Manager

yoopermark

Replacing a steam boiler.  The old boiler has two dry returns.  One is connected to the main supply.  The other goes to the front of the building and then down into the floor.  It is not connected to a main supply or anything except the boiler as I have shown in the diagram.  What function does it serve?

Rod

Drawing

Not sure what it could be. Maybe one of the steam pros would have an idea. I have usually found that odd ball things like this are left overs from earlier configurations. I "tweeked" your drawing a bit so it is easier to see. I also circled the circular branch line at the left side of the drawing as it's a bit odd.

- Rod

yoopermark

Manager

Thanks for questioning the circle branch.  After removing some plaster and dry wall, it turned out to be another parallel main.  The main goes into a wall than splits off into two mains. The two main vents service the two dry returns.  I'm guessing the old pipe, that goes into the ground and isn't attached to anything, is left over from when they converted from a goal to a gas boiler and replaced the wet return with dry returns.  Glue was on page 85 of The Lost Art of Steam Heating.  Thanks.

Rod

Piping Configuration

Glad you were able to make sense of it. Piping buried in ceilings and/or walls sometimes really surprises you as it often doesn't go in the  direction it logically should.   Your thoughts that the pipe going ground is probably an abandoned leaky wet return, is likely to be right on the money.