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one pipe steam sytem

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-sean
-sean Member Posts: 12
that one pipe provides steam as well as return.
Did you happen to see the pictures I posted above? I also posted a link about why it might have been a vacuum valve back when the boiler ran on coal.
Thanks again, We have spent alot of money on both maintaining this system and our gas bills are crazy high. And the thremostat is set at 62!
Hopefully this site and some insulating will make next years gas bills a little more resonable.
-sean

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  • -sean
    -sean Member Posts: 12
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    main air vent

    I have a one pipe steam system in my 80 year old house. This web site and your book have helped take alot of the mystery away.
    Trying to improve my system I have only found one valve on the main line in the basment. It is marked Hoffman 76 vacuum valve. When I take it off I can not blow through it like I can the valves on the radiators.
    Should I replace it with a new Hoffman 76? or is there a better valve to use? should I add another valve?
    Thank you, -sean
  • Steamhead (in transit)
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    How long is the steam main

    and what pipe size? Is this the only main in the house?

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  • -sean
    -sean Member Posts: 12
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    I'm not home but I would guess...

    that it is 3 to 4 inches OD. I think it is the only main. I have looked for plugs in elbows and other vents and haven't found any. The valve must be sort of old because it is painted green and hoffman dosen't paint them any more. (see attachment) Should it still be a vacuum valve?
  • -sean
    -sean Member Posts: 12
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    I'm not home but I would guess...

    that it is 3 to 4 inches OD. I think it is the only main. I have looked for plugs in elbows and other vents and haven't found any. Should it still be a vacuum valve?(see link)
    http://www.bellgossett.com/Press/vacuum.html
    Thank you for your responce.
    -sean
  • Steamhead (in transit)
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    Don't need vacuum now

    it worked well with coal but not so well with oil or gas. When i get the main's length and diameter I can tell you what to replace it with. All vents on that main should be at the end.

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  • -sean
    -sean Member Posts: 12
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    There seem to be two mains...

    > it worked well with coal but not so well with oil

    > or gas. When i get the main's length and diameter

    > I can tell you what to replace it with. All vents

    > on that main should be at the end.

    >

    > _A

    > HREF="http://www.heatinghelp.com/getListed.cfm?id=

    > 367&Step=30"_To Learn More About This

    > Professional, Click Here to Visit Their Ad in

    > "Find A Professional"_/A_



  • -sean
    -sean Member Posts: 12
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    There seem to be two mains...

    one on the right is 2 1/2" OD 15' long the one to the left is also 2 1/2" OD and 20' long. The right one has the vacuum valve near the boiler. I found a plug on the left pipe near the boiler.
    Thanks again,
    -sean
  • Steamhead (in transit)
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    OK, so the steam mains

    end in return lines which are above the boiler, and the vent and plug are at the ends of these returns?

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  • -sean
    -sean Member Posts: 12
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    Yes

    I believe that is what I'm looking at because just below the vacuum valve another return tees in and then that pipe ends at the receiver tank. Can you tell i'm not a heating contractor?
    thanks,
    -sean
  • Steamhead (in transit)
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    \"Receiver tank\"?

    > I believe that is what I'm looking at because

    > just below the vacuum valve another return tees

    > in and then that pipe ends at the receiver tank.

    > Can you tell i'm not a heating

    > contractor? thanks, -sean





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  • Steamhead (in transit)
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    \"Receiver tank\"?

    This is getting interesting. The usual residential one-pipe system does not have a receiver tank.

    Tell us more. How many pipes are connected to each radiator, two or just one? Are there air vents on the radiators? Post some pics if you can. We have to know just what this #76 vent is venting to recommend a good replacement.

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  • -sean
    -sean Member Posts: 12
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    One pipe per radiator...

    I have been replacing air vents on all the radiators since finding this web site and reading "we got steam heat".
    Here are some pictures. Don't tell me this is an oddball set up just when I thought replacing the vacuum valve would make this system a little more efficient.
    -sean
  • Steamhead (in transit)
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    It isn't usual

    I highly doubt that boiler-feed pump is needed on your system. Curiously, the #76 vent might not even be needed, since the tank is supposed to be vented. But the master trap at the tank inlet (another error, if you're gonna use a BFP on one-pipe you need a trap at the end of each separate main) might not be able to pass air properly. In that case you'd need more venting on the mains.

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  • -sean
    -sean Member Posts: 12
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    so what happens if ...

