Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Steam main

vinceM Member Posts: 81
I'm new to posting in the forum but have been reading for a year.
I have a few questions on different steam topics but I'll walk before I run...
I have a 40 year old, oil fired boiler. 1 pipe system.The house is 85 years old. Don't know how old the pipes are. So, I believe ALL the steam pipes in the house except for the copper returns are supposed to be pitched towards the boiler. In the basement some are some aren't. Infact, the mains(2), coming off the riser/header are sloped AWAY from the boiler. Is this a problem??



  • KC_Jones
    KC_Jones Member Posts: 5,705
    If it's a parallel flow system they should be sloped away from the boiler. If at the end of your mains they reduce down and return back to the boiler you have a parallel flow system and that slop is what is to be expected. Basically the highest pipe should be right at the boiler and everything else is lower. Continuous slope from boiler around basement and back to boiler. Returns should be sloped if they are dry returns. Dry returns are above the water line of the boiler. Once they become wet returns the slope doesn't matter.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • Steamowner
    Steamowner Member Posts: 19
    Yes, otherwise the condensate will sit in the pipe and not make it back to the boiler and cause water hammer. That was my issue. Not sure about the copper pipes but I will let others comment on that.

    Disclaimer: I'm not a plumber
  • Fred
    Fred Member Posts: 8,542
    Copper pipes below the water line (wet returns) are fine. Everything above the water line should be black pipe. As has been said slope sounds fine for a parallel (Steam and condensate flow in the same direction, in the mains)flow system.
  • vinceM
    vinceM Member Posts: 81
    edited November 2015
    Thank you for the quick responses. I apologize in advance for the lengthy follow up question.
    There are two black pipe main lines, outside diameter is 2 1/2", that leave the boiler and travel about 30 feet each. One of the mains travels away from the boiler and gives off smaller branches to the radiators above, then ends at a connection with a 6-7ft vertical, 2 " copper pipe. That copper pipe then runs along the floor of the basement and goes back to the boiler.
    The other main also travels about 30ft and ends at a vertical copper pipe (The return). However, about 6ft after it comes off the header there is a T that connects to a smaller diameter black pipe, travels about 10ft then connects to a vertical copper pipe and also runs along the floor back to the boiler. That said, I believe they are wet returns.
    From what KC_Jones stated these are wet returns since they run along the floor below the boiler water line.
    As for the Parallel Flow system, the copper returns are smaller diameter then the black pipes but I'm not sure if this is what KC means by "reduced down".
    But here is the question, since it's a 1 pipe system and if both the steam and condensate travel in the same pipe to and from the boiler, what are the copper pipes for?
    Also, I forgot to mention that there is a water zone to a baseboard that was added to the system when the house had an extension added on the first floor.