Pipe Length Question

[millerag]

Looking for some opinions.....

Right now I am in the middle of an install (Harmon P38). I have 6” then a 90 and then 13’ of strait pipe through the roof. Will 3” work or should i just go with 4”?

 

[hearthtools]

Looking for some opinions.....

Right now I am in the middle of an install (Harmon P38). I have 6” then a 90 and then 13’ of strait pipe through the roof. Will 3” work or should i just go with 4”?

Your Manual will have a hight chart
but if you are under 15' I think 3" will be ok with just one turn at the back of the stove
A T clean out will be better than a 90 so you have an ash trap.

 

[hearthtools]

This is assuming you are at a Normal UNDER 3k foot elevation
if you are higher than use 4"

 

[millerag]

Thanks for the help....

I checked the manual and it said that if greater than 15' need to go to 4". I have read on a few posts on the site that a 90 or a t clean out you should add an additional 5'. If this is true i am now looking at 18'.

 

[hearthtools]

Thanks for the help....

I checked the manual and it said that if greater than 15' need to go to 4". I have read on a few posts on the site that a 90 or a t clean out you should add an additional 5'. If this is true i am now looking at 18'.

In most cases the FIRST 90 at the back of the stove dont count
BUT I WILL SAY AGAIN USE A T CLEAN OUT
it gives you more room for ash build up. otherwise you will have to take the Stove off your pipe or remove the 90 every ton of pellets to clean out the fly ash from the 90

 

[millerag]

I will def switch to a T Clean out. Your comments make me feel much better about using 3".

Thanks

 

[millerag]

One more question....

I am utmately going through the roof so I need a Roof pass through collar and then a storm collar. Is there any thing elese that i would need?

 

[humpin iron]

4 inch to allow for build up, other wise you'll b cleaning the pipe 3 times a year. 3 inch is the same as the stv-no room for error

 

[DiggerJim]

Looking for some opinions.....

Right now I am in the middle of an install (Harmon P38). I have 6” then a 90 and then 13’ of strait pipe through the roof. Will 3” work or should i just go with 4”?

You need to go to 4" at 15 feet "Equivalent Vent Length" (although there's no harm in using it for even short runs). For you, your EVL is equal to
1/2 ' (6" straight)
5 ' (90 elbow = 5')
6.5 ' (13' vertical is divided by 2)

Total EVL is only 12 feet. I'd go with a cleanout Tee instead of the 90 in the back of the stove. (BTW, a 45 el = 3' of EVL.) Since vertical pipe naturally draft which helps exhaust the gases, it only counts half as much as a horizontal run. EVL is a measure of performance relative to horizontal piping.