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Trying to correct bad near boiler piping

Came across a boiler that has been flooding the radiators with water. I've attached a sketch (pic is worth a 1000 words and all that). Description is this:

LGB-14 with 2 4" risers into a 6" header. 5" steam main takeoff off the bull of the tee located in the center of the header between the two risers. Not only that, but the bull is oriented horizontally. As soon as I saw the piping I knew what the problem was. The real problem came when I told the owner we'd have to repipe all of the near boiler piping and I handed him an estimate.

I think the boiler has been "sort of" working because he's been running the boiler on a vaporstat cut-in at 4oz and cutout of 12 oz. The header is about 36" or so above the waterline, so I'm sure that helps a bit too. He's also added plenty of drips to the end of the mains. I told him I could try another idea, but I wasn't going to guarantee any results for him.

My idea is to cut the 5" main and weld in a 5" tee to drip to the main about 3'-4' away from the header to catch any water that might have been thrown up past the header. I know it's not perfect, but I'm hoping it'll help and should be able to keep the cost down for him. I was hoping to use a 5" weld wye to catch more water that might otherwise skip past a tee, but I don't think they make weld wyes. Don't think I've even seen cast wyes in 5".

Anyways... any ideas, opinions, suggestions?

Pic attached:


  • icesailor
    icesailor Member Posts: 7,265

    I'm not a steam pro. You sound like you are. Your diagnosis of the problem seems sound.

    Why did he call you and ask for your opinion if there wasn't a problem?

    Someone else's mistake is only a mistake until they or you fix it.

    Being a plumber, that piping proves that **** DOES flow downhill.
  • Abracadabra
    Abracadabra Member Posts: 1,948
    Bit more info..

    Well as I mentioned, the boiler has been flooding the radiators with water. This is a 19 unit building, so out of about 100 radiators about 20 or so get filled with water. Filled to the point where water is spraying out of the vents, and since they are filling with water, they don't heat up properly of course. All of them are on first floor. The radiators that I saw are all are pitched properly. Prior to adding multiple drip legs, the boiler was running at about 5psi and water was filling up 2nd floor radiators.
  • Bad piping-watery rads

    What about bringing the second riser over to the side it should have been connected to in the beginning?

    Your solution may work, but you should have a tap on each side of the main connection, for real water removal.

    Was this boiler ever skimmed?

    Filling up a dozen or more radiators to the point of water spraying out of the vents intakes a lot of water, so where is that water coming from-auto-over-feed gone wild?

    When the system is at rest, is the waterline at a normal height?--NBC
  • Abracadabra
    Abracadabra Member Posts: 1,948
    edited September 2014
    More info...

    2nd riser over.

    - Thought of that. May end up doing that as well as the drip on the main. I think a lot of the problem has to do with the bull of the tee being horizontal though. Even if both risers come up on the left side, with the loop on the right side, The main will still be getting a lot of water since the tee is horizontal.

    Tap on each side of the main connection.

    - Do you mean taps on the header? or the main line? I didn't really want to touch the header.


    - Yes, McDonnell Miller 51 autofeeder cutoff combination is installed.


    - Normal waterline owner showed me is about an inch below top of glass. So yes, boiler does get overfilled. Loop tee and feeder waterline is per manufacturer's spec.The waterline the boiler normally sits at cold is about 4-4.5" above the feeder waterline mark. I didn't look into this more because I assume the boiler is throwing up water and the feeder refills. Boiler shuts off and all the water rushes back into the boiler. I wouldn't say the boiler is getting completely flooded. I'd need to go back and look, but i believe the cold waterline is at least an inch or two into the bottom of the 4" supply nipples before they turn up into the header. So there's still somewhat of a steam chest available, although significantly decreased until a bunch of the water start flying up into the main.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    edited September 2014
    Overzealous auto feed

    Try running it for a week or so with the feeder valved off to see if the waterline behaves itself.

    Was the boiler ever cleaned when first installed? If not then teach the owner how to skim for a few long sessions.

    If you can move the riser connection, it will get the steam and water droplets flowing in the same direction, which should make the equalizer drain most of the water.

    What observed and verified (by gauge) pressure is the system attaining?--NBC
  • Eric_32
    Eric_32 Member Posts: 267
    Kind of tough

    Kind of tough when you have multiple things wrong. We are doing a replacement now similar on a smaller scale. Two boiler lines enter the header with a supply taken off between them, and that supply runs up to a bull head tee (in the middle) and feeds two mains. Decided to cut it all out and repipe it... but we are only talking 2" boiler supplies and a 3" header.

    I think some water may rush by your drip the way you want to do it. If you could offset down then drip then offset back up it would trap the water in the lower part, like the picture I have attached.

