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Wet return has started a new life as a dry return, things aren't going well

AJPA Member Posts: 4
edited September 2020 in Strictly Steam
Hello all,
I have really enjoyed reading the discussions here and have learned a lot. Thanks to everyone for sharing their knowledge, it really helps!
I think I have diagnosed a problem with our system, I just need some guidance in sorting it out.
First the basics:
It's a two pipe system with vents, with a one pipe system sitting on top of it.
It has convectors as well as the traditional standing radiators.
It was coal, then oil, and now gas.
There is a wet return that runs around the basement, and a "new" hundred year old addition to the house that has a dry return that drains into the wet return.
The two pipers that drip straight into the wet return behave themselves, the ones that drip into the dry return do not.

The problem I am currently trying to solve is that the end of the wet return has, likely from the replacing of a boiler long ago, found its way above the "new" boiler's water line. Just the last ten feet or so are above the water line but there is a lot going on in those last few feet. The attached picture shows the end of the return above the red laser I lined up with the top of the water in the sight glass. Is that the right way to do that?
Would installing an inverted "U" of iron pipe fifteen feet or so back from the problem area to raise the water level be the way to go? Am I at least on the right track?
Thanks in advance!


  • mattmia2
    mattmia2 Member Posts: 9,669
    That "inverted u" is called a false water line. It raises the effective water line in the return to that level.

    You are on the right track, the water needs to be high enough above those tees that its weight is higher than the pressure of the steam. Without the water seal in those tees, steam can move through the return to parts of the system it shouldn't be in. The coal boiler almost certainly had a much higher water line.

    Others can give you better details of how to build the false water line.
  • dopey27177
    dopey27177 Member Posts: 887
    Enclosed is the piing arrangement for a false water line.

    Taken from my book, Steam the Perfect Fluid for Heating and Some of the Problems.

    EBEBRATT-Ed Member Posts: 15,543
    I am a little confused by what your problem is but the end of the dry return that drips into the wet that you say is not behaving can be fixed by piping a loop seal.... a regular U
  • Gordo
    Gordo Member Posts: 857
    @AJPA: Here is a video of a one-pipe steam system where we installed a loop seal/false water line to stop the hammering in the old wet returns. Hope this helps!
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
  • AJPA
    AJPA Member Posts: 4
    Thanks for the info guys!
    Since only the last ten feet of the hundred foot long wet return are above the water line, and only about five inches above, could I install a false water line fifteen feet from the end, where it's still submerged? The ninety feet of submerged wet return works fine. I can post more pics and a diagram of what is going on at the end of the wet return when I get home from work tomorrow.
  • Jamie Hall
    Jamie Hall Member Posts: 23,324
    That would work -- though there would be no harm, and potential benefit, to installing the false water line right near the boiler to restore the whole thing to where it should be.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • New England SteamWorks
    New England SteamWorks Member Posts: 1,505
    False water line:

    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
  • ethicalpaul
    ethicalpaul Member Posts: 5,704
    Cool stuff, I’d have to look at that for quite awhile to “get it”!
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • dopey27177
    dopey27177 Member Posts: 887
    Obvious problem. The Y connection to the Hartford Loop is a NO NO.

    If this will work as a false water line the valve on the right side of the wet return must be closed because the condensate has to go uphill and drain out of the cross T. The valve on the left must be full open to allow the water to go back to the boiler.

    The pipe connection to the Hartford Loop can't be longer than a shoulder nipple.

    If this is not a false water line here is what you need to do!

    The section of dry return coming into the boiler room should drop down directly to the wet return not tie into the thing that looks like equalizer piping.

    The quick vent is not in the right place. It should be on the other side of the wall at the highest point of the dry return.

    On the right side of the drawing there is something that looks like a steam trap, if so get rid of it or find the dimention "B".

    Get rid of the equalizer, the cross T and the associated piping.

    Are the gate valves on the bottom fully open?