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radiator filling with water?

bob young
bob young Member Posts: 2,177
now i understand. the plumbers you contacted for your steam problem simply did not want to give you any free advise because you had no intention of hiring them to solve your problem. can't really blame them because they can't make a living giving away the store. in any case , i gave you all the information you will ever need to solve your situation F.O.C. [free of charge ] so have at it , remove the flooring and it is great you are having so much fun researching steam systeams. now you can buy Dan's books & complete your education. good luck.


  • Gabe_4
    Gabe_4 Member Posts: 9
    radiator filling with water?

    I began troubleshooting my radiator again. Been trying to fix this problem for over 2 years. Asked dozen of plumbers and noone seems to know what's happening.

    2 Story house. 2nd floor radiator. 2 rooms next to each other and the steam riser splits somewhere in the wall and feeds both radiators. One of the radiators works perfect. The other fill up with water.

    Here's what I did. After steam started coming up, I turn on the valve to the broken radiator and it fills with water. I removed the radiator and turned the steam back on with the shutoff valve off. After the steam comes up, I turned the valve on(without the radiator attached) and water starts coming out like a faucet turned halfway on. Now if I remove the main vent on the main header(so there's just a 3/4" hole there) then no water will come out of the valve. This leads me to believe it's got something to do with venting and pressure. But I don't know enough about steam to pinpoint the problem. I would ask the guys who built the system, but they are all dead.

    If anybody here knows about steam (I know it's a dying art) let me know what you think.

    It's a one pipe system with a dry return.
  • Mark Custis
    Mark Custis Member Posts: 539
    I think the floor sagged

    Try to transfer the height of the offending rad to the good one.
  • ed wallace
    ed wallace Member Posts: 1,613
    rad spits water

    reinstall the main vent put tissue over it does tissue get wetordoes it get moved by the air venting out? remove main vent put tissue over the hole does tissue get wet or get moved by escaping air? I with vent in place tissue should at least get moved with ou the vent tissue should get wet from the steam
  • bob young
    bob young Member Posts: 2,177
    trapped condensate

    Sounds like a section of horizontal branch piping is backpitched & creating a physical trap where condensate is puddling. solution : open flooring & check piping.
  • Gabe_4
    Gabe_4 Member Posts: 9

    That would be an option if you were certain. But I can't just rip up all the flooring on a hunch. What leads you to this conclusion?

  • I understand what you mean about ripping up the floor. (and if I was doing so I'd personally go in through the drywall ceiling below -start with a little hole that you can get a small mirror and flashlight into make a "studied" guess as where to start first) It's really hard trying to diagnose something like this over the internet though I think Bob is probably correct and on the right path. There is a sag or a pocket formed somewhere that is collecting a lot of condensate. When you remove the main vent there isn't enough pressure to push the slug of water up the pipe but with the pressure on, it pushes the slug along.

    Anything more you can tell us about the piping system? How far are the radiators apart? Do you think the riser splits equal distance between them. How does the steam get to the radiators? Is it is a long sloped horizontal riser (like a contra flow main) You may get a clue about this by studying the mains where they rise into the basement ceiling.

    My other thought was do you have any slack in the pipe where you could jack up the radiator and put it on blocks. This might just elevate the sag enough to drain it.
  • Gabe_4
    Gabe_4 Member Posts: 9

    The radiator was bran new. It is sloped pretty good towards the shutoff valve. In the basement(I'll have to post a pic soon)the main header is sloped up facing the same direction that the steam travels. I think this is wrong because if the steam condensed in the main riser the water would be draining towards the incoming steam. This is one of the things I suspected. Shouldn't the main be sloped down so that the condensate would drain towards the return and then come back toward the bottom of the boiler? Or would that make it harder for the steam to travel?

    One pipe goes up from the basement (vertically) and then somewhere in the walls it must split and feed two radiators. Is splitting a riser to feed two radiators problematic? Thanks for all responses.
  • bob young
    bob young Member Posts: 2,177
    mystery radiaton issue

    key question : did it work properly before new radiator was installed . new radiator inlet centerline tapping might be lower finish floor elevation than original radiator. disconnect radiator , blow out water from line, if valve & connected piping can be jacked up reconnect at highest possible elevation.thing that puzzles me is it only happens with that radiator & not the other one connected to same riser. that would indicate the problem is within the branch piping for that particular radiator. you may have issues with the main but one problem at a time.many problems result from recent changes in systems. a small adjustment can cause a world of trouble. keep us posted.
  • new rad

    can you remove the valve bonnet [system off], and see a pool of water in there?is the top of the valve perfectly level-use a good level.

    then with a helper' switch on, and listen to the air rushing out for "panting" as it goes through a puddle?--nbc
  • Gabe_4
    Gabe_4 Member Posts: 9


    If you're talking about the air valve on the side, yes, if I remove it the radiator is full with water and starts leaking out. When I remove the radiator, I have just the shotoff valve sticking out of the floor. Now, when I turn the heat on and all the other radiators begin to heat up, water literally starts coming out of the valve. It's on the second floor. What the hell is happening. Is the steam pressure really pushing water that high. I thought it operates on less than 1 psi. Don't you need more than that pressure to push water to the 2nd floor?
  • valve

    no i was talking about the shut-off valve on top of the riser which feeds that rad. you were removing the air vent.

    another reason to remove the bonnet is to check the valve disk. it may have fallen off inside the valve, thus interupting the draining out of the condensate.

