# B-vent wye



## dielectricunion (Feb 27, 2013)

I went to the 2 plumbing/HVAC supply houses here looking for a 5" b vent wye and they both said they couldn't even order one.

I know nobody's installing new 80% furnaces anymore, but I didn't think It would be a hard piece to find.

Is there another code compliant way to tie a natural draught gas water heater and 80% furnace into a common vent? 

This is replacing a masonry chimney that a removed in my own house. I wouldn't normally be doing this kind of work at a clients place.

A tee just doesn't seem right. I've seen spec diagrams showing dual appliances coupled with a tee and flex vent, but wouldn't a wye be preferable?


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## superseal (Feb 4, 2009)

They're readily available, you need new suppliers :laughing:

http://www.ventingpipe.com/duravent...!32091895622&gclid=CO6ct5Sn5MACFahj7AodH2cAVQ


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## dielectricunion (Feb 27, 2013)

I just ordered this one from grainger:

http://m.grainger.com/mobile/product/AMERI-VENT-Reduction-Wye-4E865

I don't love the ameri-vent line, seems kind of flimsy, but the supply house sell another make that I couldn't find a wye for so I'm using this brand that's stocked at Menards.


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## Tom M (Jan 3, 2007)

Why not 2 seperate tees? The smaller output appliance would enter at the higher point.


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## dielectricunion (Feb 27, 2013)

I'm planning to locate the wye directly above the 4" on the furnace and tie the 3" water heater off the side branch. 

I'm definitely open to other solutions but that seemed to be the most simple and allow optimal draught/flow.


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## flashheatingand (May 3, 2008)

Around here, we use single wall wyes. Wye is 6" from the ceiling. Hard pipe is b-vent, and should be a straight run. They make clamps / strap that make it easy to strap to the ceiling trusses...etc. Remember, 1" clearance from combustibles with b-vent. 6" clearance with single wall. 

With the flashing, it's high pitch or standard pitch. Good luck


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## dielectricunion (Feb 27, 2013)

I'll probably end up branching to the two appliances with single wall even though it's in my basement (unconditioned). 

If I ever sell the place, I'll bring it up to code and use all double wall.


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## Tom M (Jan 3, 2007)

dielectricunion said:


> I'll probably end up branching to the two appliances with single wall even though it's in my basement (unconditioned).
> 
> If I ever sell the place, I'll bring it up to code and use all double wall.


Unconditioned in an attic would be a proble , not a basement.


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## flashheatingand (May 3, 2008)

Just go with a straight b-vent From roof to Basement. 6" clearance from walls can be an issue. Flashing is sized for B-vent also. I suggest a couple of b-vent elbows, straight pipe, and a 1' adjustable fitting as well.

Should have easy access with a single wall wye.


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## dielectricunion (Feb 27, 2013)

flashheatingand said:


> Just go with a straight b-vent From roof to Basement. 6" clearance from walls can be an issue. Flashing is sized for B-vent also. I suggest a couple of b-vent elbows, straight pipe, and a 1' adjustable fitting as well. Should have easy access with a single wall wye.


I wasn't planning on using any single wall near the floor or walls, just that small area where the wye branches down to the heater and furnace.

I know single wall needs 6" clear and b vent 1"; shouldn't be a problem to keep those clearances from combustibles


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## beenthere (Mar 5, 2009)

Don't put the wye directly above either appliance. Condensate if it occurs will drip right into the appliance.


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## dielectricunion (Feb 27, 2013)

beenthere said:


> Don't put the wye directly above either appliance. Condensate if it occurs will drip right into the appliance.


If condensation occurs and there's a short length of pipe pitched toward the appliance, wouldn't the same thing happen?

Or do you suggest I use a tee with bottom capped at the end of my vertical run, send a horizontal to the appliances and another tee to split it?


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## beenthere (Mar 5, 2009)

Yes, a clean out at the bottom of the vertical. And then slope toward the appliances, and either wye or T to them.


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## dielectricunion (Feb 27, 2013)

beenthere said:


> Yes, a clean out at the bottom of the vertical. And then slope toward the appliances, and either wye or T to them.


Man, I wish I knew what the hell I was doing before I bought all my parts!

I've got to try to utilize this wye. Since it goes from 5" and branches to 4 and 3", I don't want to just cap it. I guess I want to add a 5" tee for clean out and have my wye on horizontal run to appliances


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## beenthere (Mar 5, 2009)

Yeah, use the wye on the horizontal run.


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## jlsconstruction (Apr 26, 2011)

I could be wrong, but with a 4" and 3" don't you need a 6"


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## beenthere (Mar 5, 2009)

Depending on riser and vertical height, 5" B vent can be limited to a min of 46,000 BTUs of appliances, or a max of 272,000 BTUs of appliances.


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## dielectricunion (Feb 27, 2013)

I used a table from hart and Cooley and arrived at a max BTU of 146,000.

I could have made some mistakes reading the tables and estimating design details of my setup, but I think it should be large enough.

Connected appliances will be a 75,000 BTU furnace (4" vent) and 40,000 BTU water heater (3" vent) so total of 115,000 BTU.


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## flashheatingand (May 3, 2008)

beenthere said:


> Yes, a clean out at the bottom of the vertical. And then slope toward the appliances, and either wye or T to them.


Generally, we don't do that, just wye to the appliances, but that makes good sense. Going to start doing that.


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## beenthere (Mar 5, 2009)

dielectricunion said:


> I used a table from hart and Cooley and arrived at a max BTU of 146,000.
> 
> I could have made some mistakes reading the tables and estimating design details of my setup, but I think it should be large enough.
> 
> Connected appliances will be a 75,000 BTU furnace (4" vent) and 40,000 BTU water heater (3" vent) so total of 115,000 BTU.


The vertical would have to be 100 foot high to be able to handle 272,000 BTUs. 

A 10 foot high B vent can handle something like 146,000 BTUs. So as long as your is 10 foot or higher, you'll be fine.


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