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Hoffman 17 C's

Steve_55
Steve_55 Member Posts: 30
I have a two-pipe vacum vapor system with 27 Radiators with Hoffman 17C traps. All radiators work fine (very fine for that matter) the traps seem new (but I know are over 10 years old), have no visible leaks or make any strange noises (The values seem good too).

Is it worth replacing/repacking, etc all; or take them on one by one if/when a noticable problem occurs.

I am loosing water from the system somewhere -- could the traps descroibed above be a cause of major water loss?

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 22,949
    Traps

    either work or they don't. In the building I care for, most of the traps were installed in about 1920 and haven't been touched since. I'd say that if the radiators heat, don't fix them. Leave them be until something evil happens!

    They aren't the cause of the water loss. By water loss, though, do you mean the level drops seriously when firing, then comes back up eventually after the boiler shuts down, or you have to add water regularly? Two very different problems. If the former, somewhere in the system water is getting hung up; hard to say where. If the latter, you have a leak -- wet returns are a great candidate for that. So, unfortunately, is a cracked boiler.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Steve_55
    Steve_55 Member Posts: 30
    Thanks ...

    ... Kinda what I was thinking with trap replacements. Aint't Broke don't fix it.

    Re: Water -- it is added during/after each cycle. Recently got a new boiler with a vxt 120 water meter so I can now see it happening.

    Wondering now if I lost the old bolier becuase of this, and did not realize it was happening.
  • Timco
    Timco Member Posts: 3,040


    If the traps are bad, steam will be scooting past them and into the return. Whether they are good or bad the rads will heat, but it will take more pressure to get heat to the farthest rads and depending on your vent style, steam in the return is bad. A thermal camera will tell you if steam is getting past the traps, or try listening. On bigger jobs, you can hear the steam hollering through the rad and not quieting down when the rad is fully hot. You want the steam / pressure in the main, not the return. Good traps are essential to efficiency. You can get direct replacement caps & cages, or just swap the whole thing if the caps are really stuck. The new 17c should mate with the old tailpiece & union. This is the biggest problem with steamers..."why should I pay you to 'fix' traps when we still have heat?" Working traps will also fix most banging.

    Tim
    Just a guy running some pipes.
  • Steve_55
    Steve_55 Member Posts: 30
    If there is no banging ...

    ...does that mean traps are working properly?
  • Timco
    Timco Member Posts: 3,040


    Not necessarily. I use a thermal imaging camera to check them. Maybe shut all valves, let boiler heat up, and open one valve at a time. It should heat up and when steam hits the trap, it should stop the flow of steam which you should be able to hear if only checking one at a time.

    Tim
    Just a guy running some pipes.
  • Steve_55
    Steve_55 Member Posts: 30
    Great idea Tim, thanks ...

    .....Might also place a piece of tissue on each trap as I do each on each to see if I can detect is any vapor might be leaking (valve as well).

    PS: Where do you operate out of? Anywhere near 11530?
  • Timco
    Timco Member Posts: 3,040


    I am out of 84102...a bit out of my area...best o luck!

    Tim
    Just a guy running some pipes.
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