    I replace that #76 with an air vent?
  • -sean
    -sean Member Posts: 12
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    steamhead...

    where did you go? please don't leave me hanging.
  • Steamhead (in transit)
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    It would probably work better

    but maybe not as well as it would on gravity return. The problem is, with that setup steam can enter the dry returns and may cause banging around the tee where they connect, because this tee is high and dry instead of being filled with water.

    With that said, try a Gorton #2. But you might also want to have a pro look at this system. I think it can be simplified, and can certainly use a better near-boiler steam piping job, and will work much much better as a result.

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  • T-O
    T-O Member Posts: 29
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    Hoffman valve 76 is an air valve for mains with a vacuum system. Your question: if you should replace it with the same one or not, depends on the return system that you have now. There are single steam pipe systems designed with vacuum returns where the air main vents and radiators vents must be "air vents for vacuum sytems". Vacuum pumps have a check valve and shut off valve before going directely into the bloiler's return connection and do not need a hartford loop. You would see a box connected to a power source and a breather tube going a few inches above the water line. If it is not a vacuum system you should use a "non vacuum air main valve" like Hoffman 75 or similar. Depending on the main size and length, you may need two of them.
    T-O
  • -sean
    -sean Member Posts: 12
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    None of the vents on the radiators are vacuum vents...

    > Hoffman valve 76 is an air valve for mains with a

    > vacuum system. Your question: if you should

    > replace it with the same one or not, depends on

    > the return system that you have now. There are

    > single steam pipe systems designed with vacuum

    > returns where the air main vents and radiators

    > vents must be "air vents for vacuum sytems".

    > Vacuum pumps have a check valve and shut off

    > valve before going directely into the bloiler's

    > return connection and do not need a hartford

    > loop. You would see a box connected to a power

    > source and a breather tube going a few inches

    > above the water line. If it is not a vacuum

    > system you should use a "non vacuum air main

    > valve" like Hoffman 75 or similar. Depending on

    > the main size and length, you may need two of

    > them. T-O



  • -sean
    -sean Member Posts: 12
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    None of the vents on the radiators are vacuum vents...

    they were all adjustable hoffmans when we moved in eight years ago. There is no breather tube that I can find. The # 76 main valve looks like it has been on there a long time because its rusty and factory painted blue green (hoffman says they haven't painted #76 since 1998).
  • T-O
    T-O Member Posts: 29
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    Ok - you did not say what type of return you have. If "non-vacuum", which I think is your system, then replace it with Hoffman 75 (one or two of them depending on size length of main), or similar.
    T-O
  • T-O
    T-O Member Posts: 29
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    Yes, you are right, a one pipe system means that the steam and condensate travels in opposite directions in the same pipe, but that does not give the whole information on the system. Nice pictures. I'm miss them before (good that you mentioned) and I could not find the coal boiler link that you just mentioned. Looking at the them, your boiler has a dry return, one coming from each end of the mains, sloping toward the boiler and meeting where the main vent is located. Following that pipe down it appears that it goes into a green box and also there appears to be a connection from that green box to the boiler. The picture does not give good visibility and difficult for me to make out what it is. Does it have any writing on it? any wires? any upright pipes for venting?
    T-O
  • T-O
    T-O Member Posts: 29
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    Looking at the pictures a little closer, the green box at the end of he dry return is not a vacuum pump -- The Hoffman 76 was the right main air vent when it was burning coal, but since the boiler was changed to gas now you need to change the vent as well (the radiators vents already changed with adjustable Hoffman). I would replace it with two Hoffman 75 or similar.
    Be well-
    T-O
  • thfurnitureguy_4
    thfurnitureguy_4 Member Posts: 398
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    short circuit

    Sean,
    not to say that replacing your main vent won't help but you have more problems than this. Your return (where the main vent is) apears to join above the water line. IE nothing stops the steam from crossing over to the other main.

    Your system is like a big loop. 2mains looping back to 1 return. It is like a steam race, the first main to run its steam around the loop back to the vent, will close the vent. Once closed no more air will get out (Except by the radiator vents) this trapped air will cause slow, uneven heating and large bills.

    I would call a steam pro from the find a pro section of this site.

    You should discuss removing the little green box and the T that is above the water line. Drop both returns to the floor and join them below the water line. This will allow the return to stay full of water and stop the steam from crossing over. After doing this you can vent both mains and insulate them right up to the vents. You will need to post the length and diameter of your 2 mains ( from boiler to where it drops to a return) to determine the # and size of vents you will need.
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