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When to replace water return line

punkzter Member Posts: 32
edited January 2022 in Strictly Steam
I'm writing on behalf of my duplex neighbor. We both have steam heat systems. Both of our boilers were replaced about 10 years ago. Our Neighbor hasn't really kept up with servicing hers. I guess the water sensor failed, and about two weeks ago her boiler cracked after running out of water.

I have read "We got Steam Heat" and know a bit about my system, so I've tried to give her some advice. The most promising company even referenced Dan Holohan when he was over.

He gave her three quotes: one for a new boiler, one for a new boiler with a new water return line, and one for a new boiler and all new pipes.

The last option (all new pipes) seems a little excessive. But I wondered about the new water return line. Our house (the duplex) is over a hundred years old. And the pipes are probably that old as well. But they don't seem to leak. So I just don't understand what would "trigger" needed to replace the return line, or all of the pipes.

Any thoughts or suggestions?


  • pecmsg
    pecmsg Member Posts: 4,843
    edited January 2022
    Pricing is not allowed

    If the returns are buried or in an area that you can't see it then Maybe at best replace it. I can't understand Why you would mess with the supplies unless there's issues with sagging or sizing?
  • punkzter
    punkzter Member Posts: 32
    Sorry, I removed the pricing information.

    The only thing I could figure was that perhaps rust or internal deterioration in the return pipe could damage the new boiler? But I didn't see why a flushing of the system wouldn't mostly solve this issue.
  • KC_Jones
    KC_Jones Member Posts: 5,737
    Replacement of the return piping is a judgement call. If the lines are in good shape then re use them. I can tell you my wet return lines were 32 years old when I replaced the boiler and attached is what one of them looked like when I disassembled everything. Note the missing threads, that wasn't leaking, until I touched it, then everything crumbled.

    I'd also advocate for copper wet return piping. They don't sludge up and should last a lot longer. I know at least one of the pros on here does it regularly.

    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • punkzter
    punkzter Member Posts: 32
    How can you tell if the lines are in good shape or not? All this person did was look at the pipes, they wouldn't have opened anything up.
  • Jamie Hall
    Jamie Hall Member Posts: 23,276
    So9rry about her boiler -- but may I suggest that you check the low water cutoff on yours, or have it checked when they are replacing hers -- to make sure that it really is working? Cheaper than a new boiler...

    On the return line. As @pecmsg said. Maybe. Return lines do sometimes develop leaks (unlike supplies -- if the system was working and not banging, don't mess with them!). It shouldn't be all that expensive to replace them -- you can use copper for wet returns -- so I think I just might.

    As I say on the supply mains -- they shouldn't need anything, other than checking to make sure that they still have the correct pitches and the hangers are still actually doing something.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • KC_Jones
    KC_Jones Member Posts: 5,737
    punkzter said:

    How can you tell if the lines are in good shape or not? All this person did was look at the pipes, they wouldn't have opened anything up.

    You can't really, need to get inside them. During a boiler replacement they will be able to see inside them. Given that multiple quotes were given, it doesn't seem like the contractor has communicated it's a definite.

    If I was hiring someone, I'd budget for pipe replacement, and then have them evaluate when the system was opened up. If the pipes are good, leave them, if not, it's been budgeted for an can be done.

    That said, if they are marginal, and then need replaced in a couple years, it will most likely cost more to do it then, compared to doing it all now.

    I would never consider replacing the steam only pipes, those get steam cleaned on every firing of the system and shouldn't be an issue.

    Again, many things to consider. The first thing I'd be concerned about is the contractor sizing the boiler properly, and having verbiage in the contract to pipe it properly to at least manufacturers spec, in steel/black pipe.

    We see so many catastrophes on this site, I can't stress that enough.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • punkzter
    punkzter Member Posts: 32
    edited January 2022
    Yes, we have a great relationship with a very knowledgeable company that has kept our system in good shape. But it's on my list to have them double-check the next time they are out. I'm also training myself to check the water level on a regular basis.
  • punkzter
    punkzter Member Posts: 32
    @KC_Jones Thank you! That is wonderful advice. I think that I just needed a way to help her move forward in this project (I'm trying to give her the best advice I can...and I am no expert).

    So I will recommend that she budget for the replacement but make sure that they let her know pipe condition before they go ahead with the replacement.
    EBEBRATT-Ed Member Posts: 15,517

    In general any piping above the boiler water line will last practically forever. There are many steam systems well over 100 years old running well with original piping.

    Below the water line (wet returns) are a different story. If buried under the floor they are prone to rot out and leak. Above the floor and below the water line they last a bit longer but are prone to plugging with sludge and leaking.

    Most people run the boiler until one of two thing happen.

    The return plugs up and water can't get back to the boiler fast enough

    or the returns start leaking

    Copper is a good way to go for wet returns. Some make provisions for flushing when repiping or changing the boiler by installing some extra valves
  • BobC
    BobC Member Posts: 5,477
    If any of the overhead pipes have poor slope they may be in a state of deterioration and need replacement but you may not know till you look. boiler return pipes sit in water all the time so replacing them after many decades may be the prudent thing to do while they have the threading equipment on site.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 1,005
    If the system does not have one or more drain valves, when the boiler is replaced it should be mandatory to add them. It is very likely they will be shown in the boiler piping diagram that is in the boiler manual.