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Reroute Two Pipe Return

Hello everyone,

I recently had a new supporting beam put in our home.  Originally, one of the returns for our two pipe, crossover steam heating system went through the old wooden beam.  I don't plan on cutting a hole in the new beam so I need to reroute it.

I'm not entire sure of the best way to approach it.  The two options I was considering were just dropping the return below the beam and hooking into the system a little bit lower.  What is the minimum height above the waterline for a system like ours?

The other thought I had was similar to the above but maybe I had to run a vent pipe to the air vent in addition to the water return if imthe water return is too low.  Kind of similar to sewer system in plumbing.  I'm not sure if this is valid or not.

The images below show where the original return was cut and some of the boiler system.  The system works well, just need to clean this up after the replacement of the supporting beam.

Any help is much appreciated.


Comments

  • Jamie Hall
    Jamie Hall Member Posts: 20,417
    That is -- or was -- a dry return. For the system to operate properly, both air and water must be able to flow freely through it -- the air to a main vent, and the water back to the boiler.

    You could drop it below the new beam, but it must remain at least 28 inches above the boiler water line for each pound of pressure you run in the boiler. From the photos, it's going to be close -- if you can do it at all. You can drop it all the way down to the floor, or very nearly so, and tie it into the wet return to the boiler before the Hartford Loop, but if you do that you will need to put a main vent -- not a piddly little one, but a good big one -- on the return about a foot or so before it drops. You can also make an arrangement with one line dropping down below the beam, and then back up to the existing pipt, and another pipe going up and over the beam, and then back down to the existing pipe.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    nlongworth2
  • nlongworth2
    nlongworth2 Member Posts: 10
    Thank you Jamie,

    Can you expand on how the system works if a pipe goes above and below the beam?  My assumption is it just allows both the air (up) and water (down) to flow freely similar to a single pipe with correct pitch?  Would it matter if it is a Y or T at the split?
  • Jamie Hall
    Jamie Hall Member Posts: 20,417
    Your assumption is correct. It doesn't matter whether you use Ys or Ts -- but Ts are a lot simpler.

    Ideall the pipe on the far side of the beam -- downstream side -- would be an inch or so lower than that on the upstream side, but you can't do that. I don't think that will give major problems, but it might be noisy...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • nlongworth2
    nlongworth2 Member Posts: 10
    Thanks Jamie,

    One last question, would there need to be a clean out valve of some sort on the water pipe?
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 13,097
    @nlongworth2

    What @Jamie Hall said. You have 3 choices

    1. keep it a dry return if you can maintain 28" above the water line and keep a little pitch toward the boiler
    2. Make it a wet return (run it on the floor) and install a vent before the drop as Jamie said
    3. Go over & under the beam. Keep the return line between the boiler and the beam an inch or so lower than the original return,

    There is a drawing of the over/under piping In the LAOSH & probably on this site somewhere
  • Jamie Hall
    Jamie Hall Member Posts: 20,417

    Thanks Jamie,

    One last question, would there need to be a clean out valve of some sort on the water pipe?

    I doubt it. There is almost no crud in a dry return.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England