Plugged Return Line Newbie

[BigDave]

Maybe it leaks and the previous owner just retired it in place?

[saabmarine]

It doesn't leak, I pressure tested it. And it's plumbed separate. All other return lines go through one pipe, into the ground, and split in a manifold somewhere underground. This one return has it's own pipe. Is there any reason you'd want one return to bypass the automatic chlorine feeder? I have a T just before the feeder which is capped off as well and looks like it might line up with this capped pipe.

[CarlD]

It's a mystery. The line is good, just capped?