return lines

fran_5

I've been told that I have to replace several return line pipes in my heating system because they're very old and have begun to corrode and leak. I have several questions: What are return line pipes made of--iron, steel, copper? Do return line pipes typically corrode from the inside or the outside? Is it better to have return line pipes exposed or covered in cement. Also, is it advisable to paint them with some sort of tar to protect them or would that eventually cause environmental problems because the tar would melt due to the heat of the pipes? I am more or less a novice at this and would appreciate any advice you can offer. I have a mixed used building with 20 units and a one-pipe steam heat system, using #2 fuel oil. THANKS!!!

Alan(OnVacationInOregon)Forbes

Returns

Return lines are typically black steel. insulated with at least 1" of fiberglass......no tar. Unless the pipes are in a moist environment, minimal corrosion happens from the inside, out. And it's preferable, but not always possible to keep the returns out of concrete.