Rald wrote:
I want to put in a tee for a new drip line and flexible gas connector
when I replace my water heater. It is currently connected with piping
all the way to the water heater. The problem is that there is not a
union fitting where I would like one to be.

In order to make the modification, I have to try to unscrew a section
of 30 year old Black Iron Pipe attached to an old 'T' OR I have to cut
the line after the 'T', rent a threader, cut threads, and install a
union. (after shutting gas and purging with air of course)

What are my chances of gently unscrewing the pipe out of the old 'T'
fitting and then installing a new section of piping into that old 'T'.
I have experience with new galvanized piping, but I have not tried to
re-use 35 yr old fittings. If the pipe was originally fitted to the
'T' without over-torquing, is there still a good chance that it can be
re-used OR would it be wise to just plan on renting the threader and
leaving the old fitting alone?

Rald

I would think under any case you can unscrew the existing pipe. Like
the other poster said, it may take heat or some elbow grease, but unless
the pipe has been in contact with the ground nearby, and is rusty or
corroded, it should come loose and you should have no problems
re-attaching that piece or a new piece to the existing tee. Just use
gas grade teflon (yellow spool) and a bit a pipe dope when screwing it
back in.

--
Gary Brady
Austin, TX
www.powdercoatoven.4t.com