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Well, I think it's steam?

I've been trying to find out if my house is steam heated, and can't seem to nail it down definitively.
Are these statements true?
If there is a sight glass on the boiler, it is definitely steam.
If there is only one pipe going to the radiators, it is definitely steam.

I also have a vent valve on one radiator that is spitting water. I assume I should just replace it with the same type of vent valve that is on there now? Or is there a better option?
I'm guessing the valve is way older than it should be, maybe 30 yrs old.

You guys have been invaluable in the past, and I have every confidence that you will be now also.
Thanks so much in advance!


  • The spitting vent is probably not to blame. its probably the pressure which may have increased due to a clogged pigtail.--NBC
  • BobC
    BobC Member Posts: 5,470
    I t sure sounds like a steam system to me. Do you know what pressure the boiler is operating at when actively making steam? What kind of radiator vents and what kind of main air vents do you have?

    Take pictures of the boiler showing the piping that connects to the boiler. Take a picture of a representative radiator air vent as well as one of any main air vents you find.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Abracadabra
    Abracadabra Member Posts: 1,948
    pics are worth 1000 words
  • glassman
    glassman Member Posts: 13
    Here are some pics. The maid of the mist is on another radiator, the bullet shaped one is the vent that was spitting water.
    Is this a 'main air vent'? (It looks
    like a radiator vent, except it's coming out of one of the pipes that runs the length of the basement.

  • Steamhead
    Steamhead Member Posts: 16,710
    Well, that's definitely steam. With some very nice radiators.

    Someone had the right idea regarding venting the steam mains, but a Dole 1A is not big enough for a steam main.

    Measure the length and diameter of your steam mains, and we will be able to determine what vents are needed.

    Also, where are you located?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • glassman
    glassman Member Posts: 13
    Just to be sure I'm understanding you;
    The vent showing in the first picture (1129) is a Dole 1A?
    The reason I got confused is because that seems to be the same valve which is spitting on the 3rd floor radiator.

    It is on the smaller of the 2 pipes that run the length of the basement.
    It is 27 ft long in a straight run. One end comes down 5 ft to connect to the boiler (1131), the other end makes a turn for about 3 ft and connects to the larger pipe (1132).
    Am I right in assuming the larger pipe is the supply and the smaller pipe is the return?
    The circumference of the pipe That has the vent fitting
    seems to be 5.5", so I guess the diameter is 1.75".

  • Steamhead
    Steamhead Member Posts: 16,710
    An outside diameter if 1.75" would mean an inside diameter if 1.5". So that's 1-1/2" pipe. How long is the other main, and what pipe size? Does it have a vent?

    The main vent in the pic looks like a Dole but it's not the same model as the radiator vent.

    On that 3rd floor radiator, make sure the shutoff valve is all the way open. If the vent still spits, you need a new one.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service