Wet return rotten where it meets copper

mjgordon

Single radiator branch's 3/4" wet return from a small addition built in the 50s. I realize copper to black pipe is not ideal, but it's been running this way for at least 15 years probably 30+. I replaced a similar junction a few years ago at the rear of this picture. The new problem is in the foreground. As soon as heating season is over in a few weeks here in NJ I thought I'd heat up then nearby union and replace the rotten nipple.  Can you use a dielectric joint/union here like you would on a hot water heater?  Other recommendations?  Otherwise I guess I'll just replace the rotten Piece with black pipe nipple and wait until it rots in a decade. 

Ctoilman

Replace with another black nipple, or get fancy and use brass.

EBEBRATT-Ed

Just replace the nipple. We all have seen much worse

Larry Weingarten

Hi, Might a plastic lined nipple be a good fit here?

Yours, Larry

ethicalpaul

That's got to be like the number one failure point for any steam system so don't blame the nipple too much, it did its job. I'd say Schedule 80 steel or brass like said above. Looks like most of the corrosion there happened after it started leaking.

Lance

All things are temporary, usually if there is no leak, there is no corrosion.

dopey27177

Te nipple installed in the sweat T should have been brass. Brass tied into a cast iron nipple is less likely to corrode.

Jake

mattmia2

Is that tee copper or brass?

Looks like the threads weren't sealed and were leaking a little.

dopey27177

The T can be copper or brass. Use the existing T and save the extra work.

Jake

STEAM DOCTOR

ethicalpaul said:

That's got to be like the number one failure point for any steam system so don't blame the nipple too much, it did its job. I'd say Schedule 80 steel or brass like said above. Looks like most of the corrosion there happened after it started leaking.

Agreed that this is probably the number one failure point (at least in my findings). Any thoughts on why that nipple fails more often then other male threads on the wet return?