radiator spitting steam and water?

Discussion in 'HVAC Heating & Cooling' started by GabeS, Jan 17, 2008.

  1. GabeS

    GabeS Remodel Contractor

    Messages:
    294
    Location:
    Brooklyn NY
    Hi,

    I have a one pipe steam system. The radiator on the second floor(top floor) is spitting water out of air vent. If I unscrew the air vent while the boiler is running the radiator shoots out steam and water from the hole. How can this be happening? It seems like the whole system is filling with water when the boiler runs? The boiler water is very dirty so it is hard to read the gauge glass.(could this be causing the probelm?)

    The pressuretrol is set to cut in at 1psi. I have main vents on each end of the main steam line. I also have a dry return with no hartford loop. (is a hartford loop necessary on a dry return?)

    Gabe
  2. GabeS

    GabeS Remodel Contractor

    Messages:
    294
    Location:
    Brooklyn NY
    have I stumped everyone? I'm sure someone knows the answer to this, as I am definitely not the first person this has happened to. Thanks.

    Gabe
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,183
    Location:
    New England
    Keep in mind that it is a work day and many of the voluneer pros actually have to work...
  4. lextech

    lextech New Member

    Messages:
    7
    A hartford loop is used to get condesate back into the boiler. A condensate or boiler feed pump are usually subsituted for a hartford loop. Anyway if you can't see the water level in your gauge glass your boiler is dirty and needs cleaned. Most likely your entire system needs flushed, radiator vents checked, and your main vents need checked. All steam systems need cleaned from time to time. Pipes rust on the inside due to air/moisture/carbon dioxide (which forms when steam is produced), which along with mineral deposits all travel through the system with the steam. Eventually, the rust and minerals will clog vents and inhibit the return of condensate back down the pipe that the steam is rushing up in. And if the condensate can't flow freely out of the radiator using the supply pipe it will find its way out another opening.

    I think you will find a lot of answers here: http://www.heatinghelp.com
  5. GabeS

    GabeS Remodel Contractor

    Messages:
    294
    Location:
    Brooklyn NY
    I think I understand your point about the condensate coming out of the vent. So you're saying that if the air vent is blocked then the condensate won't drain properly(kinda like a plumbing system vent?) and sit in the radiator, so when the steam comes into the radiator, it's pushing the condensate out throught the vent?

    Also, I thought the hartford loop is there to protect the boiler from draining completely if the wet return leaks. All of my dry returns are at least 30" above the boiler, do i still need a hartford loop?
  6. Wet_Boots

    Wet_Boots Sprinkler Guy

    Messages:
    798
    Location:
    Metro NYC
    Do you have a condensate return pump? Got any photos of this setup?

    Have you run water from the drain on the boiler? You can get a lot of crud out from the drain.
    Last edited: Jan 20, 2008
  7. lextech

    lextech New Member

    Messages:
    7
    Oops you're right I mis-stated about the hartford loop, you are correct. The old systems without a hartford loop usually had a check valve, which may have been upgraded to a condesate or feed pump. However, it is that the vent is blocked open by debris in your system that causes it to spit, not the other way around. The ID of the supply pipe should be designed to allow steam to go up and condensate to go down. But when the inside of the pipe narrows due to debris (rust, minerals, and the like) the condensate cannot flow back to the boiler. This can cause the radiator to accumulate more condesate than it should.
  8. GabeS

    GabeS Remodel Contractor

    Messages:
    294
    Location:
    Brooklyn NY
    I have no feed pumps. Just the dry return goes into the bottom of the boiler and connects to the equilizer. I guess I need to skim the boiler and see what happens.
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