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New House: Humming/Heartbeat and more

Hello all!

So I'm at a new house which has been poorly maintained including the steam heat systems (. I got the boilers flushed and they seem to be in decent shape. Two bigger main vents were put in for one boiler and they suggested the other boiler to have a bigger main vent put in as well. One of the long returns pipes was sagging so they recommended the pitch be increased and we may have the entire pipe replaced. I hope all that sounds pretty good.

Now I have a couple of issues:

1. It seems that one side of the house has the heat completely shutoff (the first and third-floor radiators have the shutoff valve completely open (even when the air valve on the first floor is removed, no air is coming through). The second floor is closed and the radiator is not connected). Is this something anyone has encountered before? I'm very confused by this and don't know what to think (maybe the pipes on that side have issues?).

2. Whenever I'm in the first-floor unit and the second-floor unit's heat is on, I hear a low-frequency humming/heartbeat. I contacted the gas company and they said it wasn't the gas line. So I have no clue what this could be. Could it be related to a capped pipe on the third floor?

3. The gas person said the boiler was a pretty big boiler (140k BTU/HR) for what seemed to be planned 9 radiators (7 on the second floor and 2 on the third floor) (currently 1 pipe on the third floor is capped, the other third floor has no air coming, one on the second floor is disconnected from the radiator). What is the best way to deal with an oversize boiler?

I'm overwhelmed by all this and would appreciate any help you may have! Thank you in advanced!

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 23,168
    Square One. You have two boilers. You also have two units. You have three floors. Exactly which units and floor does each boiler serve? You also mention that one side of the house has "the heat completely shut off". Is this for both units? If not, which unit? Which floors? Which boiler is involved? Does this side of the house happen to be served by the sagging "return"?

    Which brings up the next question: what main steam lines are there? From which boiler? Are the "returns" to which you refer actually direct continuations of the steam mains back to the boiler? Or are they separated from the steam mains by traps or water seals?

    You mention main vents? What line or lines were they put on? And where on the lines?

    Now on to more general things... first off, I highly recommend that you purchase the book "We Got Steam Heat", which is available from the store on this site. It's a very good, non-technical, introduction to steam heating systems.

    On boiler size. Steam boilers are sized on the basis of the radiation -- number of radiators and their sizes -- which they serve. A significantly oversized boiler will cycle on and off on pressure, which is not completely desirable. Since you have some radiation which is missing, or which doesn't get steam, it's likely that the boilers are oversized, but just how oversized one can't tell until one gets steam going to the desired radiation.

    Steam heat is not really complicated. The general idea is that the air has to get out of the system when the boiler fires up -- hence the vents -- and the steam has to get to the radiators and the condensed water has to get back to the boiler. That's it. On the side which is "completely shut off", either the air can't get out or the steam can't get in. Until we know a little more about how this thing is connected, we can't get much farther.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    matt101589ethicalpaul
  • matt101589
    matt101589 Member Posts: 9
    The first boiler serves the first floor while the second boiler serves the second and third floors.

    The radiators in the kitchens on the first and second floors have no heat. Also, the room on the third on that same side doesn't have heat. So both boilers are involved.

    The long sagging return is on the second boiler. (attached pictures of the second boiler)

    I don't think I see any steam traps or water seals?



  • Jamie Hall
    Jamie Hall Member Posts: 23,168
    Are the two boilers interconnected in some way? And does that long saggy "return" serve the part of the house with no heat?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    matt101589
  • matt101589
    matt101589 Member Posts: 9
    The two boilers are not interconnected in any way. The long saggy pipe serves the part of the house with heating. It gets warm/hot when the heat is on.
  • Jamie Hall
    Jamie Hall Member Posts: 23,168
    I suspect that you have a number of different problems here. Perhaps your best approach is going to be to try and bring the whole system -- starting at the boilers -- up to best practice. Indeed, the mindset I would have if faced with this would be to start right at the boilers, and imagine -- and work -- as though I were installing a brand new system, all the way to where radiator risers disappeared upstairs. Would I reuse things? Everything I could -- but it might wind up rather different.

