate as a grey ash behind that wall and must be vacuumed out once per ton burned. This is done by removing the burnpot and then removal of the 2"x4" plates in the firewall. At the same time the exhaust fan should be lossened and lifted out, brushed and vacuumed. 
If this is done regularly, each ton burned, the flame will burn very clean and the smoke will almost never be black...usually there will be only grey smoke visible.

I hope this helps. I recommend that whenever possible the vent should terminate above the roof, especially where wind issues come into play.

RMI Technical Support


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## sinnian (Nov 4, 2008)

Most likely the O2 then.


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