I have a Bradford White water heater (2 years old) and I noticed a problem.

The hot water coming out of the heater is connected to a copper pipe using a
copper/brass? union. There are two nipples coming out of the heater on top,
one connects to hot water out and one connects to cold water in. There is a
valve on the old water pipe.

The union that connects the hot water nipple and the copper pipe is
corroded. It has turned party green and it has also caused part of the
"top" cover area around the nipple to be a little rusted. I don't know how
much time I have before it breaks. The problem is, the union will be hard
to remove, the part you can apply an adjustable wrench to turn it is the
corroded part and will not take any stress.

I assume all I need to do is to shut off the cold water valve. Then try to
unscrew the hot water union (if possible), then take that union to a
plumbing hardware store and get a replacement? or is there more to it? Do
I need to shut it off?

MC