Explain the gas input to a water heater?

[clarke_1]

So most of the water heater videos that I have looked at show a 3/4 inch gas line to the water heater. The gas comes into a "T" fitting from the side, the top goes to the heater and there's a little stub that's sealed on the bottom end pointing down. I think that this is how my own water heater is supplied with gas. What's the downward pointing stub for? Water condensation? And does it ever need to be looked at? Just curious...

 

[MicEd69]

That dead end line below the side outlet of the tee is called a sediment trap, or some call it a drip leg. It is there to catch scale and dirt from going into the gas valve and causing problems with the valve and the gas jets.

Some places have water vapor in their gas lines, although I've never experienced that. This trap will then catch any water droplets as well. Unless there are issues with the gas valve or the burner quits, there is no reason to "service" this sediment trap.

 

[clarke_1]

Ah! That would explain it - thank you. As for water vapor in the gas, that could be a hold over from the early part of the last century. Natural gas tanks in New York city were two hundred feet in diameter and between two and four hundred feet tall. They were sealed at the bottom with a pool of water. All gone now since they were not large enough??? They provided constant pressure to customers. See: Gas Tanks: Looming Landmarks of the Five Boroughs