Expansion tank leak

why oh why is my 3 month old expansion tank leaking at the seam around the middle? ( And there is also a pinhole leak spraying out) Do these tanks often fail? Or is there some problem in the water heater? Aaargh!
Thanks, Teresa

Defective. Whoever installed it should come back and replace it @ no charge to you.

If you bought the house recently then contact the previous owners/builder and have them address the problem.

My fiancee installed it. I have lived in the house for ten years. The tank itself is leaking not at the connection.

Potable Water or Hydronic System Tank?

One problem with expansion tanks is that sometimes people put a tank intended for a furnace at 30 psi on a potable hot water heater that can get to 100 psi in some homes.

There was a post on this forum a few months ago that was just that problem.

Check the model number and verify that it is a tank for potable water, and find the pressure rating.

Bring it back to where ever it was purchased and get another.