    I wonder how the water is draining back to the boiler? There must be banging when this thing is running no? Wonder if water is not getting back into it the way it should. Is it by gravity or using a condensate pump?
  • Abracadabra
    Abracadabra Member Posts: 1,948
    Bit too early to start using heat yet ;-)

    Boiler isn't running right now since temps are still in the 70s-80s here. Gauge glass water looks clean, owner says he hasn't noted water surging in glass, but I take anything that's told to me with a grain of salt. I'm from Missouri.. so show me..

    If I get this job, I'm probably going to have to change the equalizer too, since it comes off the header with a weldolet horizontally, instead of an elbow down.
  • Abracadabra
    Abracadabra Member Posts: 1,948
    Interesting idea..

    Hmmm.. I'm kind of liking that idea. My first thought was some kind of steam seperator, but I'm not familiar with anything in the 5" region. Your pic kind of works as a steam seperator. 3 - 5" weld els, 5" weld tee, and a 5"x4" reducing weld el with a bit of 5" pipe. Headroom is a bit tight though. I'll have to go back and check how much space I've got. I have kind of re-envisioned the layout a bit. Instead of having the water hit the back of a tee and hope gravity is stronger than the kinetic energy of the steam, I'm thinking using the velocity of the steam to drive the water past the takeoff of the steam. See pic below:
  • Paul48
    Paul48 Member Posts: 4,469
    Do Nothing

    Tell the owner to just wait and see if the existing header can rip the boiler apart. If you do stop-gap measures, and then that happens......well, you know where that goes.
  • Paul48
    Paul48 Member Posts: 4,469
    edited September 2014

    2-4" risers....Not 2.4"...For God's Sake....Wipe your screen!    :-)
  • Abracadabra
    Abracadabra Member Posts: 1,948

    When I saw 2.4" in his reply I thought I had dust on my screen. Maybe next time i'll just type out "two 4" risers" :-)
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,849
    Horizontal Tee

    I don't think the orientation really matters that much. When the steam from two risers meets head-on like that, where else can the water go than into the system riser? It can't flow back into the boiler against the flow of steam. And when those two 6" pipes dump into that 5" main, the steam velocity more than doubles, and when velocity increases, pressure drops because of the principle of Bernoulli, and that's just going to suck all that water right up the main before it has time to collect, so I'm afraid your drip won't help.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Abracadabra
    Abracadabra Member Posts: 1,948

    HH, so you think bringing the one riser over to the other side is the best it's going to get?
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,849
    If you don't do at least that much, nothing else will matter.

    Once you've gotten rid of the bullhead tee, then the orientation of the bottom of the supply riser will become relevant, so one improvement kind of makes way for the next. But in the long run a stepwise approach isn't the most cost-effective. Try to take your client through this thought process and explain that you don't like spending other people's money unless you're giving them the highest possible value for the dollar.

    You have a situation here where you can really score a huge win for the client. You have a boiler that's especially sensitive to improper near-boiler piping with egregiously bad near-boiler piping. It's in a cramped space with limited headroom, which is exactly what drop headers were designed for. A drop header gives you the tallest possible boiler risers, the greates flexibility in layout, and swing arms to take the strain off the boiler sections.

    You can take a lot of small steps that might provide some benefit or one big one that will assure optimal performance--a one-time cost that gives ongoing benefits. There's a big difference between spending a little to have slightly less water in your radiators and spending a little more and getting dry steam.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    edited September 2014
    Ideal solution

    Hap you hit the nail on the head with the drop header suggestion. It will make everything much easier, and produce dry steam as well.

    If this is a welded header, then the drop header will give the yielding swing joints the boiler needs to avoid having the sections torn apart.--NBC
  • Abracadabra
    Abracadabra Member Posts: 1,948
    Comes down to cost for the owner..

    HH and NBC, My initial suggestion to this guy was of course to repipe everything and of course use a drop header. The owner completely backed off that idea due to cost. I tried to explain the situation to him, but his response was "It sort of works now, why do I need to spend all that money to completely redo all the near boiler piping". I think I may back off trying to quote something for this guy because I've been in similiar situations where the owner was pushing a bad solution and just wanted me to implement it. The owner wasn't happy even though I explained there would still be consequences. It's deja-vu all over again with this guy.
  • Steamhead
    Steamhead Member Posts: 16,726

    it's time to walk. If he tells you to do it wrong, and you do, and of course it doesn't work, you probably won't get paid.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • j a_2
    j a_2 Member Posts: 1,801
    our motto

    They all call back….Do it your way, or hit the highway, for now…LOL…Kinda just joking, but truthfully, explain how and why,without giving them a free schooling….To me it sounds like you know exactly what you are doing….I installed my first solo steam boiler in 1979…just after my 9 year military stint….Its still running, rookie me. I even used copper,type L…Learned a lot since then, and am now passing it on...