more questions about gas

Why is it that on that on a gas water heater with the exasust on the top, the pipe that takes it outside (or to the chiminey) seems to sit about an inch above the water heater (leaving a gap). It seems that anysort of breeze (esp. if it is a constant breeze like a fan or something) would make all the carbon monoxide go into the house instead of where it should be. It seems that the only time this would work would be when the air is perfectly still.


Formerly known as Nec3f on the AOL SDMB

{{{Why is it that on that on a gas water heater with the exasust on the top, the pipe that takes it outside (or to the chiminey) seems to sit about an inch above the water heater (leaving a gap). }}}—Joey P

That’s the access gap. It allows the gnome chimney sweeps to crawl up the pipe from a more readily accessable location–instead of using their tiny ladders to reach the roof.


Kalél
(The Original EnigmaOne)
Common ¢ for all ages.

I saw this question answered on a Home improvement show, and believe it or not it is that way for a reason. I wish I could recall the show, and the specific explanation, but it was along these lines. The gap is there to increase the suction, and prevent the vapor from backing up in the pipe and therefore in the house. Natural convection (and possibly other dynamics) pull the air up out the pipe, and the gap makes certain that the back pressure is low enough to not prevent the flow. If you really want to learn more about it, if you dig up a Fireplace instructional manual it will tell you there, they do the same think on the flue.

I found that if you go in your basement to where the chiminey comes down and you open up the door (you know that little access door for cleaning and whatnot) if you hold a flame (or a cigarette) in front of it, it pulls the flame (or the smoke) in wards and out the chimney but on somedays (usaully when it is very humid out) and blows which seems like it would do the same to the water heater exaust and blow the carbon monoxide into the house.


Formerly known as Nec3f on the AOL SDMB