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what is this?

bruce_21 Member Posts: 241
There is this big thing in the steam piping, I suspect it is an old water heater, but I'm not certain. The piping is certainly complicated around it. It is a two-pipe system. Can I just remove it and its associated piping? I'm replacing the boiler due to a failure of the low water cut-off. Will the dry return need attention/cleaning?


  • bruce_21
    bruce_21 Member Posts: 241
    Another pic

    There are two check valves in the wet return on either side of the return drop from this device.
  • JStar
    JStar Member Posts: 2,752
    edited October 2010
    Looks like.

    A condensate return trap. If the boiler pressure gets too high for the wet return to get back, the water will stack up inside that tank, trip a float, and pressurize the water back into the boiler.

    Those two devices near the ceiling look like air vents, with a piping configuration designed to minimize any water/steam damage to them.

    Can you see name on any of these parts? The return trap is maybe a Hoffman? Looks like it had a sight glass at one point (the two plugs on the side).

    You should be able to get rid of it, if the new boiler's water line allows for the proper A or B dimension. The whole system piping should be carefully assessed prior to a replacement.
  • bruce_21
    bruce_21 Member Posts: 241
    I'll look

    for a name and check more closely the check valves orientation, but I think now you are right. My only question is why this was installed in the first place because there is an 'A' dimension of like 4 feet. But the "B' dimension is also about 4 1/2 feet which might not be enough, especially if the original boiler had a higher water line. I'll check that too. Thanks for your help. This system is starting to become clearer to me.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    steam assessment

    the installation of that device may have been a band-aid to cure some early symptom of over-pressure, or bad return piping, which in a well thought out installation would not be needed.

    not only assess the return piping, but also the size of the boiler according to the total radiation. the old boiler may well have been too big or too small in steam capacity.

    definitely get plenty of mainline venting, or you will be paying the fuel company to squeeeeeeeeeeze the air out of the constipated little radiator vents. in addition, try to put on a vaporstat [and good low-pressure gauge-gaugestore.com, 0-15 ounces] to keep the pressure in the ounces range. have a look at the wet returns to see if there are any low spots in which trapped water will prevent the air from being let out, as steam is rising.--nbc
  • Dave in QCA
    Dave in QCA Member Posts: 1,785
    Dunham Vacuo-Vapor ?

    This reservoir looks very much like the Dunham Vacuo-Vapor set up.  Through a system of check valves and a connection "just below waterline" boiler connection, this apparatus allowed for the return of condensate to the boiler without any moving parts as were used in the return trap.  But, its use was restricted to very low pressure systems.

    See link,

    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
  • bruce_21
    bruce_21 Member Posts: 241
    The piping doesn't pitch perfectly

    I went back again today with my laser and measured Dimension "B" and checked the steam main and the return line. The pipes both loop around the outside of the basement which is about 35 feet square.

    There is 101 inches from the bottom of the lowest steam trap to the floor where the boiler is so there will be 67+ inches of "B" with a 32" water line 24" below the header. So maybe I could take the return trap out, but I'm inclined to keep it, since it seems to be working and is a protection against over pressure and maybe other problems. I originally wanted it gone when I thought it was an obsolete water heater.

    The pipes both are out of proper pitch in one corner by about an inch. I think I can correct the return without too much difficulty since it is only inch and a 1/4, but the main is 2 1/2 all the way around and has some take offs on it that cannot flex much since they are short.

    The insulation on the main was asbestos and was removed when the house changed hands 10 years ago. Part of this new boiler job will be reinsulating the main

    The HO says the system heated well everywhere (before the low water cut-off failed and the boiler cooked and cracked) and only hammered just after she heard the water filling (i.e. the return trap dumping) so I'm wondering can I just leave the main as is and correct the return as best I can?
  • JStar
    JStar Member Posts: 2,752
    It appears...

    ... that the return trap was more likely to be in operation with the original boiler which undoubtedly had a high water line, and more frequent issues with condensate returning properly. If it operates now, I would suspect a clogged return somewhere near the boiler. It's so high above the water line, that it really should never fill all the way up, assuming the boiler pressure is under 2 psi. My guess is that the original boiler was as tall as that unpainted section of wall behind the current boiler. You can cut it out, if you're comfortable with all of the dimensions after the F+T traps. Personally, I would keep it because it's a neat part of heating history. If I did cut it out, I'd hang it on my office wall. 
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