# Horizontal venting



## carlg (Nov 9, 2010)

I was looking at a pellet stove at a store that specializes in stoves.  One of the places that I would like to install my stove would require the vent to go up about 5-7 feet from the stove into an elbow and then do a horizontal run of about 10-12 feet to exit the house.  I mentioned this to the guy and he said it would be acceptable.

I started looking at a Summers Heat stove that is sold by Lowes.  When viewing the owners manual online, it says to not have a horizontal run of more than 4 feet.

So what's the story with horizontal runs of vent pipe and how much is considered acceptable?  Does it vary according to the type of stove you purchase?  This would be the only reason I could think of that the guys answer varies from the owners manual (of a different brand of stove)

Thanks for the tips

Carl


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## SmokeyTheBear (Nov 9, 2010)

carlg said:
			
		

> I was looking at a pellet stove at a store that specializes in stoves.  One of the places that I would like to install my stove would require the vent to go up about 5-7 feet from the stove into an elbow and then do a horizontal run of about 10-12 feet to exit the house.  I mentioned this to the guy and he said it would be acceptable.
> 
> I started looking at a Summers Heat stove that is sold by Lowes.  When viewing the owners manual online, it says to not have a horizontal run of more than 4 feet.
> 
> ...



No Carl run do not walk away from anyone that says a long horizontal run of vent is acceptable.  There is an actual calculation that you can do to figure out if your vent run is within acceptable limits.

45 degree elbows get a value of 3, 90 degree elbows and tees get a value of 5, each vertical foot of vent gets a value of .5, and every horizontal foot of vent gets a value of 1.  You sum up the values and that is your effective vent length, then you consult a table which tells you the limits for 3 inch and 4 inch venting and any adjustments needed because of altitude.  You want as short a vent length as possible that will allow smoke to exit through the vent if the blowers stop running and still be within the limits and conform to code.

BTW horizontal venting must always have a slight rise to it and never any downward slope.


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## stoveguy2esw (Nov 9, 2010)

that long of a horizontal run will not work with that stove , causes too much of a loss in velocity in the stack results in poor performance


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## carlg (Nov 9, 2010)

Thanks for the tips.

I guess I need to plan to put the stove elsewhere.


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## carlg (Nov 9, 2010)

Where can I find the table that you mentioned?


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## Snowy Rivers (Nov 9, 2010)

FWIW

When I installed my Advantage, I run a 2 foot horizontal pipe to a 45 then a two footer through the wall to the 45 down turned screened cap

Basically 4 foot of Horizontal.

The stove works fine.

I have to remove the cap about once every two months of continuous use and vacuum the ash out that layers along the bottom half of the pipe.

Any longer than 5 foot total would be just pushing things way too far.

The more torturous the path the poorer the stove is going to work.


Snowy


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## SmokeyTheBear (Nov 9, 2010)

Hiya Mike.

Carl,

Mike Holton who handles technical support for the company that makes the stove you were talking about is the go to guy for that entire line of stoves and his advice should be heeded.


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## SmokeyTheBear (Nov 9, 2010)

Carl,

Most of the installation manuals have the tables, in addition as Mike pointed out there sometimes are other factors that must be taken into consideration.

Most pellet stoves operate by sucking air through the burn pot and pushing exhaust out the vent.  That means you also must stay within the ability of the combustion blower on the stove.


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## dac122 (Nov 9, 2010)

Snowy Rivers said:
			
		

> The more torturous the path the poorer the stove is going to work.



Agreed, but you can get away with it.  

For instance, on my basement install I go out, up, out and then up, but because I have a 3:1 ratio of rise to run it works well.  I have not used it enough to know what kind of ash build up I am having, but I anticipate substantial.


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