Water Heaters - Water heater leakage

Hi
my new water heater leakage is from the pipe extending down. It is open at the end below, water is hot always and it is off and on. The last water heater busted from the same pipe but where it attaches to the top of the heater and comes down. Is it normal, going through the thread it seems it is not normal, is it some loose connection or else.
Thanks

What type of material is it? Copper? CPVC(yellow plastic)? Grey plastic? Blue/red/white plastic (PEX)? Brass?

It is brown in color, copper or brass. There is some valve type thing, but moves freely. It is warm, definately not plastic. It is gas water heater. I did google search image and it looks like it is called overflow pipe. On the top it is attached to relief valve.
http://www.bobvila.com/images/ArticleImages/FIG_ElectricWater_01_large.gif

Mine is gas heater.

Thanks

That part leaks when either the temperature or the pressure get too high - usually it's the pressure. If that's the case the usual cause is som kind of anti-backflow device that stops water from flowing back into the mains.

Once you're isolated from the water mains and the water heater raises the temperature the pressure expands as the water warms. Once the water exceeds 150psi is squirts out. The typical solution is to add an expansion tank designed for potable water.

You call it a new water heater..how new? You could try flicking the little relief valve open and close a few times to see if that stops it...could be kind of stuck open.

I would guess it is pressure related as Who suggested.

I would also wonder if your old heater was doing the same thing...why they just replaced it and didn't investigate this already.

If your heater is brand new..I would call back the company that installed it and tell them it is doing the same thing as the old heater....and ask them to fix the problem. tell them your not paying anymore or you want a credit on the new heater installation since it didn't fix the issue.

Thats just my opinion.