Mystery steam line locating. Need tips and tools.

WillekesEaves

So, about 40 or so feet from my Utica Peg-E 220kBTU boiler, there is this mystery steam line (1 inch or 1.25 inch) that disappears into the rear foundation wall. It seems original to the century home as the escutcheons or whatever that hang it match the 3 inch mains'.

Back at the boiler, it connects to the system seemingly below the water line. There is a main pipe air vent on it behind the boiler, one of 3 main vents about 6.5 feet up. This line is higher up in elevation than any other line in the basement.

I have no idea where it goes and it never gets hot. When the boiler runs for a while on a cold day, it will get warmish to the touch at the back foundation wall, dozens of feet from the boiler. What is this mystery line and what tools or things can I use to trace it? I tried to find it using an infrared camera to no avail. It goes into a finished hardwood area of the home, so smashing walls is not a great option. Can I just cap it and see if nothing changes? Should I even bother? I have an old meets new scenario here that I am still navigating and understanding/optimizing/balancing. Any thoughts?

Jamie Hall

It's a dry return. It shouldn't get steam hot, but it will get warm from returning condensate. The question is… what is it draining condensate from? Somewhere out there there is a radiator or two, or maybe a steam main with a crossover trap, which connects to it…

bburd

If it connects to the boiler below the water line and barely gets hot, it is a condensate return (two pipe system) or steam main extension (one pipe system). There is a good chance that the main vent at the end has failed closed.
What is your concern? Does the system heat evenly and quietly?

EBEBRATT-Ed

Through the foundation wall? Do you have a garage that has or used to have steam heat?. Is the entire house over the basement? Or is part of the house extend beyond the foundation?