Sizing combustion air (OAK)?

[snaple4]

Emailed some mfg but no response yet. The run will be about 55+' in length and have up to 10 elbows. All the documentation I have seen calls for just a 4" pipe but they give no guidance on equivalent length adjustments. Was thinking about running 6" then reducing down to 4" after the last elbow to reduce the static pressure. I just hate to be wrong because I guessed on something and have to fix it later.

 

[bholler]

Emailed some mfg but no response yet. The run will be about 55+' in length and have up to 10 elbows. All the documentation I have seen calls for just a 4" pipe but they give no guidance on equivalent length adjustments. Was thinking about running 6" then reducing down to 4" after the last elbow to reduce the static pressure. I just hate to be wrong because I guessed on something and have to fix it later.

I seriously doubt the oak will work configured like that

 

[Ludlow]

FIFTY FIVE FEET? WHY?

 

[vwmike]

Do you live in a submarine, lol?

Maybe post a diagram.

How far do you have to carry firewood inside?

 

[jetsam]

Maybe it is a centrally located stove on the main level, and he is running the OAK through the basement.

 

[Ludlow]

Still. Just drop down into the joist bay and run out to rim joist. Cant be more than 18 feet at max, unless he has two I-beams and three joist spans.

 

[SuperJ]

Check out the equivalent length factors for elbows. For ductwork in a house an 90deg elbow is considered to be equivalent to about 30' of straight duct I think. Basically, I'm saying with 55' and 10 elbows you probably have an equivalent length of a couple hundred feet.

 

[jetsam]

10 isn't that crazy. If you come in on top of the foundation and run in the joist space, dogleg across one cross member, come straight up and 90 into the stove, that is already 9 90s, assuming you use 3 to make a warm air trap right outside.

 

[Ludlow]

10 isn't that crazy. If you come in on top of the foundation and run in the joist space, dogleg across one cross member, come straight up and 90 into the stove, that is already 9 90s, assuming you use 3 to make a warm air trap right outside.

I count six for that.

 

[jetsam]

I count six for that.

I brought in internationally famous artist Purly Skribbled to illustrate this post for me.

 

[Ludlow]

I brought in internationally famous artist Purly Skribbled to illustrate this post for me.

View attachment 233528

Oh...You put two traps: one in and one out. I see. Why not just a hood on the outside?

How much for the art? Im a collector.

 

[bholler]

Emailed some mfg but no response yet. The run will be about 55+' in length and have up to 10 elbows. All the documentation I have seen calls for just a 4" pipe but they give no guidance on equivalent length adjustments. Was thinking about running 6" then reducing down to 4" after the last elbow to reduce the static pressure. I just hate to be wrong because I guessed on something and have to fix it later.

Dispite all of the other noise i think you really need to re evaluate your oak strategy. I dont think your plan is going to be functional.

 

[jetsam]

Oh...You put two traps: one in and one out. I see. Why not just a hood on the outside?

How much for the art? Im a collector.

The outside trap is so that cold air doesn't flow in when the oak is not in use. The middle 'trap' is a detour around a beam, which is the only thing I could think of that would neccesitate that many elbows.

I can get you a signed copy for $5, or the original for $50.

 

[Ludlow]

Well, we have a critic on here that came up with a good name for the piece....."Noise"!

I need three copies, thank you.

 

[bholler]

Well, we have a critic on here that came up with a good name for the piece....."Noise"!

I need three copies, thank you.

Just trying to get the thread back on topic.

 

[Highbeam]

Omit the outside trap. 4” is fine, 6” is better!

 

[Ludlow]

Just trying to get the thread back on topic.

I hear ya. Im still waiting for him to explain the 55 feet thing.

 

[snaple4]

The 55' is mainly b/c almost all of the house walls (interior and exterior) are concrete. The only place to enter is in the middle of a wall where a window is being removed (to allow combustion air pipe among other things). Then have to follow along other walls to make way to center of house. I was denied the ability to run an exposed spiral pipe along the middle of the room.

Concrete walls are also the reason I need combustion air piped in. Almost no air leaks. Right now the air is being sucked through a/c condensate drain, dryer vent, all kinds of odd spots.

I like the drawling.... Little rich for my blood. I will take a picture of it with my phone though to print off later.

Sent from my SM-G892A using Tapatalk

 

[Ludlow]

How thick is the foundation? Would be best to drop into a joist bay and run to the foundation. Then bore a 4" hole. There are ways to do that.

 

[jetsam]

You can rent a Hilti core drill and bit at home Depot. Setting up takes ~30 minutes, drilling the hole is pretty quick. You need an unfrozen garden hose, and a little putty water dam on the inside.

I normally suggest that people get their own tools, but those Hilti core bits were $500-$1500 each last time I checked. That's not including the drill!

 

[bholler]

The 55' is mainly b/c almost all of the house walls (interior and exterior) are concrete. The only place to enter is in the middle of a wall where a window is being removed (to allow combustion air pipe among other things). Then have to follow along other walls to make way to center of house. I was denied the ability to run an exposed spiral pipe along the middle of the room.

Concrete walls are also the reason I need combustion air piped in. Almost no air leaks. Right now the air is being sucked through a/c condensate drain, dryer vent, all kinds of odd spots.

I like the drawling.... Little rich for my blood. I will take a picture of it with my phone though to print off later.

Sent from my SM-G892A using Tapatalk

Is it above grade where the stove is located?