furnace venting

[setterguy]

Couple questions...I have a 3 year old carrier high efficieny furnace. I am in the process of finishing my basement and before the ceiling goes up I want to make sure I don't ever need to get at these pipes.

I have two pipes coming from the furnace (intake/vent) they then combine into one pipe before they go out of the house in the back. In the winter I get an ice build up below the furnace vent/intake. I've noticed that the pipes don't slope back to the furnace all the way, there is a dip in them due to other obstructions...is the the cause of the water?

I would like to re-route the pipes out the side of the house due to the location of a future deck, can I convert the one pipe system in to a two pipe system?

Thanks.

[fastkaw]

ILL try to make this short. Yes you can covert to a two pipe system.

Pitch on the pipe. 1/4" per.ft. same as plumbing. Support every 4ft.

You need to look up the specks on your furnace, to find out how far you can run

the vent and what size it has to be. Most vent in two or three inch pipe and

60ft. is the max length. Each elbow (90) (long sweep) accounts for 10ft.

Keep that in mind. (2") If you go over 60ft. including elbows then you must go

to 3" pipe. This all depends on the BTU's of your furnace. As said check the specks.

Do not terminate under a deck. Most codes say the exhaust may NOT be within

four feet of a window/door.(good luck with that one)

If posable run the exhaust out one side of the house and the intake on the other.

That eliminates any chance of drawing exhaust back through the intake and

frosting over the pipe. Make sure both pipes terminate above the high snow line.

Last but not least do not glue you intake pipe at the furnace. You may haff to take

it apart to clean it. I will say this one more time, find the venting specks for you

furnace.

Hope this helps.

DISCLAIMER: i am in no way an expert, at anyting. anything i say is my own opinion and/or observation, and should never be regarded as fact, unless otherwise stated.

[MNice]

Everything you need will be in your manual. DO NOT run the pipes out different sides of the house, 99% of direct vent furnaces REQUIRE they be within 1' of each other, this is to keep the pipes in the same pressure zone, because the pressure switches in these unit are very sensitive and if the exhaust & intake are different lengths or even have different winds on them, the furnace will shut down. again everything you need is in your installation manual and DO NOT vary from what it says. The current code (IFGC) will allow direct vent appliance to be within 1' of doors, windows and non-mechanical air intakes. FYI, I am an plumbing/mechanical inspector for a TC suburb and if you need any code sections to help you out let me know.

[Lindy Lee]

Make sure that you are 10' from any mechanical air intake or combustion air intake like from your air exchanger if you have one.

[fishandshroom]

mnice I agree and Just read the manual sometimes clearances are different especially commercial vs residental. Just read the book.