I just had a new furnace installed, it is a direct vent so all I have is my 40k btu 50 gal gas hot water heater to vent. I was wondering if I could use 4" B-vent out of my heater and up threw my roof. It would be about 12' total.
Venting a gas hot water heater
Jan 16, 2007
38 Replies
I just had a new furnace installed, it is a direct vent so all I have is my 40k btu 50 gal gas hot water heater to vent. I was wondering if I could use 4" B-vent out of my heater and up threw my roof. It would be about 12' total. Or do I have to go bigger than 4" .
Why do you want to heat hot water?
Heard ya the first time.... and the answer is no
4" is perfectly fine for your application. make sure you use a 4" b-vent roof jack and storm collar and b-vent top. i believe the code specifies 2' above anything within 10' of the vent termination.
C'mon fish. Where'd you come up with that "4" is perfectly fine" mumbo-jumbo? Fact is you are just guessing. You need to consult the gamma tables to get it right.
4 inch may be too big and allow unneeded condensation and improper draw on the vent. You'll notice that using the Gamma tables located here:
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"4 inch" guess is able to handle anywhere from 70,000 to 112,000 btu depending on theactual lateral and vertical length of pipe which the OP didnt give. The 3 inch will handle 36,000 to 58,000 btu again depending on the actual vertical and lateral lengths. Stop using those "Thumbs" and get the facts. Bubba :-)
the facts are Bubba, his install sounds exactly like how mine is installed only my vertical is closer to 5'. off the wawa heater is a
3", to which I installed a couple single wall 3" -45's into a 3x4 plug reducer then 4" b-vent. but yeah, :-)
Its not rocket science.
There is absolutely no problem venting it that way. As long as the Bvent is interior and not exterior and it does not exceed 6" diameter and your single appliance exceeds 30,000 btu's there is no problem. You must ensure there is no spillage or downdraft.
-Canadian Heat
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huh?? the b-vent usually starts near the appliance on the interior, then penetrates the roof to the exterior!
what dou YOU run on the exterior, single wall?
Exterior is hillbilly-style.
By interior I mean bvent that is heated by the house, usually runs down the middle. Exterior is run on the outside of the house, cold.
And I call single wall venting, CVENT.
If you have a chimney liner, I would say you need to size it properly, but bvent is fine.
-Canadian Heat
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Kinda running for "tard" of the year award?
6" on a 40,000 btu water heater? Wow! The mind wobbles........... BubbaBubba posted for all of us...
It's not rocket science but it is radiation!
Ahhhh bubba, your an idiot in every post you make. I don't understand why you waste your time here. You are an incompetent.
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Click the "Sizing Of Interior B-Vents And Metal Lined Chimneys" link and read the PDF. It clearly backs up what I am saying.
TSSA is the authority where I live. I guess bubba is the authority in bum f*ck nowhere!
-Canadian Heat
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Just for s**ts and giggles bubba, how you you vent his water heater? The draft hood is 4", his bvent is 4". Don't be so damn jealous of 4".
LOL
-Canadian Heat
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Bubba wrote
UUmmmm....Bubba...there a thousands of 50 gallon wh's vented with 4".... Unless it's a 40 gallon low input heater, all 40's and 50's that I've seen in the last 20 years are 4" venting....conventional type of course..
Around here, even the low input 40g tanks come with a 4" draft hood. bubba's an idiot...period.
I even gave him literature to read, which clearly explains the original question. bubba still hasnt told us how he would vent it.
poor bubba!
hated by the home owners, hated by the techs...why do you even post here?
LOL
-Canadian Heat
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Ok AO Smith shows 3 or 4 inch
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and Bradford White seems to use the 3 or 4 inch
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and State uses the 3 or 4 inch method
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Or Ruud/Rheem which show 3 inch until you get to a 50,000 btu model
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American also shows only 3 inch
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So although this really doesnt prove a whole hill of beans I have still yet to find a water heater in a 50 gal gas at 40,000 btu or less that specifically says it only uses a 4 inch flue. Rheem/Ruud and American specifically say 3 inch only. What I cant understand is why you would want to use 4 inch? 4 inch pipe and elbows cost more and its costs even more if you start using 4 inch B-vent and 4 inch flue liners compared to 3 inch. AGAIN, you still specifically need to consult the flue venting tables and 99% of the time the 3 inch flue will work perfectly. I have a 2 yr old Ruud 50 gal 40,000 btu standard gas water heater and it uses 3 inch as specified in the manual and per the draft hood that came with it. Im really not sure what water heaters you have been seeing in the last
20 yrs and DaNgEr................you're still a f***in clueless Canadian idiot. Bubba
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