    perhaps it's time to check your system pressure, with a good low-pressure gauge [gaugestore.com 0-5 psi]. this will enable you to verify that it is below 1 psi.

    last question= yes.--nbc
  • Gabe_4
    Gabe_4 Member Posts: 9

    I removed the entire radiator from the shutoff valve. When the heat comes on water will start to pour out of the shutoff valve.
  • Mark Custis
    Mark Custis Member Posts: 539

  • bob young
    bob young Member Posts: 2,177

    YOU NEED A PROFESSIONAL PLUMBER. do not know if i can believe what you are telling us that twelve plumbers looked at this job & could not fix it.where are you located ? are there no experienced mechanics in your area ? branch line gotta be trapped. this sounds like a simple job.
  • Gabe_4
    Gabe_4 Member Posts: 9


    Look again at my first post. It says "asked" a dozen plumbers. I never said a dozen plumbers looked at it. I still haven't given up trying to fix it myself. When I run out of ideas, or hope, I'll call a steam specialist to look at it. In the meantime, I'm learning a great deal about steam systems. It's kinda fun.
  • Gabe_4
    Gabe_4 Member Posts: 9

    Bob, uh, do you have a problem or something?

    Those plumbers were friends of mine that I give work to. The problem I have is more complicated. Most of the advise is pitch the radiator and change the air vent. Not quite solving the problem.

    Already book Dan's Book a long time ago. You sound like a grumpy old man who's angry at the world. You got to learn to chill out or your going to have a heart attack (or a 2nd if you already had one).

    How the hell can you recommend to rip up finished flooring while having no clue what's going on with the system and giving me no explanation other than " I think it's the piping in the floor".

    Honestly, you really shouldn't be posting.
  • Matthew Grallert
    Matthew Grallert Member Posts: 109

    Hi Gabe
    I would try to raise the whole rad up this way perhaps repitching the pipe under the floor. Its worked for me a number of times as long as the elbow below has the room to come up. It really seems to me there is a slope under somewere with a slug of water in it. By all means dont rip the floor up there has to be a better way.
  • now, now children.....

    have you been able to follow anyone's advice here as to determining the cause of your problem, or are you just continuing to make your own tests willy-nilly?

    one test you made shows the main vent works, but you still do not know your pressure, so check that next.

    the water doesn't just rush up from the boiler room. most likely, it comes from a sagged horizontal somewhere close, which is unable to drain.you may be able to see it if you remove the valve bonnet and stem. with a good flash-light you may see the edge of a puddle of water in the pipe.i agree that it difficult to rip up the floor on a hunch, but if you saw the puddle....

    another possibility could be that although the rad slopes right, the pipe does not, so maybe you could raise all legs of the rad up to pull the pipe higher.--nbc

  • heatguy
    heatguy Member Posts: 102
    try this

    remove radiator with system turned off.when you disconnect the valve does the pipe move up or down ? pull the pipe up until the valve is headed toward the direction of the connection to the branch piping a little tilt is all your looking for.turn system back on see if water still collects at valve.when something is not working right always look at what was recently changed:new radiator good luck
  • Gabe_4
    Gabe_4 Member Posts: 9

    There's a pressure gauge which seems to work fine. Do you think I still need to change it?

    I don't know if there is slack in the piping. I'm going to remove the radiator and pull on the pipe. If there is slack, I'll raise it up as hight as I can to see if that helps. Thanks.
  • gauge

    how many ounces of pressure is your system producing? try for 2-12 oz. max.--nbc
  • FJL
    FJL Member Posts: 354
    I Had A Similar Problem

    For many years, I had two radiators, in two separate bedroom, fed by a single riser. Both rads would fill with water and did not fully heat. The air valves for one spit occasionally, and the air valve for another had a constant stream of clear water from the air valve. The stream of water was so substantial that I had to close the steam valve, and do without the heat from that radiator. I also got loud water hammers, mostly at start up. These hammers were so loud that they would wake me up from sleep. If I closed the steam valve to the second radator, the hammers got even louder, like John Henry wielding a sledge hammer.

    The problem was a back pitched horizonal feed pipe. Condensate would pool and create the water hammers and get pushed into the radiators and spit out of the air vents. Fortunately for me, I had some loose floor boards right near the riser and radiator. I could remove the floor boards and see that the pipe was pitched. So this fall, we broke through the ceiling of the apt underneath me and put in a new pipe, giving it as much pitch as possible given the crawl space, about two inches, and the problem is basically solved. There was not enough room to raise the pipe because the elbow for the radiator was right underneath the floor board. After the new pipe went in, no more spitting air vents, and both radiators heat up. At start up, I get some noise as the steam travels through the pipes and the riser. Some of the noise is the pipes expanding, but there are other sounds that sound more like a water hammer, but they are more like solid clicks. My downstairs neighbor also says that he hears them in the riser that is in his wall and feeds the horizontal pipe that feeds the riser for both rads. The noise lasts about 15-30 seconds at start up.
  • Gabe_4
    Gabe_4 Member Posts: 9

    Thanks for the feedback. It really is narrowing down to one of the horizontal sections of pipe being pitched wrong. I may have to open up the ceiling and take a look.
  • opening the ceiling?

    good pressure!

    before digging into the ceiling, try raising up the whole rad [put washers under all 4 legs as far as it will go-1/2--1 in.]. this could tilt the hidden horizontal pipe from "puddle" to "drain"--nbc
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