    Where are you located?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    matt101589
  • matt101589
    matt101589 Member Posts: 9
    I'm located in RI. That makes sense. The boiler seems to be in good shape. I'm going to replace the air vents at each radiator as my next step.
  • Do the main vents first, and see what difference that makes.
    You can remove the radiator vents as a test, to see if steam is getting that far.
    Turn off the boiler as soon as you see steam come out of the vent tapping.—NBC
  • matt101589
    matt101589 Member Posts: 9
    Okay, I've replaced most of the air vents and the heat on one of the house was just blocked by the air vents.

    I'm still dumbfounded by low-frequency humming/heartbeat while I'm in the first-floor unit and the second-floor unit's heat is on. Could it be related to a capped pipe on the third floor? Or maybe because of the sagging pipe and it's steam pushing the water that is in the sagging pipe?

    We're going to have the sagging pipe replaced. Will update on this!

    Right now the pipes are not insulated. We're probably going to insulate the pipes but not the junctions. Should I be concerned about insulating the pipes if the boiler is oversized?
  • Jamie Hall
    Jamie Hall Member Posts: 23,168
    A humming sound is almost always a pump or blower telegraphing through the piping. Can be a little tricky to find, but look for some motor somewhere which is always running when you hear it, and never running when you don't.

    Insulation. Yes. It's not so much about the heat loss in the pipes as it is about getting dry steam quickly to the radiators. Lack of insulation produces wet steam, which can cause hammer or dripping vents or... mischief in general.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • matt101589
    matt101589 Member Posts: 9
    edited December 2019
    The system is a one-pipe steam system. Would you expect there to be a pump/blower in the system? If so, where would it be?

    The insulation makes more sense now! Thanks!
  • Jamie Hall
    Jamie Hall Member Posts: 23,168
    One source I've found in the past is that if you have oil, the pump and fan on the oil burner are noisy -- but you usually don't hear it. However, if the oil line is touching a pipe somewhere (let alone being strapped to it!) it can make a hum or whine that you may hear anywhere in the house.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • matt101589
    matt101589 Member Posts: 9
    I have gas. I had someone from the gas company come by and he said there's no way it's the gas line since the line is filled with gas...
  • Jamie Hall
    Jamie Hall Member Posts: 23,168
    Ho ho ho. Well, yes, the gas line is filled with gas. That doesn't mean it can't hum. Shouldn't, perhaps, but it can. So can the blower if there is one. So, for that matter, can the flame itself. And it can all be really hard to pin down without being there and willing to listen.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Fred
    Fred Member Posts: 8,542
    Have you listened to any transformer mounted on the boiler or on a floor joist? Also listen to the gas valve, when that boiler is running. Either of those can cause a low pitched hum if they about to fail (even though they may function for a good while).
  • DZoro
    DZoro Member Posts: 1,048
    Looks like your gas pipe to the boiler is CSST, which can be a possible cause.
    D
  • matt101589
    matt101589 Member Posts: 9
    Hmmmm... I've carefully listened to the gas valve and the transformer on the boiler and did not hear any humming. The humming is coming from the opposite side of the house of the boilers and where the gas line comes in.
  • JUGHNE
    JUGHNE Member Posts: 11,042
    Clicking/sticking gas meter rotating dials could give you the "heartbeat" sound thru the piping.

    The flex CSST could be doing a fog horn. If you have it try to straighten it or just change the shape a little to get a different sound/tone.
  • matt101589
    matt101589 Member Posts: 9
    To update everyone. The main was pitch a bit more and the steam hammer was reduced. The noise was further reduced by insulating the pipes. It was finally silenced when the pitch was lowered another 4 inches!

    The humming continues but the gas company refuses to acknowledge it's the gas meter. I know it is the cause because it sometimes makes a louder than usual sound (unfortunately, not predictable/consistent) and the humming gets even louder.

    I also get a few "clicks" at a couple of radiators when the heat starts up. It's probably the pitch but I wonder if it's worth putting the effort to fix it...
  • Jamie Hall
    Jamie Hall Member Posts: 23,168
    Good show! The clicks are probably expansion -- tough to fix.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England