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  1. #1
    Join Date
    Dec 2009
    Posts
    5

    Default Steam Heat and return water back-up in pipes

    I almost have my steam heat system working the way I want it to, but I am having one last problem. I have a one pipe steam radiator system and I am noticing that once the steam gets going in the pipes, the return water stops flowing back to the boiler from this one particular radiator at the end of the line. With all the water stuck in the pipes, the radiator stops working and the air vent gets clogged with water. I can hear the swooshing of the water in the steam pipes below. At this point, things begin to get worse. Because the water is stuck in the pipes from the forced steam, the boiler thinks that it is a gallon or two short on water and the automatic fill adds a couple of additional gallons of water to the boiler. Now with too much water in the boiler, even more water is being forced back up the pipe blocking this one radiator at the end of the line and the water starts to bang loudly on the steam valve. Not too good for the new valve that I just put in. Anyone have any thoughts on how to resolve this?

    -Sparch

  2. #2
    Join Date
    Feb 2008
    Posts
    554

    Default Re: Steam Heat and return water back-up in pipes

    All of these problems and solutions are discussed at the site below, which specializes in troubleshooting single pipe steam heat systems.

    Once at the site, click onto "Systems", then onto "Steam", then onto "Problems with a one-pipe Steam System", and "Problems common to All Steam Systems"


    The problem you mention is approached with a spirit or torpedo level to check & see that there is a slight pitch backwards for the pipe & the radiator, so the condensate (water) is allowed to flow back to the boiler by gravity---a crow bar to slightly pry up the rad or pipe may be needed & little pieces of wood may need to be put under the rad or return pipe to get a good pitch---sometimes the return line is clogged with crud stopping return condensate flow, & causing water hammer; the pipe will have to be cleaned.

    Also check the several pages of diagrams of single pipe steam systems on the 2nd site below---use the + icon and page resize key on keyboard to get larger pictures.


    http://www.heatinghelp.com
    http://illustratedhome******.com/gallery.php?gid=75
    Last edited by NashuaTech; 01-06-2010 at 04:46 PM.

  3. #3
    Join Date
    Nov 2009
    Posts
    71

    Default Re: Steam Heat and return water back-up in pipes

    Had the same problem. For me,the slope of the pipe was good. It has to slope backwards toward the boiler. Sometimes the radiator itself needs to be lifted at the vent side to achieve the slope there.

    That being said, on mine the pipe itself was clogged with debris from an earlier renovation by the previous owner. As soon as I cleared that, it worked fine.

    Hope all that is clear

  4. #4
    Join Date
    Nov 2009
    Posts
    71

    Default Re: Steam Heat and return water back-up in pipes

    Nashua,I see we posted at almost the exact time. Good link by the way.

  5. #5
    Join Date
    Dec 2009
    Posts
    5

    Default Re: Steam Heat and return water back-up in pipes

    The radiator has some pitch to it, but I put some wood blocks under it to make sure that is was not the problem. The steam line and the radiator have good pitch with the wood blocks installed, but I am still having the problem of return water getting stuck in the line. The system works fine until it really heats up, then I start to have the problem. I also blew down the boiler to make sure that there was not too much crud in the system. That did not work either. The water drains back to the boiler when the system cools down, so I do not think that the pipe is clogged. My best guess is that the boiler is over firing. It is a newer boiler that was installed several years ago by the previous owner. Any ideas on what to do with an over firing boiler or what else I might try next?

    -Sparch

  6. #6
    Join Date
    Nov 2009
    Posts
    71

    Default Re: Steam Heat and return water back-up in pipes

    As you said, this one is at the end of the line. I suspect the supply pipe is slightly undersized. One way to counter this is to put a tee at the supply to the radiator and run that back to the boiler return line.

  7. #7
    Join Date
    Dec 2009
    Posts
    5

    Default Re: Steam Heat and return water back-up in pipes

    Sounds like a possibility with the added return for the condensate at the end run pipe. I disconnected the auto water fill to the boiler because the water was staying in the pipes and the auto water fill was calling for more water to the boiler with the condensate stuck in the pipes. With the boiler over filling past the recommended fill line, the water kept making its way to all the first floor radiators along with all the banging to go along with it. One thing that I have noticed is that nipple at the looped return at the boiler is supposed to be installed 2" below the boiler water line at 26" to the centerline. It is installed at 21" to the centerline 7" below the water line, 5" lower than the distance recommended by the piping install instructions. Could this also be a source of the water remaining in the steam pipes?
    Last edited by sparch; 01-14-2010 at 10:19 PM.

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