Vent B

[nate379]

I am trying to find B vent pipe that is a combo pipe with intake and exhaust in the same pipe. It's a pipe within a pipe.

I know for sure it exists, but I can't remember what it's called. Not finding anything google... any help on here?

HVAC Contractor came out today to look at my boiler and said he would like to go that route instead of putting 2 holes in the roof, but hasn't seen that kind of pipe in a while. He is checking, but I figured I'd check as well.

 

[panel pete]

What you're describing is known as a concentric pipe. These are primarily used exactly as you described - one roof penetration that allows for both air intake and exhaust ventilation.

Hope this helps,
Pete

 

[larry4406]

Good luck.

The B vent that I am aware of is metal, dual wall pipe (internal air gap) with snap end connections - it is single flow exhaust. Typically used with less effecient equipment due to higher exhaust gas temperatures. The internal air gap and construction ofh te B- vent allows it to be close to wood products (typically 1" gap min).

The concentric pipe that I have used is a termination kit only for PVC flues associated wtih 90+ equipment. With this style, PVC air intake and comustion gas are piped separately, and then terminated thru the wall/roof via a single penetration via the concentric kit.

What type of flue does your boiler manufacturer recommend?

 

[nate379]

Burnham lists it as being an approved ducting method.

I wanted to move the exhaust up to the roof and leave the intake at the wall, but I guess you can't have intake and exhaust in different pressure zones per the contractor.

 

[redsky49]

"Burnham lists it as being an approved ducting method.

I wanted to move the exhaust up to the roof and leave the intake at the wall, but I guess you can't have intake and exhaust in different pressure zones per the contractor. "

What???

Everything you need to know about flues and vents:

http://www.selkirkcorp.com/products/venting.aspx

Now, with that being said, what does the installation manual for your particular appliance call for? That is the final authority in any installation. If you have a specific question, e-mail the support staff at the vendor. They are more than eager to assist (it's a liability thing), rather than have someone create a science project.

And have the Contractor define "pressure zones"

 

[nate379]

Wind running across the top of teh roof and nothing on the back wall = different pressure zone.

We get 60-70mph winds in the winter, so it is a concern.

Book says both through wall or both through roof.

 

[redsky49]

That's sort of correct. If you have strong prevailing winds of that strength, I would again consult the manufacturer. They would probably recommend against locating the inlet/outlet on opposite sides if the house. Be sure to maintain minimum height above roof for flue outlet

Also depends on the particular unit, whether gravity vent or fan-forced, etc.

But more importantly, why in the world do you, or anyone, live up there?
Brrr...

 

[nate379]

It's the best state in the US, why would anyone NOT live here is my question.