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water hammer/ wet steam

David Nadle
David Nadle Member Posts: 624
I don't think your boiler is making wet steam all the time. After 30 minutes most of your water is up in the radiators and streaming down the takeoffs. There is less room for new steam but you're still firing. The steam is picking up some of the water. Some of the steam suddenly condenses, creating a strong vacuum and sending slugs of water ricocheting around. Some of the steam condenses in the vents, making them wet, causing them to open and gurgle or spit the water.

One way to stop all this is to shut the boiler off before it starts. Check the cut-out setting on your pressuretrol. Try setting it as low as it can go. If it's already at 1.5 psi or below, it may not be seeing the right pressure because the pigtail it's mounted on is clogged shut.

Another thing you can try is giving the condensate a little push by increasing the radiator's pitch a little. But if you have a high pressure for the above reasons then pitching the radiators won't help you.

Let me know if any of this helps!

Comments

  • shawn indrerd
    shawn indrerd Member Posts: 28
    water hammer/ wet steam

    i have a 1 pipe steam system. i have a few MAJOR issues with my steam. i have water hammer (about 1/2 hour system start-up) from 3 of my radiators. 2 on the first floor at the ends of my main steam supply lines. and one on the second floor. (also near the end of the supply line.)
    the 2 on the first floor are very old, and make lots of gurgling noises besides the hammer (it sounds like the rads are full of water). the one on the second floor is a new radiator and it makes about 30 sec. to a minute of clicks and bangs at the same exact time every morning! (25 minutes after start-up.)
    if most of my radiators don't make noise can my problem be wet steam, or is it a lot more sinister then that?
  • wet steam

    certainly sounds like wet steam to me!
    start by getting your pressure down as low as it will go-under 16 oz. is best. you may need a good gauge [gaugestore.con 0-5 psi] to show where you are.
    also post pix of your near boiler steam supply piping, so we can have a look.--nbc
  • shawn indrerd
    shawn indrerd Member Posts: 28
    wet steam

    if it is wet steam, why are the rads right near the main riser quiet?
  • shawn indrerd
    shawn indrerd Member Posts: 28
    wet steam

    thanx for everyone's help.
    you wrote that the steam is picking up water. i have a question: the riser of this radiator (for my second floor bedroom) is right next to another riser. the other radiator (in my den on the first floor) is pitched poorly, and is built in in a way that i cannot pitch it properly. so it gurgles and clanks and bangs and sounds full of water. can it be sending water back to the main in a way that it causes my second floor radiator to start banging?

  • shawn indrerd
    shawn indrerd Member Posts: 28
    water hammer/ wet steam

    someone requested pictures of the piping near my boiler. it's a little cramped in there so this is the best i could do. i'm not sure how this helps, but anything will be better then all the noise i'm getting.
  • wet steam

    can you post some measurements of the heights of the horizontal parts of the steam supply pipes, above the waterline [either as seen in the gauge-glass, or from the boiler manual]? pipe diameters would be useful as well.--nbc
  • David Nadle
    David Nadle Member Posts: 624
    Bad news

    It's piped wrong. That takeoff between the two risers is a big no no. I'll bet if you trace that takeoff to the radiators it serves, you'll find those are the ones with the wet steam.
  • shawn indrerd
    shawn indrerd Member Posts: 28
    not so BAD NEWS

    actually, it is the one one the right that has the wet steam. the one in the middle is prety much "OK".
  • Fred Harwood_2
    Fred Harwood_2 Member Posts: 195
    Near boiler piping wrong

    And uninsulated. Both may be contributing to condensate buildup. Also, is the header at least 24 inches above the boiler water level?
  • David Nadle
    David Nadle Member Posts: 624
    Quote

    From "The Lost Art of Steam Heating." On page 51 there's a picture of what you've got with a big arrow pointing to it, labeled, "never do this!"

    "...the steam is approaching the system piping from two directions. There's no way water can make it to the equalizer. It's held in suspension by the steam "wind" like water on a car's windshield. It will just puddle up at the bull of the system-takeoff tee and reduce the internal size of the header. That increases the steam's velocity and sucks water out of the boiler."

    Maybe I was wrong about one takeoff being worse than the other, but unfortunately, I don't think I'm wrong about your near boiler piping being the primary cause of your problems.
  • shawn indrerd
    shawn indrerd Member Posts: 28
    what to do?

    so what should it look like?
  • David Nadle
    David Nadle Member Posts: 624
    Get the book

    Get yourself a copy of the Lost Art and study the chapter on near boiler piping. Also, find the installation manual for your boiler. There's always a diagram in there. Arm yourself with this knowledge, share it with whoever you bring in to repipe, and insist on correctness.

    Your boiler is using both risers, which is good. But having one takeoff between the two is not good. Both takeoffs should be between the last riser and the equalizer. It's also not clear that the header is at least 24 inches above the waterline. That's important too. And I think the horizontal run in your equalizer is also a problem.

  • shawn indrerd
    shawn indrerd Member Posts: 28
    thanx to all!!

    problem solved (more or less. i fixed the other radiator (new valve, much better pitch) and my bedroom one is now running silently. i don't know why but all is good.
    thanx to everyone for your help, and a happy new years!
  • saussyHen
    saussyHen Member Posts: 19
    Bullheaded Tee

    Looking at your photo, I see you have a bull headed Tee. This is a major problem I believe.
  • Ted Robinson
    Ted Robinson Member Posts: 126
    Youneed an electrician, too

    Fix the wiring on that outlet as well.
    The BX armor should be firmly attached to the metal box. There should be a mechanical support for the cable, about 1 ft removed from the box, as well.
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