"Proctologically Violated©®" wrote in
message ...
Damn dude, ahm online but yer link still don't answer the Q!

Your supposed to click a link and investigate,
stay and read a while. ;o)

When have YOU seen a 3" tube from the bottom to the top?? I sure ain't
seen one....

Ahhhh,,, you've never investigated a GAS water heater then.

http://home.howstuffworks.com/water-heater1.htm

-zero