High Eff Furnace and DV Venting Questions


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Old 12-20-06, 06:32 AM
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High Eff Furnace and DV Venting Questions

Well I actually have multiple questions. Last year I replaced my original late 50s furnace with a 94% eff unit. I ran the intake and exhaust pvc pipes out the side of my basement to an under deck area. Its a small rather confined space with a retaining wall on one side. Two sides of the deck are open but there is also a basement window directly next to where I had to run the pipes out so I continued the pipe under the deck to 8 away from the basement wall. Not very attractive, and Im not sure about the code implications, but it was a temporary solution until I remodeled the kitchen.

Well Im at this point now. The old furnace and dv gas water heater used to be combined into one 6 vent with a huge heat shield. Id like to size that down to a 3 b-vent for the water heater and relocate it into a 6 stud wall(which I think is possible) and run my furnace intake/exhaust in the same wall and vent both out the roof.

1. Can I go with single wall vent on the water heater in the basement until I get to the floor penetration and then go with b-vent up through the floor.
2. Im going to one floor then to the attic, do I need that sheet metal fire separation on the floor and ceiling of the first floor? Any other construction advice would be appreciated.
3. On the furnace pvc venting, is there any type of clearances required in the wall? This would work better if I can run it in an adjacent 2x4 wall.
4. On the roof penetrations, what are the requirements of the spacing with regard to each other on the dv 3, pvc intake and pvc exhaust?

Id really appreciate any advice you guys have. I had found a picture representation of the pvc venting, but I can no longer find it.
 
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Old 12-20-06, 03:33 PM
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do you have an are to sidewall vent everything out of the house. if so i would purchase a powershot water heater and use PVC for everything and vent them all out one side of the house. then you dont have to worry about going up through the house with a flue.
 
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Old 12-20-06, 05:32 PM
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Not really. The basement is walk out on one side and underground on the other. Where the laundry/utility is located is right where the transition happens. On the other side is a bathroom that I would like to get the ceiling as high as possible. Venting everything up is about my only option.

One question on the powershots....where is the best place to purchase them I may do that so I can get everything a little tighter and not have to worry about clearances.

Thanks.

Originally Posted by nomore9to5 View Post
do you have an are to sidewall vent everything out of the house. if so i would purchase a powershot water heater and use PVC for everything and vent them all out one side of the house. then you dont have to worry about going up through the house with a flue.
 
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Old 12-20-06, 08:24 PM
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any plumbing supplier nearby should carry them or know of how to get one. youll need to do research to be sure that you can vertically vent them as high as your talking about. you dont wanna purchase all of it and realize the vent motor cant overcome the height and length you need to run.
 
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Old 12-20-06, 08:41 PM
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#1 YES

Im going to one floor then to the attic, do I need that sheet metal fire separation on the floor and ceiling of the first floor? Any other construction advice would be appreciated.
I dont think that a 6" stud will do it. The stud is 5 1/2"
The 3 " B gas vent pipe is about4+". You need a cut out from the wood on the floor and ceiling of 1" from the vent pipe . That makes you have to have a 6" hole for the vent pipe to go through the wood floor. yes you need a sheet metal fire stop here and at the ceiling line thats cut out just so the vent pipe goes through it tight. This also keeps the vent pipe that 1" away from the wood
 
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Old 12-20-06, 08:54 PM
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Ok... I talked with an inspector for STL county today and got some answers.
1. 3" is fine and I can switch mid-stream as long as I switch prior to going through the floor/ceiling assembly, but I need to remain with b vent all the way out.
2. On the firestop, it's not required, but it will make it easier to determine spacing, support the weight, and stop drafts.
3. No clearance is required w/ the PVC.
4. And it looks like if I terminate the intake elsewhere I'm good on the exhaust vent clearances as well.

BTW. I think I've found another wall that makes some of my problems go away!

Thanks for the input... guess I'll have some nice expense code books coming in the mail!!!
 
 

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